U.S. patent application number 11/384456 was filed with the patent office on 2007-09-20 for system and method for obtaining formation fluid samples for analysis.
Invention is credited to Gilles Carree, Pierre-Yves Corre.
Application Number | 20070215348 11/384456 |
Document ID | / |
Family ID | 38516580 |
Filed Date | 2007-09-20 |
United States Patent
Application |
20070215348 |
Kind Code |
A1 |
Corre; Pierre-Yves ; et
al. |
September 20, 2007 |
System and method for obtaining formation fluid samples for
analysis
Abstract
A system and a methodology is utilized in a wellbore to collect
samples of formation fluid. A single expandable packer is moved
downhole into the wellbore for collection of a fluid sample. The
single packer has a sample collection portion disposed in an
intermediate location that is sealed off when the single packer is
expanded against a wellbore wall. Once engaged with the wellbore
wall, a formation fluid sample can be drawn into the single
expandable packer for distribution to a sample collection
location.
Inventors: |
Corre; Pierre-Yves; (Eu,
FR) ; Carree; Gilles; (Regniere-Ecluse, FR) |
Correspondence
Address: |
SCHLUMBERGER IPC;ATTN: David Cate
555 INDUSTRIAL BOULEVARD, MD-21
SUGAR LAND
TX
77478
US
|
Family ID: |
38516580 |
Appl. No.: |
11/384456 |
Filed: |
March 20, 2006 |
Current U.S.
Class: |
166/264 ;
166/100 |
Current CPC
Class: |
E21B 33/1277 20130101;
E21B 36/04 20130101; E21B 49/081 20130101 |
Class at
Publication: |
166/264 ;
166/100 |
International
Class: |
E21B 49/08 20060101
E21B049/08 |
Claims
1. A system for deployment in a wellbore to sample a formation
fluid, comprising: a single expandable packer structure having a
sample collection portion disposed longitudinally between a
plurality of seal members positioned for expansion against a
wellbore wall, the plurality of seal members being selectively
expandable against the wellbore wall to block contamination of a
formation fluid sample with external well fluid while the formation
fluid sample is drawn through the sample collection portion.
2. The system as recited in claim 1, further comprising an
expandable screen disposed in the sample collection portion.
3. The system as recited in claim 2, wherein the single expandable
packer structure further comprises an inner bladder that can be
filled with a fluid to expand the plurality of seal members and the
expandable screen.
4. The system as recited in claim 3, wherein the plurality of
expandable seal members comprises a pair of rubber covers.
5. The system as recited in claim 3, wherein the single expandable
packer structure comprises an expandable mechanical structure, the
inner bladder being disposed along a radial interior of the
expandable mechanical structure, the expandable screen and the
plurality of seal members being disposed along a radial exterior of
the expandable mechanical structure.
6. The system as recited in claim 5, further comprising a pumping
system fluidly coupled to the sample collection portion to draw in
a sample of formation fluid.
7. The system as recited in claim 6, wherein the pumping system
also is coupled to the inner bladder to enable selective inflation
of the inner bladder.
8. The system as recited in claim 6, wherein the pumping system is
coupled to the sample collection portion with at least one
hydraulic hose.
9. The system as recited in claim 1, wherein the single expandable
packer structure comprises a heater element to heat the formation
fluid sample.
10. A method of collecting formation fluid, comprising:
constructing a modular dynamic formation tester tool with a single
expandable packer; moving the single expandable packer downhole
into a wellbore; expanding the single expandable packer against a
wall of the wellbore to seal off an internal sample collection
region; and drawing in a formation fluid sample through the sample
collection region without exposure to wellbore fluid.
11. The method as recited in claim 10, wherein constructing
comprises locating an intake screen at the internal sample
collection region between a pair of seal members.
12. The method as recited in claim 11, wherein constructing
comprises positioning an inflatable bladder radially inward of the
intake screen and the pair of seal members.
13. The method as recited in claim 12, wherein constructing
comprises separating the inflatable bladder from both the intake
screen and the pair of seal members with an expandable mechanical
structure.
14. The method as recited in claim 10, wherein expanding comprises
pumping a fluid into an inflatable bladder.
15. The method as recited in claim 13, wherein drawing comprises
moving the formation fluid sample through a conduit routed along
the expandable mechanical structure.
16. An expandable packer system, comprising: a single expandable
packer structure having: an inflatable bladder, an expandable
mechanical structure positioned radially outward of the inflatable
bladder, a screen radially outward of the expandable mechanical
structure, a first seal member positioned at a longitudinal end of
the screen, a second seal member positioned at an opposite
longitudinal end of the screen, and a conduit to route a formation
fluid sample from the screen, along the expandable mechanical
structure and to a sample collection location.
17. The expandable packer system as recited in claim 16, further
comprising a pumping system for supplying a fluid to the inflatable
bladder to expand the single expandable packer structure.
18. The expandable packer system as recited in claim 16, wherein
the single expandable packer structure further comprises a heating
element to heat the formation fluid sample.
19. The expandable packer system as recited in claim 16, wherein
the single expandable packer structure as an expansion ratio of at
least two to one.
20. A method of collecting formation fluid, comprising: positioning
an expandable screen between a pair of longitudinally spaced seal
members; using an internal expandable member to simultaneously
expanded the pair of longitudinally spaced seal members into
engagement with the wellbore wall; and drawing a formation fluid
sample radially inward through the expandable screen.
21. The method as recited in claim 20, further comprising locating
an expandable mechanical structure between the internal expandable
member and the pair of longitudinally spaced seal members.
22. The method as recited in claim 20, wherein using comprises
using an inflatable bladder.
23. The method as recited in claim 20, wherein drawing comprises
using a pumping system to create suction between the longitudinally
spaced seal members proximate the expandable screen.
24. The method as recited in claim 23, further comprising routing
the formation fluid sample from the screen to the pumping system
via a conduit.
25. The method as recited in claim 20, further comprising heating
the formation fluid sample as it is collected.
Description
BACKGROUND
[0001] The invention generally relates to a system and method for
obtaining fluid samples from a surrounding formation. The samples
are collected for analysis in determining characteristics of the
formation and fluids contained in the formation.
[0002] A variety of sampling tools, such as modular dynamics
formation tester tools (MDT tools) can be run into a wellbore to
obtain and evaluate formation fluid samples. MDT tools have been
used with single probes or two separate inflatable packers. The
probe or separate packers are designed to insulate the formation
fluid sample from well fluid in the wellbore while a pump in the
MDT tool draws in the formation fluid sample.
[0003] However, the single probe type of tool is only capable of
placing a limited surface in contact with the formation, and this
limited contact can create difficulty in collecting formation fluid
in a variety environments, including low formation permeability
environments. The dual packer configuration can overcome some of
these problems, but depressurization between the separate packers
during sampling generates significant mechanical stress on the
packers. Accordingly, the packers must be designed to withstand
this mechanical stress which places substantial limitations on the
range of applications for which the system can be designed. For
example, the expansion capabilities of the packers may be limited
and/or the packers can be subjected to severe damage when cycled
multiple times. An additional problem associated with the dual
packer configuration is the heightened stress placed on the
formation.
SUMMARY
[0004] The present invention comprises a system and method for
taking formation fluid samples from within a wellbore. A sole or
single expandable packer is utilized to insulate the formation
fluid sample from well fluid while the formation fluid sample is
obtained. The design of the single packer enables the collection of
formation fluid samples through a relatively large area without
incurring detrimental mechanical stresses.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Certain embodiments of the invention will hereafter be
described with reference to the accompanying drawings, wherein like
reference numerals denote like elements, and:
[0006] FIG. 1 is a front elevation view of a modular dynamics
formation tester tool and a single expandable packer structure
deployed in a wellbore, according to one embodiment of the present
invention;
[0007] FIG. 2 is a view similar to that of FIG. 1 but showing the
single expandable packer structure in an expanded state, according
to an embodiment of the present invention;
[0008] FIG. 3 is a front elevation view of a modular dynamics
formation tester tool and a single expandable packer structure
deployed in a wellbore, according to an alternate embodiment of the
present invention; and
[0009] FIG. 4 is a flowchart illustrating one example of a sampling
methodology, according to an embodiment of the present
invention.
DETAILED DESCRIPTION
[0010] In the following description, numerous details are set forth
to provide an understanding of the present invention. However, it
will be understood by those of ordinary skill in the art that the
present invention may be practiced without these details and that
numerous variations or modifications from the described embodiments
may be possible.
[0011] The present invention relates to a system and methodology
for obtaining and analyzing fluid samples from a formation. A
system having an MDT tool and a single packer is deployed in a
wellbore along a desired formation. The single packer is expanded
against the wellbore wall adjacent the desired formation to seal
off a sample collection region. A pump within the MDT tool is
activated to create a suction in the sample collection region which
draws in a formation fluid sample. The formation fluid sample can
then be analyzed or directed to an appropriate collection location
for analysis.
[0012] The use of the single packer design ensures the mechanical
stress generated on the packer structure is substantially lower
than the stress that would otherwise be generated on two or more
separate packers. The single packer design further enables the
construction of a formation fluid sample collection region along
the packer that is at least as large as the surface area available
when separate packers are utilized. Accordingly, in some
applications, it becomes possible to reduce or weaken the
structural capability of the single packer without sacrificing
functionality or durability. The single packer design also
facilitates substantially higher expansion ratios and an increase
in the number of expansion/contraction cycles of the packer before
failure.
[0013] Referring generally to FIG. 1, an embodiment of a formation
fluid sampling system 20 is illustrated as deployed in a wellbore
22 formed in a formation 24 from which a formation fluid sample is
to be obtained. The formation fluid sampling system comprises a
single inflatable packer 26 combined with a modular dynamics
formation tester (MDT) tool 28. The MDT tool 28 and single
inflatable packer 26 are deployed in wellbore 22 via a deployment
system 30 that can comprise, for example, a cable, wireline, coiled
tubing or other suitable deployment system.
[0014] The MDT tool 28 can be constructed in a variety of
configurations depending on the specific sampling application. For
example, the MDT tool may comprise sample sections, multi-sample
sections, pump system sections, electric sections, hydraulic
sections, OFA modules and other sections or modules in a variety of
arrangements. MDT tools, in several configurations, are
commercially available from Schlumberger Corporation. To facilitate
explanation of the formation fluid sampling system 20, however, the
MDT tool 28 is illustrated as having an electric section 32, a
pumping system section 34, and a sample section 36 for storing a
formation fluid sample obtained through packer 26. In some
applications, sample section 36 may comprise a plurality of sample
chambers individually activated by a surface control 38. For
example, when pumping system 34 is operated to draw formation fluid
samples from a desired location, electromechanically actuated
throttle/seal valves (not shown) can be controlled by surface
control 38 to direct each individual formation fluid sample into an
appropriate corresponding sample chamber.
[0015] In the illustrated embodiment, MDT tool 28 is able to
selectively expand single packer 26 when desired for the collection
and analysis of a formation fluid sample. For example, MDT tool 28
and single packer 26 can be designed so the MDT tool is able to
selectively inflate the packer which causes it to expand against
the surrounding wellbore wall. Once expanded, a formation fluid
sample can be drawn in through the packer structure.
[0016] The illustrated single packer 26 comprises fixed mechanical
ends 40 and 42 which define the longitudinal extremities of the
packer. An inner sealing bladder 44 is positioned between fixed
ends 40 and 42 and may be selectively inflated by pumping system 34
via a supply conduit 46, such as a hydraulic tube. Radially outward
of inner sealing bladder 44, an expandable mechanical structure 48
is positioned to provide support for the overall packer structure.
The expandable mechanical structure 48 also can be used to provide
space for routing one or more conduits 50, e.g. hydraulic hoses,
through which fluid samples are obtained and directed to a
collection location, such as sample section 36. The expandable
mechanical structure 48 may comprise a variety of mechanical
elements, including longitudinal slats, crisscrossing slats, mesh
material or other materials or structures that accommodate repeated
cycles of expansion and contraction.
[0017] The single expandable packer 26 further comprises at least
two seal members 52 and 54 that are longitudinally separated to
create a formation fluid sample intake region 56 through which
formation fluid samples are drawn into packer 26 from the
surrounding formation 24. The seal members 52 and 54 are designed
to form a seal against a surrounding wall 58 that defines wellbore
22. The seal members are formed from appropriate sealing materials
and may comprise elastomeric covers, e.g. rubber covers. In the
embodiment illustrated, seal members 52 and 54 are positioned along
the exterior of expandable mechanical structure 48 and may be
located adjacent fixed ends 40 and 42, respectively. In fact, the
longitudinally outlying ends of seal members 52 and 54 may be
connected to fixed ends 40 and 42, respectively.
[0018] With further reference to FIG. 1, an expandable screen 60
may be positioned along an exterior of expandable mechanical
structure 48 in the fluid sample intake region 56. Expandable
screen 60 blocks the influx of sand or other fines that would
otherwise enter single packer 26 with the formation fluid sample.
The fluid sample intake region 56 is generally enclosed other than
expandable screen 60 and the one or more conduits 50. Thus, when
single packer 26 is expanded and pumping system 34 is operated to
create a decreased pressure or suction along conduit 50, formation
fluid is drawn in through expandable screen 60 and along conduit 50
to the desired collection location. In the embodiment illustrated,
the seal members 52 and 54 are located at opposed longitudinal ends
of expandable screen 60.
[0019] Referring generally to FIG. 2, the single expandable packer
26 is illustrated in its expanded configuration. A fluid, such as
well fluid, has been directed by pumping system 34 into the
interior of inner sealing bladder 44 via supply conduit 46. The
delivery of fluid via supply conduit 46 causes inner sealing
bladder 44 to expand radially which forces mechanical structure 48,
screen 60 and seal members 52, 54 to also expand radially outward.
The radial expansion drives seal members 52, 54 against wellbore
wall 58 to seal off fluid sample intake region 56. The seal members
52, 54 create sealing contact regions 62 that enable the creation
of a low-pressure area within conduit 50 and expandable mechanical
structure 48 proximate fluid sample intake region 56. It should be
noted the pumping system 34 can be designed to pump fluid in a
manner similar to that used in conventional dual packer
configurations.
[0020] By creating a low-pressure area, i.e. suction, a formation
fluid sample is drawn into sample intake region 56 from the
surrounding formation 24. The seal at contact regions 62 enables
passage of the formation fluid sample through expandable screen 60
and into the one or more conduits 50 for transport to sample
section 36 without being contaminated by wellbore fluid. The
suction can be created by operation of pumping system 34. For
example, the pump used to inflate inner sealing bladder 44 can be
reversed to draw the formation fluid sample into the packer
structure. Alternatively, separate pumps can be used to expand the
packer and to draw in the fluid sample, respectively. A valve
system 64 also can be incorporated into the design and controlled
via surface control 38 and/or electric section 32 to selectively
control flow through supply conduit 46 and sample conduit 50. In
one embodiment, the single pump can be used to inflate the inner
sealing bladder 44 and to subsequently draw in the fluid sample
while valve system 64 holds fluid within inner sealing bladder 44
to prevent premature contraction and release of packer 26.
[0021] In another embodiment, single expandable packer 26 is
provided with at least one heating element 66, as illustrated in
FIG. 3. Heating elements 66 can be positioned within expandable
mechanical structure 48, as illustrated, or they can be positioned
in other regions along the flow path followed by the formation
fluid sample as it enters and flows through the packer structure.
Power can be supplied to heating elements 66 via conductors 68 to
heat the incoming fluid sample for analysis. The ability to heat
the fluid sample enables analysis of a greater variety of fluid
samples from a greater number of environments, including the
analysis of high viscosity/cold fluids and the taking of other
measurements that are not readily performed without the addition of
heat.
[0022] The single expandable packer design also is conducive to
constructing an overall packer wall thickness that is thinner than
conventional systems. Thus, even if the packer does not fully
recover its initial diameter after many cycles, the packer can be
retrieved through the wellbore even when restrictions exist in the
wellbore. Furthermore, the single expandable packer design allows
the creation of a large communication area between the packer
structure and the well fluid. This allows the packer structure to
maintain balance with the hydrostatic pressure, thus reducing any
negative impact of hydrostatic pressure on packer performance. The
single expandable packer design also enables an increased expansion
ratio relative to conventional systems. For example, the diameter
of the single expandable packer 26 can increase by a ratio of more
than 2 to 1 when expanded from its contracted state, as illustrated
in FIG. 1, to its expanded state, as illustrated in FIG. 2. By way
of one specific example, the single expandable packer can be
manufactured with an outside diameter of approximately 5 inches and
inflated to seal against the inside diameter of a well, i.e.
wellbore wall 58, having a diameter of approximately 11 inches. Of
course, the actual diameter of single packer 26 and the expansion
ratio selected depends on the specific application parameters,
including size of the wellbore and type of equipment with which the
packer is utilized.
[0023] One embodiment of a methodology for operating the formation
fluid sampling system 20 can be described with reference to the
flowchart illustrated in FIG. 4. In this embodiment, MDT tool 28 is
initially combined with single expandable packer 26, as illustrated
by block 70. Subsequently, the single packer 26 is moved downhole
into wellbore 22 by deployment system 30 until the single packer is
positioned at a desired formation location, as illustrated by block
72. Once properly positioned, pumping system 34 directs a fluid,
such as well fluid, through supply conduit 46 to the interior of
inner sealing bladder 44. The filling of inner sealing bladder 44
expands single expandable packer 26 until seal members 52 and 54
seal against the surrounding wellbore wall 58 to seal off fluid
sample collection region 56, as illustrated by block 74. The sealed
sample collection region 56 enables pumping system 34 to create a
low-pressure region in conduit 50 and fluid sample intake region
56, the low-pressure region effectively drawing fluid into single
packer 26 from the surrounding formation, as illustrated by block
76. The formation fluid sample is then directed to a desired sample
collection location, such as sample section 36, via the one or more
conduits 50, as illustrated by block 78.
[0024] Following collection of the formation fluid sample, single
packer 26 can be collapsed by removing fluid from the interior of
inner sealing bladder 44, as illustrated by block 80. The removal
of well fluid from bladder 44 can be achieved by pumping system 34
and the appropriate reversal of the pumping system or adjustment of
the valve system 64 to route fluid out of the inner sealing
bladder. The removal of fluid from bladder 44 allows the bladder,
along with mechanical structure 48, screen 60 and seal members 52,
54, to collapse inwardly away from surrounding wellbore wall 58.
Once collapsed or contracted, the single packer can be moved to
another desired formation location to obtained one or more
additional samples, as illustrated by block 82.
[0025] As described above, the single expandable packer system
provides a unique and desirable system and methodology for
collecting formation fluid samples. It should be noted, however,
that a variety of components other than those illustrated can be
used with the MDT tool or incorporated into the single expandable
packer. For example, expansion mechanisms other than inflatable
inner sealing bladder 44 can be used to selectively expand the
packer structure. Additionally, a variety of materials and
configurations can be used to construct expandable mechanical
structure 48, expandable screen 60 and seal members 52 and 54.
[0026] Accordingly, although only a few embodiments of the present
invention have been described in detail above, those of ordinary
skill in the art will readily appreciate that many modifications
are possible without materially departing from the teachings of
this invention. Such modifications are intended to be included
within the scope of this invention as defined in the claims.
* * * * *