U.S. patent number 3,891,033 [Application Number 05/430,989] was granted by the patent office on 1975-06-24 for annulus pressure controlled testing apparatus.
This patent grant is currently assigned to Byron Jackson Inc.. Invention is credited to Lyle B. Scott.
United States Patent |
3,891,033 |
Scott |
June 24, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Annulus pressure controlled testing apparatus
Abstract
An annulus pressure controlled testing tool is disposed in a
well bore above a packer which is set in the well bore and
separates the productive earth formation from the annular space
above the packer. The testing tool is a shut-in valve assembly
having a valve openable for successive periods under the control of
an annulus pressure actuated escapement mechanism which allows the
formation fluid to flow through the shut-in valve for a desired
period of time.
Inventors: |
Scott; Lyle B. (Los Angeles,
CA) |
Assignee: |
Byron Jackson Inc. (Long Beach,
CA)
|
Family
ID: |
23709958 |
Appl.
No.: |
05/430,989 |
Filed: |
January 4, 1974 |
Current U.S.
Class: |
166/133; 166/162;
166/152; 166/336 |
Current CPC
Class: |
E21B
49/087 (20130101); E21B 49/001 (20130101); E21B
33/12 (20130101); E21B 33/129 (20130101) |
Current International
Class: |
E21B
49/00 (20060101); E21B 33/12 (20060101); E21B
33/129 (20060101); E21B 49/08 (20060101); E21b
049/00 () |
Field of
Search: |
;166/133,142,152,151,150,169,162,226,148,149,.5,264 ;73/151 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Attorney, Agent or Firm: Evans, Jr.; John O.
Claims
I claim:
1. Apparatus for performing a drill stem test in a well bore
traversing an earth formation in which casing is set comprising: a
test string adapted to be connected to a string of pipe and run
into the well casing, said test string including a packer having
anchor means and packing means expansible into anchoring and
sealing engagement with said well casing above said earth formation
to anchor said test string in said casing and separate said
formation from the casing above said packer, test instrument means
associated with said packer and in communication with said earth
formation, and shut-in valve means above said packer for
controlling the flow of fluid from said formation through said test
string, said shut-in valve means including a body connected in said
test string, said body having therein a tubular mandrel shiftable
longitudinally of said body, valve means including a valve member
carried by said mandrel and shiftable therewith to a plurality of
successive open and closed positions for enabling and for shutting
off the flow of fluid from said formation through said mandrel a
plurality of times as said tubular mandrel is shifted
longitudinally in one direction, and escapement control means
responsive to the pressure of fluid in said well casing above said
packer for controlling the progressive movement of said mandrel and
said valve member in said one direction through said plurality of
successive positions.
2. Apparatus as defined in claim 1, wherein said control means
comprises escapement means on said mandrel and in said body.
3. Apparatus as defined in claim 1, wherein said control means
comprises escapement means on said mandrel and in said body,
including stops on said mandrel and detent means carried by said
body and engageable with said stops, means responsive to said fluid
in said well casing for releasing said detent means, and spring
means normally biasing said detent means to a mandrel stopping
position.
4. Apparatus as defined in claim 1, wherein said control means
comprises escapement means on said mandrel and in said body,
including stops on said mandrel and detent means carried by said
body and engageable with said stops, means responsive to said fluid
in said well casing for releasing said detent means, and spring
means normally biasing said detent means to a mandrel stopping
position, said spring means comprising a plurality of Belleville
springs stacked in concentric relation in edge-to-edge peripheral
engagement.
5. Apparatus as defined in claim 1, wherein said control means
comprises escapement means on said mandrel and in said body,
including stops on said mandrel and detent means carried bu said
body and engageable with said stops, means responsive to said fluid
in said well casing for releasing said detent means, and spring
means normally biasing said detent means to a mandrel stopping
position, said spring means comprising a plurality of Belleville
springs stacked in concentric relation to edge-to-edge peripheral
engagement, and adjustable means for preloading said springs.
6. Apparatus as defined in claim 1, wherein said mandrel is sealed
in said body and exposed to the pressure of fluid in said formation
to urge said mandrel through said positions.
7. Apparatus as defined in claim 1, wherein said mandrel is sealed
in said body and exposed to the pressure of fluid in said formation
to urge said mandrel through said positions, and including
energizing means responsive to the pressure of fluid in said casing
above said packer also urging said mandrel through said
positions.
8. Apparatus as defined in claim 1, wherein said mandrel is sealed
in said body and exposed to the pressure of fluid in said formation
to urge said mandrel through said positions, and including
energizing means responsive to the pressure of fluid in said casing
above said packer also urging said mandrel through said positions,
and means for dampening such movement of said mandrel.
9. Apparatus as defined in claim 1, wherein said control means
comprises escapement means on said mandrel and in said body,
including stops on said mandrel and detent means carried by said
body and engageable with said stops, means responsive to said fluid
in said well casing for releasing said detent means, and spring
means normally biasing said detent means to a mandrel stopping
position, and including energizing means responsive to the pressure
of fluid in said casing above said packer for urging said mandrel
through said positions when said detent means are released.
10. Apparatus as defined in claim 1, wherein said control means
comprises escapement means on said mandrel and in said body,
including stops on said mandrel and detent means carried by said
body and engageable with said stops, means responsive to said fluid
in said well casing for releasing said detent means, and spring
means normally biasing said detent means to a mandrel stopping
position, and including energizing means responsive to the pressure
of fluid in said casing above said packer for urging said mandrel
through said positions when said detent means are released, and
means for dampening such movement of said mandrel.
11. A shut-in valve for use in performing drill stem tests in a
well bore, comprising: an elongated tubular body, an elongated
tubular mandrel axially shiftably disposed in said body, said body
and said mandrel having valve means successively openable and
closeable a plurality of times upon longitudinal movement in one
direction of said mandrel relative to said body to enable and to
prevent the flow of fluid through said mandrel, escapement means
for controlling said longitudinal movement of said mandrel within
said body and limiting said movement of said mandrel to successive
positions at which said valve means is opened and closed, and fluid
pressure operated means for operating said escapement means to
enable successive movements of said mandrel in said body.
12. A shut-in valve as defined in claim 11, wherein said escapement
means comprises successive stops on said mandrel and detent means
carried by said body, said means for operating said escapement
means including fluid pressure responsive means for releasing said
detent means.
13. A shut-in valve as defined in claim 11, wherein said escapement
means comprises successive stops on said mandrel and detent means
carried by said body, said means for operating said escapement
means including fluid pressure responsive means for releasing said
detent means, and spring means normally biasing said detent means
to a mandrel stopping position.
14. A shut-in valve as defined in claim 11, wherein said escapement
means comprises successive stops on said mandrel and detent means
carried by said body, said means for operating said escapement
means including fluid pressure responsivve means for releasing said
detent means, and spring means normally biasing said detent means
to a mandrel stopping position, said spring means comprising a
plurality of Belleville springs stacked in concentric relation in
edge-to-edge peripheral engagement.
15. A shut-in valve as defined in claim 11, wherein said escapement
means comprises successive stops on said mandrel and detent means
carried by said body, said means for operating said escapement
means including fluid pressure responsive means for releasing said
detent means, and spring means normally biasing said detent means
to a mandrel stopping position, said spring means comprising a
plurality of Belleville springs stacked in concentric relation in
edge-to-edge peripheral engagement, and adjustable means for
preloading said springs.
16. A shut-in valve as defined in claim 11, wherein said fluid
pressure operated means comprises differential piston and cylinder
means in said body, and means including a bladder exposed
externally of said body and confining a quantity of oil for
actuating said piston means responsive to external pressure applied
to said bladder.
17. A shut-in valve as defined in claim 11, wherein said fluid
pressure operated means includes a cylinder sleeve in said body
having differential internal diameters, an annular piston slideably
engaged with said sleeve and defining therewith a pressure chamber,
said piston having differential areas exposed to the pressure of
fluid in said chamber.
18. A shut-in valve as defined in claim 11, wherein said fluid
pressure operated means includes a cylinder sleeve in said body
having differential diameters, an annular piston slideably engaged
with said sleeve and defining therewith a pressure chamber, said
piston having differential areas exposed to the pressure of fluid
in said chamber, and means removably mounting said cylinder sleeve
and said piston in said body.
19. A shut-in valve as defined in claim 11, wherein said mandrel is
sealed in said body to be responsive to the pressure of fluid in
said body to move said mandrel.
20. A shut-in valve as defined in claim 11, including energizing
means for moving said body responsive to applied fluid
pressure.
21. A shut-in valve as defined in claim 11, including energizing
means for moving said body responsive to applied fluid pressure,
said energizing means comprising an annular piston on said mandrel
and a cylinder sleeve encircling said annular piston and defining
with said mandrel a pressure chamber, and means for applying
pressure to fluid in said chamber.
22. A shut-in valve as defined in claim 11, including energizing
means for moving said body responsive to applied fluid pressure,
said energizing means comprising an annular piston on said mandrel
and a cylinder sleeve encircling said annular piston and defining
with said mandrel a pressure chamber, and means for applying
pressure to fluid in said chamber including a bladder exposed at
the exterior of said body.
23. A shut-in valve as defined in claim 11, including energizing
means for moving said body responsive to applied fluid pressure,
said energizing means comprising an annular piston on said mandrel
and a cylinder sleeve encircling said annular piston and defining
with said mandrel a pressure chamber, and means for applying
pressure to fluid in said chamber, and said body and said mandrel
having cylinder and piston meanse for dampening movement of said
mandrel.
24. A shut-in valve as defined in claim 11, wherein said escapement
means comprises a plurality of circumferential lands spaced
longitudinally of said mandrel and each having an upwardly facing
stop shoulder, a ball cage surrounding said mandrel and having
vertically spaced ball detents radially shiftably carried thereby,
an axially shiftable indexing guide disposed about said ball cage
and having internal axially spaced ball detent engaging surfaces
and intermediate clearance spaces for receiving said ball detents,
said fluid pressure operated means including means acting on said
indexing guide to shift the latter axially in one direction, spring
means acting on said indexing guide to force the latter axially in
the other direction, said shoulders, said ball detents, said ball
detent engaging surfaces and said relief spaces being axially
spaced so that said ball detents alternately are held radially
inwardly for engagement by one of said shoulders and are free to
move radially outwardly upon axial movement of said indexing guide
in opposite directions to open and close said valve means
successively upon each increment of movement of said mandrel.
25. A shut-in valve as defined in claim 11, wherein said escapement
means comprises a plurality of circumferential lands spaced
longitudinally of said mandrel and each having an upwardly facing
stop shoulder, a ball cage surrounding said mandrel and having
vertically spaced ball detents radially shiftably carried thereby,
an axially shiftable indexing guide disposed about said ball cage
and having internal axially spaced ball detent engaging surfaces
and intermediate clearance spaces for receiving said ball detents,
said fluid pressure operated means including means acting on said
indexing guide to shift the latter axially in one direction, spring
means acting on said indexing guide to force the latter axially in
the other direction, said shoulders, said ball detents, said ball
detent engaging surfaces and said relief spaces being axially
spaced so that said ball detents alternately are held radially
inwardly for engagement by one of said shoulders and are free to
move radially outwardly upon axial movement of said indexing guide
in opposite directions to open and close said valve means
successively upon each increment of movement of said mandrel, said
fluid pressure operated means further including a cylinder sleeve
in said body having differential internal diameters, an annular
piston slideably engaged with said sleeve and defining therewith a
pressure chamber, said piston having differential areas exposed to
the pressure of fluid in said chamber, and means removably mounting
said cylinder sleeve and said piston in said body.
26. A shut-in valve as defined in claim 11, wherein said escapement
means comprises a plurality of circumferential lands spaced
longitudinally of said mandrel and each having an upwardly facing
stop shoulder, a ball cage surrounding said mandrel and having
vertically spaced ball detents radially shiftably carried thereby,
an axially shiftable indexing guide disposed about said ball cage
and having internal axially spaced ball detent engaging surfaces
and intermediate clearance spaces for receiving said ball detents,
said fluid pressure operated means including means acting on said
indexing guide to shift the latter axially in one direction, spring
means acting on said indexing guide to force the latter axially in
the other direction, said shoulders, said ball detents, said ball
detent engaging surfaces and said relief spaces being axially
spaced so that said ball detents alternately are held radially
inwardly for engagement by one of said shoulders and are free to
move radially outwardly upon axial movement of said indexing guide
in opposite directions to open and close said valve means
successively upon each increment of movement of said mandrel, said
fluid pressure operated means further including a cylinder sleeve
in said body having differential internal diameters, an annular
piston slideably engaged with said sleeve and defining therewith a
pressure chamber, said piston having differential areas exposed to
the pressure of fluid in said chamber, and means removably mounting
said cylinder sleeve and said piston in said body, said mandrel and
said body having means defining an energizing piston chamber, and
said mandrel having a piston area exposed to the pressure of fluid
in said energizing piston chamber to move said mandrel
longitudinally as aforesaid.
27. A shut-in valve as defined in claim 11, wherein said escapement
means comprises a plurality of circumferential lands spaced
longitudinally of said mandrel and each having an upwardly facing
stop shoulder, a ball cage surrounding said mandrel and having
vertically spaced ball detents radially shiftably carried thereby,
an axially shiftable indexing guide disposed about said ball cage
and having internal axially spaced ball detent engaging surfaces
and intermediate clearance spaces for receiving said ball detents,
said fluid pressure operated means including means acting on said
indexing guide to shift the latter axially in one direction, spring
means action on said indexing guide to force the latter axially in
the other direction, said shoulders, said ball detents, said ball
detent engaging surfaces and said relief spaces being axially
spaced so that said ball detents alternately are held radially
inwardly for engagement by one of said shoulders and are free to
move radially outwardly upon axial movement of said indexing guide
in opposite directions to open and close said valve means
successively upon each increment of movement of said mandrel, said
fluid pressure operated means further including a cylinder sleeve
in said body having differential internal diameters, an annular
piston slideably engaged with said sleeve and defining therewith a
pressure chamber, said piston having differential areas exposed to
the pressure of fluid in said chamber, and means removably mounting
said cylinder sleeve and said piston in said body, said mandrel and
said body having means defining an energizing piston chamber, and
said mandrel having a piston area exposed to the pressure of fluid
in said energizing piston chamber to move said mandrel
longitudinally as aforesaid, said pressure chamber of said fluid
pressure operated means and said energizing piston chamber being
filled with oil and including bladders exposed externally of said
body and confining said oil in said chamber.
28. A shut-in valve as defined in claim 11, wherein said mandrel is
sealed in said body to be responsive to the pressure of fluid in
said body to move said mandrel, and said escapement means normally
limits movement of said mandrel to a position at which said valve
means is closed.
Description
BACKGROUND OF THE INVENTION
Testing tools or apparatus for use in performing drill stem tests
of earth formations are well known. An example is the drill stem
fluid sampler of my prior U.S. Pat. No. 3,437,138, granted Apr. 8,
1969.
Typically, drill stem testing tools have been operated in response
to rotation or longitudinal movement of the string of drill pipe in
which the testing tool is installed and by which the testing tool
is run into the well. When the testing operations are being
performed from a stable platform, in most cases, these prior tools
have been quite satisfactory, since the rotative or longitudinal
movement of the drill string can be readily accomplished with the
usual hoist mechanism. However, in the case of slant-hole drilling
or drilling from an unstable platform, such as a floating vessel,
the control of testing tools by manipulation of the pipe is very
difficult. When slant-hold drilling, friction of the drill pipe
within the well casing renders very uncertain the actual position
or orientation of the drill pipe at any given depth due to twist or
stretch of the pipe. When performing a drill stem test from an
unstable platform such as a floating or partially submerged vessel
or platform in the ocean which is subject to motion caused by tidal
and wave action, longitudinal movement of the drill pipe string
cannot be relied upon for the control of drill stem testing
equipment.
Another problem encountered in the performance of drill stem
testing operations from a floating or partially submerged platform
is that in the event of heavy seas, the platform may be pulled from
its moorings rupturing the drill pipe string between the vessel and
the downhole drill stem tester. If the drill stem tester does not
automatically close, then well fluid may flow into the sea.
SUMMARY OF THE INVENTION
The present invention provides a shut-in valve for drill stem
testing of a productive earth formation traversed by a well bore,
wherein the shut-in valve is normally closed by formation pressure
and is adapted to be opened by the application of pressure to the
annulus above a packer which isolates the productive formation.
With such a drill stem tester or formation testing tool, a bumper
sub or telescopic joint can be employed in the drill pipe string
above the shut-in valve to compensate for the rise and fall of the
floating or semi-submerged platform. In the event the drill pipe
string ruptures for any reason, a normally closed shut-in valve
will confine the productive formation fluids against flow into the
sea.
More particularly, the shut-in valve is constructed to enable it to
be successively opened and closed to enable a series of drill stem
tests, under the control of an escapement mechanism activated in
response to the pressure of fluids in the annulus above the packer
and spring means adapted to be overcome by annulus fluid pressure
to release the escapement mechanism for one increment of motion.
The spring means comprises a stack of Belleville spring washers
which occupy a small space and which may have a constant spring
rate.
The shut-in valve and the escapement mechanisms are influenced by
the pressure of formation fluid below the packer to hold the
shut-in valve closed. When the escapement mechanism is released,
the formation pressure acts on the shut-in valve to shift the
shut-in valve to an open position. In the absence of sufficient
formation pressure to effect opening of the shut-in valve, the
testing tool also includes energizing means responsive to pressure
in the annulus above the packer to assist in the shifting of the
shut-in valve to an open position.
Since under some differential pressure conditions the forces acting
to open the shut-in valve may be substantial, the tool also
includes buffer means for limiting the rate of movement of the
shut-in valve towards the open position, thereby minimizing
potentially destructive inertia forces otherwise applicable to the
escapement mechanism.
Among the objects of the invention is the provision of a drill stem
testing tool which is particularly well suited for performing drill
stem testing operations in a well drilled from a floating or
partially submerged platform subject to vertical motion caused by
tide or wave action, the tool being operable by annulus fluid
pressure and being safe and reliable in its operation.
This invention possesses many other advantages, and has other
purposes which may be made more clearly apparent from a
consideration of the form in which it may be embodied. This form is
shown in the drawings accompanying and forming part of the present
specification. It will now be described in detail, for the purpose
of illustrating the general principals of the invention; but it is
to be understood that such detailed description is not to be taken
in a limiting sense, since the scope of the invention is best
defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagramatic view illustrating a testing tool string in
accordance with the invention and disposed in a well bore;
FIGS. 2a through 2c together constitute a view partly in elevation
and partly in longitudinal section illustrating the shut-in valve
of the invention in a running-in condition;
FIG. 3 is a transverse section as taken on the line 3--3 of FIG.
2b;
FIG. 4 is a transverse section as taken on the line 4--4 of FIG.
2b;
FIG. 5 is a transverse section as taken on the line 5--5 of FIG.
2b;
FIG. 6 is a transverse section as taken on the line 6--6 of FIG.
2c;
FIG. 7 is an enlarged fragmentary detail view in longitudinal
section illustrating the Belleville spring pack centering
means;
FIGS. 8a through 8c together constitute a view partly in elevation
and partly in longitudinal section illustrating the shut-in valve
of the invention in a testing condition;
FIG. 9 is an enlarged fragmentary view in longitudinal section
showing the escapement mechanism in the running-in condition;
FIG. 10 is a view corresponding to FIG. 9, but showing the
escapement mechanism in the testing condition; and
FIG. 11 is a view corresponding to FIGS. 9 and 10, but showing the
escapement mechanism in the retrieving condition.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As seen in the drawings referring first to FIG. 1, a testing tool
string S is shown in a well bore W in which casing C has been set
and perforated at P to establish communication between a productive
formation F and the inside of the casing C. At its lower end, the
testing tool string S has a perforated testing instrument I which
is adapted to record flow, and if desired, pressure and/or
temperature of production fluid flowing from the formation F
upwardly through the testing tool S under the control of the
annulus controlled shut-in valve assembly V, in accordance with the
invention. Between the shut-in valve V and the instrument I is a
typical hook-wall packer assembly H adapted to form a seal with the
casing C, as is well known. Such packers are adapted to be set in
the well bore with slips 10 in anchoring engagement with the casing
C, and with resilient packing ring elements 11 deformed into
sealing engagement with the casing C to isolate the annular space
13 above the packer H. Preferably, the tool string S includes above
the packer H an unloader valve assembly U openable when it is
desired to retrieve the testing tool string S to balance the fluid
between the annuli 12 and 13. Above the testing tool V is a drill
pipe string D adapted to extend to the platform at the top of the
well, and, as will be recognized by those skilled in the art, when
the platform is a floating or partially submerged platform, the
pipe string D will incorporate a bumper sub or telescopic joint
adapted to compensate for relative vertical movement between the
platform and the stationary elements anchored in the casing C by
the packer H.
Referring particularly to FIGS. 2a through 2c, the shut-in valve
assembly V is shown in detail in a condition with the shut-in valve
means closed. The shut-in valve assembly comprises an elongated
outer tubular assembly including an upper energizing section 15,
beneath which is a buffer section 16, escapement mechanism section
17, and a valve section 18. Extending longitudinally within the
tubular assembly is an inner tubular mandrel, generally denoted at
19, through which fluid from the formation F is adapted to flow
when the shut-in valve means is actuated by annulus fluid pressure
above the packer 14.
At its lower end, the tubular mandrel 19 is connected by a coupling
20, sealed by an O-ring 21, to a downwardly extending, elongated
valve sleeve 22 having a plug 23' closing its lower end. This valve
sleeve is reciprocable within a stationary cylindrical valve body
23, and the valve sleeve 22 has a vertically spaced series of ports
24, 25, 26, and 27 located between vertically spaced sealing rings
collectively designated 28. The sealing rings 28 prevent the
passage of fluid between the valve sleeve and the inner wall of the
valve body 23, these seals being spaced above and below annular
grooves 29 with which the respective ports 24 through 27
communicate. In the valve body 23 is a set of radial valve ports 30
spaced circumferentially of the body and communicating with the
annular space 31 defined between the valve body 23 and an outer
tubular body section 32, which has at its lower end a threaded pin
33 adapted for connection to the downwardly extending test string,
say to the upper end of the unloader valve u, as shown in FIG. 1.
The fluid in the annular space 31 will be the fluid which enters
the well through the perforations P, enters the testing instrument
I, enters the packer H and passes on upwardly into the annular 31.
As will be later described, the valve sleeve 22 is adapted to move
progressively upwardly in increments of motion so that the ports
24, 25, 26 and 27 are progressively in communication with the valve
ports 30, and alternatively, the valve ports 30 are closed off
between the progressively vertically spaced sealing rings 28.
The valve body 23 is fixedly mounted within the outer body section
32 by means of a spider formed by radiating flanges 34 projecting
outwardly from the valve body 23 in the region of the ports 30 into
centering engagement within the outer body 32, these ribs setting
on a shoulder 35 within the body 32. At its upper end, the valve
body 23 has a radially outwardly extended flanged section 36
engaged within the outer body 32, and provided with sealing rings
37, the flange 36 abutting with the lower end of an upwardly
extended tubular outer body section 38 which is threaded into and
sealed at 39 in the upper end of the lower body section 32.
As is apparent in FIG. 2c, the lower end of the valve sleeve 22 is
exposed to the pressure of fluid coming from the formation F which
provides a force biasing the valve sleeve 22 and the entire mandrel
assembly 19 upwardly. This upward movement is assisted by the
energizing section 15 of the tool, is dampened by the buffer
section 16 of the tool, and is controlled by the escapement section
17 of the tool.
The energizing section 15 comprises an upper and outer main body 40
of tubular form threaded, as at 41, to the upwardly extending drill
pipe string D. Within the body 40 is a cylinder sleeve 42 having a
pair of vertically spaced outer sealing rings 43 sealingly engaged
within the cylindrical inner wall of the body 40. The cylinder
sleeve 42 has a reduced diameter mid-section 44 between the seal
rings 43 and opposed by the inner wall of the body 40 to form a
chamber 45 which communicates with a radial port 46 in the cylinder
sleeve 42. The port 46 leads to an inner annular chamber 47 defined
between upper and lower sealing rings 48 which slideably engage the
upper section 49 of the inner mandrel assembly 19. At its upper
end, the mandrel section 49 is of an enlarged diameter to provide a
differential piston area 50 within the chamber 47 on which pressure
acts to complement the force derived from well fluid pressure
acting to shift the mandrel assembly 19 upwardly. The pressure
acting on the piston area 50 is the pressure in the well bore
annulus 13 above the packer H. Since such fluid is not clean fluid,
means are provided for transmitting the annulus fluid pressure to
the piston area 50 while protecting the working parts from the
annulus fluid.
More particularly, the body 40 has a reduced mid-section 51 spanned
by a circular bladder 52. At its upper end, the bladder has a bead
53 clamped against the body 40 by a gage ring 54. At its lower end
the bladder has a similar bead 55 clamped against the body 40 by a
gage ring 56. A slotted protective sleeve 57 is disposed about the
bladder between the gage rings 54 and 56. The bladder and the body
portion 51 define a chamber 58, a clean fluid such as oil being
utilized to fill the chamber 58, as well as the annular space 45,
between the body 40 and the cylinder sleeve 42 and the chamber 47
between the cylinder sleeve 42 and the mandrel section 49. Suitable
fill and bleed openings and passages are provided at 59 and 60.
The buffer section 16 comprises an elongated cylinder 61 threaded
at 62 to the lower end of the cylinder sleeve 42 and extends
downwardly within an upper outer body section 63. At the lower end
of the cylinder 61 is a head 64 slideably and sealingly engaged
with a lower inner mandrel section 65 which is threaded at 66 to
the above described upper mandrel section 49. At its lower end, the
mandrel section 49 has a flange 67 slideably and sealingly engaged
within the cylinder 61 and having an orifice 68. During assembly,
the annular space 69 between the cylindrical sleeve 61 and the
mandrel section 49 above the cylinder head 64 is filled with fluid
such as oil, so that upward movement of the mandrel assembly 19 is
dampened due to the transfer of oil through the orifice 68 as the
mandrel moves upwardly.
From the foregoing, it will be recognized that upward movement of
the mandrel 19 is adapted to establish communication successively
between the valve sleeve ports 24, 25, 26 and 27 and the valve body
ports 30, so that fluid from the well bore below the well packer H
is enabled to flow upwardly through the shut-in valve assembly V,
and more particularly, through the tubular mandrel 19, and thence
into the drill pipe string D. Such flow is controlled by a
conventional choke 70 comprising a tubular body 71 having a flow
passage 72 in which is installed the usual flow bean 73 having a
flow controlling orifice 74. It is desired that the mandrel 19 be
moved upwardly to establish communication between the valve sleeve
ports 24 through 27 and the valve body ports 30 in response to an
increase in the pressure of fluid in the annulus 13 between the
well casing and the valve assembly V, and that the increments of
motion of the inner mandrel 19 correspond to the axial spacing
between the valve ports 24 through 27.
The escapement mechanism 17 of the invention is provided to
accomplish these purposes, and includes a stop mechanism 75
normally biased by spring means 76 to cooperate with the mandrel 19
to limit upward movement of the mandrel 19. Annulus pressure
responsive means 77 is provided for operating the stop mechanism 75
and to allow an increment of upward movement of the mandrel 19 in
response to the application of pressure to the fluid in the annulus
13, whereby the shut-in valve assembly V is operable independently
of pipe string motion, while the lower portion of the pipe string D
and the shut-in valve, as well as the test instrument I, are all
precisely located within the well bore with respect to the
formation F to be tested.
The escapement mechanism comprises an outer housing or tubular body
78 threadedly connected at 79 to the lower end of the previously
described upper housing 63 and threadedly connected at 80 at its
lower end to the previously described lower body section 38. Within
the housing 78 is an axially shiftable, annular indexing guide 81.
Concentric within the indexing guide 81 is an annular ball cage 82
having a supporting flange 83 disposed between a stop shoulder 84
in the housing 78 and the upper end shoulder 85 on the body 38,
whereby the ball cage 82 is fixed with respect to the indexing
guide 81 in the housing 78. The ball cage 82 has an upper set of
circumferentially spaced balls 86 disposed and captive in radial
openings 87 in the cage 82 and constituting upper detent means and
a lower set of circumferentially spaced balls 88 disposed and
captive in radial openings 89 in the cage 82 and constituting lower
detent means. The arrangement of the balls 86, as shown in FIG. 5,
is typical of the sets of balls 86 and 88. These balls 86 and 88,
as will be more particularly described hereinafter, cooperate with
a number of axially spaced lands 230, 240, 250, 260 and 270 spaced
longitudinally of a section 90 of the tubular mandrel 19 to
progressively locate the valve sleeve 22 to open and close the
shut-off valve means, when annulus fluid pressure applicable to the
pressure responsive means 77 is increased and decreased.
The spring means 76 normally acts to shift the indexing guide 81 in
a downward direction. In the form shown, the spring means comprises
a cartridge including a stack of frusto-conical spring washers 91
disposed in peripheral engagement so as to be axially deformed,
such spring washers being generally known as Belleville springs.
The stack of Belleville springs, as shown, is constructed and
supported so as to minimize hysteresis which can be caused by the
centering of the Belleville springs on inner or outer centering
means. Such a stack of spring washers is more particularly the
subject of the co-pending application for U.S. Pat. Ser. No.
430,980, filed contemporaneously herewith, in the name of Felix
Kuus, for "Belleville Spring Cartridge." The Belleville spring
cartridge, as herein illustrated, comprises an inner sleeve 92
disposed within the outer body 78 and supported by the latter in an
upper support ring 93, threaded at 94 into the body 78, the inner
sleeve 92 having a supporting collar 95 threaded thereon and
engaged with the ring 93. At its lower end, the sleeve 92 receives
in a seat 96 a lower support ring 97. Beneath the upper ring 93 is
a stop ring 98 against which the uppermost Belleville spring 91
abuts at its inner periphery, the lowermost Belleville spring 91
abutting at its inner periphery with a thrust collar 99. As seen in
FIG. 4, the thrust collar 99 has downwardly extending fingers 100
spaced circumferentially which entend through circumferentially
spaced arcuate slots or openings 101 in the lower ring 97 into
abutting contact with the upper end of the indexing guide 81.
Upward movement of the indexing guide 81 from the position of FIG.
9 to the position of FIG. 10 causes corresponding upward movement
of the thrust collar 99 and compression of the Belleville springs
91. The Belleville springs are preferred because they occupy a
relatively small space as compared with conventional coiled
compression springs and provide a high load spring which, as is
well known, can have a constant spring rate. The Belleville springs
91, as best seen in FIGS. 3 and 7, are centralized or maintained in
concentric relation with respect to one another without contacting
either the outer housing 78 or the inner support sleeve 92 by means
of outer peripheral centering rings 102 and inner peripheral
centering rings 103. The stack of Belleville springs, as a whole,
is centralized on the ring 98 and on the thrust collar 99, as seen
in FIG. 2b. The centering ring 102 is radially split at 102a and
the centering ring 103 is radially split at 103a, these rings being
resiliently expansible to facilitate their application to the
peripheries of the Belleville springs as well as to minimize
constraint of the peripheral expansion which occurs as the
frusto-conical springs are axially deformed. In addition, the inner
periphery of each of the outer peripheral centering rings 102 is
provided with a circumferentially extended groove 102b and the
outer periphery of each of the inner peripheral centering rings 103
is provided with a corresponding groove 103b, these grooves 102b
and 103b being generally V-shaped and affording clearance space
enabling the contacting edges of the Belleville springs 91 to
expand outwardly and inwardly, respectively, upon axial deflection,
thereby minimizing friction and resultant hysteresis.
At the upper and lower inner edges of the outer centering ring 102
are retainer flanges 102c which project radially inwardly and
retain the contacting peripheries of adjacent Belleville spring
washers in assembled relation at their outer peripheries.
Corresponding radial flanges 103c engage the inner peripheries of
the Belleville springs to retain the same in assembled relation.
Thus, the entire stack of Belleville springs can be installed as a
unit over the upper end of the inner support member 92 before
assembly of the stop ring 98 and the upper ring 93 in the support
sleeve 92. The collar 95 can be threaded downwardly on the sleeve
92 to appropriately preload the Belleville spring assembly before
it is installed in the housing 78 to overcome the hydrostatic
pressure of fluid in the well bore annulus 13. The upper retainer
rings 93 also clamps a lower flange 104 of a supporting sleeve 105
against the lower end of the housing section 63, this support
sleeve 105 being connected at 106 to an upwardly extended member
107 which in turn is threadedly connected at 108 to the cylinder
sleeve 61 which fixedly supports the cylinder sleeve 42 of the
energizing section 15 previously described.
The annulus pressure responsive means 77 is adapted to apply an
upward force to the indexing guide 81 to compress the Belleville
springs 91 and shift the indexing guide 81 upwardly with respect to
the ball cage 82 when the mandrel is to be allowed to move
upwardly. Accordingly, within the body section 38 is a cylinder
sleeve 110 having a sealing ring 111 at its upper end and a lower
sealing ring 112 engaged within the body 38. This cylinder sleeve
110 has a suitable number of radial ports 113 communicating with an
internal chamber 114 defined between the inner periphery of the
cylinder sleeve 110 and the outer periphery of an annuluar
differential piston 115 having an upper sealing ring 116 and a
lower sealing ring 116' slideably engaged with the cylinder sleeve
110 to confine pressure fluid within the chamber 114. The inner
periphery of the cylinder sleeve below the ports 113 is of a
smaller diameter at 110a than the larger diameter 110b above the
ports 113, and the differential piston 115 has complemental smaller
and larger diameters which determine the differential pressure
responsive area of the piston 115. Different size cylinder sleeve
110 and piston 115 sets can be utilized in the assembly depending
upon the desired pressure response of the apparatus. The cylinder
sleeve 110 is held against an upwardly facing shoulder 117 by a
suitable spacer sleeve 118 which engages the upper end of the
cylinder sleeve 110 and abuts with an upper retainer ring 119
snapped into the body section 38, facilitating substitution of
different sizes of the cylinder sleeve 110 and the piston 115.
Disposed between the upper end of the piston 115 and fingers 83a
which depend from the indexing guide 81 through slots 83b in the
guide flange 83, is a thrust sleeve 120 by which the indexing guide
81 is forced upwardly when pressure fluid is applied to the
differential piston chamber 114 to force the piston 115 upwardly.
Here again, the fluid by which the piston 115 is pressurized is
preferably a clean fluid, such as oil, rather than the usually
dirty fluid in the well bore annulus 13. Accordingly, the body 38
has an annular cavity 121 covered by an annular bladder 122. The
bladder 122 has an upper bead 123 clamped against the body 38 by a
gage ring 124 and a lower bead 125 clamped against the body 38 by a
lower gage ring 126. Suitable fill and bleed openings 127 and 128
are provided, whereby the chamber 121, the annular space 127 and
the piston chamber 114 can be filled with clean oil. Extending
between the gage rings 124 and 126 is a slotted protective sleeve
129. When the annulus 13 outside the shut-in valve assembly is
pressurized, fluid in the chamber 121 will be displaced through
ports 121a in the body 38 and from the chamber 127 through the
ports 113 in the cylinder sleeve 110 into the piston chamber 114,
forcing the piston 115, the thrust sleeve 120 and the indexing
guide 81 upwardly from the position of FIG. 9 to the position of
FIG. 10, thereby, as will now be described, allowing the mandrel 19
to move upwardly one increment of motion.
As best seen in FIGS. 9, 10, 11, the land 230 has an upwardly
facing shoulder 230a and a downwardly facing shoulder 230b. The
indexing guide 81 has an upper inner cylindrical surface 81a
engageable with the balls 86, when the indexing sleeve is in its
lowermost position, for holding the balls 86 in an inwardly
displaced location engageable by the upwardly facing shoulder 230a,
thereby preventing upward movement of the mandrel 19. Thus, the
mandrel is held in its lowermost position, as seen in FIGS. 2a
through 2c, with the valve passages 24 through 27 all closed. When
by the application of annulus pressure to the piston 115, the
piston and the indexing sleeve 81 are moved upwardly to the
position of FIG. 10, the balls 86 are traversed by a clearance
space or annular groove 186 in the inner periphery of the indexing
guide 81 allowing the balls 86 to shift outwardly, releasing the
mandrel 19 for upward movement under the influence of differential
pressure across the lower end of the valve sleeve 22 and the upward
bias of the energizing means 15, as previously described. The land
230 passes over the balls 86, but upward movement of the mandrel 19
is limited by engagement of an upper shoulder 240a on the land 240
with the balls 88 which are held in an inwardly displaced condition
by a lower inner cylindrical surface 81b of the indexing guide 81.
At this same time, the lower shoulder 230b of the land 230 prevents
downward movement of the mandrel 19, since the balls 86 are held in
the inwardly displaced position by an intermediate cylindrical
surface 81c within the indexing guide 81. The lands 230 and 240 are
spaced apart and correspondingly the balls 86 and 88 are spaced
apart axially of the assembly a distance corresponding to the
distance necessary for the mandrel 19 to travel upwardly to bring
the valve sleeve ports 24 into communication with the valve body
ports 30 in one increment of motion of the mandrel 19, further
upward motion being prevented, as seen in FIG. 10, by engagement of
the land shoulder 230a with the balls 88.
When annulus pressure is relieved, the Belleville springs 91 will
force the indexing guide 81 downwardly until the balls 88 are again
free for outward movement into an annular relief groove 188 within
the indexing guide 81. The balls 86 are again held inwardly
displaced by the indexing guide surface 81a, thereby allowing the
mandrel 19 to move upwardly until the land shoulder 240a contacts
the inwardly held balls 86. This latter increment of motion of the
mandrel 19 is sufficient to move the sealing ring 28 below the
valve sleeve ports 24 to a location above the valve body port 30
and will locate the cylindrical valve sleeve 22, with the body port
30 straddled by the sealing rings 28, below the sleeve port 24 and
above the sleeve port 25, at which position the valve is again
closed. This operation can be repeated until each of the additional
lands 250, 260 and 270 have been moved upwardly to a stop position
engaged by the balls 88 at which position the successive ports 25,
26 and 27 of the valve sleeve have been opened. Various numbers of
lands on the mandrel and ports in the valve may be utilized, but in
general, it has been found that in the typical drill stem testing
of an oil or gas well the valve is not opened more than three or
four times at the most. On the other hand, if more openings are
desired, the above operations can be reversed and the mandrel can
be forced downwardly by dropping a plug through the drill pipe
string which will land on top of the mandrel, closing the choke 70,
and can be pressurized through the drill pipe string to overcome
formation pressure acting upwardly on the mandrel and force the
mandrel back downwardly. Such a plug is well known in the oil well
drilling and producing fields.
From the foregoing, it will now be apparent that the present
invention provides a simple, efficient drill stem testing
apparatus, including a novel shut-in valve aseembly which can be
operated responsive to annulus pressure above the packer, so that
the testing operation is independent of motion of a floating vessel
from which the testing operation is being performed.
* * * * *