U.S. patent application number 10/911357 was filed with the patent office on 2005-02-10 for apparatus for obtaining high quality formation fluid samples.
This patent application is currently assigned to PathFinder Energy Services, Inc.. Invention is credited to Moody, Michael J..
Application Number | 20050028974 10/911357 |
Document ID | / |
Family ID | 32991034 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050028974 |
Kind Code |
A1 |
Moody, Michael J. |
February 10, 2005 |
Apparatus for obtaining high quality formation fluid samples
Abstract
A well fluid sampling tool is provided. The sampling tool
includes at least one insulated sample chamber mounted in a tool
collar. The tool collar may be coupled with a drill string such
that, when the tool collar is deployed in a well bore, selected
sample chambers may receive a fluid sample from outside the drill
string without removing the drill string from the well bore (e.g.,
during measurement while drilling or logging while drilling
operations). A heating module in thermal communication with at
least one of the sample chambers is disposed to selectively heat
the sample chambers in thermal communication therewith. The
sampling tool may be particularly useful for acquiring and
preserving substantially pristine formation fluid samples.
Inventors: |
Moody, Michael J.; (Katy,
TX) |
Correspondence
Address: |
W-H ENERGY SERVICES, INC.
10370 RICHMOND AVENUE
SUITE 990
HOUSTON
TX
77042
US
|
Assignee: |
PathFinder Energy Services,
Inc.
Houston
TX
|
Family ID: |
32991034 |
Appl. No.: |
10/911357 |
Filed: |
August 4, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60492483 |
Aug 4, 2003 |
|
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|
Current U.S.
Class: |
166/264 ; 166/57;
175/50 |
Current CPC
Class: |
E21B 49/081
20130101 |
Class at
Publication: |
166/264 ;
166/057; 175/050 |
International
Class: |
E21B 027/00 |
Claims
I claim:
1. A downhole sampling tool, comprising: a tool collar, the tool
collar including at least one sample chamber deployed therein, each
sample chamber including an insulating layer deployed thereabout;
the tool collar disposed to be operatively coupled with a drill
string deployed in a well bore such that, when the tool collar is
coupled to the drill string, sample chambers may be selectively
placed in fluid communication with formation fluid drawn from
outside the drill string without removing the drill string from the
well bore; and a heating module in thermal communication with at
least one of the sample chambers, the heating module disposed to
selectively heat said sample chambers in thermal communication
therewith.
2. The sampling tool of claim 1, further comprising a sample inlet
port on an outer surface of the tool collar, the sample inlet port
connected to the sample chamber via a fluid passageway.
3. The sampling tool of claim 2, further comprising a pump in fluid
communication with the sample inlet port.
4. The sampling tool of claim 3, wherein the pump comprises a
bi-directional piston pump.
5. The sampling tool of claim 1, wherein the tool collar comprises
a plurality of sample chambers deployed therein.
6. The sampling tool of claim 1, wherein the at least one sample
chamber is deployed substantially coaxially with the tool
collar.
7. The sampling tool of claim 1, wherein the insulating layer
comprises an r-value of greater than or equal to 12.
8. The sampling tool of claim 1, wherein the insulating layer
comprises an insulating material selected from the group consisting
of a polyurethane coating and an aerogel foam.
9. The sampling tool of claim 1, wherein the insulating layer
comprises an evacuated region.
10. The sampling tool of claim 1, wherein the heating module
comprises an electrical resistance heater.
11. The sampling tool of claim 10, wherein a portion of the heating
module is wound about the sample chamber.
12. The sampling tool of claim 10, wherein the heating module
comprises an electrically resistive coating deployed about the
sample chamber.
13. The sampling tool of claim 1, further comprising an electronic
controller in control communication with the heating module.
14. The sampling tool of claim 13, wherein the electronic
controller is further in control communication with at least one
temperature sensor deployed in the sample chamber.
15. The sampling tool of claim 14, wherein the electronic
controller is configured to maintain a temperature of the sample
chamber above a predetermined minimum temperature.
16. The sampling tool of claim 1, being coupled to a logging while
drilling tool.
17. The sampling tool of claim 1, wherein the sample chamber and
the heating module are deployed in a sample chamber insert, the
sample chamber insert sized and shaped for removable receipt within
the tool collar.
18. A downhole sampling tool, comprising: a tool collar, the tool
collar including a sample chamber insert deployed therein, the
sample chamber insert sized and shaped for removable receipt within
the tool collar; at least one sample chamber deployed in the sample
chamber insert, each sample chamber including an insulating layer
deployed thereabout; a heating module deployed in the sample
chamber insert in thermal communication with at least one of the
sample chambers, the heating module disposed to selectively heat
said sample chambers in thermal communication therewith; and the
tool collar disposed to be operatively coupled with a drill string
deployed in a well bore such that, when the tool collar is coupled
to the drill string, sample chambers may be selectively placed in
fluid communication with formation fluid drawn from outside the
drill string without removing the drill string from the well
bore.
19. The sampling tool of claim 18 wherein the insulating layer
comprises an insulating material selected from the group consisting
of a polyurethane coating and an aerogel foam.
20. The sampling tool of claim 19, wherein the insulating layer
comprises an evacuated region.
21. The sampling tool of claim 18, wherein the heating module
comprises an electrical resistance heater, a portion of the
electrical resistance heater wound about at least one of the sample
chambers.
22. The sampling tool of claim 18, further comprising an electronic
controller communicably coupled with (i) the heating module and
(ii) at least one temperature sensor deployed in the sample
chamber.
23. The sampling tool of claim 22, wherein the electronic
controller is configured to maintain a temperature of the sample
chamber above a predetermined minimum temperature.
24. The sampling tool of claim 18, further comprising a
bi-directional piston pump connected to a sample inlet port, the
sample inlet port connected to the sample chamber via a fluid
passageway.
25. A logging while drilling tool comprising: a tool collar, the
tool collar including at least one sample chamber mounted therein,
each sample chamber including an insulating layer deployed
thereabout; the tool collar disposed to be operatively coupled with
a drill string deployed in a well bore such that, when the tool
collar is coupled to the drill string, sample chambers may be
selectively placed in fluid communication with formation fluid
drawn from outside the drill string without removing the drill
string from the well bore; a heating module in thermal
communication with at least one of the sample chambers, the heating
module disposed to selectively heat said sample chambers in thermal
communication therewith; at least one packer element, each packer
element disposed to seal the wall of the well bore around the
logging while drilling tool, each packer element being selectively
positionable between sealed and unsealed positions; and a sample
inlet port connected to the at least one sample chamber via an
inlet passageway.
26. The logging while drilling tool of claim 25, comprising first
and second packer elements, the sample inlet port being disposed
between the first and second packer elements.
27. The logging while drilling tool of claim 25, further comprising
a fluid identification module in fluid communication with the inlet
passageway, the fluid identification module including at least one
sensor disposed to sense a property of a formation fluid.
28. The logging while drilling tool of claim 27, wherein at least
one of the sensors in the fluid identification module is selected
from the group consisting of a resistivity sensor, a dielectric
sensor, a pressure sensor, a temperature sensor, an optical sensor,
an acoustic sensor, a nuclear magnetic resonance sensor, a density
sensor, a viscosity sensor, and a pH sensor.
29. The logging while drilling tool of claim 27, further
comprising: a first fluid passageway connecting the fluid
identification module to the at least one sample chamber; and a
second fluid passageway connecting the fluid identification module
to an output port through which fluid may be expelled from the
tool.
30. The logging while drilling tool of claim 25, wherein the tool
collar comprises a plurality of sample chambers mounted
therein.
31. The logging while drilling tool of claim 25, wherein the
insulating layer comprises an r-value of greater than or equal to
12.
32. The logging while drilling tool of claim 25, wherein the
heating module comprises an electrical resistance heater wound
about the sample chamber.
33. The logging while drilling tool of claim 25, further comprising
an electronic controller in control communication with the heating
module.
34. The logging while drilling tool of claim 25, further comprising
a bi-directional piston pump in fluid communication with the sample
inlet port.
35. The logging while drilling tool of claim 25, wherein the sample
chamber and the heating module are deployed in a sample chamber
insert, the sample chamber insert sized and shaped for removable
receipt within the tool collar.
36. An integrated apparatus for retrieving a fluid sample from a
well bore, the apparatus comprising: a drill string having a drill
bit disposed on one end thereof; a formation evaluation tool
disposed on the drill string proximate to the drill bit; and a
formation fluid sampling apparatus also disposed on the drill
string proximate to the drill bit, the formation fluid sampling
apparatus including: a tool collar, the tool collar including at
least one sample chamber deployed therein, each sample chamber
including an insulating layer deployed thereabout; the tool collar
disposed to be operatively coupled with the drill string such that
sample chambers may be selectively placed in fluid communication
with formation fluid drawn from outside the drill string without
removing the drill string from the well bore; and a heating module
in thermal communication with at least one of the sample chambers,
the heating module disposed to selectively heat said sample
chambers in thermal communication therewith.
37. A method for acquiring a formation fluid sample from a
formation of interest in a well bore, the method comprising: (a)
deploying a formation fluid sampling tool at a location of a
formation of interest in a well bore, the sampling tool being
operative coupled with a drill string proximate to a drill bit, the
sampling tool comprising: a tool collar, the tool collar including
at least one sample chamber deployed therein, each sample chamber
including an insulating layer deployed thereabout; the tool collar
disposed such that the at least one sample chamber may be
selectively placed in fluid communication with formation fluid
drawn from outside the drill string without removing the drill
string from the well bore; and a heating module in thermal
communication with at least one of the sample chambers, the heating
module disposed to selectively heat said sample chambers in thermal
communication therewith; (b) pumping formation fluid into selected
ones of the sample chambers; and (c) heating the formation fluid
received in (b) in the selected sample chambers using the heating
module.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 60/492,483 entitled Apparatus for Obtaining
High Quality Formation Fluid Samples, filed Aug. 4, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the drilling of
oil and gas wells, and more specifically, to a formation fluid
sampling tool and method of use for acquiring and preserving
substantially pristine formation fluid samples.
BACKGROUND OF THE INVENTION
[0003] The commercial development of hydrocarbon (e.g., oil and
natural gas) fields requires significant capital investment. Thus
it is generally desirable to have as much information as possible
pertaining to the contents of a hydrocarbon reservoir and/or
geological formation in order to determine its commercial
viability. There have been significant advances in measurement
while drilling and logging while drilling technology in recent
years (hereafter referred to as MWD and LWD, respectively). These
advances have improved the quality of data received from downhole
sensors regarding subsurface formations. It is nonetheless still
desirable to obtain one or more formation fluid samples during the
drilling and completion of an oil and/or gas well. Once retrieved
at the surface, these samples typically undergo specialized
chemical and physical analysis to determine the type and quality of
the hydrocarbons contained therein. In general, it is desirable to
collect the samples as early as possible in the life of the well to
minimize contamination of the native hydrocarbons by drilling
damage.
[0004] As is well known to those of ordinary skill in the art,
formation fluids (e.g., water, oil, and gas) are found in
geological formations at relatively high temperatures and pressures
(as compared to ambient conditions at the surface). At these
relatively high temperatures and pressures, the formation fluid is
typically a single-phase fluid, with the gaseous components being
dissolved in the liquid. A reduction in pressure (such as may occur
by exposing the formation fluid to ambient conditions at the
surface) typically results in the separation of the gaseous and
liquid components. Cooling of the formation fluid towards such
ambient temperatures typically results in a reduction in volume
(and therefore a reduction in pressure if the fluid is housed in a
sealed container), which also tends to result in a separation of
the gaseous and liquid components. Cooling of the formation fluid
may also result in substantially irreversible precipitation and/or
separation of other compounds previously dissolved therein. Thus it
is generally desirable for a sampling apparatus to be capable of
substantially preserving the temperature and/or pressure of the
formation fluid in its primitive formation condition.
[0005] Berger et al., in U.S. Pat. No. 5,803,186, disclose an
apparatus and method for obtaining samples of formation fluid using
a work string designed for performing other downhole work such as
drilling, workover operations, or re-entry operations. The
apparatus includes sensors for sensing downhole conditions while
using a work string that permits working fluid properties to be
adjusted without withdrawing the work string from the well bore.
The apparatus also includes a relatively small integral sample
chamber coupled to multiple input and output valves for collecting
and housing a formation fluid sample.
[0006] Schultz et al., in U.S. Pat. No. 6,236,620, disclose an
apparatus and method for drilling, logging, and testing a
subsurface formation without removing the drill string from the
well bore. The apparatus includes a surge chamber and surge chamber
receptacle for use in sampling formation fluids. The surge chamber
is lowered through the drill string into engagement with the surge
chamber receptacle, receives a sample of formation fluid, and then
is retrieved to the surface. Repeated sampling may be accomplished
without removing the drill string by removing the surge chamber,
evacuating it, and then lowering it back into the well. While the
Berger and Schultz apparatuses apparently permit samples to be
collected relatively early in the life of a well, without retrieval
of the drill string, they include no capability to preserve the
temperature of the formation fluid. Further, it is a relatively
complex operation to remove the formation fluid sample from the
Berger apparatus.
[0007] Brown et al., in U.S. Pat. No. 5,901,788 disclose a wire or
slick line apparatus in which the sample chamber may be thermally
insulated, given a high heat capacity, and/or provided with a
heating source such as an electric heater, with the intent of
maintaining the sample at a temperature similar to that of the
formation. Corrigan et al., in PCT Publication WO 00/34624,
disclose a slick line apparatus including a sample chamber
contained within an evacuated jacket for maintaining the
temperature of a formation fluid sample. The Corrigan apparatus
further includes multiple heaters spaced along the sample chamber.
One drawback of the Brown and Corrigan apparatuses is that they
require the retrieval of the drill string from the well bore prior
to being lowered therein, which typically involves significant cost
and time, and increases the risk of subsurface damage to the
formation of interest.
[0008] Therefore, there exists a need for improved apparatuses and
methods for obtaining samples of formation fluid from a well. In
particular, an apparatus that does not require retrieval of the
drill string from the well and that has the capability of
preserving the sample of formation fluid in substantially pristine
conditions is highly desirable.
SUMMARY OF THE INVENTION
[0009] The present invention addresses difficulties in acquiring
and preserving samples of pristine formation fluid, including those
difficulties described above. Aspects of this invention include a
sampling tool for obtaining samples of relatively pristine
formation fluid without removing the drill string from the well
bore. Sampling tools according to the invention may retrieve
samples from both deep and shallow wells. Exemplary sampling tool
embodiments of this invention are configured for coupling to the
drill string and include one or more sample chambers. The sample
chambers are typically insulated and/or provided with a heat source
(also referred to as a heating module, e.g., an electric heater)
for maintaining the temperature of the formation fluid. Sampling
tool embodiments according to this invention typically further
include on-board electronics disposed to collect multiple samples
of pristine formation fluid at substantially any predetermined
moment or time interval.
[0010] Exemplary embodiments of the present invention may
advantageously provide several technical advantages. For example,
sampling tool embodiments according to this invention may
advantageously provide for improved sampling of formation fluid
from, for example, deep wells. In particular, embodiments of this
invention are configured with the intent to try to maintain, for as
long as possible, the fluid at about the same temperature and
pressure conditions as found in the formation. A tool according to
this invention, in combination with a logging while drilling (LWD)
tool, is couplable to a drill string, and thus in such a
configuration provides for sampling of formation fluid shortly
after penetration of the formation of interest. Advantages are thus
provided for the acquisition and preservation of relatively high
quality formation fluid sample in substantially pristine
conditions. These high quality samples may provide for more
accurate determination of formation properties and thus may enable
a better assessment of the economic viability of an oil and/or gas
reservoir.
[0011] In one aspect the present invention includes a downhole
sampling tool. The downhole sampling tool includes a tool collar
having at least one sample chamber deployed therein. Each sample
chamber includes an insulating layer deployed thereabout. The tool
collar is disposed to be operatively coupled with a drill string
deployed in a well bore such that, when the tool collar is coupled
to the drill string, sample chambers may be selectively placed in
fluid communication with formation fluid drawn from outside the
drill string without removing the drill string from the well bore.
The sampling tool further includes a heating module in thermal
communication with at least one of the sample chambers. The heating
module is disposed to selectively heat the sample chambers in
thermal communication therewith.
[0012] In another aspect this invention includes a logging while
drilling (LWD) tool. The logging while drilling tool includes a
tool collar having at least one chamber mounted therein. Each
sample chamber includes an insulating layer deployed thereabout.
The tool collar is disposed to be operatively coupled with a drill
string deployed in a well bore such that, when the tool collar is
coupled to the drill string, sample chambers may be selectively
placed in fluid communication with formation fluid drawn from
outside the drill string without removing the drill string from the
well bore. The LWD tool further includes a heating module in
thermal communication with at least one of the sample chambers. The
heating module is disposed to selectively heat the sample chambers
in thermal communication therewith. The LWD tool still further
includes at least one packer element. Each packer element is
disposed to seal the wall of the well bore around the LWD tool.
Each packer element is further selectively positionable between
sealed and unsealed positions. The LWD yet further includes a
sample inlet port connected to the at least one sample chamber via
an inlet passageway.
[0013] The foregoing has outlined rather broadly the features and
technical advantages of the present invention in order that the
detailed description of the invention that follows may be better
understood. Additional features and advantages of the invention
will be described hereinafter, which form the subject of the claims
of the invention. It should be appreciated by those skilled in the
art that the conception and the specific embodiment disclosed may
be readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
invention. It should also be realized by those skilled in the art
that such equivalent constructions do not depart from the spirit
and scope of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a more complete understanding of the present invention,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0015] FIG. 1 is a schematic illustration of an offshore oil and/or
gas drilling platform utilizing an exemplary embodiment of the
present invention.
[0016] FIG. 2 is a partially cutaway schematic representation of an
exemplary sampling module embodiment according to the present
invention.
[0017] FIG. 3 is a partially cutaway schematic representation of an
exemplary embodiment of a sample chamber insert for use with the
exemplary sampling module of FIG. 2.
[0018] FIG. 4 is a partially cutaway schematic representation of an
exemplary sampling tool according to the present invention,
including the exemplary sampling module of FIG. 2.
DETAILED DESCRIPTION
[0019] Referring now to FIG. 1, one exemplary embodiment of
sampling module 100 according to this invention is schematically
illustrated in use in an offshore oil or gas drilling assembly,
generally denoted 10. A semisubmersible drilling platform 12 is
positioned over an oil or gas formation 14 disposed below the sea
floor 16. A subsea conduit 18 extends from deck 20 of platform 12
to a wellhead installation 22. The platform may include a derrick
26 and a hoisting apparatus 28 for raising and lowering the drill
string 30 including drill bit 32, sampling module 100, and
formation tester 200. Drill string 30 may further include a
downhole drill motor, a mud pulse telemetry system, and one or more
sensors, such as a nuclear logging instrument, for sensing downhole
characteristics of the well, bit, and reservoir.
[0020] During a drilling, testing, and sampling operation, drill
bit 32 is rotated on drill string 30 to create a well bore 40.
Shortly after the drill bit 32 intersects the formation 14 of
interest, drilling typically stops to allow formation testing
before contamination of the formation occurs, e.g., by invasion of
working fluid or filter cake build-up. Expandable packers 220 are
inflated to sealing engage the wall of well bore 40. The inflated
packers 220 isolate a portion of the well bore 40 adjacent the
formation 14 to be tested. Formation fluid is then received at port
216 of formation tester 200 and may be pumped into one or more
sample chambers 122 illustrated on FIG. 2. As described in more
detail hereinbelow with respect to FIG. 4, embodiments of formation
tester 200 may include a fluid identification module 210 including
one or more sensors for sensing properties of the various fluids
that may be encountered. Formation tester 200 may further pass
fluid through a fluid passageway to one or more sample tanks housed
in sample module 100.
[0021] It will be understood by those of ordinary skill in the art
that the sampling module 100 and the formation tester 200 of the
present invention are not limited to use with a semisubmersible
platform 12 as illustrated on FIG. 1. Sampling module 100 and
formation tester 200 are equally well suited for use with any kind
of subterranean drilling operation, either offshore or onshore.
[0022] Referring now to FIGS. 2 and 3, a schematic illustration of
one exemplary embodiment of the sampling module 100 (also referred
to herein as a sampling tool) according to this invention is shown.
Sampling module 100 includes one or more sample tanks 120 disposed
in a collar 110. Collar 110 is typically configured for mounting on
a drill string, e.g., drill string 30 (FIG. 1), and thus may
include conventional threaded connectors on the top and bottom
thereof. While FIGS. 2 and 3 show a sampling module including three
sample tanks 120, the artisan of ordinary skill will readily
recognize that sampling module 100 may include substantially any
number of sample tanks disposed in substantially any arrangement in
the collar 110.
[0023] As described hereinabove, sample tanks 120 are configured to
maintain the temperature of the formation fluid at a value
substantially equal to that of the formation (e.g., formation 14 in
FIG. 1). In the embodiment of FIG. 2, sample tanks 120 include a
sample chamber 122 surrounded by one or more insulating layers 124.
The sample chamber 122 may be fabricated from, for example,
stainless steel or a titanium alloy, although it will be
appreciated that it may be fabricated from substantially any
suitable material in view of the service temperatures and
pressures, exposure to corrosive formation fluids, and other
downhole conditions. Insulating layer 124 may include substantially
any suitable thermally insulating material, such as a polyurethane
coating or an aerogel foam disposed on the sample chamber 122.
Insulating layer 124 may further include an evacuated annular
region, the vacuum around the sample chamber 122 further enhancing
the thermal insulation thereof. In one desirable embodiment
insulating layer 124 is sufficient to substantially maintain the
temperature of a sample at the formation temperature, the sample
chamber 124 having an revalue of, for example, greater than or
equal to about 12.
[0024] With further reference to the embodiment of FIG. 2, the
exterior of the sample chamber 122 is wound with an electrical
resistance heating module 128 typically in the form of a tape,
foil, or chain. Sample chamber 122 may alternately be coated with
an electrically resistive coating. The heating module 128 is
typically communicably coupled to a controller (shown schematically
at 140) mounted inside the collar 110. In embodiments in which the
heating module 128 includes an electrical heating mechanism,
electric power may be provided by substantially any known
electrical system, such as a battery pack mounted in the tool body
110, or elsewhere in the drill string, or a turbine disposed in the
flow of drilling fluid. Alternately and/or additionally, the sample
chamber may be heated using known chemical techniques, e.g., by a
controlled exothermic chemical reaction in a separate chamber (not
shown).
[0025] Referring again to FIG. 2, the one or more sample chambers
122 are in fluid communication with a sample fluid passageway 130
including an inlet port 134 for receiving formation fluid (e.g.
from an LWD tool). Passageway 130 is further in fluid communication
with inlet valves 132 for controlling the flow of the formation
fluid to the one or more sample chambers 122. Inlet valves 132 are
communicably coupled to the controller 140 and allow collection of
separate fluid samples in each of the sample chambers 122 (e.g., at
unique times or penetration depths). Multiple samples may also be
collected simultaneously and optionally held at separate
temperatures, thus providing additional information about the
temperature and pressure stability of the formation fluid.
[0026] With continued reference to FIG. 2, controller 140 may
include a programmable processor (not shown), such as a
microprocessor or a microcontroller, and may also include processor
readable or computer readable program code embodying logic,
including instructions for controlling the function of valves 132
and heating modules 128. Controller 140 may be disposed in
communication with one or more temperature probes (not shown)
appropriately sized, shaped, positioned, and configured for
providing temperature readings of the interior of the sample
chambers 122. The temperature probes may include, for example a
thermistor or a thermocouple in thermal contact with the samples.
Controller 140 may optionally be disposed in electronic
communication with other sensors and/or probes for monitoring other
physical parameters of the samples (e.g., a pressure sensor for
measuring the pressure of the interior of the sample chamber 122).
Controller 140 may also optionally be disposed in electronic
communication with other sensors for measuring well bore
properties, such as a gamma ray depth detection sensor or an
accelerometer, gyro or magnetometer to detect azimuth and
inclination. Controller 140 may also optionally communicate with
other instruments in the drill string, such as telemetry systems
that communicate with the surface. Controller 140 may further
optionally include volatile or non-volatile memory or a data
storage device. The artisan of ordinary skill will readily
recognize that while controller 140 is shown disposed in collar 110
(FIG. 2), it may alternately be disposed elsewhere, such as in
identification module 210 of fluid tester 200.
[0027] In alternative embodiments, sampling module 100 may be
configured to include a sample chamber insert 150 mountable in the
collar 110 as illustrated on FIG. 3. The sample chamber insert 150
may, for example, include the one or more sample tanks 120, the
fluid passageway 130, the inlet valves 132, and the controller 140
disposed in a housing 152. This embodiment may be advantageous in
that the sample chamber insert 150, including the sample tanks 120,
may be removed from the collar 110 and transported to a remote
location for sample testing.
[0028] Referring now to FIG. 4, another embodiment of the present
invention includes a sample module 100 coupled to a formation
tester 200 (e.g., a LWD tool). While sample module 100 and
formation tester 200 are shown coupled at 235 (e.g., threaded to
one another), the artisan of ordinary skill will readily recognize
that consistent with the present invention they may also be
fabricated as an integral unit. Formation tester 200 may be
according to embodiments described and claimed in U.S. Pat. No.
6,236,620 to Schultz, et al. and typically includes one or more
packer elements 220 for selectively sealing the wall of the well
bore around formation tester 200. FIG. 4 illustrates two packer
elements 220 for isolating a substantially annular portion of the
well bore adjacent to a formation of interest. The packer elements
220 may comprise any type packer element, such as compression type
or inflatable type. Inflatable type packer elements 220 may be
inflated by substantially any suitable technique, such as by
injecting a pressurized fluid into the packer. The packer elements
220 may further include optional covers (not illustrated on FIG. 4)
to shield the components thereof from the potentially damaging
effects of the various forces encountered during drilling (e.g.,
collisions with the wall of the well bore).
[0029] With further reference to FIG. 4, the formation tester 200
further includes at least one inlet port 216 disposed between
packer elements 220. In embodiments including only one packer
element 220, inlet port 216 is typically disposed therebelow (e.g.,
further towards the bottom of the well). Inlet port 216 is in fluid
communication with a fluid identification module (shown
schematically at 210) via fluid passageway 218. Fluid
identification module 210 typically includes instrumentation
including one or more sensors for monitoring and recording
properties of the various fluids that may be encountered in the
well bore, from which a fluid type may be determined. For example,
sensor measurements may distinguish between working fluid (e.g.,
drilling mud) and formation fluid. The fluid identification module
210 may include any of a relatively wide variety of sensors,
including a resistivity sensor for sensing fluid or formation
resistivity and a dielectric sensor for sensing the dielectric
properties of the fluid or formation. Module 210 may further
include pressures sensors, temperature sensors, optical sensors,
acoustic sensors, nuclear magnetic resonance sensors, density
sensors, viscosity sensors, pH sensors, and the like. Fluid
identification module 210 typically further includes numerous
valves and fluid passageways (not shown) for directing formation
fluid to the various sensors and for directing fluid to, for
example, a sample output passageway 214 or a fluid discharge
passageway 212, in fluid communication with output port 213.
[0030] Formation tester 200 typically further includes a control
module (not shown) of analogous purpose to that described above
with respect to controller 140. The control module, for example
controls the function of the various sensors described above and
communicates sensor output with operators at the surface, for
example, by conventional mud telemetry or electric line
communications techniques. The control module may further be
communicably coupleable with controller 140.
[0031] In operation, formation tester 200 is advantageously
positioned adjacent a formation of interest in the well bore. The
packer elements 220 are inflated, thereby isolating a substantially
annular portion of the well bore adjacent the formation. One or
more pumps 250 are utilized to pump formation fluid into the tool
at port 216. The pump 250 may include, for example, a
bi-directional piston pump, such as that disclosed in U.S. Pat.
Nos. 5,303,775 and 5,377,755 to Michaels et al., or substantially
any other suitable pump in view of the service temperatures and
pressures, exposure to corrosive formation fluids, and other
downhole conditions. Fluid is typically pumped into the tool
(rather than flowing by the force of the reservoir pressure) in
order to maintain it above its bubble pressure (i.e., the pressure
below which a single phase fluid becomes a two phase fluid).
Sampled formation fluid then passes through the fluid
identification module 210 where it is tested using one or more of
the various sensors described above. Fluid is typically pumped in
and then discharged from the tool via passageway 212 and output
port 213 until it is sensed to have predetermined properties (e.g.,
a resistivity in a certain range) identifying it as likely to be a
substantially pristine formation fluid. Typically, upon first
pumping, the formation fluid is contaminated with drilling fluid.
After some time, however, substantially pristine formation fluid
may be drawn into the tool and routed to sampling module 100 via
passageway 214. Samples may be obtained using substantially any
protocol (e.g., at a various time intervals or matching certain
predetermined fluid properties measured by identification module
210).
[0032] Referring now to FIG. 2, with further reference to FIG. 4,
substantially pristine formation fluid may be received at inlet
port 134, which is in fluid communication with fluid passageway
214, and routed to one or more sample chambers 122 through valves
132. If the sample temperature falls, such a temperature change may
be detected by the controller 140, (e.g., using a thermistor or
thermocouple in thermal contact with the sample). In response to
the detected temperature drop, the control circuit may, for
example, connect an electrical power supply (e.g., a battery
source) with the electrical heating module 128 to heat the sample
chamber 122 and thus stabilize the temperature of the sample.
[0033] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alternations can be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims.
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