U.S. patent application number 12/181468 was filed with the patent office on 2010-02-04 for in-situ refraction apparatus and method.
This patent application is currently assigned to Baker Hughes Incorporated. Invention is credited to Ansgar Cartellieri, Peter Schaefer, Stefan Sroka.
Application Number | 20100025112 12/181468 |
Document ID | / |
Family ID | 41607176 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100025112 |
Kind Code |
A1 |
Sroka; Stefan ; et
al. |
February 4, 2010 |
IN-SITU REFRACTION APPARATUS AND METHOD
Abstract
An apparatus and method for estimating a fluid property downhole
includes an electromagnetic energy emitter, a window having an
input interface that receives electromagnetic energy emitted from
the electromagnetic energy emitter and converges the
electromagnetic energy entering the window, a fluid interface and
an output interface. A detector detects electromagnetic energy
exiting the window from the output interface.
Inventors: |
Sroka; Stefan;
(Adelheidsdorf, DE) ; Cartellieri; Ansgar;
(Lueneburg, DE) ; Schaefer; Peter; (Grob Kreutz,
DE) |
Correspondence
Address: |
CANTOR COLBURN LLP- BAKER HUGHES INCORPORATED
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
Baker Hughes Incorporated
|
Family ID: |
41607176 |
Appl. No.: |
12/181468 |
Filed: |
July 29, 2008 |
Current U.S.
Class: |
175/49 ;
175/59 |
Current CPC
Class: |
G01N 21/43 20130101;
E21B 47/113 20200501 |
Class at
Publication: |
175/49 ;
175/59 |
International
Class: |
E21B 7/00 20060101
E21B007/00; E21B 49/00 20060101 E21B049/00 |
Claims
1. An apparatus for estimating a fluid property downhole
comprising: an electromagnetic energy emitter; a window having an
input interface that receives electromagnetic energy emitted from
the electromagnetic energy emitter and converges the
electromagnetic energy entering the window, a fluid interface and
an output interface; and a detector that detects electromagnetic
energy exiting the window from the output interface.
2. An apparatus according to claim 1, wherein the electromagnetic
energy emitter emits non-collimated electromagnetic energy.
3. An apparatus according to claim 1, wherein the electromagnetic
energy emitter includes one or more LED emitters.
4. An apparatus according to claim 1, wherein the window comprises
cone-shaped or conical frustum window.
5. An apparatus according to claim 1, wherein the window and at
least one of the input interface, fluid interface and the output
interface comprise a monolithic structure.
6. An apparatus according to claim 1, wherein the window and at
least one of the input interface and the output interface comprise
discrete members.
7. An apparatus according to claim 1, wherein the window comprises
a sapphire material.
8. An apparatus according to claim 1, wherein the window provides a
high-pressure barrier for evaluating a high pressure downhole
fluid.
9. An apparatus according to claim 1, wherein at least one of the
input interface and the output interface includes a convex surface
portion.
10. An apparatus according to claim 1, further comprising a
reflective material disposed on a surface of the window.
11. An apparatus according to claim 10, wherein the reflective
material includes aluminum, silver, gold, copper, chromium, or
combinations thereof.
12. An apparatus according to claim 1, wherein the detector
comprises a detector array.
13. An apparatus according to claim 12, wherein the detector array
comprises a plurality of photodetectors.
14. An apparatus according to claim 12, wherein the detector array
comprises a CMOS.
15. An apparatus according to claim 1 further comprising a
controller that receives one or more signals from the detector.
16. An apparatus according to claim 15, wherein the controller
includes a processor that processing the received signals according
to programmed instructions to estimate the refractive index of a
fluid.
17. An apparatus according to claim 16, wherein the estimated
refractive index is in a range of about 1.25 nD to about 1.65
nD.
18. A method for estimating a fluid property downhole comprising:
emitting electromagnetic from an electromagnetic energy emitter;
receiving the emitted electromagnetic energy at a window having an
input interface that converges the electromagnetic energy entering
the window, the electromagnetic energy being transmitted to a fluid
interface, wherein at least a portion of the electromagnetic energy
is transmitted to an output interface; detecting electromagnetic
energy exiting the window from the output interface using a
detector; and estimating the fluid property at least in part by
using the detected electromagnetic energy.
19. A method according to claim 18, wherein emitting
electromagnetic from an electromagnetic energy emitter includes
emitting non-collimated electromagnetic energy.
20. A method according to claim 18, wherein detecting
electromagnetic energy includes using a CMOS detector array.
21. A method according to claim 18, wherein estimating the fluid
property includes estimating a refractive index that is in a range
of about 1.25 nD to about 1.65 nD.
22. A method according to claim 18 further comprising using the
window at least in part as a pressure barrier for high pressure
downhole fluids.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure generally relates to well bore tools
and in particular to apparatus and methods for downhole fluid
evaluations.
[0003] 2. Background Information
[0004] Oil and gas wells have been drilled at depths ranging from a
few thousand feet to as deep as five miles. A large portion of the
current drilling activity involves directional drilling that
includes drilling boreholes deviated from vertical by a few degrees
to horizontal boreholes to increase the hydrocarbon production from
earth formations. Various downhole tools have been developed to
obtain information regarding the drilling system and the formations
surrounding the borehole.
[0005] Information about the subterranean formations traversed by
the borehole may be obtained by any number of techniques.
Techniques used to obtain formation information include obtaining
one or more core samples of the subterranean formations and
obtaining fluid samples produced from the subterranean formations.
These samplings are collectively referred to herein as formation
sampling. Core samples are often retrieved from the borehole and
tested in a rig-site or remote laboratory to determine properties
of the core sample, which properties are used to estimate formation
properties. Modem fluid sampling includes various downhole tests
and sometimes fluid samples are retrieved for surface laboratory
testing.
[0006] It is often desirable to evaluate fluids in the downhole
environment to estimate various characteristics and properties of
the fluids. Downhole evaluations where the fluid under
investigation remains substantially at downhole conditions increase
efficiency of the operation by reducing or eliminating the need to
remove the evaluation tool from the borehole and provide better
estimates by maintaining the fluid at substantially downhole
conditions.
SUMMARY
[0007] The following presents a general summary of several aspects
of the disclosure in order to provide a basic understanding of at
least some aspects of the disclosure. This summary is not an
extensive overview of the disclosure. It is not intended to
identify key or critical elements of the disclosure or to delineate
the scope of the claims. The following summary merely presents some
concepts of the disclosure in a general form as a prelude to the
more detailed description that follows.
[0008] Disclosed is an apparatus for estimating a fluid property
downhole. The apparatus may include an electromagnetic energy
emitter, a window having an input interface that receives
electromagnetic energy emitted from the electromagnetic energy
emitter and converges the electromagnetic energy entering the
window, a fluid interface and an output interface. A detector
detects electromagnetic energy exiting the window from the output
interface.
[0009] A method for estimating a fluid property downhole includes
emitting electromagnetic from an electromagnetic energy emitter and
receiving the emitted electromagnetic energy at a window having an
input interface that converges the electromagnetic energy entering
the window, the electromagnetic energy being transmitted to a fluid
interface, wherein at least a portion of the electromagnetic energy
is transmitted to an output interface. The method may further
include detecting electromagnetic energy exiting the window from
the output interface using a detector, and estimating the fluid
property at least in part by using the detected electromagnetic
energy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a detailed understanding of the present disclosure,
reference should be made to the following detailed description of
the several non-limiting embodiments, taken in conjunction with the
accompanying drawings, in which like elements have been given like
numerals and wherein:
[0011] FIG. 1 illustrates a non-limiting example of a downhole
refractometer according to one or more embodiments of the
disclosure;
[0012] FIGS. 2A and 2B illustrate an example of a sensor array that
may be used with several embodiments of the disclosure;
[0013] FIG. 3 shows an example of a light intensity transition
curve;
[0014] FIG. 4 illustrates a non-limiting example of a downhole
refractometer according to one or more embodiments of the
disclosure; and
[0015] FIG. 5 is an elevation view of a well drilling system
conveying a downhole tool according to one or more non-limiting
examples of the disclosure.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0016] FIG. 1 illustrates a non-limiting example of a downhole
refractometer 100 according to one or more embodiments of the
disclosure. The refractometer 100 shown in this example may include
an electromagnetic energy emitter 102 and a window 104 having an
input interface 106 that converges light entering the window 104
from the electromagnetic energy emitter 102. The window 104 may
include a fluid interface 108 and an output interface 110. A
detector array 112 may be disposed in cooperation with the output
interface 110, so that the detector array 112 can detect
electromagnetic energy exiting the window 104 from the output
interface 110.
[0017] The electromagnetic energy emitter 102 may include any
suitable source of electromagnetic energy. For example, the
electromagnetic energy emitter 102 may include a broadband source,
a narrow band source, a tunable source or a combination thereof. In
one or more embodiments, the electromagnetic energy emitter 102 may
include a light-emitting diode (LED). In one or more embodiments,
the electromagnetic energy emitter 102 emits non-collimated energy
in the form of light. The emitted electromagnetic energy may
include infrared (IR), near IR, visible light, ultraviolet (UV) or
electromagnetic energy that includes two or more spectra. The
electromagnetic energy emitter 102 may emit electromagnetic energy
of a selected wavelength or band of wavelengths as desired toward
the window 104.
[0018] The window 104 may be in communication with a fluid 114 via
the fluid interface 108. In one or more embodiments, the fluid 114
may have a high pressure associated therewith. For example, the
fluid 114 may have a pressure that is substantially higher than a
pressure on an opposing side of the window 104. The pressure of the
fluid 114 may be substantially the downhole environment pressure as
in the borehole pressure or formation pressure. The window may
include one or more angled outer walls 116, and the angle of the
outer wall may be selected based in part on a selected design
limit, on an expected fluid pressure maximum, on a critical optical
angle, or on a combination thereof. In one or more embodiments, the
window may be substantially cone-shaped as shown in FIG. 1. In one
or more embodiments, the window may include conical frustum shape.
In one or more embodiments, the window 104 may be operable as a
pressure barrier between the fluid 114 and the several internal
elements of the refractometer 100.
[0019] The input interface 106 may include a lens 118 that alters
the beam spread of the electromagnetic energy emanating from the
emitter 102. The lens may be a separate component as shown here or
may be included as a portion of the window 104. The window 104 may
further include one or more internal reflectors 120 that may
provide total internal reflections for wavelengths exceeding the
reflector critical angle.
[0020] The window 104 may be constructed using any suitable
material that may be substantially transparent to selected
electromagnetic energy wavelengths. The window material may further
provide internal reflection and refraction properties, and
combinations thereof. In one non-limiting example, the window may
be constructed using a sapphire material.
[0021] The detector array 112 may be selected based in part on the
electromagnetic energy source used. In one or more embodiments, the
detector array 112 may include an array of photodetectors. In one
or more embodiments, the detector array 112 may include a
complementary metal oxide semiconductor (CMOS).
[0022] Referring now to FIGS. 1-3, non-limiting operational
examples will be explained. The refractometer 100 of the present
disclosure may be operated at high pressures in combination with a
broad measuring range of the refraction index (nD) from 1.25 to
1.65 nD. This broad measurement range may be used to determine the
refraction index for crude oil with low API gravities and high nD
values (refraction index up to 1.65) as well as for gaseous
substances with low nD values (refraction index less than 1.3).
[0023] The refractometer 100 may be used to determine the
refractive index of fluids present in a downhole environment. A
non-collimated light may be transmitted through the window material
to the fluid interface 108. The energy may pass through the fluid
interface 108 and through the fluid 120. The energy may also be
refracted and/or reflected as shown in FIG. 1. The angle at which
the energy changes from refraction to reflection is dependent on
the ratio of the refractive indices of the window material and the
fluid. The detector array 112 receives the reflected energy passing
through the output interface 116 and detects the transition from
refraction to reflection as shown in FIGS. 2 and 3. In these
examples, higher reflection intensity results in more sensor
elements being illuminated as shown in FIG. 2. FIG. 3 illustrates
that a transition zone indicating refraction is between a
substantially constant low intensity zone and a substantially
constant high intensity zone. The constant level low intensity zone
indicates that energy is being transmitted through the fluid
interface. The constant level high intensity zone indicates that
energy is being totally reflected off the fluid interface. The
refractive index of the window is known and the fluid refractive
index may be estimated using the energy intensity detected at the
detector array, the angle of the received energy and the ratio
relationship. The angle may be determined by the known geometric
construction of the window and by the position and number of array
elements 122 illuminated by the received energy.
[0024] Turning now to FIG. 4, a schematic diagram illustrates a
downhole refractometer 400 that may be used for analyzing a fluid
in the downhole environment. The refractometer 400 includes an
electromagnetic energy emitter 402 and a window 404 that may be
positioned to interface with a fluid 414 and a sensor array 412
having two or more sensor elements 422. The refractometer 400
further includes a controller 424 and a transceiver 426. The
controller 424 may further include a processor 428, a memory 430
and programs 432.
[0025] The electromagnetic energy emitter 402 may include any
suitable source of electromagnetic energy. For example, the
electromagnetic energy emitter 402 may include a broadband source,
a narrow band source, a tunable source or a combination thereof. In
one or more embodiments, the electromagnetic energy emitter 402 may
include an LED. In one or more embodiments, the electromagnetic
energy emitter 402 emits non-collimated energy in the form of
light. The emitted electromagnetic energy may include infrared
(IR), near IR, visible light, ultraviolet (UV) or electromagnetic
energy that includes two or more spectra. The electromagnetic
energy emitter 402 may emit electromagnetic energy of a selected
wavelength or band of wavelengths as desired toward the window 404.
The electromagnetic energy emitter 402 of this example may be a
single emitter or an array of emitters producing energy within a
relatively narrow wavelength band of non-collimated electromagnetic
energy.
[0026] In one or more non-limiting embodiments, the window 404 may
include an input interface 406, a fluid interface 408 and an output
interface 410. The window 404 and at least one of the input
interface 406, fluid interface 408 and the output interface 410 may
be manufactured as a monolithic structure as shown in FIG. 4. In
one or more embodiments, the window 404 and the input interface 406
may be discrete members and the output interface 401 may be a
discrete member. The window 404 may further include one or more
angled walls 416 and internal reflectors 420. In one or more
embodiments, the input interface 406 may include one or more lenses
418, 434 for altering the beam spread of the electromagnetic energy
at the input interface 406. In one or more embodiments, the input
interface lens 418 may include a convex surface portion for
converging electromagnetic energy passing through the lens 418. In
one non-limiting example, the input interface may include a
collimating lens 434 and a focusing lens 418 and the output
interface 410 may include a collimating lens 436. In one or more
embodiments, the output interface 410 may include a convex surface
portion.
[0027] In one or more embodiments, the detector array 412 may be
substantially similar to the detector array 112 described above and
shown in FIG. 1. The detector array 412 may be selected based in
part on the electromagnetic energy source used. In one or more
embodiments, the detector array 412 may include an array of
photodetectors. In one or more embodiments, the detector array 412
may include a CMOS.
[0028] The controller 424 may include any suitable processor 428
and memory 430 for operations downhole. In one or more embodiments,
the controller may be housed within a cooling device and/or have
active cooling.
[0029] In operation, the refractometer 400 emits electromagnetic
energy toward a fluid 414 through the window 404 housed in a wall
of a fluid chamber 438. The electromagnetic energy converges within
the window and reflects off one or more of the internal reflectors
420. In one or more embodiments, a reflective material 440 may be
disposed on a surface of the window to provide total reflections at
the window wall. The reflective materials may be applied by coating
or other suitable process. In one or more embodiments, the
reflective material 440 may include aluminum, silver, gold, copper,
or chromium. Any combination of these or other reflective materials
are within the scope of the disclosure.
[0030] The electromagnetic energy then interacts with the fluid
interface at a plurality of angles. Depending on the angle of
incidence with the plane of the fluid interface, the non-collimated
electromagnetic energy will pass directly through fluid interface
and the fluid and/or reflect or refract. Energy with incident
angles less than the critical angle will refract and energy with
incident angles greater than the critical angle will reflect. The
reflected electromagnetic energy may further reflect off the
internal reflectors 420 and reflective material 440 to exit the
window at the output interface toward the detector array 412.
[0031] The detector array 412 produces a signal responsive to the
received energy, which signal is received by the controller 424 for
analysis. The controller 424 may further be used to control the
electromagnetic energy source 402. The controller 424 may be
located downhole with the refractometer 400 or at a surface
location as discussed below and shown in FIG. 5. In one or more
embodiments, the several component parts of the controller, such as
the processor, memory and programs may be disposed partly downhole
and partly at a surface location or at other locations along a
drill string, wireline or other carrier.
[0032] The controller 424 receives and processes the signals
received from the detector array 412 using the processor 428 and
programs 432. In one aspect, the controller 424 may analyze or
estimate the detected energy and transmit processed information to
a surface controller using the transceiver 426. In one aspect, the
controller 424 may analyze or estimate one or more properties or
characteristics of the fluid downhole and transmit the results of
the estimation to a surface controller using the transceiver 426.
In another aspect, the controller 424 may process the signals
received from the detector array 412 to an extent and telemeter the
processed information to a surface controller for producing a
spectrum and for providing an in-situ estimate of a property of the
fluid, including the contamination levels of the fluid. In one or
more embodiments, control of the downhole refractometer may be
conducted using the programmed instructions, or simply programs
432. Information obtained and information processed downhole may be
stored in the controller memory 430 and retrieved when the
refractometer is removed from the borehole.
[0033] Any of the several refractometer embodiments of the present
disclosure may be conveyed in a well borehole on any number of
carrier types. For example, the refractometer may be incorporated
into a downhole tool and carried on a wireline sonde. In other
embodiments, the refractometer may be carried on a drill string in
a logging-while-drilling (LWD) arrangement, which may also be
considered as a measurement-while-drilling arrangement (MWD) for
the purposes of the present disclosure. For brevity, the discussion
below will describe a while drilling arrangement without limiting
the scope of disclosure.
[0034] FIG. 5 schematically illustrates a non-limiting example of a
drilling system 500 in a measurement-while-drilling ("MWD")
arrangement according to several non-limiting embodiments of the
disclosure. A derrick 502 supports a drill string 504, which may be
a coiled tube or drill pipe. The drill string 504 may carry a
bottom hole assembly ("BHA") referred to as a downhole sub 506 and
a drill bit 508 at a distal end of the drill string 504 for
drilling a borehole 510 through earth formations.
[0035] The exemplary drill string 504 operates as a carrier, but
any carrier is considered within the scope of the disclosure. The
term "carrier" as used herein means any device, device component,
combination of devices, media and/or member that may be used to
convey, house, support or otherwise facilitate the use of another
device, device component, combination of devices, media and/or
member. Exemplary non-limiting carriers include drill strings of
the coiled tube type, of the jointed pipe type and any combination
or portion thereof. Other carrier examples include casing pipes,
wirelines, wireline sondes, slickline sondes, drop shots, downhole
subs, BHA'S, drill string inserts, modules, internal housings and
substrate portions thereof.
[0036] Drilling operations according to several embodiments may
include pumping drilling fluid or "mud" from a mud pit 512, and
using a circulation system 514, circulating the mud through an
inner bore of the drill string 504. The mud exits the drill string
504 at the drill bit 508 and returns to the surface through an
annular space between the drill string 504 and inner wall of the
borehole 510. The drilling fluid is designed to provide a
hydrostatic pressure that is greater than the formation pressure to
avoid blowouts. The pressurized drilling fluid may further be used
to drive a drilling motor 516 and may be used to provide
lubrication to various elements of the drill string 504.
[0037] In the non-limiting embodiment of FIG. 5, the downhole sub
506 includes a formation evaluation tool 518. In one or more
embodiments, the formation evaluation tool 518 may be adapted to
carry any of the several refractometer embodiments described
herein. The formation evaluation tool 518 may include an assembly
of several tool segments that are joined end-to-end by threaded
sleeves or mutual compression unions 520. An assembly of tool
segments suitable for the present disclosure may include a power
unit 522 that may include one or more of a hydraulic power unit, an
electrical power unit and an electromechanical power unit. In the
example shown, a formation sample tool 524 may be coupled to the
formation evaluation tool 518 below the power unit 522.
[0038] The exemplary formation sample tool 524 shown comprises an
extendable probe 526 that may be opposed by bore wall feet 528. The
extendable probe 526, the opposing feet 528, or both may be
hydraulically and/or electro-mechanically extendable to firmly
engage the well borehole wall. The formation sample tool 524 may be
configured for extracting a formation core sample, a formation
fluid sample, formation images, nuclear information,
electromagnetic information, and/or downhole information, such as
pressure, temperature, location, movement, and other information.
In several non-limiting embodiments, other formation sample tools
not shown may be included in addition to the formation sample tool
524 without departing from the scope of the disclosure.
[0039] Continuing now with FIG. 5, several non-limiting embodiments
may be configured with the formation sample tool 524 operable as a
downhole fluid sampling tool. In these embodiments, a large
displacement volume motor/pump unit 530 may be provided below the
formation sample tool 524 for line purging. A similar motor/pump
unit 532 having a smaller displacement volume may be included in
the tool in a suitable location, such as below the large volume
pump, for quantitatively monitoring fluid received by the downhole
evaluation tool 518 via the formation sample tool 524. As noted
above, the formation sample tool 524 may be configured for any
number of formation sampling operations. Construction and
operational details of a suitable non-limiting fluid sample tool
524 for extracting fluids are more described by U.S. Pat. No.
5,303,775, the specification of which is incorporated herein by
reference.
[0040] The downhole evaluation tool 518 may include a downhole
evaluation system 534 for evaluating several aspects of the
downhole sub 506, the drilling system 500, aspects of the downhole
fluid in and/or around the downhole sub 506, formation samples
received by the downhole sub 506, of the surrounding formation, and
combinations thereof. The downhole evaluation system 534 may be
adapted to carry any of the several refractometer embodiments
described herein.
[0041] One or more formation sample containers 536 may be included
for retaining formation samples received by the downhole sub 506.
In several examples, the formation sample containers 536 may be
individually or collectively detachable from the downhole
evaluation tool 518.
[0042] A downhole transceiver 546 may be coupled to the downhole
sub 506 for bidirectional communication with a surface transceiver
540. The surface transceiver 540 communicates received information
to a surface controller 538 that includes a memory 542 for storing
information and a processor 544 for processing the information. The
memory 542 may also have stored thereon programmed instructions
that when executed by the processor 544 carry out one or more
operations and methods described in the present disclosure. The
memory 542 and processor 544 may be located downhole on the
downhole sub 506 in several non-limiting embodiments, such as the
embodiments described above and shown in FIG. 4.
[0043] The present disclosure is to be taken as illustrative rather
than as limiting the scope or nature of the claims below. Numerous
modifications and variations will become apparent to those skilled
in the art after studying the disclosure, including use of
equivalent functional and/or structural substitutes for elements
described herein, use of equivalent functional couplings for
couplings described herein, and/or use of equivalent functional
actions for actions described herein. Such insubstantial variations
are to be considered within the scope of the claims below.
* * * * *