U.S. patent application number 14/362434 was filed with the patent office on 2015-12-03 for methods for assaying ionic materials using an integrated computational element.
The applicant listed for this patent is Halliburton Energy Services, Inc.. Invention is credited to Robert P. Freese, Johanna Haggstrom, Aaron Gene Russell.
Application Number | 20150346084 14/362434 |
Document ID | / |
Family ID | 52744264 |
Filed Date | 2015-12-03 |
United States Patent
Application |
20150346084 |
Kind Code |
A1 |
Russell; Aaron Gene ; et
al. |
December 3, 2015 |
Methods for Assaying Ionic Materials Using an Integrated
Computational Element
Abstract
The binding state of ionic materials, including metal ions, in a
fluid phase can be determined using an integrated computational
element. Methods for determining the binding state of an ionic
material in a fluid phase can comprise optically interacting
electromagnetic radiation with an ionic material and one or more
integrated computational elements, the ionic material being located
in a fluid phase while being optically interacted with the
electromagnetic radiation; and determining one or more binding
states of the ionic material in the fluid phase, using the one or
more integrated computational elements.
Inventors: |
Russell; Aaron Gene;
(Humble, TX) ; Haggstrom; Johanna; (Kingwood,
TX) ; Freese; Robert P.; (Pittsboro, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halliburton Energy Services, Inc. |
Houston |
TX |
US |
|
|
Family ID: |
52744264 |
Appl. No.: |
14/362434 |
Filed: |
September 30, 2013 |
PCT Filed: |
September 30, 2013 |
PCT NO: |
PCT/US2013/062602 |
371 Date: |
June 3, 2014 |
Current U.S.
Class: |
356/402 |
Current CPC
Class: |
G01N 33/442 20130101;
G01N 21/31 20130101; G01N 2201/061 20130101; G01N 21/85 20130101;
G01N 21/27 20130101 |
International
Class: |
G01N 21/27 20060101
G01N021/27; G01N 33/44 20060101 G01N033/44 |
Claims
1. A method comprising: optically interacting electromagnetic
radiation with an ionic material and one or more integrated
computational elements, the ionic material being located in a fluid
phase while being optically interacted with the electromagnetic
radiation; and determining one or more binding states of the ionic
material in the fluid phase, using the one or more integrated
computational elements.
2. The method of claim 1, wherein determining one or more binding
states of the ionic material in the fluid phase comprises measuring
a distribution of the ionic material between an unbound state and
one or more bound states, the one or more bound states being
selected from the group consisting of a bound state to a polymer, a
bound state to a ligand, a bound state to a polymer fragment, a
bound state to a monomer, and any combination thereof.
3. The method of claim 2, wherein the ionic material comprises a
metal ion.
4. The method of claim 3, further comprising: determining an
oxidation state of the metal ion from the one or more binding
states.
5. The method of claim 1, further comprising: determining if the
fluid phase contains a crosslinked polymer by determining the one
or more binding states of the ionic material.
6. The method of claim 1, wherein the fluid phase comprises a
treatment fluid.
7. The method of claim 1, further comprising: detecting the
electromagnetic radiation that has optically interacted with the
ionic material and the one or more integrated computational
elements; and generating an output signal based on the detected
electromagnetic radiation, the output signal being correlatable to
the one or more binding states of the ionic material in the fluid
phase.
8. A method comprising: providing a treatment fluid comprising an
ionic material, the ionic material comprising a metal ion;
introducing the treatment fluid into a subterranean formation;
optically interacting electromagnetic radiation with the ionic
material and one or more integrated computational elements, the
ionic material being located in a fluid phase comprising the
treatment fluid, a formation fluid, or a produced fluid while being
optically interacted with the electromagnetic radiation; and
determining one or more binding states of the ionic material in the
fluid phase, using the one or more integrated computational
elements.
9. The method of claim 8, wherein determining one or more binding
states of the ionic material in the fluid phase comprises measuring
a distribution of the ionic material between an unbound state and
one or more bound states, the one or more bound states being
selected from the group consisting of a bound state to a polymer, a
bound state to a ligand, a bound state to a polymer fragment, a
bound state to a monomer, and any combination thereof.
10. The method of claim 9, further comprising: formulating the
treatment fluid with a produced fluid comprising the ionic
material.
11. The method of claim 9, wherein the treatment fluid further
comprises a crosslinkable polymer.
12. The method of claim 11, further comprising: determining if the
crosslinkable polymer is crosslinked by measuring the distribution
of the ionic material between the unbound state and the one or more
bound states.
13. The method of claim 11, wherein the treatment fluid is selected
from the group consisting of a fracturing fluid, a drilling fluid,
a completion fluid, a diversion fluid, and any combination
thereof.
14. The method of claim 8, wherein optically interacting
electromagnetic radiation with the ionic material and the one or
more integrated computational elements takes place before the
treatment fluid is introduced into the subterranean formation.
15. The method of claim 14, further comprising: altering one or
more properties of the treatment fluid to change the one or more
binding states of the ionic material.
16. The method of claim 8, wherein optically interacting
electromagnetic radiation with the ionic material and the one or
more integrated computational elements takes place while the
treatment fluid is located in the subterranean formation.
17. The method of claim 8, wherein optically interacting
electromagnetic radiation with the ionic material and the one or
more integrated computational elements takes place after producing
the ionic material from the subterranean formation.
18. The method of claim 8, wherein the ionic material comprises a
metal ion selected from the group consisting of a zirconium ion, an
aluminum ion, a titanium ion, a magnesium ion, a calcium ion, and
any combination thereof.
19. A method comprising: providing a treatment fluid comprising a
crosslinkable polymer and an ionic material, the ionic material
comprising a metal ion that forms crosslinks between molecules of
the crosslinkable polymer; introducing the treatment fluid into a
subterranean formation; after introducing the treatment fluid into
the subterranean formation, optically interacting electromagnetic
radiation with the ionic material and one or more integrated
computational elements, the ionic material being located in a fluid
phase while being optically interacted with the electromagnetic
radiation; and determining one or more binding states of the ionic
material in the fluid phase, using the one or more integrated
computational elements, the determining one or more binding states
of the ionic material comprising measuring a distribution of the
ionic material between an unbound state and one or more bound
states, the one or more bound states being selected from the group
consisting of a bound state to the crosslinkable polymer, a bound
state to a ligand, a bound state to a polymer fragment, a bound
state to a monomer, and any combination thereof.
20. The method of claim 19, wherein optically interacting
electromagnetic radiation with the ionic material and the one or
more integrated computational elements takes place while the
treatment fluid is located in the subterranean formation.
21. The method of claim 20, further comprising: determining if the
crosslinkable polymer is crosslinked by measuring the distribution
of the ionic material between the unbound state and the one or more
bound states.
22. The method of claim 21, further comprising: introducing a
breaker into the subterranean formation after determining if the
crosslinkable polymer is crosslinked.
23. The method of claim 19, wherein optically interacting
electromagnetic radiation with the ionic material and the one or
more integrated computational elements takes place in a produced
fluid.
24. The method of claim 19, wherein the treatment fluid is selected
from the group consisting of a fracturing fluid, a drilling fluid,
a completion fluid, a diversion fluid, and any combination
thereof.
25. The method of claim 19, wherein the ionic material comprises a
metal ion selected from the group consisting of a zirconium ion, an
aluminum ion, a titanium ion, a magnesium ion, a calcium ion, and
any combination thereof.
Description
BACKGROUND
[0001] The present disclosure generally relates to methods for
assaying ionic materials, and, more specifically, to methods for
assaying ionic materials using an integrated computational element
to determine their binding state.
[0002] The analysis of ionic materials, both inorganic and organic
in nature, is ubiquitous throughout numerous industrial processes.
In many such cases, it can be desirable to determine the total
quantity and/or types of ionic materials that are present in a
fluid phase. Although some ionic materials can be readily assayed
by routine spectroscopic techniques to determine their overall
concentration of a fluid phase, certain types of ionic materials
are much less readily analyzed by spectroscopy. For ionic materials
that are not readily analyzable by routine spectroscopic
techniques, their overall concentration in a fluid phase can
sometimes be determined by various wet analytical techniques such
as, for example, colligative property measurements and ion
chromatography. For both spectroscopic and wet analytical
techniques, interfering substances can be problematic for the
analyses, and substantial sample preparation can sometimes be
involved.
[0003] Although the total concentration of an ionic material in a
fluid phase can represent a useful process diagnostic, an ionic
material's total concentration may inaccurately represent the true
nature of the ionic material in the fluid phase. For example, an
ionic material can often be present in a fluid phase in various
"complexed" or "bound" states, or it can simply be solvated by the
fluid phase, the latter representing "free" or "unbound" ionic
material. These groups of terms will be used synonymously herein.
"Complexed" and "free" ionic materials can often behave very
differently in a fluid phase, and as a result, the total ionic
concentration may not be a representative diagnostic by which to
judge or regulate an ongoing process. For example, a "complexed"
Ionic material may be non-reactive and/or non-damaging in a
process, but a "free" ionic material may be highly problematic. As
a specific example, "free" metal ions may be particularly prone to
scale formation in some instances. Collectively, various
"complexed" and "free" ionic materials will be referred to herein
as the "ionic species" or "binding states" of an ionic
material.
[0004] Although certain ionic materials can be readily analyzed by
spectroscopy to determine their overall concentration in a fluid
phase, it can sometimes be much more difficult to determine the
various fluid phase binding states of the ionic material,
particularly by spectroscopy. If different regions of a spectrum
can be conclusively identified as being produced predominantly by a
particular binding state of an ionic material, an estimated binding
state distribution can be obtained. However, the spectral
differences between ionic materials in various binding states are
often not well distinguished from one another by conventional
spectroscopy, and the ability to successfully deconvolute a
spectrum to determine the presence of various binding states can
often be a matter of chance. Even when spectral deconvolution is
possible in principle, the analyses can be costly, time-consuming,
and extremely sensitive to the presence of interfering substances.
Moreover, conventional spectroscopic instruments often require
precise calibration and controlled operating conditions that can
sometimes be unsuitable for field or process environments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The following figures are included to illustrate certain
aspects of the present disclosure, and should not be viewed as
exclusive embodiments. The subject matter disclosed is capable of
considerable modifications, alterations, combinations, and
equivalents in form and function, as will occur to one having
ordinary skill in the art and the benefit of this disclosure.
[0006] FIG. 1 shows a schematic of an illustrative integrated
computational element (ICE).
[0007] FIGS. 2 and 3 show schematics of illustrative optical
computing devices employing an integrated computational
element.
[0008] FIG. 4 shows a schematic of illustrative arrays of
integrated computational elements.
DETAILED DESCRIPTION
[0009] The present disclosure generally relates to methods for
assaying ionic materials, and, more specifically, to methods for
assaying ionic materials using an integrated computational element
to determine their binding state.
[0010] As described above, there may be several difficulties
associated with conventional analyses of ionic materials,
particularly for determining the distribution and relative
abundance of their various binding states in a fluid phase. In many
instances, such analyses may be specialized for particular ionic
materials and not broadly applicable, especially in the presence of
interferents, or the analyses may not proceed rapidly enough to
satisfy various process requirements. These difficulties can be
especially pronounced for metal ions. Moreover, for analyses
conducted in field or process environments, including those of the
oilfield services industry, conventional spectroscopic instruments
may be difficult to deploy and maintain due to their sensitive
hardware and typical need for controlled analysis conditions.
[0011] In contrast to conventional spectroscopic analyses, which
may be sensitive to the presence of interferents and require
time-consuming sample processing and/or spectral deconvolution
techniques, the methods described herein may be performed much more
rapidly to assay for various binding states of an ionic material in
a fluid phase without significant influence from potential
interferents. More specifically, the methods described herein
utilize optical computing devices containing one or more integrated
computational elements (ICE) in conjunction with analyzing for the
presence of one or binding states of an ionic material in a fluid
phase. Further disclosure regarding integrated computational
elements and their advantages in this regard is presented below.
Each integrated computational element within an optical computing
device can be specifically configured to analyze for a particular
binding state of an ionic material, even in the presence of
interferents, based on the spectral perturbation that the ionic
material produces in each state. Specifically, unbound ionic
materials perturb the spectrum of a fluid phase differently than do
bound ionic materials, and various bound states of an ionic
material also differentially perturb a fluid phase spectrum. Thus,
by using an integrated computational element configured for
assaying a particular binding state of an ionic material, the
abundance of the binding state can be quantified. Armed with
detailed information regarding the abundance and distribution of
various binding states of an ionic material in a fluid phase, an
operator can then make more informed process control decisions, as
further discussed herein.
[0012] Using one or more integrated computational elements for
determining a binding state of an ionic material may present a
number of advantages. A leading advantage is that measurements made
using an integrated computational element are much less influenced
by the presence of interferents than are other types of analyses,
including conventional spectroscopic analyses, thereby allowing an
ionic material to be assayed under a much broader array of
conditions than is otherwise typically possible. Integrated
computational elements and their associated hardware are also much
more robust and less sensitive to corruption by field or process
environments than are conventional spectroscopic instruments.
Moreover, integrated computational elements and their associated
hardware can produce extremely rapid analytical output, thereby
making them suitable for determining one or more binding states of
an ionic material in real-time or near real-time. All of these
features can prove advantageous when analyzing for a binding state
of an ionic material in a process or like environment.
[0013] In addition to the foregoing, the methods described herein
may allow mechanistic insights to be gained that are difficult or
impossible to determine by other analysis techniques, spectroscopic
or otherwise. For example, the crosslinking and breaking mechanism
of metal-crosslinked polymers may be followed by determining a
progression of metal-binding states over time. These types of
analyses are not readily performed by conventional spectroscopic
techniques, whereas they may be performed readily, in real-time or
near real-time, using an integrated computational element. In
addition, such analyses using an integrated computational element
may provide mechanistic insight into the potential re-healing of a
broken polymer fluid, which is not believed to be possible by any
conventional analytical techniques. Analyses using an integrated
computational element to monitor polymer crosslinking may be of
particular relevance in certain treatment operations conducted in
the oilfield services industry, as discussed further
hereinafter.
[0014] From an operational standpoint, the methods described herein
may be particularly advantageous, since they may allow early
intervention to take place in a process in which an ionic material
can be present in one or more binding states. For example, a
treatment operation conducted using a fluid phase containing an
ionic material may be monitored to determine if the treatment
operation has been successful, as determined by the binding state
of the ionic material following the treatment operation. If a
desired binding state of the ionic material has not been attained,
various process intervention operations may take place. More
specific examples in this regard follow hereinbelow. By determining
the binding state(s) of an ionic material during a treatment
operation and intervening as needed, significant cost and time
savings may be realized. For example, by knowing the binding states
of an ionic material and possibly intervening in a treatment
operation, one may avoid having to repeat the treatment operation
and/or possibly remediating subterranean formation damage.
[0015] One or more illustrative embodiments incorporating the
disclosure herein are presented below. Not all features of an
actual implementation are described or shown in this application
for the sake of clarity. It is to be understood that in the
development of an actual embodiment incorporating the present
disclosure, numerous implementation-specific decisions must be made
to achieve the developer's goals, such as compliance with
system-related, business-related, government-related and other
constraints, which may vary by implementation and from time to
time. While a developer's efforts might be complex and
time-consuming, such efforts would be, nevertheless, a routine
undertaking for one having ordinary skill in the art and the
benefit of this disclosure.
[0016] The theory behind optical computing and a description of
some conventional optical computing devices are provided in more
detail in the following commonly owned United States patents and
United States patent application Publications, each of which is
incorporated herein by reference in its entirety: U.S. Pat. Nos.
6,198,531; 6,529,276; 7,123,844; 7,834,999; 7,911,605; 7,920,258;
2009/0219538; 2009/0219539; and 2009/0073433. Accordingly, the
theory behind optical computing will not be discussed in any
extensive detail herein unless needed to better describe one or
more embodiments of the present disclosure. Unlike conventional
spectroscopic instruments, which produce a spectrum needing further
interpretation to obtain a result, the ultimate output of optical
computing devices is a real number that can be correlated in some
manner with a binding state of a particular ionic material. For
example, in the embodiments described herein, the optical computing
device may output a real number that may be correlated with a
concentration of a first binding state of an ionic material. A
second integrated computational element and associated detection
hardware in the optical computing device may be used to determine
the concentration of a second binding state of the ionic material.
The first and second binding states may exist at different times in
a fluid phase, or they may be present together in a fluid phase at
the same time. The operational simplicity of optical computing
devices allows them to rapidly produce an output, in real-time or
near real-time, in some embodiments. Correlation of the numerical
output for a given binding state of an ionic material may take
place by comparing the numerical output obtained from a fluid phase
having an unknown concentration of an ionic material in a
particular binding state with the numerical output obtained from a
previously measured fluid phase having a known concentration of the
ionic material in the given binding state.
[0017] In addition, significant benefits can sometimes be realized
by combining the outputs from two or more integrated computational
elements with one another, even when analyzing for a single binding
state of interest. Specifically, in some instances, significantly
increased detection accuracy may be realized. Techniques for
combining the output of two or more integrated computational
elements with one another, particularly computationally combining
the outputs, are described in commonly owned U.S. patent
application Ser. Nos. 13/456,255; 13/456,264; 13/456,283;
13/456,302; 13/456,327; 13/456,350; 13/456,379; 13/456,405; and
13/456,443, each filed on Apr. 26, 2012 and incorporated herein by
reference in its entirety. Any of the methods described herein may
be carried out by combining the outputs of two or more integrated
computational elements with one another. The integrated
computational elements whose outputs are being combined may be
associated or disassociated with the binding state of interest,
display a positive or negative response when analyzing the binding
state, or any combination thereof. Illustrative configurations of
optical computing devices containing two or more integrated
computational elements are shown in FIG. 4 and described in more
detail hereinbelow.
[0018] As alluded to above, the operational simplicity of optical
computing devices makes them rugged and well suited for field or
process environments, including deployment within a subterranean
formation. Uses of conventional optical computing devices for
analyzing fluids commonly encountered in the oil and gas industry,
including while deployed within a subterranean formation, are
described in commonly owned United States Patent Application
Publications 2013/0031970, 2013/0031971, 2013/0031972,
2013/0032333, 2013/0032334, 2013/0032340, 2013/0032344,
2013/0032345 and 2013/0032545, each of which is incorporated herein
by reference in its entirety.
[0019] As used herein, the term "ionic material" refers to a
substance that bears a non-zero charge when in an unbound state or
in a bound state.
[0020] As used herein, the term "bound state" refers to a condition
that exists when an ionic material is ligated with a complexing
species. As used herein, the term "unbound state" refers to a
condition that exists when an ionic material is substantially only
solvated by solvent molecules in a fluid phase. In either state,
the overall charge may be balanced by a counterion of opposite
charge.
[0021] As used herein, the term "electromagnetic radiation" refers
to radio waves, microwave radiation, infrared and near-infrared
radiation, visible light, ultraviolet radiation, X-ray radiation,
and gamma ray radiation.
[0022] As used herein, the term "optically interact" and variants
thereof refer to the reflection, transmission, scattering,
diffraction, or absorption of electromagnetic radiation through or
from a fluid phase or one or more integrated computational
elements. Accordingly, optically interacted electromagnetic
radiation refers to electromagnetic radiation that has been
reflected, transmitted, scattered, diffracted, absorbed, emitted,
or radiated from a fluid phase or an integrated computational
element.
[0023] As used herein, the term "optical computing device" refers
to an optical device that is configured to receive an input of
electromagnetic radiation associated with an ionic material and
produce an output of electromagnetic radiation from a processing
element arranged within the optical computing device. The
electromagnetic radiation may optically interact with the ionic
material in a fluid phase before or after optically interacting
with the optical computing device. The processing element may be,
for example, an integrated computational element (ICE), also known
as a multivariate optical element (MOE) or an ICE CORE (Halliburton
Energy Services), an illustrative example of which is described in
more detail below. The electromagnetic radiation that optically
interacts with the processing element may be changed so as to be
readable by a detector, such that an output of the detector can be
correlated to one or more binding states of the ionic material. The
output of electromagnetic radiation from the processing element can
comprise reflected, transmitted, and/or dispersed electromagnetic
radiation. Whether the detector analyzes reflected, transmitted, or
dispersed electromagnetic radiation may be dictated by the
structural parameters of the optical computing device as well as
other considerations known to one having ordinary skill in the art.
In addition, emission and/or scattering of the electromagnetic
radiation, for example, via fluorescence, luminescence, Raman, Mie,
and/or Raleigh scattering, can also be monitored by the optical
computing devices.
[0024] As used herein, the term "formation" or "subterranean
formation" refers to a body or section of geologic strata,
structure, formation or other subsurface solid or collected
material that is sufficiently distinctive and continuous with
respect to other geologic strata or characteristics that it can be
mapped, for example, by seismic techniques. A formation can be a
body of geologic strata of predominantly one type or a combination
of types, or a fraction of strata having substantially common set
of characteristics. A formation can contain one or more
hydrocarbon-bearing zones. The terms "formation,"
"hydrocarbon-bearing subterranean formation," "reservoir," and
"interval" may be used interchangeably herein, but may generally be
used to denote progressively smaller subsurface regions, zones, or
volumes. More specifically, a geologic formation may generally be
the largest subsurface region, a subterranean formation may
generally be a region within the geologic formation and may
generally be a hydrocarbon-bearing zone (a formation, reservoir, or
interval having oil, gas, heavy oil, and any combination thereof),
and an interval may generally refer to a sub-region or portion of a
reservoir. A hydrocarbon-bearing zone can be separated from other
hydrocarbon-bearing zones by zones of lower permeability such as
mudstones, shales, or shale-like (highly compacted) sands. In one
or more embodiments, a hydrocarbon-bearing zone may include heavy
oil in addition to sand, clay, or other porous solids.
[0025] As used herein, the term "fluid" refers to any substance
that is capable of flowing, including particulate solids, liquids,
gases, slurries, emulsions, powders, muds, glasses, any combination
thereof, and the like. In some embodiments, the fluid can comprise
an aqueous fluid, including water, mixtures of water and
water-miscible fluids, brine, and the like. In some embodiments,
the fluid can comprise a non-aqueous fluid, including organic
compounds (i.e., hydrocarbons, oil, a refined component of oil,
petrochemical products, and the like). In some embodiments, the
fluid can comprise a treatment fluid or a formation fluid.
[0026] As used herein, the term "formation fluid" refers to a fluid
phase that natively occurs within a subterranean formation.
Illustrative fluid phases that are found in a subterranean
formation and which may be analyzed by the methods described herein
to determine one or more binding states of an ionic material
therein include, for example, oil, liquid hydrocarbons, gaseous
hydrocarbons, natural gas, reservoir brines, formation water, any
combination thereof, and the like.
[0027] As used herein, the term "treatment fluid" refers to a fluid
that is placed in a location (e.g., a subterranean formation or a
pipeline) in order to perform a desired function. Treatment fluids
can be used in a variety of subterranean operations, including, but
not limited to, drilling operations, production treatments,
stimulation treatments, remedial treatments, fluid diversion
operations, fracturing operations, secondary or tertiary enhanced
oil recovery (EOR) operations, and the like. As used herein, the
terms "treat," "treatment," "treating," and other grammatical
equivalents thereof refer to any operation that uses a fluid in
conjunction with performing a desired function and/or achieving a
desired purpose. The terms "treat," "treatment," and "treating," as
used herein, do not imply any particular action by the fluid or any
particular component thereof unless otherwise specified. Treatment
fluids for subterranean operations can include, for example,
drilling fluids, fracturing fluids, acidizing fluids, conformance
treatment fluids, damage control fluids, remediation fluids, scale
removal and inhibition fluids, diversion fluids, chemical floods,
and the like. Any of these types of treatment fluids may contain an
ionic material, which may be present in one or more binding states
therein.
[0028] As used herein, the term "produced fluid" refers to a fluid
phase obtained (i.e., produced) from a subterranean formation
following a treatment operation.
[0029] As used herein, the terms "real-time" and "near real-time"
refer to an output from an integrated computational element that is
produced on substantially the same time scale as the optical
interrogation of a substance with electromagnetic radiation. That
is, a "real-time" or "near real-time" output does not take place
offline after data acquisition and post-processing techniques. An
output that is returned in "real-time" may be returned essentially
instantaneously. A "near real-time" output may be returned after a
brief delay, which may be associated with processing or data
transmission time, or the like. It will be appreciated by one
having ordinary skill in the art that the rate at which an output
is received may be dependent upon the processing and data
transmission rate.
[0030] FIG. 1 shows a schematic of an illustrative integrated
computational element (ICE) 100. As illustrated in FIG. 1, ICE 100
may include a plurality of alternating layers 102 and 104 of
varying thicknesses disposed on optical substrate 106. In general,
the materials forming layers 102 and 104 have indices of refraction
that differ (i.e., one has a low index of refraction and the other
has a high index of refraction), such as Si and SiO.sub.2. Other
suitable materials for layers 102 and 104 may include, but are not
limited to, niobia and niobium, germanium and germania, MgF, and
SiO. Additional pairs of materials having high and low indices of
refraction can be envisioned by one having ordinary skill in the
art, and the composition of layers 102 and 104 is not considered to
be particularly limited. In some embodiments, the material within
layers 102 and 104 can be doped, or two or more materials can be
combined in a manner to achieve a desired optical response. In
addition to solids, ICE 100 may also contain liquids (e.g., water)
and/or gases, optionally in combination with solids, in order to
produce a desired optical response. The material forming optical
substrate 106 is not considered to be particularly limited and may
comprise, for example, BK-7 optical glass, quartz, sapphire,
silicon, germanium, zinc selenide, zinc sulfide, various polymers
(e.g., polycarbonates, polymethylmethacrylate, polyvinylchloride,
and the like), diamond, ceramics, and the like. Opposite to optical
substrate 106, ICE 100 may include layer 108 that is generally
exposed to the environment of the device or installation in which
it is used.
[0031] The number, thickness, and spacing of layers 102 and 104 may
be determined using a variety of approximation methods based upon a
conventional spectroscopic measurement of a sample. These methods
may include, for example, inverse Fourier transform (IFT) of the
optical transmission spectrum and structuring ICE 100 as a physical
representation of the IFT. The approximation methods convert the
IFT into a structure based on known materials with constant
refractive indices.
[0032] It should be understood that illustrative ICE 100 of FIG. 1
has been presented for purposes of illustration only. Thus, it is
not implied that ICE 100 is predictive for any particular binding
state of a given ionic material. Furthermore, it is to be
understood that layers 102 and 104 are not necessarily drawn to
scale and should therefore not be considered as limiting of the
present disclosure. Moreover, one having ordinary skill in the art
will readily recognize that the materials comprising layers 102 and
104 may vary depending on factors such as, for example, the types
of substances being analyzed and the ability to accurately conduct
their analysis, cost of goods, and/or chemical compatibility
issues.
[0033] The weightings that the layers 102 and 104 of ICE 100 apply
at each wavelength are set to the regression weightings described
with respect to a known equation, or data, or spectral signature.
Briefly, ICE 100 may be configured to perform the dot product of
the input electromagnetic radiation into ICE 100 and produce a
desired loaded regression vector represented by each layer 102 and
104 for each wavelength. As a result, the output electromagnetic
radiation intensity of the ICE 100 may be correlated to a
particular binding state of a given ionic Material. Further details
regarding how ICE 100 is able to distinguish and process
electromagnetic radiation are described in U.S. Pat. Nos.
6,198,531, 6,529,276, and 7,920,258, each of which was previously
incorporated by reference in its entirety.
[0034] It is to be recognized that the embodiments herein may be
practiced with various blocks, modules, elements, components,
methods and algorithms, which can be implemented through using
computer hardware, software and combinations thereof. To illustrate
this interchangeability of hardware and software, various
illustrative blocks, modules, elements, components, methods and
algorithms have been described generally in terms of their
functionality. Whether such functionality is implemented as
hardware or software will depend upon the particular application
and any imposed design constraints. For at least this reason, it is
to be recognized that one of ordinary skill in the art can
implement the described functionality in a variety of ways for a
particular application. Further, various components and blocks can
be arranged in a different order or partitioned differently, for
example, without departing from the spirit and scope of the
embodiments expressly described.
[0035] Computer hardware used to implement the various illustrative
blocks, modules, elements, components, methods and algorithms
described herein can include a processor configured to execute one
or more sequences of instructions, programming or code stored on a
readable medium. The processor can be, for example, a general
purpose microprocessor, a microcontroller, a digital signal
processor, an application specific integrated circuit, a field
programmable gate array, a programmable logic device, a controller,
a state machine, a gated logic, discrete hardware components, an
artificial neural network or any like suitable entity that can
perform calculations or other manipulations of data. In some
embodiments, computer hardware can further include elements such
as, for example, a memory (e.g., random access memory (RAM), flash
memory, read only memory (ROM), programmable read only memory
(PROM), erasable PROM), registers, hard disks, removable disks,
CD-ROMS, DVDs, or any other like suitable storage device.
[0036] Executable sequences described herein can be implemented
with one or more sequences of code contained in a memory. In some
embodiments, such code can be read into the memory from another
machine-readable medium. Execution of the sequences of instructions
contained in the memory can cause a processor to perform the
process steps described herein. One or more processors in a
multi-processing arrangement can also be employed to execute
instruction sequences in the memory. In addition, hard-wired
circuitry can be used in place of or in combination with software
instructions to implement various embodiments described herein.
Thus, the present embodiments are not limited to any specific
combination of hardware and software.
[0037] As used herein, a machine-readable medium will refer to any
non-transitory medium that directly or indirectly provides
instructions to a processor for execution. A machine-readable
medium can take on many forms including, for example, non-volatile
media, volatile media, and transmission media. Non-volatile media
can include, for example, optical and magnetic disks. Volatile
media can include, for example, dynamic memory. Transmission media
can include, for example, coaxial cables, wire, fiber optics, and
wires that form a bus. Common forms of machine-readable media can
include, for example, floppy disks, flexible disks, hard disks,
magnetic tapes, other like magnetic media, CD-ROMs, DVDs, other
like optical media, punch cards, paper tapes and like physical
media with patterned holes, RAM, ROM, PROM, EPROM and flash
EPROM.
[0038] Illustrative configurations for optical computing devices
containing a single integrated computational element will now be
described in more detail. It is to be recognized that the device
configurations depicted in FIGS. 2 and 3 are illustrative in nature
only and can be modified extensively to accommodate the
requirements of a particular analysis. As non-limiting examples,
the single integrated computation elements of FIGS. 2 and 3 may be
replaced by multiple integrated computational elements, the outputs
of which may or may not be computationally combined with one
another. In some embodiments, multiple integrated computational
elements may be placed in series or parallel, or disposed in an
array on a movable assembly such that the electromagnetic radiation
optically interacts with different integrated computational
elements over time, as depicted in FIG. 4. The different integrated
computational elements may be used to analyze for distinct binding
states of an ionic material, or the output from one or more
integrated computational elements may be computationally combined
to determine a single binding state.
[0039] FIG. 2 shows an illustrative optical computing device 200
configured for monitoring fluid 202 by reflection, according to one
or more embodiments. In the illustrated embodiment, fluid 202 may
be contained or otherwise flowing within flow path 204. Flow path
204 may be a flow line, a pipeline, a wellbore, an annulus defined
within a wellbore, or any flow lines or pipelines extending to/from
a wellbore. Fluid 202 within flow path 204 may be flowing in the
general direction indicated by the arrows A (i.e., from upstream to
downstream). Portions of flow path 204 may be arranged
substantially vertically, substantially horizontally, or any
directional configuration therebetween, without departing from the
scope of the disclosure.
[0040] Optical computing device 200 may be configured to determine
a binding state of an ionic material within fluid 202, such as
whether the ionic material is unbound or bound to various
substances therein. Device 200 may include electromagnetic
radiation source 208 configured to emit or otherwise generate
electromagnetic radiation 210. Electromagnetic radiation source 208
may be any device capable of emitting or generating electromagnetic
radiation, as defined herein. For example, electromagnetic
radiation source 208 may be a light bulb, a light emitting diode
(LED), a laser, a blackbody, a photonic crystal, an X-Ray source,
any combination thereof, and the like. In some embodiments, lens
212 may be configured to collect or otherwise receive
electromagnetic radiation 210 and direct beam 214 of
electromagnetic radiation 210 toward fluid 202. Lens 212 may be any
type of optical device configured to transmit or otherwise convey
electromagnetic radiation 210 as desired, such as a normal lens, a
Fresnel lens, a diffractive optical element, a holographic
graphical element, a mirror (e.g., a focusing mirror), or a type of
collimator. In some embodiments, lens 212 may be omitted from
device 200 and electromagnetic radiation 210 may instead be
directed toward fluid 202 directly from electromagnetic radiation
source 208.
[0041] In some embodiments, device 200 may also include sampling
window 216 arranged adjacent to or otherwise in contact with fluid
202 for detection purposes. Sampling window 216 may be made from a
variety of transparent, rigid or semi-rigid materials that are
configured to allow transmission of electromagnetic radiation 210
therethrough. For example, sampling window 216 may be made of
glasses, plastics, semiconductors, crystalline materials,
polycrystalline materials, hot or cold-pressed powders, any
combination thereof, and the like. After passing through sampling
window 216, electromagnetic radiation 210 impinges upon and
optically interacts with fluid 202. As a result, optically
interacted electromagnetic radiation 218 is generated by and
reflected from fluid 202. It is to be recognized, however, that
alternative configurations of device 200 may allow optically
interacted electromagnetic radiation 218 to be generated by being
transmitted, scattered, diffracted, absorbed, emitted, or
re-radiated by and/or from fluid 202, without departing from the
scope of this disclosure.
[0042] Optically interacted electromagnetic radiation 218 generated
by the interaction with fluid 202 may be directed to or otherwise
be received by ICE 220 arranged within the device 200. ICE 220 may
be a spectral component substantially similar to ICE 100 described
above with reference to FIG. 1. Accordingly, ICE 220 may be
configured to receive the optically interacted electromagnetic
radiation 218 and produce modified electromagnetic radiation 222
corresponding to a binding state of an ionic material within fluid
202. In particular, modified electromagnetic radiation 222 is
electromagnetic radiation that has optically interacted with ICE
220, whereby an approximation of the regression vector
corresponding to the binding state of the ionic material is
obtained.
[0043] While FIG. 2 depicts ICE 220 as receiving reflected
electromagnetic radiation from fluid 202, ICE 220 may be arranged
at any point along the optical train of device 200, without
departing from the scope of this disclosure. For example, in one or
more embodiments, ICE 220 (as shown in dashed) may be arranged
within the optical train prior to the sampling window 216, while
obtaining substantially the same results. In other embodiments, ICE
220 may generate modified electromagnetic radiation 222 through
reflection, instead of transmission therethrough.
[0044] Modified electromagnetic radiation 222 generated by ICE 220
may subsequently be conveyed to detector 224 for quantification of
the signal. Detector 224 may be any device capable of detecting
electromagnetic radiation, and may be generally characterized as an
optical transducer. In some embodiments, detector 224 may be, but
is not limited to, a thermal detector such as a thermopile or
photoacoustic detector, a semiconductor detector, a piezoelectric
detector, a charge coupled device (CCD) detector, a video or array
detector, a split detector, a photon detector (such as a
photomultiplier tube), a photodiode, any combination thereof, and
the like. Other detectors known to one having ordinary skill in the
art may also be used.
[0045] In some embodiments, detector 224 may be configured to
produce output signal 226 in real-time or near real-time in the
form of a voltage (or current) that corresponds to a binding state
of an ionic material in fluid 202. The voltage returned by detector
224 is essentially the dot product of the optical interaction of
optically interacted electromagnetic radiation 218 with ICE 220 as
a function of the magnitude of the quantity of a particular binding
state that is present. As such, output signal 226 produced by
detector 224 and the abundance of the binding state may be related,
such as directly proportional, for example. In other embodiments,
however, the relationship may correspond to a polynomial function,
an exponential function, a logarithmic function, and/or a
combination thereof.
[0046] In some embodiments, device 200 may include second detector
228, which may be similar to first detector 224 in that it may be
any device capable of detecting electromagnetic radiation. Second
detector 228 may be used to detect radiating deviations stemming
from electromagnetic radiation source 208. Undesirable radiating
deviations can occur in the intensity of electromagnetic radiation
210 due to a wide variety of reasons and potentially cause various
negative effects on device 200. These negative effects can be
particularly detrimental for measurements taken over a period of
time. In some embodiments, radiating deviations can occur as a
result of a build-up of film or material on sampling window 216,
which may have the effect of reducing the amount and quality of
electromagnetic radiation ultimately reaching first detector 224.
Without proper compensation, such radiating deviations may result
in false readings that result in output signal 226 no longer being
correlatable with the binding state of interest.
[0047] To compensate for radiating deviations, second detector 228
may be configured to generate compensating signal 230 that is
generally indicative of the radiating deviations of electromagnetic
radiation source 208, thereby normalizing output signal 226
generated by first detector 224. As illustrated, second detector
228 may be configured to receive a portion of optically interacted
electromagnetic radiation 218 via beamsplitter 232 in order to
detect the radiating deviations. In other embodiments, however,
second detector 228 may be arranged to receive electromagnetic
radiation from any portion of the optical train in device 200 in
order to detect the radiating deviations, without departing from
the scope of this disclosure.
[0048] In some embodiments, output signal 226 and compensating
signal 230 may be conveyed to or otherwise received by signal
processor 234 that is communicably coupled to both of detectors 224
and 228. Signal processor 234 may be a computer including a
processor and a machine-readable storage medium having instructions
stored thereon, which, when executed by signal processor 234,
result in optical computing device 200 performing a number of
operations, such as determining a binding state of an ionic
material in fluid 202. Signal processor 234 may utilize an
artificial neural network, such as those described in commonly
owned United States Patent Application Publication 2009/0182693,
which is incorporated herein by reference in its entirety. Signal
processor 234 may also be configured to computationally combine the
outputs of two or more integrated computational elements, if
desired, for quantifying a particular binding state of
interest.
[0049] In real-time or near real-time, signal processor 234 may be
configured to provide output signal 236 corresponding to a binding
state of interest for an ionic material in fluid 202. Output signal
236 may be readable by an operator who can consider the results and
take appropriate action, if needed. In some embodiments, output
signal 236 may be conveyed, either wired or wirelessly, to an
operator for consideration. In other embodiments, output signal 236
may be recognized by signal processor 234 as being within or
outside a predetermined or preprogrammed range of suitable values
for operation and may alert an operator in the event of an
out-of-range value. In still other embodiments, signal processor
234 may autonomously undertake an appropriate corrective action in
order to return output signal 236 to within a desired range.
[0050] FIG. 3 shows an illustrative optical computing device 300
configured for monitoring a fluid 202 by transmission, according to
one or more embodiments. Optical computing device 300 may be
similar in some respects to optical computing device 200 of FIG. 2,
and therefore may be best understood with reference thereto, where
like reference characters have been used to enumerate elements
having similar functions. Unlike device 200, however, optical
computing device 300 of FIG. 3 may be configured to transmit
electromagnetic radiation 210 through fluid 202 via first sampling
window 302a and second sampling window 302b arranged
radially-opposite first sampling window 302a on flow path 204.
First and second sampling windows 302a and 302b may be similar to
sampling window 216 described above in FIG. 2 and therefore will
not be described in detail again.
[0051] As electromagnetic radiation 210 passes through fluid 202
via first and second sampling windows 302a and 302b, it optically
interacts with fluid 202, and optically interacted electromagnetic
radiation 218 is subsequently directed to or is otherwise received
by ICE 220. It is again noted that, ICE 220 may be arranged at any
point along the optical train of the device 300, without departing
from the scope of this disclosure. For example, in one or more
embodiments, ICE 220 may be arranged within the optical train prior
to first sampling window 302a. In yet other embodiments, ICE 220
may generate modified electromagnetic radiation 222 through
reflection, instead of transmission therethrough.
[0052] Modified electromagnetic radiation 222 generated by ICE 220
is subsequently conveyed to detector 224 for quantification of the
signal and generation of output signal 226, which corresponds to a
binding state of an ionic material in fluid 202. Device 300 may
also include second detector 228 for detecting radiating deviations
stemming from electromagnetic radiation source 208. As illustrated,
second detector 228 may be configured to receive a portion of the
optically interacted electromagnetic radiation 218 via beamsplitter
232 in order to detect radiating deviations and produce
compensating signal 230. Output signal 226 and compensating signal
230 may then be conveyed to or otherwise received by signal
processor 234 to provide, in real-time or near real-time, output
signal 236 that corresponds to a binding state of an ionic material
in fluid 202.
[0053] In some embodiments, the single ICE 220 of FIGS. 2 and 3 may
be replaced by an array of integrated computational elements, as
illustratively depicted in FIG. 4. By moving the integrated
computational elements of the depicted arrays with respect to the
electromagnetic radiation, different integrated computational
elements may be exposed to the electromagnetic radiation over time.
In some embodiments, the array may comprise rotating disc 403
containing integrated computational elements 404a-404e thereon. In
other embodiments, the array may comprise movable assembly 405
having integrated computational elements 406a-406e thereon, in
which movable assembly 405 is shifted or reciprocated laterally
over the course of time to expose integrated computational elements
406a-406e to electromagnetic radiation. It is to be recognized that
although the arrays of FIG. 4 have depicted five integrated
computational elements in the array, any number may be present.
[0054] In some embodiments, methods described herein may comprise:
optically interacting electromagnetic radiation with an ionic
material and one or more integrated computational elements, the
ionic material being located in a fluid phase while being optically
interacted with the electromagnetic radiation; and determining one
or more binding states of the ionic material in the fluid phase,
using the one or more integrated computational elements. In some
embodiments, the methods may further comprise detecting the
electromagnetic radiation that has optically interacted with the
ionic material and the one or more integrated computational
elements; and generating an output signal based on the detected
electromagnetic radiation, where the output signal is correlatable
to one or more binding states of the ionic material in the fluid
phase. In some embodiments, the output signal may provide a measure
of the quantity of a particular binding state of the ionic material
that is present in the fluid phase.
[0055] In some embodiments, the methods may further comprise
providing the electromagnetic radiation that optically interacts
with the ionic material and the one or more integrated
computational elements. In some embodiments, the electromagnetic
radiation may be provided from an external source such as a lamp, a
laser, a light-emitting diode (LED), a blackbody, or the like. The
type of electromagnetic radiation that is optically interacted with
the ionic material and the one or more integrated computational
elements is not believed to be particularly limited. Suitable
electromagnetic radiation sources may include visible light,
infrared radiation, near-infrared radiation, ultraviolet radiation,
X-ray radiation, gamma ray radiation, radio wave radiation,
microwave radiation, any combination thereof, and the like.
Particular types of electromagnetic radiation that optically
interact strongly with the ionic material or a bound variant
thereof may dictate the chosen type and specific wavelengths of
electromagnetic radiation employed in the methods described
herein.
[0056] In some embodiments, the electromagnetic radiation detected
after optically interacting with the ionic material and the one or
more integrated computational elements may lie in the near-infrared
region of the electromagnetic spectrum. In some embodiments, the
detected electromagnetic radiation may lie within a wavelength
range of about 1000 nm to about 5000 nm, or a range of about 1000
nm to about 4000 nm, or a range of about 1000 nm to about 3000 nm.
Other detected wavelength ranges are possible and can include, for
example, detection in the radio wave region, the microwave
radiation region, the infrared radiation region, the visible light
region, the ultraviolet radiation region, the X-ray radiation
region, the gamma ray radiation region, or any combination thereof.
The particular detection region chosen will depend, at least in
part, upon the nature of the optical interaction of the
electromagnetic radiation with the particular ionic material or
bound variant thereof. Moreover, one of ordinary skill in the art
will be able to choose a suitable detector for use in detecting a
particular type of electromagnetic radiation.
[0057] The type of ionic material whose binding state can be
quantified according to the methods described herein is not
believed to be particularly limited. In this regard, the binding
states of both organic and inorganic ionic materials can be
detected and quantified with the methods described herein. In more
particular embodiments, the ionic material may be inorganic and
comprise a metal ion. As discussed above, determination of the
binding states of metal ions in a fluid phase can sometimes be
problematic. In still more particular embodiments, the ionic
material may comprise a metal ion that can form crosslinks between
molecules of a crosslinkable polymer. Suitable metals ions for
forming crosslinks between polymer molecules can include, for
example, chromium ions, zirconium ions, aluminum ions, titanium
ions, antimony ions, magnesium ions, calcium ions, and any
combination thereof. Knowing the binding state of these metal ions
and other types of metal ions may allow one to determine if
effective crosslinking or breaking of a crosslinked polymer has
occurred.
[0058] The methods described herein may also be of relevance to
determine the scaling potential of metal ions in a fluid phase.
Generally, metal ions in an unbound state in a fluid phase have a
considerably greater scaling potential than do metal ions in a
bound state. Illustrative metal ions with a high scaling potential
in their unbound state include, for example, calcium ions,
magnesium ions, and any combination thereof, although any metal ion
in an unbound state represents some potential for scale formation
to occur. Unbound metal ions may also have a high propensity to
interact undesirably with scale control agents that may be used in
mitigating that formation of scale during various types of
industrial processes. Hence, it can be very desirable to know the
binding state of a metal ion in a fluid phase.
[0059] As alluded to above, various binding states of an ionic
material to a substance in a fluid phase may be determined using
the methods described herein. Specifically, the methods described
herein may determine one or more binding states of an ionic
material in a fluid phase as a distribution of the ionic material
between an unbound (i.e., "free") state and one or more bound
states. In various embodiments, the one or more bound states can
include, for example, a bound state to a polymer, a bound state to
a ligand, a bound state to a polymer fragment, a bound state to a
monomer, and any combination thereof. As used herein, the term
"monomer" will refer to a single repeating unit of a polymer, and
the term "polymer fragment" will refer to an oligomer comprising
two or more monomers that are bonded to each other. As further
alluded to above, the various bound and unbound states of a metal
ion may be of considerable relevance toward the crosslinking of a
polymer and formation of a gelled fluid therefrom.
[0060] Polymers that may be present in a fluid phase and interact
in a binding state with an ionic material are not believed to be
particularly limited. However, in more specific embodiments, the
polymer may comprise a crosslinkable polymer, particularly a
polymer that is crosslinkable by entering into a binding state with
a metal ion. Particularly suitable crosslinkable polymers may
include those utilized in the course of treating a subterranean
formation by forming a gelled treatment fluid. In this regard,
illustrative crosslinkable polymers that may be present in the
fluid phase include, for example, biopolymers, particularly a
polysaccharide or a modified polysaccharide. Illustrative
polysaccharides may include, for example, a cellulose or modified
cellulose, a guar or modified guar, a xanthan, a welan, a diutan, a
scleroglucan, a succinoglycan, a chitosan, a chitin, a dextran, a
starch, a sugar, any crosslinkable derivative thereof, or any
combination thereof. Illustrative celluloses and modified
celluloses may include, for example, carboxymethylcellulose,
carboxymethylhydroxyethylcellulose, carboxyethylcellulose,
hydroxyethylcellulose, and the like. Illustrative guars and
modified guars may include, for example, hydroxypropylguar,
carboxymethylhydroxypropylguar, carboxymethylguar,
hydroxyethylguar, carboxymethylhydroxyethylguar, and the like.
Other crosslinkable polymers that may be present in a fluid phase
in concert with an ionic material, either in combination with a
biopolymer or in lieu of a biopolymer, can include, for example, a
polyacrylamide, a polyacrylate, a partially hydrolyzed
polyacrylamide, a polymethacylamide, a polymethacrylate, a
partially hydrolyzed methacrylamide, a polyester, a
poly(orthoester), a polyanhydride, a polycarbonate, a polyamide, a
polyphosphazene, a polyvinyl alcohol, a 2-acrylamido-2-methyl
propane sulfonate-containing polymer or copolymer, a poly(vinyl
pyrollidone), a poly(diallyldimethylammonium chloride), a
poly(ethylene glycol), a poly(ethylene oxide), a polylysine, a
poly(vinylamine), a poly(ethyleneimine), a poly(lactic acid), a
poly(glycolic acid), any crosslinkable derivative thereof, and the
like.
[0061] After forming a metal-crosslinked polymer, which may result
in formation of a gelled fluid, the gelled fluid may be broken in
some embodiments. In some embodiments, gel breaking may occur
natively due to a reactant or temperature condition that is already
present where the gelled fluid is deployed. In other embodiments, a
breaker may be added to facilitate the breaking process.
Illustrative breakers will be familiar to one having ordinary skill
in the art and are not believed to be particularly limited in
practicing the embodiments described herein. Breaking may decrease
the viscosity of the fluid phase, depolymerize the polymer
molecules, and/or remove crosslinks between the polymer molecules.
In some embodiments, the methods described herein may be used to
distinguish between these various breaking processes. For example,
the methods may be used to determine if unbound metal ions are
present, possibly being indicative of crosslink removal, or if the
metal ions remain bound to a monomer or a larger polymer fragment,
possibly being indicative of polymer molecule scission. Thus, the
methods described herein may be applicable both in the lab and in
the field to determine the various factors that may be associated
with establishing the binding state of an ionic material, thereby
potentially allowing manipulation of the binding state and better
utilization of the ionic material to take place.
[0062] Many industrial processes, including those conducted in the
upstream energy industry, utilize treatment fluids, particularly
viscosified treatment fluids. In some embodiments, the fluid phase
in which the ionic material is present may comprise a treatment
fluid. In some embodiments, the methods described herein may
further comprise introducing the treatment fluid into a
subterranean formation. Such treatment fluids may include, but are
not limited to, fracturing fluids, drilling fluids, completion
fluids, diversion fluids, gravel packing fluids, acidizing fluids,
conformance fluids, the like, and any combination thereof. Further
disclosure regarding particular types of treatment operations and
control thereof are described hereinbelow. Generally, viscosified
treatment fluids that are used in a subterranean formation in the
course of performing a treatment operation are aqueous-based fluids
that comprise a crosslinkable polymer, such as those described
above.
[0063] In many cases, treatment fluids can be utilized in a gelled
state when performing a treatment operation. For example, in a
fracturing operation, a treatment fluid can be gelled to increase
its viscosity and improve its ability to carry a proppant or other
particulate material. In other cases, a gelled treatment fluid can
be used to at least temporarily divert or block the flow of fluids
within at least a portion of a subterranean formation. In either
case, it can be desirable to know if a polymer has remained
crosslinked and the treatment fluid possesses the capabilities for
performing as intended. The methods described herein make such
analyses possible by allowing one to determine the binding states
of an ionic material, such as a metal ion.
[0064] In some embodiments, the methods described herein may
comprise determining if the fluid phase contains a crosslinked
polymer by determining the one or more binding states of the ionic
material. For example, if unbound metal ions or metal ions only
bound to a polymer fragment are detected, one may infer that a
crosslinked polymer is no longer present.
[0065] In further embodiments, the methods described herein may
allow one to determine an oxidation state of a metal ion.
Specifically, a metal ion in a first oxidation state may exhibit
significantly different binding properties to a complexing species
than does a metal ion in a second oxidation state. Thus, by
determining the particular binding state of a metal ion that is
present in a fluid phase, the oxidation state of the metal ion may
be inferred. For example, a metal ion in a first oxidation state
may have limited binding affinity for a particular ligand, whereas
it may have high affinity for the ligand in a second oxidation
state. Hence, by determining if a metal ion is bound or unbound to
a ligand, the oxidation state of the metal ion may be inferred.
Such determinations of oxidation state may also be of relevance for
monitoring and controlling various processes.
[0066] In some embodiments, methods described herein may comprise
providing a treatment fluid comprising an ionic material, the ionic
material comprising a metal ion; introducing the treatment fluid
into a subterranean formation; optically interacting
electromagnetic radiation with the ionic material and one or more
integrated computational elements, the ionic material being located
in a fluid phase comprising the treatment fluid, a formation fluid,
or a produced fluid while being optically interacted with the
electromagnetic radiation; and determining one or more binding
states of the ionic material in the fluid phase, using the one or
more integrated computational elements.
[0067] As generally discussed above, any type of treatment fluid
that may contain a crosslinked polymer at any point during its
lifetime may be analyzed according to the present methods in order
to determine the binding state of an ionic material. In some
embodiments, the treatment fluid may comprise a fracturing fluid.
In some or other embodiments, the treatment fluid may comprise a
drilling fluid, a completion fluid, or a diversion fluid.
[0068] In monitoring a treatment operation, the location at which a
fluid phase containing a metal ion is optically interacted with
electromagnetic radiation and determination of the binding state is
made is also not believed to be particularly limited. Depending on
whether one needs to monitor a binding state before, after, or
during a treatment operation, or whether one needs to proactively
or reactively address the presence of a particular binding state
will determine the location(s) at which the analysis of a fluid
containing the metal ion may most effectively take place.
Illustrative examples of possible analysis scenarios are provided
below.
[0069] In some embodiments, the treatment fluid can be optically
interacted with electromagnetic radiation before it is introduced
into the subterranean formation. That is, in some embodiments,
optically interacting electromagnetic radiation with the ionic
material and one or more integrated computational elements may take
place before the treatment fluid is introduced into a subterranean
formation. Determining the binding state(s) of the ionic material
before its introduction to the subterranean formation may serve as
a quality control check of whether the treatment fluid has suitable
properties for use in a particular treatment operation. For
example, determining the binding state(s) of the ionic material may
provide a measure of the extent of crosslinking that has taken
place in the treatment fluid and guidance as to whether the
treatment fluid is gelled or ungelled. In addition, determining if
the ionic material is in the proper binding state can allow one to
conclude if the treatment fluid has the capacity for becoming
properly gelled. If the treatment fluid is ungelled at the time of
measurement, assaying the binding state of the ionic material can
determine if the ionic material can eventually initiate
crosslinking and gelation of the treatment fluid. For example, if
the ionic material is bound by the proper ligands, the ionic
material may be released into the treatment fluid in an unbound
state at a desired time or location downhole, at which point it may
interact with a crosslinkable polymer to initiate crosslinking.
However, if the ionic material is bound by the incorrect ligands,
the ionic material may be released too slowly in order to initiate
effective crosslinking at the proper time downhole. Conversely, if
the ionic material enters an unbound state too soon, premature
crosslinking may occur, which may be undesirable in some
embodiments. In some embodiments, the ionic material can be
optically interacted with electromagnetic radiation both before its
introduction to a subterranean formation and at some point
thereafter.
[0070] In some embodiments, methods described herein may comprise
formulating a treatment fluid. In more specific embodiments,
methods described herein may comprise formulating the treatment
fluid with a produced fluid comprising the ionic material.
Formulating the treatment fluid with a produced fluid may be
particularly advantageous, since it can reduce the need to source
and transport an external supply of a carrier fluid for formulating
the treatment fluid. Moreover, in some embodiments, an ionic
material in a produced fluid may be assayed to determine its
binding state therein, as discussed in more detail below. In other
embodiments, however, a treatment fluid can be assayed without
having first determined the binding states of an ionic material
therein. In these and other cases, the composition of the treatment
fluid may be adjusted after its formulation to alter one or more of
its properties. Specifically, altering one or more properties of
the treatment fluid may change one or more binding states of an
ionic material that is present therein. Altering one or more
properties of the treatment fluid to change one or more binding
states of the ionic material may take place such that the treatment
fluid has a better capacity for functioning as intended once placed
downhole.
[0071] In some embodiments, optically interacting electromagnetic
radiation with the ionic material and the one or more integrated
computational elements may take place while the treatment fluid is
located in the subterranean formation. In some embodiments,
determining the binding state of the ionic material in the
subterranean formation may allow one to determine if the treatment
fluid contains a crosslinked polymer and if the treatment fluid is
properly gelled in the subterranean formation. For example,
determining if the polymer is crosslinked may take place in some
embodiments by measuring the distribution of the ionic material
between the unbound state and one or more bound states. In some or
other embodiments, measuring the distribution between a bound state
and an unbound state of an ionic material may allow one to
determine if an effective break has occurred and a shut-in period
can be ended, for example. In some embodiments, measuring the
distribution between a bound state and an unbound state may allow a
break time for the treatment fluid to be determined. In some
embodiments, if the treatment fluid has not broken or the break has
occurred too slowly, the methods described herein may further
comprise introducing a breaker to the subterranean formation.
Thereafter, the ionic material can again be optically interacted
with electromagnetic radiation in order to determine the nature of
its binding state(s) in the subterranean formation.
[0072] When utilized for analyzing the binding state of an ionic
material within a subterranean formation, one or more integrated
computational elements may be present in a fixed location within
the subterranean formation, or they may be movable. In some
embodiments, optical computing devices employing integrated
computational element(s) may be affixed at one or more locations
within the subterranean formation (e.g., on tubulars). In other
embodiments, optical computing devices employing integrated
computational element(s) may be removably placed at one or more
locations within the subterranean formation, such as through
wireline deployment, for example. In related embodiments, optical
computing devices employing integrated computational element(s) may
be located external to the subterranean formation but be in optical
communication therewith by way of an optical fiber or like
electromagnetic radiation conduit extending into the subterranean
formation. In either case, the integrated computational element(s)
may receive electromagnetic radiation from one or more points of
interest within the subterranean formation in order to determine
the binding state of an ionic material therein.
[0073] The methods described herein are not limited to determining
if a treatment fluid is gelled or broken based upon the measurement
of one or more binding states of an ionic material therein. By
extension, one of ordinary skill in the art may utilize such
information to determine, for example, if a fluid diversion,
chelation, or scaling is occurring in a subterranean formation or
Is likely to occur.
[0074] Similarly, in some embodiments, optically interacting
electromagnetic radiation with the ionic material and the one or
more integrated computational elements may take place after
producing the ionic material from the subterranean formation. That
is, in some embodiments, the ionic material may be optically
interacted with electromagnetic radiation while it is in a produced
fluid. The produced fluid may be the original treatment fluid, a
spent version of the original treatment fluid, another treatment
fluid, a breaker fluid, a formation fluid, or any combination
thereof. In some embodiments, the produced fluid being analyzed by
the methods described herein may comprise a produced aqueous fluid.
As alluded to above, in some embodiments, the treatment fluids
described herein may be formulated with a produced fluid,
particularly a produced aqueous fluid, which can prove advantageous
in many instances.
[0075] In some embodiments, the methods described herein may
further comprise determining if a produced fluid is suitable for
reuse in formulating a particular treatment fluid. Such
determinations can be problematic using conventional analytical
techniques. Depending on the intended function of the ionic
material in the treatment fluid after its formulation, the ionic
material may be in a bound state or an unbound state in the
produced fluid. For example, when it is desired that the ionic
material initiate crosslinking of the polymer in the treatment
fluid, it may be more desirable for the ionic material in the
produced fluid to be in an unbound state. However, if it is desired
that the ionic material be present as an inert component of the
treatment fluid, or if the ionic material should initiate
crosslinking of a polymer in the treatment fluid at a later time,
it may be more desirable for the ionic material to be present in a
bound state. For example, a treatment fluid may be initially
formulated using a produced fluid that contains metal ions bound to
a polymer fragment, and the metal ions may be released in an
unbound state at later time, if desired. Similarly, it may be more
desirable to formulate a treatment fluid using an ionic material in
a bound state if a decreased propensity toward scaling is desired.
As discussed above, a produced fluid may be further altered in some
manner to make it suitable for use in formulating a particular
treatment fluid. For example, if an ionic material is present in an
unbound state, a suitable complexing species may be added to the
produced fluid to form a bound state of the ionic material.
[0076] In some embodiments, the treatment fluids being assayed by
the methods described herein may further comprise a polymer,
particularly a crosslinkable polymer, in addition to the ionic
material. In some embodiments, the polymer, a fragment of the
polymer, or a monomer related to the polymer may enter into a
binding state with the ionic material. In some embodiments, the
binding state of the ionic material may result in crosslinking of
the polymer, such that the treatment fluid contains a crosslinked
polymer. In some or other embodiments, the treatment fluid may
initially be gelled and contain a crosslinked polymer. Thereafter,
the treatment fluid may be broken by changing the binding state of
the ionic material therein. For example, in some embodiments, a
crosslinked polymer in a gelled treatment fluid may be formed with
a metal ion forming crosslinking bridges between the polymer
chains. After breaking occurs, the metal ion may be found in an
unbound state, or bound to a fragment of the polymer depending upon
whether the crosslinking bridges are directly attacked during the
breaking process, or if scission of the polymer molecules occurs
instead, with the metal ion remaining bound to the smaller
fragments of the original polymer.
[0077] In some embodiments, the treatment fluid may comprise a
fracturing fluid. In some embodiments, in addition to a polymer and
an ionic material, a fracturing fluid may also comprise a plurality
of proppant particulates. Proppant particulates are not
particularly limited in size or composition and may include, for
example, particulates comprising sand, bauxite, ceramic materials,
glass materials, polymer materials, polytetrafluoroethylene
materials, nut shell pieces, cured resinous particulates comprising
nut shell pieces, seed shell pieces, cured resinous particulates
comprising seed shell pieces, fruit pit pieces, cured resinous
particulates comprising fruit pit pieces, wood, composite
particulates, and combinations thereof. Suitable composite
particulates may comprise a binder and a filler material wherein
suitable filler materials include silica, alumina, fumed carbon,
carbon black, graphite, mica, titanium dioxide, meta-silicate,
calcium silicate, kaolin, talc, zirconia, boron, fly ash, hollow
glass microspheres, solid glass, and combinations thereof. One
having ordinary skill in the art will understand suitable ranges
for viscosity values of a fracturing fluid in order to transport a
plurality of proppant particulates to a desired location within a
wellbore. One having ordinary skill in the art will further
recognize that a fracturing fluid may be viscosified by a
crosslinked polymer.
[0078] It is to be recognized that other than the ionic materials
described hereinabove, various additional components may be present
in the treatment fluids and other compositions described herein.
The presence of these additional components is not believed to
significantly alter the techniques for assaying the binding state
of the ionic material, as described herein. Illustrative components
that can be present in any of the treatment fluids described herein
include, for example, polymers, acids, acid-generating compounds,
bases, base-generating compounds, surfactants, scale inhibitors,
corrosion inhibitors, gelling agents, crosslinking agents,
anti-sludging agents, foaming agents, defoaming agents, antifoam
agents, emulsifying agents, de-emulsifying agents, iron control
agents, proppants or other particulates, gravel, particulate
diverters, salts, fluid loss control additives, gases, catalysts,
clay control agents, chelating agents, corrosion inhibitors,
dispersants, flocculants, scavengers (e.g., H.sub.2S scavengers,
CO.sub.2 scavengers or O.sub.2 scavengers), lubricants, breakers,
delayed release breakers, friction reducers, bridging agents,
viscosifiers, weighting agents, solubilizers, rheology control
agents, viscosity modifiers, pH control agents (e.g., buffers),
hydrate inhibitors, relative permeability modifiers, diverting
agents, consolidating agents, fibrous materials, bactericides,
tracers, probes, nanoparticles, any combination thereof, and the
like.
[0079] In some embodiments, methods described herein may comprise:
providing a treatment fluid comprising a crosslinkable polymer and
an ionic material, the ionic material comprising a metal ion that
forms crosslinks between molecules of the crosslinkable polymer;
introducing the treatment fluid into a subterranean formation;
after introducing the treatment fluid into the subterranean
formation, optically interacting electromagnetic radiation with the
ionic material and one or more integrated computational elements,
the ionic material being located in a fluid phase while being
optically interacted with the ionic material; and determining one
or more binding states of the ionic material in the fluid phase,
using the one or more integrated computational elements, the
determining one or more binding states of the ionic material
comprising measuring a distribution of the ionic material between
an unbound state and one or more bound states, the one or more
bound states being selected from the group consisting of a bound
state to the polymer, a bound state to a ligand, a bound state to a
polymer fragment, a bound state to a monomer, and any combination
thereof.
[0080] In some embodiments, methods described herein may comprise:
optically interacting electromagnetic radiation with an ionic
material and one or more integrated computational elements, the
ionic material being located in a fluid phase while being optically
interacted with the electromagnetic radiation; and determining one
or more binding states of the ionic material in the fluid phase,
using the one or more integrated computational elements.
[0081] In some embodiments, methods described herein may comprise:
providing a treatment fluid comprising an Ionic material, the ionic
material comprising a metal ion; introducing the treatment fluid
into a subterranean formation; optically interacting
electromagnetic radiation with the ionic material and one or more
integrated computational elements, the ionic material being located
in a fluid phase comprising the treatment fluid, a formation fluid,
or a produced fluid while being optically interacted with the
electromagnetic radiation; and determining one or more binding
states of the ionic material in the fluid phase, using the one or
more integrated computational elements.
[0082] Embodiments disclosed herein include:
[0083] A. Methods for determining the binding state of an ionic
material. The methods comprise: optically interacting
electromagnetic radiation with an ionic material and one or more
integrated computational elements, the ionic material being located
in a fluid phase while being optically interacted with the
electromagnetic radiation; and determining one or more binding
states of the ionic material in the fluid phase, using the one or
more integrated computational elements.
[0084] B. Methods for determining the binding state of an ionic
material in a treatment operation. The methods comprise: providing
a treatment fluid comprising an ionic material, the ionic material
comprising a metal ion; introducing the treatment fluid into a
subterranean formation; optically interacting electromagnetic
radiation with the ionic material and one or more integrated
computational elements, the ionic material being located in a fluid
phase comprising the treatment fluid, a formation fluid, or a
produced fluid while being optically interacted with the
electromagnetic radiation; and determining one or more binding
states of the ionic material in the fluid phase, using the one or
more integrated computational elements.
[0085] C. Methods for determining the binding state of an ionic
material in a treatment operation. The methods comprise: providing
a treatment fluid comprising a crosslinkable polymer and an ionic
material, the ionic material comprising a metal ion that forms
crosslinks between molecules of the crosslinkable polymer;
introducing the treatment fluid into a subterranean formation;
after introducing the treatment fluid into the subterranean
formation, optically interacting electromagnetic radiation with the
ionic material and one or more integrated computational elements,
the ionic material being located in a fluid phase while being
optically interacted with the electromagnetic radiation; and
determining one or more binding states of the ionic material in the
fluid phase, using the one or more integrated computational
elements, the determining one or more binding states of the ionic
material comprising measuring a distribution of the ionic material
between an unbound state and one or more bound states, the one or
more bound states being selected from the group consisting of a
bound state to the crosslinkable polymer, a bound state to a
ligand, a bound state to a polymer fragment, a bound state to a
monomer, and any combination thereof.
[0086] Each of embodiments A, B, and C may have one or more of the
following additional elements in any combination:
[0087] Element 1: wherein determining one or more binding states of
the ionic material in the fluid phase comprises measuring a
distribution of the ionic material between an unbound state and one
or more bound states, the one or more bound states being selected
from the group consisting of a bound state to a polymer, a bound
state to a ligand, a bound state to a polymer fragment, a bound
state to a monomer, and any combination thereof.
[0088] Element 2: wherein the ionic material comprises a metal
ion.
[0089] Element 3: wherein the method further comprises determining
an oxidation state of the metal ion from the one or more binding
states.
[0090] Element 4: wherein the method further comprises determining
if the fluid phase contains a crosslinked polymer by determining
the one or more binding states of the ionic material.
[0091] Element 5: wherein the fluid phase comprises a treatment
fluid.
[0092] Element 6: wherein the method further comprises formulating
the treatment fluid with a produced fluid comprising the ionic
material.
[0093] Element 7: wherein the treatment fluid further comprises a
crosslinkable polymer.
[0094] Element 8: wherein the method further comprises determining
if the crosslinkable polymer is crosslinked by measuring the
distribution of the ionic material between the unbound state and
the one or more bound states.
[0095] Element 9: wherein the treatment fluid is selected from the
group consisting of a fracturing fluid, a drilling fluid, a
completion fluid, a diversion fluid, and any combination
thereof.
[0096] Element 10: wherein optically interacting electromagnetic
radiation with the ionic material and the one or more integrated
computational elements takes place before the treatment fluid is
introduced into the subterranean formation.
[0097] Element 11: wherein optically interacting electromagnetic
radiation with the ionic material and the one or more integrated
computational elements takes place while the treatment fluid is
located in the subterranean formation.
[0098] Element 12: wherein optically interacting electromagnetic
radiation with the ionic material and the one or more integrated
computational elements takes place after producing the ionic
material from the subterranean formation.
[0099] Element 13: wherein the method further comprises altering
one or more properties of the treatment fluid to change the one or
more binding states of the ionic material.
[0100] Element 14: wherein the ionic material comprises a metal ion
selected from the group consisting of a zirconium ion, an aluminum
ion, a titanium ion, a magnesium ion, a calcium ion, and any
combination thereof.
[0101] Element 15: wherein the method further comprises introducing
a breaker into the subterranean formation after determining if the
crosslinkable polymer is crosslinked.
[0102] Element 16: wherein optically interacting electromagnetic
radiation with the ionic material and the one or more integrated
computational elements takes place in a produced fluid.
[0103] Element 17: wherein the method further comprises detecting
the electromagnetic radiation that has optically interacted with
the ionic material and the one or more integrated computational
elements; and generating an output signal based on the detected
electromagnetic radiation, the output signal being correlatable to
the one or more binding states of the ionic material in the fluid
phase.
[0104] By way of non-limiting example, exemplary combinations
applicable to A, B, and C include:
[0105] The method of A in combination with elements 1 and 2.
[0106] The method of A in combination with elements 2 and 3.
[0107] The method of A in combination with elements 2 and 5.
[0108] The method of A in combination with elements 2, 5 and 7.
[0109] The method of A in combination with elements 5, 6 and 7.
[0110] The method of A or B in combination with elements 1 and
4.
[0111] The method of A or B in combination with elements 1 and
17.
[0112] The method of A or B in combination with elements 4 and 10,
elements 4 and 11, or elements 4 and 12.
[0113] The method of A, B or C in combination with elements 4 and
14.
[0114] The method of B or C in combination with elements 8 and
9.
[0115] The method of B or C in combination with elements 8 and 14.
The method of B or C in combination with elements 9 and 14.
[0116] The method of B in combination with elements 1 and 6.
[0117] The method of B in combination with elements 7, 8 and 9.
[0118] The method of B in combination with elements 7 and 13.
[0119] The method of C in combination with elements 8 and 11, or
elements 8 and 12.
[0120] To facilitate a better understanding of the embodiments of
the present disclosure, the following examples of preferred or
representative embodiments are given. In no way should the
following examples be read to limit, or to define, the scope of the
disclosure.
EXAMPLES
Prophetic Example
[0121] The optical spectra of a set of fluid samples having a known
binding state of an ionic material over a range of concentrations
will be prepared. Next, a series of optical transmission
interference regression vectors will be generated for the samples,
and their performance will be optimized for accuracy, sensitivity
and manufacturability by varying the number of layers, the
thickness of layers, and/or the material indices of refraction
within a design candidate by comparison to the optical spectra.
Once one or more suitable design candidates have been identified,
an ICE will be manufactured using thin-film or like deposition
techniques. The detector output obtained from the ICE will then be
calibrated against fluid samples having known concentrations of the
binding state to obtain a standard calibration curve. By reading
the detector output of an unknown sample, the concentration of a
particular binding state will be determined using the calibration
curve.
[0122] Therefore, the present disclosure is well adapted to attain
the ends and advantages mentioned as well as those that are
inherent therein. The particular embodiments disclosed above are
illustrative only, as the present disclosure may be modified and
practiced in different but equivalent manners apparent to one
having ordinary skill in the art and the benefit of the teachings
herein. Furthermore, no limitations are intended to the details of
construction or design herein shown, other than as described in the
claims below. It is therefore evident that the particular
illustrative embodiments disclosed above may be altered, combined,
or modified and all such variations are considered within the scope
and spirit of the present disclosure. The embodiments
illustratively disclosed herein suitably may be practiced in the
absence of any element that is not specifically disclosed herein
and/or any optional element disclosed herein. While compositions
and methods are described in terms of "comprising," "containing,"
or "including" various components or steps, the compositions and
methods can also "consist essentially of" or "consist of" the
various components and steps. All numbers and ranges disclosed
above may vary by some amount. Whenever a numerical range with a
lower limit and an upper limit is disclosed, any number and any
included range falling within the range is specifically disclosed.
In particular, every range of values (of the form, "from about a to
about b," or, equivalently, "from approximately a to b," or,
equivalently, "from approximately a-b") disclosed herein is to be
understood to set forth every number and range encompassed within
the broader range of values. Also, the terms in the claims have
their plain, ordinary meaning unless otherwise explicitly and
clearly defined by the patentee. Moreover, the indefinite articles
"a" or "an," as used in the claims, are defined herein to mean one
or more than one of the element that it introduces. If there is any
conflict in the usages of a word or term in this specification and
one or more patent or other documents that may be incorporated
herein by reference, the definitions that are consistent with this
specification should be adopted.
[0123] Unless otherwise indicated, all numbers expressing
quantities of ingredients, properties such as molecular weight,
reaction conditions, and so forth used in the present specification
and associated claims are to be understood as being modified in all
instances by the term "about." Accordingly, unless indicated to the
contrary, the numerical parameters set forth in the specification
and attached claims are approximations that may vary depending upon
the desired properties sought to be obtained in a particular
implementation of the present disclosure. At the very least, and
not as an attempt to limit the application of the doctrine of
equivalents to the scope of the claim, each numerical parameter
should at least be construed in light of the number of reported
significant digits and by applying ordinary rounding
techniques.
* * * * *