U.S. patent application number 16/161495 was filed with the patent office on 2019-02-14 for suspensions for removing hydrocarbons from subterranean formations and related methods.
The applicant listed for this patent is Baker Hughes, a GE company, LLC. Invention is credited to Devesh Kumar Agrawal, Valery N. Khabashesku, Sankaran Murugesan.
Application Number | 20190048251 16/161495 |
Document ID | / |
Family ID | 57546177 |
Filed Date | 2019-02-14 |
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United States Patent
Application |
20190048251 |
Kind Code |
A1 |
Agrawal; Devesh Kumar ; et
al. |
February 14, 2019 |
SUSPENSIONS FOR REMOVING HYDROCARBONS FROM SUBTERRANEAN FORMATIONS
AND RELATED METHODS
Abstract
A suspension for removing hydrocarbons from a subterranean
formation includes a fluid comprising at least one of water, brine,
steam, carbon dioxide, a light hydrocarbon, and an organic solvent;
and a plurality of nanoparticles dispersed with the fluid.
Nanoparticles of the plurality comprise silica and carbon. A method
includes forming a plurality of nanoparticles and dispersing the
plurality of nanoparticles with a fluid to form a suspension
comprising the nanoparticles. A method of recovering a hydrocarbon
material includes introducing a suspension into a subterranean
formation containing hydrocarbons, forming a stabilized emulsion of
the suspension and the hydrocarbons within the subterranean
formation; and removing the emulsion from the subterranean
formation. The suspension comprises a plurality of nanoparticles,
and at least some nanoparticles of the plurality comprise silica
and carbon.
Inventors: |
Agrawal; Devesh Kumar;
(Houston, TX) ; Murugesan; Sankaran; (Katy,
TX) ; Khabashesku; Valery N.; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Baker Hughes, a GE company, LLC |
Houston |
TX |
US |
|
|
Family ID: |
57546177 |
Appl. No.: |
16/161495 |
Filed: |
October 16, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14744520 |
Jun 19, 2015 |
10155899 |
|
|
16161495 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/20 20130101;
E21B 43/16 20130101; C09K 2208/10 20130101; C09K 8/58 20130101 |
International
Class: |
C09K 8/58 20060101
C09K008/58; E21B 43/20 20060101 E21B043/20; E21B 43/16 20060101
E21B043/16 |
Claims
1. A suspension for removing hydrocarbons from a subterranean
formation, the suspension comprising: a fluid comprising at least
one of water, brine, steam, carbon dioxide, a light hydrocarbon,
and an organic solvent; and a plurality of nanoparticles dispersed
with the fluid, at least some nanoparticles of the plurality
comprising both silica and carbon.
2. The suspension of claim 1, wherein the at least some
nanoparticles of the plurality comprise a silica nanoparticle
attached to at least one material selected from the group
consisting of carbon nanodots, graphene, graphene oxide, carbon
nanotubes, and functionalized carbon nanotubes.
3. The suspension of claim 1, wherein the at least some
nanoparticles of the plurality of nanoparticles exhibit a mean
diameter from about 5 nm to about 50 nm.
4. The suspension of claim 1, wherein the at least some
nanoparticles of the plurality are hydrophilic.
5. The suspension of claim 1, wherein the at least some
nanoparticles of the plurality comprise silica and carbon bonded by
hydroxyl groups.
6. The suspension of claim 1, further comprising a surfactant.
7. The suspension of claim 1, wherein the at least some
nanoparticles of the plurality comprise silica and carbon quantum
dots.
8. The suspension of claim 1, wherein the fluid comprises liquid
water.
9. The suspension of claim 1, wherein the suspension comprises a
concentration of the nanoparticles from about 10 ppm to about
10,000 ppm.
10. The suspension of claim 1, wherein the at least some
nanoparticles of the plurality comprise functionalized carbon.
11. The suspension of claim 10, wherein the at least some
nanoparticles of the plurality comprise hydrophobic functionalized
carbon.
12. The suspension of claim 10, wherein the at least some
nanoparticles of the plurality comprise hydrophilic functionalized
carbon.
13. The suspension of claim 1, wherein the suspension is
substantially homogeneous.
14. The suspension of claim 1, wherein the nanoparticles are
monomodal.
15. A method of removing hydrocarbons from a subterranean
formation, the method comprising: introducing a suspension into a
subterranean formation, the suspension comprising: a fluid
comprising at least one of water, brine, steam, carbon dioxide, a
light hydrocarbon, and an organic solvent; and a plurality of
nanoparticles dispersed with the fluid, at least some nanoparticles
of the plurality comprising both silica and carbon; forming a
stabilized emulsion in the subterranean formation, the stabilized
emulsion comprising the nanoparticles and a hydrocarbon from the
formation; and withdrawing the stabilized emulsion from the
subterranean formation.
16. The method of claim 15, further comprising passing the
suspension through perforations in the subterranean formation.
17. The method of claim 15, further comprising destabilizing at
least a portion of the stabilized emulsion removed from the
subterranean formation to form distinct, immiscible phases
including at least an aqueous phase and a hydrocarbon phase.
18. The method of claim 17, wherein destabilizing at least a
portion of the stabilized emulsion comprises modifying a property
of the stabilized emulsion selected from the group consisting of
temperature, pH, material composition, and pressure.
19. The method of claim 17, wherein destabilizing at least a
portion of the stabilized emulsion comprises adding an acid to the
stabilized emulsion.
20. The method of claim 15, further comprising recovering at least
a portion of the nanoparticles.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/744,520, filed Jun. 19, 2015, the disclosure of which
is hereby incorporated herein in its entirety by this
reference.
FIELD
[0002] Embodiments of the present disclosure relate generally to
methods of recovering a hydrocarbon material from a subterranean
formation. More particularly, embodiments of the disclosure relate
to methods of forming a suspension including nanoparticles
comprising silica and carbon, methods of recovering hydrocarbons
using the nanoparticles, and to suspensions including the
nanoparticles.
BACKGROUND
[0003] Water flooding is a conventional process of enhancing the
extraction of hydrocarbon materials (e.g., crude oil, natural gas,
etc.) from a subterranean formation. In this process, an aqueous
fluid (e.g., water, brine, etc.) is injected into the subterranean
formation through injection wells to sweep a hydrocarbon material
contained within interstitial spaces (e.g., pores, cracks,
fractures, channels, etc.) of the subterranean formation toward
production wells. One or more additives may be added to the aqueous
fluid to assist in the extraction and subsequent processing of the
hydrocarbon material.
[0004] For example, in some approaches, a surfactant, solid
particles (e.g., as colloids), or both, are added to the aqueous
fluid. The surfactant and/or the solid particles can adhere to or
gather at interfaces between a hydrocarbon material and an aqueous
material to form a stabilized emulsion of one of the hydrocarbon
material and the aqueous material dispersed in the other of the
hydrocarbon material and the aqueous material. Surfactants may
decrease the surface tension between the hydrocarbon phase and the
water phase, such as in an emulsion of a hydrocarbon phase
dispersed within an aqueous phase. Stabilization by the surfactant,
the solid particles, or both, lowers the interfacial tension
between the hydrocarbon and water and reduces the energy of the
system, preventing the dispersed material (e.g., the hydrocarbon
material, or the aqueous material) from coalescing, and maintaining
the one material dispersed as units (e.g., droplets) throughout the
other material. Reducing the interfacial tension increases the
permeability and the flowability of the hydrocarbon material. As a
consequence, the hydrocarbon material may be more easily
transported through and extracted from the subterranean formation
as compared to water flooding processes that do not employ a
surfactant and/or solid particles. The effectiveness of the
emulsion is determined in large part by the ability of the emulsion
to remain stable and ensure mixing of the two phases.
[0005] However, application of surfactants is usually limited by
the ability of the surfactant to sufficiently contact a large
portion of a volume of hydrocarbons located within the subterranean
formation and form an emulsion containing the hydrocarbons and the
aqueous material carrying the surfactants. For example, the
surfaces of the hydrocarbon-containing reservoir may not be
sufficiently contacted by the surfactants, or the surfactants may
not sufficiently adhere to hydrocarbon-bearing surfaces of the
subterranean formation.
BRIEF SUMMARY
[0006] In some embodiments, a suspension for removing hydrocarbons
from a subterranean formation includes a fluid comprising at least
one of water, brine, steam, carbon dioxide, a light hydrocarbon,
and an organic solvent; and a plurality of nanoparticles dispersed
within the fluid. At least some nanoparticles of the plurality
comprise both silica and carbon.
[0007] In other embodiments, a method includes forming a plurality
of nanoparticles to comprise silica and carbon, and dispersing the
plurality of nanoparticles with a fluid to form a suspension
comprising the nanoparticles.
[0008] In certain embodiments, a method of recovering a hydrocarbon
material includes introducing a suspension into a subterranean
formation containing hydrocarbons, forming a stabilized emulsion of
the suspension and the hydrocarbons within the subterranean
formation; and removing the emulsion from the subterranean
formation. The suspension comprises a plurality of nanoparticles,
and at least some nanoparticles of the plurality comprise silica
and carbon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] While the specification concludes with claims particularly
pointing out and distinctly claiming what are regarded as
embodiments of the present disclosure, various features and
advantages of embodiments of the disclosure may be more readily
ascertained from the following description of example embodiments
of the disclosure when read in conjunction with the accompanying
drawings, in which:
[0010] FIG. 1 is a simplified side view illustrating an embodiment
of a suspension according to the present disclosure; and
[0011] FIG. 2 is a simplified schematic showing how the suspension
shown in FIG. 1 may be used for recovering hydrocarbons from
subterranean formations.
DETAILED DESCRIPTION
[0012] The following description provides specific details, such as
material types, compositions, material thicknesses, and processing
conditions in order to provide a thorough description of
embodiments of the disclosure. However, a person of ordinary skill
in the art will understand that embodiments of the disclosure may
be practiced without employing these specific details. Indeed,
embodiments of the disclosure may be practiced in conjunction with
conventional techniques employed in the industry. In addition, the
description provided below does not form a complete process flow
for recovering hydrocarbons from a hydrocarbon-bearing subterranean
formation. Only those process acts and structures necessary to
understand the embodiments of the disclosure are described in
detail below. A person of ordinary skill in the art will understand
that some process components (e.g., pipelines, line filters,
valves, temperature detectors, flow detectors, pressure detectors,
etc.) are inherently disclosed herein and that adding various
conventional process components and acts would be in accord with
the disclosure. Additional acts or materials to extract a
hydrocarbon material from a subterranean formation or from bitumen
may be performed by conventional techniques.
[0013] As used herein, the singular forms "a," "an," and "the" are
intended to include the plural forms as well, unless the context
clearly indicates otherwise.
[0014] As used herein, the term "and/or" includes any and all
combinations of one or more of the associated listed items.
[0015] As used herein, relational terms, such as "first," "second,"
"top," "bottom," "upper," "lower," "over," "under," etc., are used
for clarity and convenience in understanding the disclosure and
accompanying drawings and do not connote or depend on any specific
preference, orientation, or order, except where the context clearly
indicates otherwise.
[0016] As used herein, the term "substantially," in reference to a
given parameter, property, or condition, means to a degree that one
of ordinary skill in the art would understand that the given
parameter, property, or condition is met with a small degree of
variance, such as within acceptable manufacturing tolerances.
[0017] As used herein, the term "nanoparticle" means and includes
particles having a mean diameter of less than about 1,000 nm
(nanometers).
[0018] As used herein, the term "suspension" means and includes a
material including at least one carrier material with which a
material of a different phase is dispersed. A suspension of solid
particles in a gaseous carrier fluid may also be referred to in the
art as an aerosol or particulate. A suspension can also include a
foam, in which a liquid or solid material forms discrete or
connected pockets of a gas, or an aerosol, in which solid or liquid
particles are dispersed in a gas.
[0019] As used herein, "mean diameter" refers to the number average
particle size based on the largest linear dimension of the particle
(sometimes referred to as "diameter"), whether the particle is
spherical or not. Diameters, including average, maximum, and
minimum particle sizes, may be determined by an appropriate method
of sizing particles such as, for example, static or dynamic light
scattering (SLS or DLS) using a laser light source.
[0020] Methods of recovering hydrocarbons from a subterranean
formation using a suspension including nanoparticles of silica and
carbon are described. In particular, nanoparticles that include
carbon attached to or bonded to silica appear to have beneficial
properties in excess of the properties of either silica or carbon
alone. The suspension including such nanoparticles is introduced
into the subterranean formation and contacts the hydrocarbons
within the formation. Upon contacting the hydrocarbons, the
suspension appears to reduce an interfacial tension between an
aqueous phase and the hydrocarbon phase. For example, without being
bound by any particular theory, it appears that nanoparticles
enable a mechanism of separation based on "disjoining pressure."
That is, nanoparticles adjacent interfaces between the aqueous
phase, the hydrocarbon phase, and the surface of the formation may
tend to form a wedge-like structure and between the hydrocarbon
phase and the formation. Thus, the attraction between the
hydrocarbon phase and the formation may be decreased, and the
hydrocarbon may be more easily swept away from the formation. Such
a process is described in Paul McElfresh, et al., "Application of
Nanofluid Technology to Improve Oil Recovery in Oil and Gas Wells,"
in SPE International Oilfield Nanotechnology Conference 2012, pp.
46-51, SPE 154827. The nanoparticles stabilize an emulsion of the
hydrocarbon phase dispersed within the aqueous phase of the
suspension or an emulsion of the aqueous phase dispersed within the
hydrocarbon phase. The stabilized emulsion is transported to the
surface where the emulsion may be destabilized and the hydrocarbons
recovered therefrom.
[0021] FIG. 1 is a simplified side view illustrating a suspension
100 (within a container 101) having a plurality of nanoparticles
102a, 102b, 102c, 102d (referred to generally herein as
"nanoparticles 102") dispersed within a fluid 104. The fluid 104
may include, for example, water, brine, steam, an organic solvent,
carbon dioxide, light hydrocarbons (e.g., propane, butane, etc.),
or any combination thereof. The pH or other properties of the fluid
104 may be selected to control the distribution of the
nanoparticles 102 in the fluid 104.
[0022] At least some nanoparticles 102 may include both silica 106
and carbon 108 in the same particle. For example, nanoparticles
102a may include nanoparticles of silica 106 bonded to or attached
to nanoparticles of carbon 108. Some nanoparticles 102b may include
a mixture of silica and carbon. Other nanoparticles 102c may
include silica 106 coated or otherwise treated with carbon 108 or a
carbon-containing compound, such as graphite, graphene, graphene
oxide, carbon nanotubes, carbon nanodots (or quantum dots),
nanodiamonds (i.e., nanoparticles of carbon having sp.sup.3
hybridization), fullerenes, etc. . . . . Certain nanoparticles 102d
may include carbon 108 coated or otherwise treated with silica 106
or another silicon-containing compound. In embodiments in which the
nanoparticles 102 include carbon nanotubes, the carbon nanotubes
may be single-walled carbon nanotubes (SWCNTs), multi-walled carbon
nanotubes (MWCNTs), or combinations thereof. The carbon 108 and/or
the silica 106 may be functionalized with one or more functional
groups.
[0023] For example, surfaces of the silica 106 may be
functionalized with one or more functional groups to impart desired
physical and chemical properties to the surface of the
nanoparticles 102, such as to improve reaction with the carbon 108
or carbon-containing compound. In some embodiments, the silica 106
may be fumed silica nanoparticles, amorphous silica nanoparticles,
or any other type or morphology of silica. For example, the silica
106 may be colloidal silica made by growing mono-dispersed,
negatively charged, amorphous silica particles in water. Such
colloidal silica is sold by Nissan Chemical America Corporation, of
Houston, Tex., under the trade name SNOWTEX.RTM.. Surfaces of the
silica 106 may include hydroxyl (OH.sup.-) ions, and the silica 106
may be stabilized in a suspension by repulsion between negatively
charged particles. Functionalization of silica particles is
described in U.S. Patent Application Publication 2015/0218435,
published Aug. 6, 2015, titled "Nano-Surfactants for Enhanced
Hydrocarbon Recovery, and Methods of Forming and Using Such
Nano-Surfactants."
[0024] The carbon 108 may be deposited or attached to the silica
106 by physical or chemical bonds. For example, hydroxyl groups on
the surfaces of the silica 106 may bond with the carbon 108.
[0025] The nanoparticles 102 may be structured and formulated to
react with hydrocarbons and other carbon-containing materials
present within a subterranean formation. By way of non-limiting
example, contacting a porous, hydrocarbon-containing material with
a suspension 100 including the nanoparticles 102 may form an
emulsion at locations where the suspension 100 contacts the porous
material. The nanoparticles 102 may stabilize the emulsion during
transportation of the emulsion to the surface of the subterranean
formation.
[0026] The nanoparticles 102 may include one or more functional
groups configured and formulated to increase an interaction between
the nanoparticles 102 and at least one of the subterranean
formation, hydrocarbons within the subterranean formation, and
other nanoparticles (if any) within the suspension 100.
Functionalization of nanoparticles is described in, for example,
U.S. Patent Application Publication 2014/0187449, titled
"Functionalized Silicate Nanoparticle Composition, Removing and
Exfoliating Asphaltenes with Same," published Jul. 3, 2014, the
entire disclosure of which is hereby incorporated herein by
reference.
[0027] In some embodiments, the suspension 100 may include a
mixture of nanoparticles 102 having different properties. For
example, a mixture of nanoparticles 102 may include a portion of
nanoparticles 102 with at least one type of functional group and at
least another portion of nanoparticles 102 with at least another
type of functional group. In certain embodiments, each of the
nanoparticles 102 may include more than one type of functional
group.
[0028] In some embodiments, silica nanoparticles may be coated with
graphene or another carbon-containing material by functionalizing
outer surfaces of the silica nanoparticles with a charged species
(e.g., cationic functional groups or anionic functional groups) and
then immersing the functionalized silica nanoparticles in a
solution containing an oppositely charged species, such as a
graphene species having a charge opposite to the charged species on
the surfaces of the silica nanoparticles.
[0029] In other embodiments, at least one type of nanoparticle
(e.g., containing silica 106) may be attached to at least another
type of nanoparticle (e.g., containing carbon 108) by at least one
covalent bond. Such nanoparticles may be bonded to each other by
coupling reactions to form the nanoparticles 102.
[0030] In some embodiments, the nanoparticles 102 may exhibit a
mean diameter from about 1 nm to about 100 nm, such as from about 5
nm to about 50 nm. For example, the nanoparticles 102 may exhibit a
mean diameter of about 40 nm. The nanoparticles 102 may have any
selected particle-size distribution (i.e., any selected
distribution of particle diameters). For example, the nanoparticles
102 may be monomodal (i.e., having diameters clustered around a
single mode), bi-modal, etc.
[0031] The nanoparticles 102 may be hydrophilic or may contain a
hydrophilic material. For example, if the nanoparticles 102 have
one or more functional groups attached thereto, a functional group
may be selected to make the nanoparticles 102 more hydrophilic.
[0032] In addition to the nanoparticles 102, the suspension 100 may
include at least one additive. By way of non-limiting example, the
additive may be at least one of a surfactant, a catalyst, a
dispersant, a scale inhibitor, a scale dissolver, a defoamer, a
biocide, or another additive used in the well-service industry. The
suspension 100 may be substantially homogeneous (e.g., the
nanoparticles 102 and the additive, if present, may be uniformly
dispersed throughout the suspension 100), or may be heterogeneous
(e.g., the nanoparticles 102 and the additive, if present, may be
non-uniformly dispersed throughout the suspension 100).
[0033] The suspension 100 may be formed by dispersing the
nanoparticles 102 in the fluid. In some embodiments, the
nanoparticles 102 may be formed by mixing solid carbon 108 with
nanoparticles comprising silica 106 in a liquid medium, then
evaporating the liquid. As the liquid evaporates, the nanoparticles
102 may form from the silica 106 and carbon 108. At least some of
the nanoparticles 102 may include both silica 106 and carbon 106.
The solid carbon 108 and the silica 106 may be mixed in an acidic
or basic medium. For example, a basic medium may promote dispersion
of particles due to interactions between hydroxyl groups of the
solid with hydroxyl groups of the liquid. As the liquid evaporates,
the carbon 108 may become bonded to the silica 106. In some
embodiments, the carbon 108 and/or the silica 106 may be in the
form of nanoparticles, and the nanoparticles may bond to one
another during evaporation of the liquid to form the nanoparticles
102.
[0034] The nanoparticles 102 may then be dispersed in any
appropriate fluid 104, such as those fluids conventionally used for
enhanced oil recovery (EOR) processes. For example, the
nanoparticles 102 may be dispersed in water, brine, steam, carbon
dioxide, a light hydrocarbon, (e.g., propane, butane, etc.) an
organic solvent (e.g., methanol, ethanol, propanol, hexane,
heptane, toluene, benzene, etc.), or any combination thereof.
[0035] In some embodiments, the nanoparticles 102 may be formed by
chemical reaction. For example, reaction of functionalized carbon
108 with hydroxyl groups of silica 108 may form nanoparticles 102
having covalent bonds. Functionalization of carbon 108 may be
either hydrophilic or hydrophobic.
[0036] The nanoparticles 102 may be formulated to be compatible
with other components (e.g., materials, constituents, etc.) of the
suspension 100. As used herein, the term "compatible" means that a
material does not impair the functionality of another material used
in conjunction therewith.
[0037] The suspension 100 may be formulated to include a
concentration of the nanoparticles 102 ranging from about 10 ppm to
about 10,000 ppm. For example, the suspension 100 may have a
concentration of the nanoparticles 102 ranging from about 10 ppm to
about 100 ppm, from about 100 ppm to about 500 ppm, from about 500
ppm to about 1,000 ppm, from about 1,000 ppm to about 2,000 ppm,
from about 2,000 ppm to about 5,000 ppm, or from about 5,000 ppm to
about 10,000 ppm.
[0038] The suspension 100 may be introduced into a subterranean
formation to detach a hydrocarbon material from surfaces of the
subterranean formation and form a stabilized emulsion containing
the hydrocarbon material. The suspension 100 may be provided into
the subterranean formation through conventional processes. For
example, pressurized steam may be pumped into an injection well
extending to a desired depth in the subterranean formation, and may
infiltrate (e.g., permeate, diffuse, etc.) into interstitial spaces
of the subterranean formation. The extent to which the suspension
100 infiltrates the interstitial spaces of the subterranean
formation at least partially depends on the properties of the
suspension 100 (e.g., density, viscosity, material composition
(e.g., properties of the nanoparticles 102), etc.), and the
hydrocarbon materials (e.g., molecular weight, density, viscosity,
etc.) contained within interstitial spaces of the subterranean
formation, as well as on the nature of the hydrocarbons within the
formation and formation porosity.
[0039] The nanoparticles 102 may be structured and formulated to
facilitate formation of a stabilized emulsion containing a
hydrocarbon material. For example, the nanoparticles 102 may be
structured and formulated to gather (e.g., agglomerate) at, adhere
to, and/or absorb to interfaces of a hydrocarbon material and an
aqueous material (e.g., the fluid 104 or another fluid) to form an
emulsion comprising units (e.g., droplets) of one of the
hydrocarbon material and the aqueous material dispersed in the
other of the hydrocarbon material and the aqueous material. The
nanoparticles 102 may prevent the dispersed material (e.g., the
hydrocarbon material or the aqueous material) from coalescing, and
may thus maintain the dispersed material as units throughout the
other material.
[0040] The emulsion including the nanoparticles and hydrocarbons
may include the same, a higher, or a lower concentration of the
nanoparticles than the suspension 100. Furthermore, in some
embodiments, the suspension 100 may be diluted or otherwise mixed
with another fluid before injection into a well.
[0041] Due to the particle-size distribution of the nanoparticles
102, the suspension 100 may be particularly useful for contacting
hydrocarbons disposed within pores defined by the subterranean
formation, particularly within nanopores (i.e., pores having a
maximum opening of about 1 micron or less). That is, the
nanoparticles 102 and the fluid 104 may penetrate into pores and
voids in the formation, and may promote separation of hydrocarbons
from such pores and voids. Without being bound to any particular
theory, it appears that the relatively large specific surface area
of nanoparticles 102, the ability of the nanoparticles 102 to
travel into small volumes, and the possibility of better
interaction with the oil in pore bodies and on pore surfaces
improve the effectiveness of oil recovery from porous
formations.
[0042] The surface-to-volume ratio is higher for smaller particles
than for larger particles. Thus, results based on surface
interactions can be achieved at relatively lower solids
concentrations when the solids are provided as nanoparticles 102.
This may assist in keeping the materials and process costs low.
[0043] The silica 106 may help to "peel off" crude oil or other
hydrocarbon-based material deposited on rock surfaces. A theory of
"disjoining pressure," which appears to at least partially
characterize this effect is described in, for example, U.S. Patent
Application Publication 2010/0096139, titled "Method for
Intervention Operations in Subsurface Hydrocarbon Formations,"
published Apr. 22, 2010, the entire disclosure of which is hereby
incorporated herein by reference. The carbon 108 may help exfoliate
bitumen and improve flow through throats of the pores.
Stabilization of emulsion droplets by the nanoparticles 102 appears
to depend upon the particle-particle interactions. Thus, the
combination of the carbon 108 and the silica 106 may simultaneously
improve oil removal from rock surfaces and exfoliation.
[0044] In some embodiments, the nanoparticles 102 may include both
hydrophobic and hydrophilic domains. The hydrophilic domain may
improve dispersion in water and improve compatibility with
water-based fluids. The hydrophobic domain may trap organic
compounds and stabilize the organic compounds, allowing the organic
compounds to be removed from the formation.
[0045] The process of extracting hydrocarbons from subsurface
formations may include flowing (e.g., driving, sweeping, forcing,
etc.) the stabilized emulsion from the subterranean formation to
the surface. The nanoparticles 102 prevent the dispersed material
from coalescing and enable substantial removal of hydrocarbons from
the subterranean formation.
[0046] FIG. 2 is a simplified schematic showing how the suspension
100 shown in FIG. 1 may be used for recovering hydrocarbons from
subterranean formations. A first well 202 may traverse subterranean
formations 204 and 206, and may have openings at a formation 208.
Portions 212 of the formation 208 may be optionally fractured
and/or perforated. A second well 216 may traverse the subterranean
formations 204 and 206, and may have openings at the formation 208.
Portions 218 of the formation 406 may be optionally fractured
and/or perforated.
[0047] The suspension 100 (FIG. 1) may be introduced into the
formation 208. A stabilized emulsion of the suspension 100 and
hydrocarbons within the formation 208 may form, and may be removed
from the formation 208 through the portions 218 thereof. The
emulsion may travel up the second well 216 to a production facility
220. The production facility 220 at the surface may include pumps,
filters, storage tanks, and other equipment for recovering
hydrocarbons. The production facility 220 may separate the
recovered hydrocarbons from at least a portion of the suspension
100. For example, gases may be stored in a first tank 222, liquid
hydrocarbons may be stored in a second tank 224, and the portion of
the suspension 100 may be stored in a third tank 226. The
suspension 100 may be reintroduced to the formation 208 through the
first well 202.
[0048] Once the hydrocarbons are removed from the subterranean
formation, at least a portion of the emulsion may be destabilized
to form distinct, immiscible phases including an aqueous phase and
a hydrocarbon phase. One or more properties (e.g., temperature, pH,
material composition, pressure, etc.) of the stabilized emulsion or
the aqueous phase may be modified (e.g., altered, changed) to at
least partially destabilize the emulsion. For example, the pH of
the aqueous phase may be modified to increase the solubility of the
nanoparticles 102 within the aqueous phase and destabilize the
emulsion, forming distinct, immiscible phases. In some embodiments,
the aqueous phase may be separated from the hydrocarbon phase by
decreasing a pH of the emulsion. The pH of the emulsion may be
decreased by adding hydrochloric acid, phosphoric acid, acetic
acid, another acid, or combinations thereof to the emulsion.
[0049] A demulsifier may be added to the emulsion to destabilize
the emulsion and form distinct, immiscible phases including an
aqueous phase and the hydrocarbon phase. In some embodiments, the
emulsion is destabilized by adjusting the pH of at least one of the
aqueous phase and the emulsion and by adding a demulsifier to the
emulsion. In some embodiments, at least a portion of the
nanoparticles 102 may be recovered and recycled for use in
subsequent operations.
EXAMPLES
Example 1: Oil Recovery from Canadian Oil Sand from Athabasca
[0050] Commercially available silica nanoparticle dispersions were
obtained from Nissan Chemical America Corporation, of Houston, Tex.
The silica nanoparticles had a mean particle diameter from about 5
nm to about 40 nm, and the particles were dispersed in water
(product numbers for each sample are shown in Table 1, below). The
silica nanoparticles were coated with carbon quantum dots by mixing
carbon particles into the dispersions. The liquid phase was then
evaporated, leaving particles of silica and carbon.
[0051] The particles were redispersed in deionized water and mixed
with Canadian oil sands in glass vials. The vials were heated to
approximately 80.degree. C. for 10 days, and the color of the
liquid phase was observed (with darker color corresponding to more
oil removed from the sand). The liquid phase was then removed and
the sand was dried and analyzed with an optical microscope (with
lighter sand color corresponding to more oil removed from the
sand). The sand was analyzed by thermogravimetric analysis (TGA) to
determine differences in materials that decompose at elevated
temperatures. Table 1 shows the results of the tests, with oil
recovery determined by the change in color of the liquid phase, the
change in color of the dried sand, and the TGA curves.
TABLE-US-00001 TABLE 1 Nissan Mean particle Chemical America
diameter of silica Sample # product number (before adding carbon)
Oil recovery Water n/a n/a No 1 250624 5 nm Yes 2 210818 8 nm Yes 3
240707 40 nm Yes 4 131204 12 nm Yes 5 LB130410 50 nm Yes
Example 2: Oil Dispersion
[0052] A commercially available silica nanoparticle dispersion was
obtained from Nissan Chemical America Corporation, of Houston, Tex.
(240707). The silica nanoparticles had a mean particle diameter of
about 40 nm, and the particles were dispersed in water. One portion
of the silica nanoparticles was coated with carbon quantum dots by
mixing carbon particles into the dispersions. The liquid phase was
then evaporated, leaving particles of silica and carbon. The
particles were redispersed in deionized water. Another portion of
the silica particles was used without the carbon modification.
[0053] Both portions were mixed with oil in glass vials. The vials
were heated to approximately 60.degree. C., and the color and
consistency of the liquid phases were observed (with darker color
corresponding to more oil in a phase). Table 2 shows the results of
the tests, with oil dispersion determined by the change in color of
the liquid phases and the separation of the phases.
TABLE-US-00002 TABLE 2 Sample Composition # of particles Oil
dispersion Water n/a No-water phase remained almost entirely clear
while oil phase was dark 6 Silica only Some-two phases were present
and water phase was lighter than oil phase (but appreciably darker
than the control sample) 7 Silica and Yes-the oil and water
appeared to form a single carbon liquid phase
[0054] Additional non limiting example embodiments of the
disclosure are described below.
Embodiment 1
[0055] A suspension for removing hydrocarbons from a subterranean
formation, comprising a fluid comprising at least one of water,
brine, steam, carbon dioxide, a light hydrocarbon, and an organic
solvent; and a plurality of nanoparticles dispersed with the fluid.
At least some nanoparticles of the plurality comprise both silica
and carbon.
Embodiment 2
[0056] The suspension of Embodiment 1, wherein the at least some
nanoparticles of the plurality comprise a silica nanoparticle
attached to at least one material selected from the group
consisting of carbon nanodots, graphene, graphene oxide, carbon
nanotubes, and functionalized carbon nanotubes.
Embodiment 3
[0057] The suspension of Embodiment 1 or Embodiment 2, wherein the
at least some nanoparticles of the plurality of nanoparticles
exhibit a mean diameter from about 5 nm to about 50 nm.
Embodiment 4
[0058] The suspension of any of Embodiments 1 through 3, wherein
the at least some nanoparticles of the plurality are
hydrophilic.
Embodiment 5
[0059] The suspension of any of Embodiments 1 through 4, wherein
the at least some nanoparticles of the plurality comprise silica
and carbon bonded by hydroxyl groups.
Embodiment 6
[0060] The suspension of any of Embodiments 1 through 5, further
comprising a surfactant.
Embodiment 7
[0061] A method comprising forming a plurality of nanoparticles to
comprise silica and carbon, and dispersing the plurality of
nanoparticles with a fluid to form a suspension comprising the
nanoparticles.
Embodiment 8
[0062] The method of Embodiment 7, further comprising introducing
the suspension into a subterranean formation and contacting
hydrocarbons within the subterranean formation with the suspension
to form an emulsion comprising the nanoparticles, an aqueous phase,
and a hydrocarbon phase dispersed within the aqueous phase.
Embodiment 9
[0063] The method of Embodiment 8, wherein contacting the
subterranean formation with the suspension comprises contacting
hydrocarbons within nanopores of the subterranean formation.
Embodiment 10
[0064] The method of Embodiment 8 or Embodiment 9, further
comprising transporting the emulsion to a surface of the
subterranean formation and separating hydrocarbons from the
emulsion.
Embodiment 11
[0065] The method of any of Embodiments 7 through 10, wherein
forming a plurality of nanoparticles comprises forming
nanoparticles comprising silica and at least one material selected
from the group consisting of carbon nanodots, graphene, graphene
oxide, carbon nanotubes, and functionalized carbon nanotubes.
Embodiment 12
[0066] The method of any of Embodiments 7 through 11, wherein
forming a plurality of nanoparticles comprises reacting carbon with
nanoparticles comprising silica.
Embodiment 13
[0067] The method of Embodiment 12, wherein reacting carbon with
nanoparticles comprising silica comprises reacting carbon with
nanoparticles comprising silica in a liquid medium and evaporating
the liquid.
Embodiment 14
[0068] The method of Embodiment 13, wherein reacting carbon with
nanoparticles comprising silica in a liquid medium comprises
reacting carbon with nanoparticles comprising silica in a basic
medium.
Embodiment 15
[0069] The method of any of Embodiments 7 through 14, wherein
forming a plurality of nanoparticles comprises bonding carbon to
silica.
Embodiment 16
[0070] The method of Embodiment 15, wherein bonding carbon to
silica comprises bonding nanoparticles comprising carbon to
nanoparticles comprising silica.
Embodiment 17
[0071] A method of recovering a hydrocarbon material, the method
comprising introducing a suspension into a subterranean formation
containing hydrocarbons, forming a stabilized emulsion of the
suspension and the hydrocarbons within the subterranean formation;
and removing the emulsion from the subterranean formation. The
suspension comprises a plurality of nanoparticles, and at least
some nanoparticles of the plurality comprise silica and carbon.
Embodiment 18
[0072] The method of Embodiment 17, wherein introducing a
suspension into a subterranean formation comprises introducing the
at least some nanoparticles comprising silica and at least one
material selected from the group consisting of carbon nanodots,
graphene, graphene oxide, carbon nanotubes, and funcationalized
carbon nanotubes.
Embodiment 19
[0073] The method of Embodiment 17 or Embodiment 18, wherein
introducing a suspension into a subterranean formation comprises
introducing the at least some nanoparticles having a mean diameter
from about 5 nm to about 50 nm.
Embodiment 20
[0074] The method of any of Embodiments 17 through 19, further
comprising introducing the at least some nanoparticles into voids
defined by the subterranean formation.
[0075] While the present disclosure has been described herein with
respect to certain illustrated embodiments, those of ordinary skill
in the art will recognize and appreciate that it is not so limited.
Rather, many additions, deletions, and modifications to the
illustrated embodiments may be made without departing from the
scope of the invention as hereinafter claimed, including legal
equivalents thereof. In addition, features from one embodiment may
be combined with features of another embodiment while still being
encompassed within the scope of the disclosure as contemplated by
the inventors. Further, embodiments of the disclosure have utility
with different and various particle types and formulations.
* * * * *