U.S. patent number 3,780,575 [Application Number 05/313,235] was granted by the patent office on 1973-12-25 for formation-testing tool for obtaining multiple measurements and fluid samples.
This patent grant is currently assigned to Schlumberger Technology Corporation. Invention is credited to Harold J. Urbanosky.
United States Patent |
3,780,575 |
Urbanosky |
December 25, 1973 |
FORMATION-TESTING TOOL FOR OBTAINING MULTIPLE MEASUREMENTS AND
FLUID SAMPLES
Abstract
In the representative embodiment of the new and improved
wireline formation-testing apparatus disclosed herein,
pressure-responsive fluid-admitting means and tool-anchoring means
are cooperatively arranged on a tool body for selectively anchoring
the tool in position in a well bore for obtaining at least one
measurement or fluid sample from a sub-surface earth formation. The
new and improved tool further includes a selectively-operable
hydraulic pump which is coupled by a plurality of
selectively-operable hydraulic valves to the pressure-responsive
means as well as to one or more pressure-responsive flow-control
valves. By arranging each of the hydraulic control valves to
operate only at selected hydraulic pressures, the new and improved
formation-testing tool is sequentially operated as required to
obtain selected measurements and, if desired, one or more samples
of the formation fluids from one or more formation intervals before
removing the tool from the well bore.
Inventors: |
Urbanosky; Harold J. (Pearland,
TX) |
Assignee: |
Schlumberger Technology
Corporation (New York, NY)
|
Family
ID: |
23214911 |
Appl.
No.: |
05/313,235 |
Filed: |
December 8, 1972 |
Current U.S.
Class: |
73/152.26;
166/100; 73/152.51 |
Current CPC
Class: |
F15B
11/16 (20130101); E21B 49/10 (20130101); F15B
2211/7142 (20130101); F15B 2211/555 (20130101); F15B
2211/6651 (20130101); F15B 2211/7716 (20130101); F15B
2211/426 (20130101); F15B 2211/6309 (20130101); F15B
2211/50563 (20130101); F15B 2211/20515 (20130101); F15B
2211/7055 (20130101); F15B 2211/6051 (20130101); F15B
2211/40515 (20130101); F15B 2211/6313 (20130101); F15B
2211/575 (20130101); F15B 2211/7128 (20130101); F15B
2211/30505 (20130101); F15B 2211/50518 (20130101); F15B
2211/41572 (20130101); F15B 2211/7107 (20130101); F15B
2211/6653 (20130101) |
Current International
Class: |
E21B
49/00 (20060101); E21B 49/10 (20060101); F15B
11/00 (20060101); F15B 11/16 (20060101); E21b
049/00 () |
Field of
Search: |
;73/151,152,421R,155
;166/100 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Myracle; Jerry W.
Claims
What is claimed is:
1. Formation-testing apparatus adapted for suspension in a well
bore traversing earth formations and comprising:
a body having a fluid passage adapted to receive connate
fluids;
fluid-admitting means on said body and adapted to be selectively
engaged with a well bore wall for isolating a portion thereof from
well bore fluids;
first pressure-responsive means on said body and operable in
response to a first operating pressure of a selected magnitude for
moving said fluid-admitting means against a well bore wall to
establish communication with earth formations therebeyond;
second pressure-responsive means on said body and operable in
response to a second operating pressure of a selected different
magnitude for communicating said fluid passage with said
fluid-admitting means; and
means on said body coupled to said first and second
pressure-responsive means and selectively operable for successively
developing at least said first and second operating pressures in
turn to operate said first and second pressure-responsive means in
a predetermined sequence.
2. The formation-testing apparatus of claim 1 wherein said second
operating pressure is greater than said first operating
pressure.
3. The formation-testing apparatus of claim 1 further including
transducer means on said body and in communication with said fluid
passage for measuring at least one characteristic of connate
fluids.
4. The formation-testing apparatus of claim 3 wherein said
transducer means include a pressure-measuring transducer.
5. The formation-testing apparatus of claim 1 further
including:
means on said body defining a fluid-receiving chamber; and
third pressure-responsive means coupled to said motive means and
operable in response to a third operating pressure of a selected
magnitude developed by said motive means and different than said
first and second operating pressures for communicating said fluid
passage with said fluid-receiving chamber.
6. The formation-testing apparatus of claim 5 wherein said second
operating pressure is greater than said first operating pressure,
and said third operating pressure is greater than said second
operating pressure.
7. The formation-testing apparatus of claim 5 further including
transducer means on said body and in communication with said fluid
passage for measuring at least one characteristic of connate fluids
entering said fluid passage and said fluid-receiving chamber.
8. The formation-testing apparatus of claim 7 wherein said
transducer means include a pressure-measuring transducer.
9. Formation-testing apparatus adapted for suspension in a well
bore traversing earth formations and comprising:
a body having a fluid passage adapted to receive connate
fluids;
fluid-admitting means on said body and adapted to be selectively
engaged with a well bore wall for isolating a portion thereof from
well bore fluids;
actuating means on said body and adapted for supplying an actuating
fluid at a range of varying output pressures;
first pressure-responsive means on said body operable in response
to a first predetermined pressure for selectively placing said
fluid-admitting means against a well bore wall to establish
communication with earth formations therebeyond and operable in
response to a fourth predetermined pressure for selectively
displacing said fluid-admitting means from a well bore wall to
discontinue such communication;
second pressure-responsive means on said body operable in response
to a second predetermined pressure for selectively communicating
said fluid-admitting means with said fluid passage and operable in
response to a third predetermined pressure for selectively
discontinuing communication between said fluid-admitting means and
said fluid passage; and
control means selectively operable from the surface for
communicating an actuating fluid from said actuating means with
each of said pressure-responsive means to sequentially place said
fluid-admitting means against a well bore wall, communicate and
then discontinue communication between said fluid-admitting means
and said fluid passage, and finally displace said fluid-admitting
means from a well bore wall in response to successive changes of
said output pressures of said actuating means to each of said
predetermined pressures in turn.
10. The formation-testing apparatus of claim 9 wherein said fourth
predetermined pressure is greater than said first predetermined
pressure.
11. The formation-testing apparatus of claim 9 wherein said third
predetermined pressure is greater than said second predetermined
pressure.
12. The formation-testing apparatus of claim 9 wherein said fourth
and third predetermined pressures are respectively greater than
said first and second predetermined pressures.
13. The formation-testing apparatus of claim 9 further
including:
sample-collecting means on said body and adapted for receiving a
sample of connate fluids in said fluid passage; and
third pressure-responsive means on said body operable in response
to a fifth predetermined operating pressure for communicating said
fluid passage with said sample-collecting means as said control
means communicate an actuating fluid with said third
pressure-responsive means and operable in response to a sixth
predetermined operating pressure for discontinuing communication
between said fluid passage and said sample-collecting means as said
control means communicate an actuating fluid with said third
pressure-responsive means.
14. The formation-testing apparatus of claim 13 wherein said
control means further include:
valve means on said body and selectively operable from the surface
for controlling fluid communication between said third
pressure-responsive means and said actuating means.
15. The formation-testing apparatus of claim 13 wherein said fifth
predetermined pressure is greater than said fourth predetermined
pressure and said fourth predetermined pressure is greater than
said first predetermined pressure.
16. The formation-testing apparatus of claim 15 wherein said third
predetermined pressure is greater than said second predetermined
pressure and said second predetermined pressure is greater than
said sixth predetermined pressure.
17. The formation-testing apparatus of claim 9 further
including:
pressure-measuring means cooperatively associated with said fluid
passage and adapted for providing signals at the surface
representative of pressures of fluids in said fluid passage.
18. The formation-testing apparatus of claim 9 wherein said first
pressure-responsive means include:
piston-actuator means on said body and including at least one
piston member adapted for extension from said body upon application
of said first predetermined pressure to said piston-actuator means
and adapted for retraction away from a well bore wall upon
application of said fourth predetermined pressure to said
piston-actuator means.
19. The formation-testing apparatus of claim 18 further
including:
wall-engaging means coupled to said piston member and adapted for
movement thereby into anchoring engagement with a well bore wall
upon extension of said piston member from said body.
20. The formation-testing apparatus of claim 18 further
including:
means cooperatively coupling said fluid-admitting means to said
piston member for movement thereby into engagement with a well bore
wall upon extension of said piston member from said body.
21. The formation-testing apparatus of claim 9 wherein said first
pressure-responsive means include:
piston-actuator means on said body and including at least first and
second piston members respectively adapted for extension in
opposite directions from said body upon application of said first
predetermined pressure to said piston-actuator means and
respectively adapted for retraction back to said body upon
application of said fourth predetermined pressure to said
piston-actuator means;
wall-engaging means coupled to said first piston member and adapted
for movement thereby into and out of anchoring engagement with a
well bore wall upon extension and retraction of said first piston
member; and
means cooperatively coupling said fluid-admitting means to said
second piston member for movement thereby into and out of
engagement with a well bore wall upon extension and retraction of
said second piston member.
22. The formation-testing apparatus of claim 21 further
including:
wall-sealing means cooperatively arranged on said fluid-admitting
means and adapted for sealing engagement with a well bore wall upon
extension of said second piston member.
23. Formation-testing apparatus adapted for suspension in a well
bore traversing earth formations and comprising:
a body having a fluid passage arranged thereon for receiving
connate fluids;
fluid-admitting means coupled to said fluid passage and
cooperatively arranged on said body for engagement with a well bore
wall to isolate a portion thereof from well bore fluids;
first pressure-responsive means adapted for selectively engaging
and disengaging said fluid-admitting means with and from a well
bore wall and including first piston means operatively arranged for
extension toward a well bore wall in response to a pressure
differential acting on one end of said first piston means and for
retraction from a well bore wall in response to a pressure
differential acting on the other end of said first piston
means;
second pressure-responsive means adapted for selectively
controlling the flow of fluids in said fluid passage and including
valve means movable between open and closed operating positions and
coupled to said fluid passage, and second piston means connected to
said valve means and operatively arranged for selectively moving
said valve means to one of said operating positions in response to
a pressure differential acting on one end of said second piston
means and for selectively moving said valve means to the other of
said operating positions in response to a pressure differential
acting on the other end of said second piston means;
hydraulic actuating means on said body and including a pump
selectively operable from the surface and adapted for supplying a
hydraulic fluid at progressively-increasing pressures over a
selected range of operating pressures, a first hydraulic conduit
coupled to said one end of said first piston means, a second
hydraulic conduit coupled to said other end of said first piston
means and to said other end of said second piston means, and a
third hydraulic conduit coupled to said one end of said second
piston means;
first control means operable upon a first operating cycle of said
pump for selectively coupling said first hydraulic conduit to the
outlet of said pump and coupling said second hydraulic conduit to
the inlet of said pump to extend said first piston means as said
pump first supplies a hydraulic fluid at a first selected pressure
level to said first hydraulic conduit;
second control means operable only upon a further increase in fluid
pressure in said first hydraulic conduit above said first selected
pressure level for coupling said first hydraulic conduit to said
third hydraulic conduit to supply hydraulic fluid to said one end
of said second piston means only so long as the fluid pressure in
said first hydraulic conduit is no less than said first selected
pressure level;
third control means operable upon a second operating cycle of said
pump for selectively coupling said second hydraulic conduit to said
pump outlet and coupling said third hydraulic conduit to said pump
inlut to supply hydraulic fluid at a second selected pressure level
to said other end of said second piston means; and
fourth control means operable only upon a further increase in fluid
pressure in said second hydraulic conduit above said second
selected pressure level for coupling said first hydraulic conduit
to said pump inlet only so long as the fluid pressure in said
second hydraulic conduit is no less than said second selected
pressure level.
24. The formation-testing apparatus of claim 23 wherein said one
operating position of said valve means is said open position of
said valve means.
25. The formation-testing apparatus of claim 23 wherein said one
operating position of said valve means is said closed position of
said valve means.
26. The formation-testing apparatus of claim 23 further
including:
control means selectively operable from the surface for controlling
the admission of hydraulic fluid from said third hydraulic conduit
to said one end of said second piston means.
27. The formation-testing apparatus of claim 23 further
including:
means cooperatively coupling said fluid-admitting means to said
first piston means for moving said fluid-admitting means into and
out of engagement with a well bore wall upon extension and
retraction of said first piston means.
28. The formation-testing apparatus of claim 23 further
including:
sample-collecting means coupled to said fluid passage downstream of
said valve means.
29. The formation-testing apparatus of claim 28 further
including:
control means selectively operable from the surface for controlling
the admission of hydraulic fluid from said third hydraulic conduit
to said one end of said second piston means.
30. Formation-testing apparatus adapted for suspension in a well
bore traversing earth formations and comprising:
a body having a fluid passage arranged thereon for receiving
connate fluids;
fluid-admitting means coupled to said fluid passage and
cooperatively arranged on said body for engagement with a well bore
wall to isolate a portion thereof from well bore fluids;
first pressure-responsive means adapted for selectively engaging
and disengaging said fluid-admitting means with and from a well
bore wall and including first piston means operatively arranged for
extension toward a well bore wall in response to a pressure
differential acting on one end of said first piston means and for
retraction from a well bore wall in response to a pressure
differential acting on the other end of said first piston
means;
second pressure-responsive means adapted for selectively
controlling the flow of fluids in said fluid passage and including
valve means movable between open and closed operating positions and
coupled to said fluid passage, and second piston means connected to
said valve means and operatively arranged for selectively moving
said valve means to one of said operating positions in response to
a pressure differential acting on one end of said second piston
means and for selectively moving said valve means to the other of
said operating positions in response to a pressure differential
acting on the other end of said second piston means;
hydraulic actuating means on said body and including a pump
selectively operable from the surface and adapted for supplying a
hydraulic fluid at progressively-increasing pressures over a
selected range of operating pressures, a first hydraulic conduit
coupled to said one end of said first piston means and to said one
end of said second piston means, and a second hydraulic conduit
coupled to said other end of said first piston means;
first control means operable upon a first operating cycle of said
pump for selectively coupling said first hydraulic conduit to the
outlet of said pump and coupling said second hydraulic conduit to
the inlet of said pump to extend said first piston means as said
pump first supplies a hydraulic fluid at a first selected pressure
level to said first hydraulic conduit;
second control means operable only upon a further increase in fluid
pressure in said first hydraulic conduit above said first selected
pressure level for coupling said second hydraulic conduit to said
other end of said second piston means to receive hydraulic fluid
therefrom only so long as the fluid pressure in said first
hydraulic conduit is no less than said first selected pressure
level;
third control means operable upon a second operating cyle of said
pump for selectively coupling said second hydraulic conduit to said
pump outlet to supply hydraulic fluid at a second preselected
pressure level to said other end of said second piston means;
and
fourth control means operable only upon a further increase in fluid
pressure in said second hydraulic conduit above said second
selected pressure level for coupling said first hydraulic conduit
to said pump inlet only so long as the fluid pressure in said
second hydraulic conduit is no less than said second selected
pressure level.
31. The formation-testing apparatus of claim 30 further
including:
means coupling said fluid-admitting means to said first piston
means for moving said fluid-admitting means into and out of
engagement with a well bore wall upon extension and retraction of
said first piston means.
32. The formation-testing apparatus of claim 30 wherein said
fluid-admitting means include:
a sealing member cooperatively arranged for sealing engagement with
a well bore wall and having a central opening, and a tubular
fluid-conducting member coupled to said fluid passage and disposed
within said central opening.
33. The formation-testing apparatus of claim 32 wherein said second
pressure-responsive means are cooperatively arranged on said
tubular fluid-conducting member for controlling the flow of fluids
between said tubular fluid-conducting member and said fluid
passage.
34. The formation-testing apparatus of claim 33 further
including:
means coupling said fluid-admitting means to said first piston
means for moving said fluid-admitting means into and out of
engagement with a well bore wall upon extension and retraction of
said first piston means.
35. Formation-testing apparatus adapted for suspension in a well
bore traversing earth formations and comprising:
a body having a fluid passage arranged thereon for receiving
connate fluids;
fluid-admitting means coupled to said fluid passage and
cooperatively arranged on said body for engagement with a well bore
wall to isolate a portion thereof from well bore fluids;
first pressure-responsive means adapted for selectively engaging
and disengaging said fluid-admitting means with and from a well
bore wall and including piston means operatively arranged for
extension toward a well bore wall in response to a pressure
differential acting on one end of said piston means and for
retraction from a well bore wall in response to a pressure
differential acting on the other end of said piston means;
second pressure-responsive means adapted for selectively
controlling the flow of fluids in said fluid passage and including
first valve means coupled to said fluid passage and movable between
an open position to admit well bore fluids into said fluid passage
and a closed position to block the entrance of well bore fluids
into said fluid passage, first piston-actuator means connected to
said first valve means and operatively arranged for selectively
moving said first valve means to its said closed position in
response to a pressure differential acting on one end of said first
piston-actuator means and for selectively moving said first valve
means to its said open position in response to a pressure
differential acting on the other end of said first piston-actuator
means, second valve means connected in said fluid passage and
movable between a closed position to block the flow of fluids
through said fluid passage and an open position to allow fluids to
flow through said fluid passage, and second piston-actuator means
connected to said second valve means and operatively arranged for
selectively moving said second valve means to its said open
position in response to a pressure differential acting on one end
of said second piston-actuator means and for selectively moving
said second valve means to its said closed position in response to
a pressure differential acting on the other end of said second
piston-actuator means;
hydraulic actuating means on said body and including a pump
selectively operable from the surface and adapted for supplying a
hydraulic fluid at progressively-increasing pressures over a
selected range of operating pressures, a first hydraulic conduit
coupled to said one end of said piston means, a second hydraulic
conduit coupled to said other end of said piston means and to said
other ends of said first and second piston-actuator means, and a
third hydraulic conduit coupled to said one ends of said first and
second piston-actuator means;
first control means operable upon a first operating cycle of said
pump for selectively coupling said first hydraulic conduit to the
outlet of said pump and coupling said second hydraulic conduit to
the inlet of said pump to extend said piston means as said pump
first supplies a hydraulic fluid at a first selected pressure level
to said first hydraulic conduit;
second control means operable only upon a further increase in fluid
pressure in said first hydraulic conduit above said first selected
pressure level for coupling said first hydraulic conduit to said
third hydraulic conduit to supply hydraulic fluid to said ends of
said first and second piston-actuator means only so long as the
fluid pressure in said first hydraulic conduit is no less than said
first selected pressure level;
third control means operable upon a second operating cycle of said
pump for selectively coupling said second hydraulic conduit to said
pump outlet and coupling said third hydraulic conduit to said third
hydraulic conduit to said pump inlet to supply hydraulic fluid at a
second selected pressure level to said other ends of said first and
second piston-actuator means; and
fourth control means operable only upon a further increase in fluid
pressure in said second hydraulic conduit above said second
selected pressure level for coupling said first hydraulic conduit
to said pump inlet only so long as the fluid pressure in said
second hydraulic conduit is no less than said second selected
pressure level.
36. The formation-testing apparatus of claim 35 wherein said piston
means include a laterally-extendible piston member adapted for
extension and retraction relative to one side of said body, and
said fluid-admitting means are mounted on the other side of said
body for engagement with one well bore wall upon extension of said
extendible piston member against the opposite well bore wall.
37. The formation-testing apparatus of claim 35 wherein said piston
means include a laterally-extendible piston member adapted for
extension and retraction relative to one side of said body, and
further including:
means cooperatively coupling said fluid-admitting means to said
piston member for moving said fluid-admitting means into and out of
engagement with a well bore wall upon extension and retraction of
said piston member.
38. The formation-testing apparatus of claim 35 wherein said piston
means include first and second laterally-extendible piston members
respectively adapted for simultaneous extension and retraction
relative to opposite sides of said body, and further including:
means cooperatively coupling said fluid-admitting means to said
first piston member for moving said fluid-admitting means into and
out of engagement with a well bore wall upon extension of said
first and second piston members.
39. The formation-testing apparatus of claim 35 further
including:
sample-collecting means coupled to said fluid passage downstream of
said second valve means.
40. The formation-testing apparatus of claim 39 further
including:
fifth control means selectively operable from the surface for
controlling the admission of hydraulic fluid from said third
hydraulic conduit to said one end of said second piston-actuator
means.
Description
Heretofore, the typical wireline formation testers (such as the
tool disclosed in U.S. Pat. No. 3,011,554) which have been most
successful in commercial service have been limited to attempting
only a single test of one selected formation interval. Those
skilled in the art will appreciate that once one of these typical
tools is positioned in a well bore and a sampling or testing
operation is initiated, the tool cannot be again operated without
first removing it from the well bore and reconditioning various
tool components for another run. Thus, even should it be quickly
realized that a particular sampling or testing operation already
underway will probably be unsuccessful, the operator has no choice
except to discontinue the operation and then return the tool to the
surface. This obviously results in a needless loss of time and
expense which would usually be avoided if another attempt could be
made without having to remove the tool from the well bore.
To counter this significant limitation, more-modern tools such as
shown in U.S. Pat. No. 3,385,364 have been used with some success.
As disclosed there, these formation testers typically include two
or more self-contained testing units which are tamdemly coupled to
one another and cooperatively arranged for independent operation.
Although tools such as these have been commercially employed, it
has been found that their overall weight and length make it
difficult to use such tools in many situations.
Various proposals have, of course, been advanced heretofore for
providing formation-testing tools which are presumably capable of
conducting more than one testing or sampling operation during a
single run. Most of these proposed tools have, however, employed
such unduly complicated arrays of solenoid-actuated valves and
elaborate downhole controls that it is doubtful that these fanciful
tools would be suited for reliable commercial operation under the
adverse well bore conditions typically encountered today.
Another problem which has heretofore prevented the production of a
commercially successful repetitively-operable formation-testing
tool has been in providing a suitable arrangement for reliably
establishing fluid or pressure communication with incompetent or
unconsolidated earth formations. Although the several new and
improved testing tools respectively shown in U.S. Pat. No.
3,352,361, U.S. Pat. No. 3,530,933, U.S. Pat. No. 3,565,169 and
U.S. Pat. No. 3,653,436 are especially arranged for testing
unconsolidated formations, for one reason or another these tools
are not adapted for performing more than one testing operation
during a single run in a given well bore.
One of the better prior-art repetitively-operable testing tools
which is suited for commercial operations is shown in FIG. 2 of
U.S. Pat. No. 3,577,781. As disclosed there, this new and improved
tool employs a straight-forward control system having only a single
solenoid-actuated valve and a selectively-reversible hydraulic
pump. It will be recognized, however, that this tool is not
arranged for collecting a fluid sample which can be returned to the
surface for examination. Moreover, since the fluid-admission port
in this tool is permanently open, a tool such as this is not
intended for operation where the formation being investigated is
relatively unconsolidated.
Accordingly, it is an object of the present invention to provide
new and improved well bore apparatus for reliably obtaining
multiple measurements of one or more fluid or formation
characteristics as well as selectively collecting one or more
samples of formation fluids, if desired, without regard to the
nature or competency of the formations being tested.
This and other objects of the present invention are attained by
providing a formation tester with selectively-operable means
arranged for releasably anchoring the tool in a well bore as well
as for establishing isolated communication with an earth formation
while limiting or preventing the admission of loose formation
materials and also including selectively-operable means for
obtaining at least measurements indicative of one or more
characteristics of the earth formation or connate fluids contained
therein. To selectively operate the tool for one or more testing
cycles, each of the several selectively-operable means as well as
various flow control valves arranged in the tool are cooperatively
coupled to a selectively-operable hydraulic pump by way of a
control system including a plurality of hydraulic control valves
respectively adapted to operate at different predetermined
hydraulic pressures. In this manner, by simply starting the
hydraulic pump, as the output pressure of the pump rises, each of
the several hydraulic control valves will be successively operated
in a predetermined sequence as required for carrying the tool
through a selected operating cycle.
The novel features of the present invention are set forth with
particularity in the appended claims. The invention, together with
further objects and advantages thereof, may be best understood by
way of the following description of exemplary apparatus employing
the principles of the invention as illustrated in the accompanying
drawings, in which:
FIG. 1 depicts the surface and downhold portions of a preferred
embodiment of new and improved formation-testing apparatus
incorporating the principles of the present invention;
FIGS. 2A and 2B together show a somewhat-schematic representation
of the formation-testing tool illustrated in FIG. 1 as the tool
will appear in its initial operating position;
FIG. 3 is a representative performance curve graphically depicting
the operation of the new and improved formation-testing tool of the
present invention as it selectively conducts a typical testing and
sampling operation;
FIGS. 4-7 respectively depict the successive positions of various
components of the new and improved tool shown in FIGS. 2A and 2B
during the course of a typical testing and sampling operation;
FIG. 8 is similar to FIG. 3 but graphically illustrates the
operation of the formation-testing tool as it selectively returns
to its initial operating position following a complete testing and
sampling operation; and
FIGS. 9-11 respectively show the successive positions of the
several components of the new and improved formation-testing tool
as the tool is returned to its initial operating position.
Turning now to FIG. 1, a preferred embodiment of a new and improved
formation-testing tool 20 incorporating the principles of the
present invention is shown as it will appear during the course of a
typical measuring and sampling operation in a well bore such as a
borehole 21 penetrating one or more earth formations as at 22 and
23. As illustrated, the tool 20 is suspended in the borehole 21
from the lower end of a typical multiconductor cable 24 that is
spooled in the usual fashion on a suitable winch (not shown) at the
surface and coupled to the surface portion of a new and improved
tool-control system 25 as well as typical recording and indicating
apparatus 26 and a power supply 27. In its preferred embodiment,
the tool 20 includes an elongated body 28 which encloses the
downhole portion of the new and improved control system 25 and
carries selectively-extendible tool-anchoring means 29 and new and
improved fluid-admitting means 30 arranged on opposite sides of the
body as well as one or more tandemly-coupled fluid-collecting
chambers 31 and 32.
As will be subsequently explained in greater detail, the new and
improved formation-testing tool 20 and the control system 25 are
cooperatively arranged so that, upon command from the surface, the
tool can be selectively placed in any one or more of five selected
operating positions. As will be subsequently described, the control
system 25 will function to either successively place the tool 20 in
one or more of these positions or else cycle the tool between
selected ones of these operating positions. These five operating
positions will be described later by reference to various ones of
the several drawings depicting the versatility of the unique
tool-control system 25 which functions to operate the tool 20 for
achieving the objects of the present invention by selectively
moving suitable control switches, as schematically represented at
33 and 34, included in the surface portion of the system to various
switching positions, as at 35-40, so as to selectively apply power
to different conductors 41-48 in the cable 24.
Turning now to FIGS. 2A and 2B, the entire downhole portion of the
control system 25 as well as the tool-anchoring means 29, the
fluid-admitting means 30 and the fluid-collecting chambers 31 and
32 of the tool 20 are schematically illustrated with their several
elements or components depicted as they will respectively be
arranged when the new and improved tool is fully retracted and the
switches 33 and 34 are in their first or "off" operating positions
35. In the preferred embodiment of the selectively-extendible
tool-anchoring means 29 schematically illustrated in FIG. 2A, an
upright wall-engaging anchor member 50 is coupled in a typical
fashion to a longitudinally-spaced pair of rearwardly-movable
piston actuators 51 and 52 of a typical design mounted transversely
on the tool body 28. As will be subsequently explained, the lateral
extension and retraction of the wall-engaging member 50 in relation
to the rear of the tool body 28 is controlled by the control system
25 which is operatively arranged to selectively admit and discharge
a pressured hydraulic fluid to and from the piston actuators 51 and
52.
The fluid-admitting means 30 employed with the preferred embodiment
of the new and improved tool 20 are cooperatively arranged for
sealing-off or isolating selected portions of the wall of the
borehole 21; and, once a selected portion of the borehole wall is
packed-off or isolated from the well bore fluids, establishing
pressure of fluid communication with the adjacent earth formations.
As depicted in FIG. 2A, the fluid-admitting means 30 preferably
include an annular elastomeric sealing pad 53 mounted on the
forward face of an upright support member or plate 54 that is
coupled to a longitudinally-spaced pair of forwardly-movable piston
actuators 55 and 56 respectively arranged transversely on the tool
body 28 for moving the sealing pad laterally in relation to the
forward side of the tool body. Accordingly, as the new and improved
control system 25 selectively supplies a pressured hydraulic fluid
to the piston actuators 55 and 56, the sealing pad 53 will be moved
laterally between a retracted position adjacent to the forward side
of the tool body 28 and an advanced or forwardly-extended
position.
By arranging the annular sealing member 53 on the opposite side of
the tool body 28 from the wall-engaging member 50, the lateral
extension of these two members will, of course, be effective for
urging the sealing pad into sealing engagement with the adjacent
wall of the borehole 21 and anchoring the tool 20 each time the
piston actuators 51, 52, 55 and 56 are extended. It will, however,
be appreciated that the wall-engaging member 50 as well as its
piston actuators 51 and 52 would not be needed if the effective
stroke of the piston actuators 55 and 56 would be sufficient for
assuring that the sealing member 53 can be extended into firm
sealing engagement with one wall of the borehole 21 with the rear
of the tool body 28 securely anchored against the opposite wall of
the borehole. Conversely, the piston actuators 55 and 56 could be
similarly omitted where the extension of the wall-engaging member
50 alone would be effective for moving the other side of the tool
body 28 forwardly toward one wall of the borehole 21 so as to place
the sealing pad 53 into firm sealing engagement therewith. However,
in the preferred embodiment of the formation-testing tool 20, both
the tool-anchoring means 29 and the fluid-admitting means 30 are
made selectively extendible to enable the tool to be operated in
boreholes of substantial diameter. This preferred design of the
tool 20, of course, resulsts in the overall stroke of the piston
actuators 51 and 52 and the piston actuators 55 and 56 being kept
to a minimum so as to reduce the overall diameter of the tool body
28.
To conduct connate fluids into the new and improved tool 20, the
fluid-admitting means 30 further include an enlarged tubular member
57 having an open forward portion coaxially disposed within the
sealing pad 53 and a closed rear portion which is slidably mounted
within a larger tubular member 58 secured to the rear face of the
plate 54 and extended rearwardly therefrom. By arranging the nose
of the tubular fluid-admitting member 57 to normally protrude a
short distance ahead of the forward face of the sealing pad 53,
extension of the fluid-admitting means 30 will engage the forward
end of the fluid-admitting member with the adjacent surface of the
wall of the borehole 21 as the annular sealing pad is also forced
thereagainst for isolating that portion of the borehole wall as
well as the nose of the fluid-admitting member from the well bore
fluids. To selectively move the tubular fluid-admitting member 57
in relation to the enlarged outer member 58, the smaller tubular
member is slidably disposed within the outer tubular member and
fluidly sealed in relation thereto as by sealing members 59 and 60
on inwardly-enlarged end portions 61 and 62 of the outer member and
a sealing member 63 on an enlarged-diameter intermediate portion 64
of the inner member.
Accordingly, it will be appreciated that by virtue of the sealing
members 59, 60 and 63, enclosed piston chambers 65 and 66 are
defined within the outer tubular member 58 and on opposite sides of
the outwardly-enlarged portion 64 of the inner tubular member 57
which, of course, functions as a piston member. Thus, by increasing
the hydraulic pressure in the rearward chamber 65, the
fluid-admitting member 57 will be moved forwardly in relation to
the outer tubular member 58 as well as to the sealing pad 53.
Conversely, upon the application of an increased hydraulic pressure
to the forward piston chamber 66, the fluid-admitting member 57
will be retracted in relation to the outer member 58 and the
sealing pad 53.
Pressure or fluid communication with the fluid-admitting means 30
is controlled by means such as a generally-cylindrical valve member
67 which is coaxially disposed within the fluid-admitting member 57
and cooperatively arranged for axial movement therein between a
retracted or open position and the illustrated advanced or closed
position where the enlarged forward end 68 of the valve member is
substantially, if not altogether, sealingly engaged with the
forwardmost interior portion of the fluid-admitting member. To
support the valve member 67, the rearward portion of the valve
member is axially hollowed, as at 69, and coaxially disposed over a
tubular member 70 projecting forwardly from the transverse wall
closing the rear end of the fluid-admitting member 57. The axial
bore 69 is reduced and extended forwardly along the valve member 67
to a termination with one or more transverse fluid passages 71 in
the forward portion of the valve member just behind its enlarged
head 68.
To provide piston means for selectively moving the valve member 67
in relation to the fluid-admitting member 57, the rearward portion
of the valve member is enlarged, as at 72, and outer and inner
sealing members 73 and 74 are coaxially disposed thereon and
respectively sealingly engaged with the interior of the
fluid-admitting member and the exterior of the forwardly-extending
tubular member 70. A sealing member 75 mounted around the
intermediate portion of the valve member 67 and sealingly engaged
with the interior wall of the adjacent portion of the
fluid-admitting member 57 fluidly seals the valve member in
relation to the fluid-admitting member. Accordingly, it will be
appreciated that by increasing the hydraulic pressure in the
enlarged piston chamber 76 defined to the rear of the enlarged
valve portion 72 which serves as a piston member, the valve member
67 will be moved forwardly in relation to the fluid-admitting
member 57. Conversely, upon application of an increased hydraulic
pressure to the forward piston chamber 77 defined between the
sealing members 73 and 75, the valve member 67 will be moved
rearwardly along the forwardly-projecting tubular member 70 so as
to retract the valve member in relation to the fluid-admitting
member 57.
Those skilled in the art will, of course, appreciate that many
earth formations, as at 22, are relatively unconsolidated and are,
therefore, readily eroded by the withdrawal of connate fluids.
Thus, to prevent any significant erosion of such unconsolidated
formation materials, the fluid-admitting member 57 is arranged to
define an internal annular space 78 and a flow passage 79 in the
forward portion of the fluid-admitting member and a tubular screen
80 of suitable fineness is coaxially mounted around the annular
space. In this manner, when the valve member 67 is retracted,
formation fluids will be compelled to pass through the exposed
forward portion of the screen 80 ahead of the enlarged head 68,
into the annular space 78, and then through the fluid passage 79
into the fluid passages 71 and 69. Thus, as the valve member 67 is
retracted, should loose or unconsolidated formation materials be
eroded from a formation as connate fluids are withdrawn therefrom,
the materials will be stopped by the exposed portion of the screen
80 ahead of the enlarged head 68 of the valve member thereby
quickly forming a permeable barrier to prevent the continued
erosion of loose formation materials once the valve member
halts.
A sample or flow line 81 is cooperatively arranged in the
formation-testing tool 20 and has one end coupled, as by a flexible
conduit 82, to the fluid-admitting means and its other end
terminated in a pair of branch conduits 83 and 84 respectively
coupled to the fluid-collecting chambers 31 and 32. To control the
communication between the sample-admitting means 30 and the
fluid-collecting chambers 31 and 32, normally-closed flow-control
valves 85-87 of a similar or identical design are arranged
respectively in the flow line 81 and in the branch conduits 83 and
84 leading to the sample chambers. For rreasons which will
subsequently be described in greater detail, a normally-open
control valve 88 which is similar to the normally-closed control
valves 85-87 is cooperatively arranged in a branch conduit 89 for
selectively controlling communication between the well bore fluids
exterior of the tool 20 and the upper portion of the flow line 81
extending between the flow-line control valve 85 and the
fluid-admitting means 30.
As illustrated, the flow-line control valve 85 (as well as each of
the chamber control valves 86 and 87) is comprised of an elongated
body 90 having an enlarged piston cylinder 91 cooperatively
arranged for carrying an actuating piston 92 which is normally
biased to a lower position by a spring 93 of a predetermined
strength. A valve member 94 coupled to the piston member 92 is
cooperatively arranged for blocking fluid communication between
inlet and outlet ports 95 and 96 so long as the piston is in its
lower position. To control the operation of the valve 85, ports 97
and 98 are provided for the admission and discharge of hydraulic
fluid into the cylinder 91 above and below the actuating piston 92.
The valve 88 is similar to the valves 85-87 except that a spring 99
of selected strength normally biases the valve member 100 to an
open position.
As shown in FIGS. 2A-2B, a branch conduit 101 is coupled to the
flow line 81 at a convenient location between the sample chamber
control valves 86 and 87 and the flow-line control valve 85, with
this branch conduit being terminated by selectively-operable
pressure-reduction means 102. In its preferred form, the
pressure-reduction means 102 include a body 103 having an enlarged
piston cylinder 104 in which an actuating piston 105 is operatively
mounted for carrying a reduced-diameter displacement piston 106
between selected upper and lower positions within a reduced chamber
107 of a predetermined volume. To control the movements of the
displacement piston 106, hydraulic ports 108 and 109 are provided
for admitting and exhausting hydraulic fluid into and from the
isolated portions of the larger actuating cylinder 104 on opposite
sides of the actuating piston 105. Accordingly, it will be
appreciated that upon movement of the displacement piston 106 from
its lower position as illustrated in FIG. 2A to an elevated or
upper position, the combined volume of whatever fluids that are
then contained in the branch conduit 101 as well as that portion of
the flow line 81 between the flow-line control valve 85 and the
sample chamber control valves 86 and 87 will be correspondingly
increased. The significance of the substantial reduction in
pressure caused by this selective increase in volume will be
subsequently explained.
As best seen in FIG. 2A, the preferred embodiment of the control
system 25 further includes a pump 110 that is coupled to a driving
motor 111 and cooperatively arranged for pumping a suitable
hydraulic fluid such as oil or the like from a reservoir 112 into a
discharge or outlet line 113. Since the tool 20 is to be operated
in well bores, as at 21, which typically contain dirty and usually
corrosive fluids, the reservoir 112 is preferably arranged to
totally immerse the pump 110 and the motor 111 in the clean
hydraulic fluid. Inasmuch as the formation-testing tool 20 must
operate at depths where the hydrostatic pressure of the surrounding
well bore fluids can be as high as 15-20,000-psig, the reservoir
112 is provided with an inlet 114 for well bore fluids and an
isolating piston 115 is movably arranged in the reservoir for
maintaining the hydraulic fluid contained therein at a pressure
about equal to the hydrostatic pressure at whatever depth the tool
is then situated. Biasing means, such as a spring 116 acting on the
piston 115, are provided for maintaining the pressure of the
hydraulic fluid in the reservoir 112 at an increased level slightly
above the well bore hydrostatic pressure so as to at least minimize
the influx of well bore fluids into the reservoir. It will, of
course, be recognized that in addition to isolating the hydraulic
fluid in the reservoir 112, the piston 115 will also be free to
move as required to accommodate volumetric changes in the hydraulic
fluid which may occur under different well bore conditions. One or
more inlets, as at 117 and 118, are provided for returning
hydraulic fluid from the control systems 25 to the reservoir 112
during the operation of the tool 20.
The fluid outlet line 113 is divided into two major branch lines
which are respectively designated as the "set" line 119 and the
"retract" line 120. As will be subsequently described, the control
system 25 is arranged to selectively direct hydraulic fluid at
selected pressures and times through the "set" and "retract" lines
119 and 120 to one or more of the several components of the
formation-testing tool 20 as required to operate the tool during
the course of a testing or sampling operation. The preferred
operating sequences will be discussed later.
To control the admission of hydraulic fluid to the "set" and
"retract" lines 119 and 120, the new and improved control system 25
further includes selectively-operable valve means such as a pair of
normally-closed solenoid-actuated valves 121 and 122 which are
cooperatively arranged to selectively admit hydraulic fluid to the
two lines as the control switch 33 at the surface is selectively
positioned. For reasons which will subsequently be explained, a
typical check valve 123 is arranged in the "set" line 119
downstream of the control valve 121 for preventing the reverse flow
of the hydraulic fluid whenever the pressure in the "set" line is
greater than that then existing in the fluid outlet line 113.
Control devices, such as typical pressure switches 124-126, are
cooperatively arranged in the "set" and "retract" lines 119 and 120
for selectively discontinuing operation of the pump 110 whenever
the pressure of the hydraulic fluid in either of these lines
reaches a desired maximum operating pressure and then restarting
the pump whenever the pressure drops below this value so as to
maintain the line pressure within a selected operating range.
It will, of course, be recognized that since it is preferred that
the pump 110 be a positive-displacement type to achieve a rapid
predictable rise in the operating pressures in the "set" and
"retract" lines 119 and 120 in a minimum length of time, the
control system 25 should also provide for temporarily opening the
outlet line 113 until the motor 111 has reached its rated operating
speed. Accordingly, the control system 25 is cooperatively arranged
so that each time the pump 110 is to be started, the control valve
122 (if it is not already open) as well as a third normally-closed
solenoid-actuated valve 127 will be temporarily opened to bypass
hydraulic fluid directly from the output line 113 to the reservoir
112 by way of the return line 117. Once the motor 111 has reached
operating speed, the bypass valve 127 will, of course, be reclosed
and either the "set" line control valve 121 or the "retract" line
control valve 122 will be selectively opened as required for that
particular operational phase of the tool 20. It should be noted
that during those times that the "retract" line control valve 122
and the fluid-bypass valve 127 are opened to allow the motor 111 to
reach its operating speed, the check valve 123 will function to
prevent the reverse flow of hydraulic fluid from the "set" line 119
when the "set" line control valve 121 is open.
Accordingly, it will be appreciated that the control system 25
cooperates for selectively supplying pressured hydraulic fluid to
the "set" and "retract" lines 119 and 120. Since the pressure
switches 124 and 125 respectively function only to limit the
pressures in the "set" and "retract" lines to a selected maximum
pressure range commensurate with the rating of the pump 110, the
new and improved control system 25 is further arranged to
cooperatively regulate the pressure of the hydraulic fluid which is
being supplied at various times to selected portions of the system.
Although this regulation can be accomplished in different manners,
it is preferred to employ a number of pressure-actuated control
valves such as shown schematically at 128-131 in FIGS. 2A and 2B.
As shown in FIG. 2A, the control valve 128, for example, includes a
valve body 132 having a valve seat 133 coaxially arranged therein
between inlet and outlet fluid ports 134 and 135. The upper portion
of the valve body 132 is enlarged to provide a piston cylinder 136
carrying an actuating piston 137 in coincidental alignment with the
valve seat 133. Biasing means, such as a spring 138 of a
predetermined strength, are arranged for normally urging the
actuating piston 137 toward the valve seat 133 and a control port
139 is provided for admitting hydraulic fluid into the cylinder 136
at a sufficient pressure to overcome the force of this spring
whenever the piston is to be selectively moved away from the valve
seat. Since the control system 25 operates at pressures no less
than the hydrostatic pressure of the well bore fluids, a relief
port 140 is provided in the valve body 132 for communicating the
space in the cylinder 136 above the actuating piston 137 with the
reservoir 112. A valve member 141 complementally shaped for seating
engagement with the valve seat 133 is cooperatively coupled to the
actuating piston 137 as by an upright stem 142 which is slidably
disposed in an axial bore 143 in the piston. A spring 144 of
selected strength is disposed in the axial bore 143 for normally
urging the valve member 141 into seating engagement with the valve
seat 133.
Accordingly, in its operating position depicted in FIG. 2A, the
control valve 128 (as well as the valve 129) will simply function
as a normally-closed check valve. That is to say, in this operating
position, hydraulic fluid can flow only in a reverse direction from
the outlet 135 to the inlet 134 whenever the pressure at the outlet
is sufficiently greater than the inlet pressure to elevate the
valve member 141 from the valve seat 133 against the predetermined
closing force imposed by the spring 144. On the other hand, when
sufficient fluid pressure is applied to the control port 139 for
elevating the actuating piston 137, opposed shoulders, as at 145,
on the stem 142 and the piston will engage for elevating the valve
member 141 from the valve seat 133.
As shown in FIGS. 2A and 2B, it will be appreciated that the
control valve 130 (as well as the valve 131) is similar to the
control valve 128 except that in the first-mentioned control valve,
the valve member 146 is preferably rigidly coupled to its
associated actuating piston 147. Thus, the control valve 130 (as
well as the valve 131) has no alternate checking action allowing
reverse flow and is simply a normally-closed pressure-actuated
valve for selectively controlling fluid communication between its
inlet and outlet ports 148 and 149. Hereagain, the hydraulic
pressure at which the control valve 130 (as well as the valve 131)
is to selectively open is governed by the predetermined strength of
the spring 150 normally biasing the valve member 146 to its closed
position.
The "set" line 119 downstream of the check valve 123 is comprised
of a low-pressure section 151 having one branch 152 coupled to the
fluid inlet of the control valve 130 and another branch 153 which
is coupled to the fluid inlet of the control valve 128 to
selectively supply hydraulic fluid to a high-pressure section 154
of the "set" line which is itself terminated at the fluid inlet of
the control valve 131. To regulate the supply of hydraulic fluid
from the low-pressure section 151 to the high-pressure section 154
of the "set" line 119, a pressure-communicating line 155 is coupled
between the low-pressure section and the control port of the
control valve 128. Accordingly, so long as the pressure of the
hydraulic fluid in the low-pressure section of the "set" line 119
remains below the predetermined actuating pressure required to open
the control valve 128, the high-pressure section 154 will be
isolated from the low-pressure section 151. Conversely, once the
hydraulic pressure in the low-pressure line 151 reaches the
predetermined actuating pressure of the valve 128, the control
valve will open to admit the hydraulic fluid into the high-pressure
line 154.
The control valves 130 and 131 are respectively arranged to
selectively communicate the low-pressure and high-pressure sections
151 and 154 of the "set" line 119 with the fluid reservoir 112. To
accomplish this, the control ports of the two control valves 130
and 131 are each connected to the "retract" line 120 as by suitable
pressure-communicating lines 156 and 157. Thus, whenever the
pressure in the "retract" line 120 reaches their respective
predetermined actuating levels, the control valves 130 and 131 will
be respectively opened to selectively communicate the two sections
151 and 154 of the "set" line 119 with the reservoir 112 by way of
the return line 117 coupled to the respective fluid outlets of the
two control valves.
As previously mentioned, in FIGS. 2A-2B the formation-testing tool
20 and the sub-surface portion of the control system 25 are
depicted as their several components will appear when the tool is
in its initial or "retracted"operating position. At this point, the
wall-engaging member 50 and the sealing pad 53 are respectively
retracted against the tool body 28 to facilitate passage of the
tool 20 into the borehole 21. To prepare the tool 20 for lowering
into the borehole 21, the switches 33 and 34 are moved to their
second or "initialization" positions 36. At this point, the
hydraulic pump 110 is started to raise the pressure in the
"retract" line 120 to maximum pressure to be certain that the pad
53 and the wall-engaging member 50 are fully retracted. As
previously mentioned, the control valves 122 and 127 will be
momentarily opened when the pump 110 is started until the pump
motor 111 has reached its operating speed. At this time also, the
control valve 88 is open and that portion of the flow line 81
between the closed flow-line control valve 85 and the
fluid-admitting means 30 will be filled with well bore fluids at
the hydrostatic pressure at the depths at which the tool 20 is then
situated.
In operating the new and improved tool 20, it is necessary only to
selectively position the control switches 33 and 34 (FIG. 1) at one
or more of their several switching positions 35-40. Thus, when the
tool 20 is at a selected operating depth, the switches 33 and 34
are advanced to their third positions 37. By this time the pump 110
will have been halted so that moving of the switch 33 to its "set"
position 37 will restart the pump for developing an increased
pressure in the "set" line. Hereagain, the valves 122 and 127 will
be momentarily opened to allow the motor 111 to reach its full
speed before the control system 25 begins to function to initiate
setting of the tool 20. Then, as schematically represented by the
exemplary system performance curve 158 in FIG. 3, once the pump 110
has reached its rated operating speed, the hydraulic pressure in
the output line 113 will rapidly rise to its selected maximum
operating pressure as determined by the maximum or "off" setting of
the pressure switch 124. As the pressure progressively rises, the
control system 25 will successively function at selected
intermediate pressure levels respectively designated by the letters
"A"-"D" in FIG. 3.
Turning now to FIG. 4, selected portions of the control system 25
and various components of the formation-testing tool 20 are
schematically represented to illustrate the operation of the tool
at about the time that the pressure in the hydraulic output line
113 reaches its lowestmost operating pressure as designated at "A"
in FIG. 3. To facilitate an understanding of the operation of the
tool 20 and the control system 25, only those components which are
then operating are shown in FIG. 4.
At this time, since the control switch 33 (FIG. 1) is in its third
position 37, the solenoid valves 121 and 127 will be open; and,
since the hydraulic pressure in the "set" line 119 has not yet
reached the upper pressure limit as determined by the pressure
switch 124, the pump motor 111 will be operating. Since the control
valve 128 (not shown in FIG. 4) is closed, the high-pressure
section 154 of the "set" line 119 will still be isolated from the
low-pressure section 151. Simultaneously, the hydraulic fluid
contained in the forward pressure chambers of the piston actuators
51, 52, 55 and 56 will be displaced (as shown by the arrows as at
159) to the "retract" line 120 and returned to the reservoir 112 by
way of the open solenoid valve 127. These actions will, of course,
cause the wall-engaging member 50 as well as the sealing pad 53 to
be respectively extended in opposite lateral directions until each
has moved into firm engagement with the opposite sides of the
borehole 21.
It will be noticed in FIG. 4 that hydraulic fluid will be admitted
by way of branch hydraulic lines 160 and 161 to the annular chamber
65 to the rear of the enlarged-diameter portion 64 of the
fluid-admitting member 57. At the same time, hydraulic fluid from
the piston chamber 66 ahead of the enlarged-diameter portion 64
will be discharged by way of branch hydraulic lines 162 and 163 to
the "retract" line 120 to progressively move the fluid-admitting
member 57 forwardly in relation to the sealing member 53 until the
nose of the fluid-admitting member engages the wall of the borehole
21 and then halts. The sealing pad 53 is then urged forwardly in
relation to the now-halted tubular member 57 until the pad
sealingly engages the borehole wall for packing-off or isolating
the isolated wall portion from the well bore fluids.
It should also be noted that although the pressured hydraulic fluid
is also admitted at this time into the forward piston chamber 77
between the sealing members 73 and 75 on the valve member 67, the
valve member is temporarily prevented from moving rearwardly in
relation to the inner and outer tubular members 57 and 58 inasmuch
as the control valve 129 (not shown in (FIG. 4) is still closed
thereby temporarily trapping the hydraulic fluid in the rearward
piston chamber 76 to the rear of the valve member. The significance
of this delay in the retraction of the valve member 67 will be
subsequently explained.
As also illustrated in FIG. 4, the hydraulic fluid in the
low-pressure section 151 of the "set" line 119 will also be
directed by way of a branch hydraulic line 164 to the actuating
cylinder 104 of the pressure-reduction means 102. This will, of
course, result in the displacement piston 106 being elevated in
relation to the body 103 as the hydraulic fluid above the actuating
piston 105 is returned to the "retract" line 120 by way of a branch
hydraulic conduit 165. As previously mentioned, elevation of the
displacement piston 106 in the reduced chamber 107 will be
effective for significantly decreasing the pressure initially
existing in the isolated portions of the branch line 101 and the
flow line 81 between the still-closed flow-line control valve 85
and the still-closed chamber control valves 86 and 87 (not shown in
FIG. 4). The purpose of this pressure reduction will be
subsequently explained.
Once the wall-engaging member 50, the sealing pad 53 and the
fluid-admitting member 57 have respectively reached their extended
positions as illustrated in FIG. 4, it will be appreciated tht the
hydraulic pressure delivered by the pump 110 will again rise as
shown by the curve 158 in FIG. 3. Then, once the pressure in the
output line 113 has reached the second level of operating pressure
(as represented at "B" in FIG. 3), the control valve 129 will open
in response to this increased pressure level to now discharge the
hydraulic fluid previously trapped in the piston chamber 76 to the
rear of the valve member 67 back to the reservoir 112.
As illustrated in FIG. 5, once the control valve 129 opens, the
hydraulic fluid will be displaced from the rearward piston chamber
76 by way of branch hydraulic lines 166 and 167 to the "retract"
line 120 as pressured hydraulic fluid from the "set" line 119
enters the piston chamber 77 ahead of the enlarged-diameter portion
72 of the valve member 67. This will, of course, cooperate to shift
the valve member 67 rearwardly in relation to the fluid-admitting
member 57 for establishing fluid or pressure communication between
the isolated portion of the earth formation 22 and the flow
passages 69 and 71 in the valve member by way of the filter screen
80.
Although this is not illustrated in FIG. 5, it will be recalled
from FIGS. 2A and 2B that the control valves 85-87 are initially
closed to isolate the lower portion of the flow line 81 between
these valves as well as the branch line 101 leading to the
pressure-reduction means 102. However, the flow-line
pressure-equalizing control valve 88 will still be open at the time
the control valve 129 opens to retract the valve member 67 as
depicted in FIG. 5. Thus, as the valve member 67 progressively
uncovers the filtering screen 80, well bore fluids at a pressure
greater than that of any connate fluids which may be present in the
isolated earth formation 22 will be introduced (as shown by the
arrow 168) into the upper portion of the flow line 81 and, by way
of the flexible conduit member 82, into the rearward end of the
tubular member 70. As these high-pressure well bore fluids pass
into the annular space 78 around the filtering screen 80, they will
be forcibly discharged (as shown by the arrows 169) from the
forward end of the fluid-admitting member 57 for washing away any
plugging materials such as mudcake or the like which may have
become deposited on the internal surface of the filtering screen
when the valve member 67 first uncovers the screen. Thus, the
control system 25 is operative for providing a momentary flow of
well bore fluids for cleansing the filtering screen 80 of unwanted
debris or the like before a sampling or testing operation is
commenced.
Referring again to FIG. 3, it will be appreciated that once the
several components of the formation-testing tool 20 and the control
system 25 have reached their respective positions as depicted in
FIG. 5, the hydraulic pressure in the output line 113 will quickly
increase from the operating level "B" to the operating level "C."
Once the pump 110 has increased the hydraulic pressure in the
output line 113 to the predetermined level "C," the control valve
128 will selectively open as depicted in FIG. 6A. As seen there,
opening of the control valve 128 will be effective for now
supplying hydraulic fluid to the high-pressure section 154 of the
"set" line 119 and two branch conduits 170 and 171 connected
thereto for successively closing the control valve 88 and then
opening the control valve 85.
In this manner, as depicted by the several arrows at 172 and 173,
hydraulic fluid at a pressure representative of the operating level
"C" will be supplied by way of a typical check valve 174 to the
upper portion of the piston cylinder 175 of the normally-open
control valve 88 as fluid is exhausted from the lower portion
thereof by way of a conduit 176 coupled to the "retract" line 120.
This will, of course, be effective for closing the valve member 100
so as to now block further communication between the flow line 81
and the well bore fluids exterior of the tool 20. Simultaneously,
the hydraulic fluid will also be admitted into the lower portion of
the piston cylinder 91 of the control valve 85. By arranging the
biasing spring 99 for the normally-open control valve 88 to be
somewhat weaker than the biasing spring 93 for the normally-closed
control valve 85, the second valve will be momentarily retained in
its closed position until the first valve has had time to close.
Thus, once the valve 88 closes, as the hydraulic fluid enters the
lower portion of the piston cylinder 91 of the control valve 85,
the valve member 94 will be opened as hydraulic fluid is exhausted
from the upper portion of the cylinder through a typical check
valve 177 and a branch return line 178 coupled to the "retract"
line 120.
It will be appreciated, therefore, that with the tool 20 in the
position depicted in FIG. 6A, the flow line 81 is now isolated from
the well bore fluids and is in communication with the isolated
portion of the earth formation 22 by way of the flexible conduit
82. It will also be recalled from the preceding discussion of FIG.
4 that the branch flow line 101 as well as the portion of the main
flow line 81 between the flow-line control valve 85 and the sample
chamber control valves 86 and 87 were previously expanded by the
upward movement of the displacement piston 106 in the
reduced-volume chamber 107. Thus, upon opening of the flow-line
control valve 85, the isolated portion of the earth formation 22
will be rapidly communicated with the reduced-pressure space
temporarily represented by the previously-isolated portions of the
flow line 81 and the branch conduit 101.
Accordingly, should there by any producible connate fluids in the
isolated earth formation 22, the formation pressure will be
effective for displacing these connate fluids by way of the
fluid-admitting means 30 into the flow line until such time that
the previously-isolated lower portion of the flow line 81 and the
branch conduit 101 are filled and pressure equilibrium is again
established in the entire flow line. By arranging a typical
pressure-measuring transducer, as at 179 (or, if desired, one or
more other suitable measuring transducers) in the flow line 81, one
or more measurements representative of the characteristics of the
connate fluids and the formation 22 may be transmitted to the
surface by a conductor 180 and, if desired, recorded on the
recording apparatus 26 (FIG. 1). The pressure measurements provided
by the transducer 179 will, of course, permit the operator at the
surface to readily determine the formation pressure as well as to
obtain one or more indications representative of the potential
producing ability of the formation 22. The various techniques for
analyzing formation pressures are well known in the art and are,
therefore, of no significance to understanding the present
invention.
Of equal importance, those skilled in the art will also appreciate
that the operator can also use the measurements provided by the
pressure transducer 179 to reliably determine whether the sealing
pad 53 has, in fact, established complete sealing engagement with
the earth formation 22 so as to prevent well bore fluids from
entering the forward end of the fluid-admitting member 57. The
failure of the sealing pad 53 to completely effect sealing
engagement with the wall of the borehole 21 will, of course, be
readily recognized inasmuch as the formation pressures expected to
be present in the earth formation 22 will be recognizably lower
than the hydrostatic pressure of the well bore fluids at the
particular depth which the tool 20 is then situated. This ability
to determine the effectiveness of the sealing engagement will, as
will subsequently be explained, allow the operator to immediately
retract the wall-engaging member 50 and the sealing pad 53 without
having to unwittingly or needlessly continue the remainder of the
complete operating sequence.
Assuming, however, that the pressure measurements provided by the
pressure transducer 179 show that the sealing pad 53 is firmly
seated, the operator may leave the formation-testing tool 20 in the
position shown in FIGS. 6A and 6B as long as it is desired to
observe as well as record the pressure measurements. As a result,
the operator can determine such things as the time required for the
formation pressure to reach equilibrium as well as the rate of
pressure increase and thereby obtain valuable information
indicative of various characteristics of the earth formation 22
such as permeability and porosity. Moreover, with the new and
improved tool 20 of the present invention, the operator can readily
determine if collection of a fluid sample is warranted.
It should be particularly noted in FIG. 6B that since the formation
22 is relatively unconsolidated, the rearward movement of the valve
member 67 in cooperation with the forward movement of the
fluid-admitting member 57 will allow only those loose formation
materials displaced by the advancement of the fluid-admitting
member into the formation to enter the fluid-admitting member. This
is to say, the fluid-admitting member 57 can advance into the
formation 22 only by displacing loose formation materials; and,
since the space opened by the rearward displacement of the valve
member 67 is the only available place into which these loose
formation materials can enter, further erosion of the formation
materials will be halted once the fluid-admitting member has been
filled with loose materials. On the other hand, should a formation
interval which is being tested be relatively well-compacted, the
advancement of the fluid-admitting member 57 will be relatively
slight with its nose making little or no penetration into the
isolated earth formation. It will, of course, be appreciated that
the nose of the fluid-admitting member 57 will be urged outwardly
with sufficient force to at least penetrate the mudcake which
typically lines the borehole walls adjacent to permeable earth
formations. In this situation, however, the forward movement of the
fluid-admitting member 57 will be unrelated to the rearward
movement of the valve member 67 as it uncovers the filtering screen
80. In either case, the sudden opening of the valve 85 will cause
mudcake to be pulled to the rear of the screen 80 to leave it clear
for the subsequent passage of connate fluids.
Referring again to FIG. 3, it will be appreciated that once the
several components of the tool 20 and the control system 25 have
moved to their respective positions shown in FIGS. 6A and 6B, the
hydraulic pressure will again rise until such time that the "set"
line pressure switch 124 operates to halt the hydraulic pump 110.
Inasmuch as the pressure switch 124 has a selected operating range
(as at 181) with its lower limit preferably being no lower than the
operating pressure level "C," it will be seen that in the typical
situation the pump 110 will be halted shortly after the control
valve 88 closes and the control valve 85 opens. At this point in
the operating cycle of the formation-testing tool 20, once a
sufficient number of pressure measurements have been obtained, a
decision can be made whether it is advisable to obtain one or more
samples of the producible connate fluids in the earth formation 22.
If such samples are not desired, the operator can simply operate
the switches 33 and 34 for retracting the wall-engaging member 50
and the sealing pad 53 without further ado.
On the other hand, should a fluid sample be desired, the control
switches 33 and 34 (FIG. 1) are advanced to the next or so-called
"sample" position 38 to open, for example, a solenoid valve 182 for
admitting pressured hydraulic fluid from the high-pressure section
154 of the "set" line 119 into the lower portion of the piston
cylinder 183 of the sample chamber control valve 86. As depicted in
FIG. 7, this will be effective for opening the control valve 86 to
admit connate fluids as shown by the arrows 184 through the flow
line 81 and the branch conduit 83 into the sample chamber 31. If
desired, a "chamber selection" switch 185 in the surface portion of
the system 25 could also be moved from its "first sample" position
186 to its so-called "second sample" position 187 (FIG. 1) to
energize a solenoid valve 188 for opening the control valve 87 to
also admit connate fluids into the other sample chamber 32. In
either case, one or more samples of the connate fluids which are
present in the isolated portion of the earth formation 22 can be
selectively obtained by the new and improved tool 20. It should be
noted that if the formation-testing tool 20 is to be repositioned
in the borehole 21 for obtaining pressure measurements from a
different formation, as at 23, the unique control system 25 will
allow the operator to reserve the sample chamber 32 for a sample
from this formation.
As previously mentioned, the new and improved control system 25
functions in such a manner that the hydraulic pump 110 is not
operating for any great length of time. As shown in FIG. 3, the
pump 110 rapidly reaches its maximum operating pressure as
determined by the settings of the pressure switch 124. The pump 110
is then halted and will quite possibly remain halted until it is
desired to close-off the sample chambers 31 and 32 and retract the
wall-engaging member 50 and the sealing member 53. At this time,
the motor 111 will again be started upon moving of the control
switches 33 and 34 to their so-called "sample-trapping" positions
39 so as to restart the pump 110. As previously mentioned, the
control valves 122 and 127 momentarily open to enable the pump 110
to reach operating speed and are then reclosed. Hereagain, the
check valve 123 will function to prevent reverse flow of the
pressured hydraulic fluid which is then contained in the "set" line
119. Once the pump 110 has reached operating speed, it will
commence to operate much in the same manner as previously described
with reference to FIG. 3. Thus, as best seen in FIG. 8, the
hydraulic pressure in the output line 113 will again begin rising
as shown by the curve 189 with momentary halts at various operating
levels respectively designated as "W"-"Z" which respectively
correspond to the various operating positions of the tool as
successively depicted in FIGS. 9-11.
Accordingly, as best seen in FIG. 9, when the control switches 33
and 34 have been placed in their "sample trapping" positions 39,
the solenoid valve 122 will open to admit hydraulic fluid into the
"retract" line 120. By means of the electrical conductor 41,
however, the pressure switch 125 is enabled and the pressure switch
126 is disabled so that in this position of the control switches 33
and 34 the maximum operating pressure which the pump 110 can
initially reach is limited to the pressure at the operating
pressure level "W" as determined by the pressure switch 125. Thus,
by arranging the control valve 131 to open in response to a
hydraulic pressure corresponding to the predetermined pressure of
the operating level "W," hydraulic fluid in the high-pressure
section 154 of the "set" line 119 will be returned to the reservoir
112 by means of the return line 117. As the hydraulic fluid in the
high-pressure section 154 returns to the reservoir 112, the
pressure in this portion of the "set" line 119 will be rapidly
decreased to close the control valve 128 once the pressure in the
line is insufficient to hold the valve open. Once the control valve
128 closes, the pressure remaining in the low-pressure section 151
of the "set" line 119 will remain at a reduced pressure which is
nevertheless effective for retaining the wall-engaging member 50
and the sealing pad 53 fully extended.
As the hydraulic fluid is discharged from the lower portion of the
piston cylinder 183 by way of the still-open solenoid valve 182 and
fluid from the "retract" line 120 enters the upper portion of the
cylinder by way of a branch line 190, the chamber control valve 86
will close to trap the sample of connate fluids which is then
present in the sample chamber 31. Similarly, should there also be a
fluid sample in the other sample chamber 32, the control valve 87
can also be readily closed by operating the switch 185 to reopen
the solenoid valve 188. Closure of the control valve 86 (as well as
the valve 87) will, of course, be effective for trapping fluid
samples in one or the other or both of the sample chambers 31 and
32.
Once the control valve 86 (and, if necessary, the control valve 87)
has been reclosed, the control switches 33 and 34 are moved to
their next or so-called "retract" switching positions 40 for
initiating the simultaneous retraction of the well-engaging member
50 and the sealing pad 53. In this final position of the control
switches 33 and 34, the pressure switch 125 is again rendered
inoperative and the pressure switch 126 is enabled so as to now
permit the hydraulic pump 110 to be operated at rated capacity for
attaining hydraulic pressures greater than the operating level "W."
Thus, as depicted in FIG. 8, once the pressure switch 125 has again
been disabled, the pressure switch 126 will now function to operate
the pump 110 so that the pressure will now quickly rise until it
reaches the operating level "X."
At this point, as shown in FIG. 10, hydraulic fluid at the pressure
level "X" will be supplied as shown by the arrows 191 through the
"retract" line 120 and the branch hydraulic line 176 for reopening
the pressure-equalizing control valve 88 to admit well bore fluids
into the flow line 81 as shown by the arrows 192. Opening of the
pressure-equalizing valve 88 will admit well bore fluids into the
isolated space defined by the sealing pad 53 so as to equalize the
pressure differential existing across the pad. Hydraulic fluid
displaced from the upper portion of the piston chamber 175 of the
control valve 88 will be discharged through a typical relief valve
193 which is arranged to open only in response to pressures equal
or greater than that of the operating level "X." The hydraulic
fluid displaced from the piston chamber 175 through a relief valve
193 will be returned to the reservoir 112 by way of the branch
hydraulic line 170, the high-pressure section 154 of the "set" line
119, the still-open control valve 131 and the return line 117.
Turning now to FIG. 11, the situation illustrated there is
representative of the operation of the formation-testing tool 20
when the hydraulic pressure in the output line 113 has either
reached the operating level "Y" or, if desired, a higher level as
at "Z" (FIG. 8). At this point, pressured hydraulic fluid in the
"retract" line 120 will reopen the control valve 130 to communicate
the low-pressure section 151 of the "set" line 119 with the
reservoir 112. When this occurs, hydraulic fluid in the "retract"
line will be admitted to the "retract" side of the several piston
actuators, 51, 52, 55 and 56 as shown by the arrows at 195.
Similarly, the pressured hydraulic fluid will also be admitted into
the annular space 66 in front of the enlarged-diameter piston
portion 64 for retracting the fluid-admitting member 57 as well as
into the annular space 76 for returning the valve member 67 to its
forward position. The hydraulic fluid exhausted from the several
piston actuators 51, 52, 55 and 56 as well as the piston chambers
65 and 77 will be returned directly to the reservoir 112 by way of
the high-pressure section 151 of the "set" line 119 and the control
valve 130. This action will, of course, retract the wall-engaging
member 50 as well as the sealing pad 53 against the tool body 28 to
permit the tool 20 to be either repositioned in the well bore 21 or
returned to the surface if no further testing is desired.
Referring again to FIG. 10, it will be noted that although there is
an operating pressure applied to the upper portion of the piston
cylinder 91 for the flow-line control valve 85 at the time that the
control valve 88 is reopened, a normally-closed relief valve 194
which is paralleled with the check valve 177 is held in a closed
position until the increasing hydraulic pressure developed by the
pump 110 exceeds the operating level ("Y" to "Z") used to retract
the wall-engaging member 50 and the sealing pad 53. At this point
in the operating sequence of the new and improved tool 20, the
flow-line control valve 85 will be reclosed (not shown in FIG.
11).
The pump 110 will, of course, continue to operate until such time
that the hydraulic pressure in the output line 113 reaches the
upper limit determined by the setting of the pressure switch 126.
At some convenient time thereafter, the control switches 33 and 34
are again returned to their initial or "Off" positions 35 for
halting further operation of the pump motor 111 as well as
reopening the solenoid valve 127 to again communicate the "retract"
line 120 with the fluid reservoir 112. This completes the preferred
operating cycle of the new and improved formation-testing tool
20.
It will be appreciated, therefore, that the new and improved
testing tool 20 is capable of performing one or more testing or
sampling operations as may be required without having to remove the
tool from the borehole 21 between each operation. Moreover, of
equal importance, it will be recognized that the versatility of the
new and improved control system 25 will enable the operator to
monitor the performance of the tool 20 during the course of a given
testing or sampling operation so that either changes can be made as
required to properly respond to various downhole conditions or else
the operation can be terminated without further loss of time should
this be deemed necessary. Those skilled in the art will, of course,
recognize the significance of this flexibility.
Although the usual situation will be that the new and improved tool
20 will be operated as previously described in detail for obtaining
a series of pressure measurements and one or two fluid samples, it
is not at all uncommon for unexpected or unwanted conditions to
occur which will hamper or prevent the successful completion of
that particular testing or sampling operation. For example, as
previously mentioned, it is quite often found that the sealing pad
53 has, for one reason or another, failed to effect complete
sealing with the wall of the borehole 21. Obviously, this condition
will absolutely preclude the securing of either formation pressure
measurements or representative fluid samples since borehole fluids
will simply enter the fluid-admitting means 30 should the testing
or sampling operation be continued.
This condition will, of course, be readily apparent since the flow
line 81 is initially filled with well bore fluids (FIGS. 2A-2B and
4) and this will cause the pressure transducer 179 to indicate the
hydrostatic pressure of the well bore fluids. When the control
switches 33 and 34 are advanced to their third positions 37 to
"set" the tool 20 and the output pressure of the pump 113 reaches
the pressure level "B," the control valve 129 will function to open
the fluid-admitting means 30 as the valve member 67 moves
rearwardly to place the formation, as at 22, in communication with
the flow line 81 (FIG. 5). Then, as shown in FIG. 6A, once the pump
113 reaches the pressure level "C," the equalizing valve 88 will
close and the flow-line control valve 85 will then open to rapidly
communicate the remaining or reduced-pressure portion of the flow
line 81 with the fluid-admitting means 30. When this occurs, only
one of three things can be considered. First of all, if there is a
substantial drop in the pressure reading provided by the surface
devices 26 followed by an increase in pressure to a level
characteristic of typical formation pressures, it can be concluded
that the sealing pad 53 is sealingly engaged with the wall of the
borehole 21 and that the formation, as at 22, is permeable so as to
warrant the continuance of the testing or sampling operation as
previously described to determine the nature of the formation and
whatever connate fluids may be present therein.
On the other hand, if the pressure in the flow line 81 fails to
drop and instead remains at the same level, it will be known that
the sealing pad 53 is not tightly sealed with the wall of the
borehole 21 and that well bore fluids are entering the nose of the
fluid-admitting member 57. Alternatively, if the pressure in the
flow line 81 drops but fails either to rise at all or to increase
at a reasonable rate, it can be safely concluded either that the
formation under investigation is not productive or else that the
fluid-admitting means 30 were somehow plugged despite the flushing
action depicted in FIG. 5. Either situation, of course, makes it
futile to continue further with the testing or sampling operation.
Thus, in keeping with the objects of the present invention, the
control switches 33 and 34 are simply skipped over the positions 38
and 39 and advanced directly to their switching positions at 40
without further ado. As shown in FIGS. 10 and 11, this will, of
course, return the tool 20 to its initial position (FIGS. 2A and
2B) so that one or more attempts can be made after moving the tool
slightly so as to hopefully shift it to a better position in
relation to the formation as at 22. This will allow the operator to
better determine whether the formation is in fact not productive or
if the fluid-admitting means 30 were merely plugged
temporarily.
The unique versatility or flexibility of the new and improved tool
20 is further demonstrated when it is considered that the operator
can still discontinue the testing or sampling operation at any
later time even if the sealing pad 53 is firmly engaged with the
wall of the borehole 21. For example, assume that the tool 20 is
now in the testing position illustrated in FIGS. 6A and 6B. If the
pressure measurements provided by the tranducer 179 indicate it is
desirable to obtain one or more fluid samples, the switches 33 and
34 are simply moved to their respective "sampling" positions at 38
and the switch 185 is operated as required to capture at least one
sample as shown in FIG. 7 and as previously described. On the other
hand, if these pressure measurements are not encouraging, the
operator again has the option of skipping the switches 33 and 34
over their positions 38 and 39 and moving directly to the "retract"
positions at 40. The tool 20 can then be either repositioned with
respect to the formation 22, or moved to a different formation
interval, as at 23, or else returned to the surface.
Accordingly, it will be recognized that by virtue of the new and
improved cooperative arrangement of the tool 20 and the control
system 25, one or more testing or sampling operations can be
conducted without undue loss of time should the fluid-admitting
means 30 not be in isolated communication with a selected formation
or if the formation is found to have little or no production
capability. Moreover, by arranging the several pressure-responsive
control valves as described to function at selected pressure
levels, the tool 20 can be selectively placed in any one of its
several operating positions with a minimum of switching
operations.
While only a particular embodiment of the present invention has
been shown and described, it is apparent that changes and
modifications may be made without departing from this invention in
its broader aspects; and, therefore, the aim in the appended claims
is to cover all such changes and modifications as fall within the
true spirit and scope of this invention.
* * * * *