U.S. patent number 3,858,649 [Application Number 05/471,119] was granted by the patent office on 1975-01-07 for apparatus for testing oil wells using annulus pressure.
This patent grant is currently assigned to Halliburton Company. Invention is credited to John C. Holden, Gary Q. Wray.
United States Patent |
3,858,649 |
Wray , et al. |
January 7, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
APPARATUS FOR TESTING OIL WELLS USING ANNULUS PRESSURE
Abstract
An annulus pressure operated oil well testing and sampling
apparatus utilizes hydrostatic pressure to supplement spring means
which biases against valve means to hold the valve means closed
until application of sufficient hydraulic pressure to the annular
fluid opens the tool to the formation and allows testing operations
to be performed. A subsequent intentional or inadvertent release or
sudden extreme increase of applied pressure on the annular fluid
actuates means to close the valve means against further formation
fluid flow.
Inventors: |
Wray; Gary Q. (Duncan, OK),
Holden; John C. (Duncan, OK) |
Assignee: |
Halliburton Company (Duncan,
OK)
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Family
ID: |
26989973 |
Appl.
No.: |
05/471,119 |
Filed: |
May 17, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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335980 |
Feb 26, 1973 |
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Current U.S.
Class: |
166/162; 166/152;
166/336; 166/264; 73/152.01 |
Current CPC
Class: |
E21B
49/081 (20130101); E21B 34/108 (20130101); E21B
33/12 (20130101); E21B 49/001 (20130101) |
Current International
Class: |
E21B
49/00 (20060101); E21B 33/12 (20060101); E21B
49/08 (20060101); E21B 34/00 (20060101); E21B
34/10 (20060101); E21b 047/00 () |
Field of
Search: |
;166/.5,150,152,72,264,224,226S,162,169 ;73/151,155 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Attorney, Agent or Firm: Tregoning; John H. Gonzales; Floyd
A.
Parent Case Text
This is a continuation, of application Ser. No. 335,980, filed Feb.
26, 1973, now abandoned.
Claims
What is claimed is:
1. Oil well sampling apparatus for placement in a testing string,
comprising:
power section means arranged to receive applied fluidic pressure on
fluids between the test string and the well casing and convert said
pressure applications into sampler actuating movement in the test
string; and
sampler means arranged to be attached to said power section means
and receive said actuating movements thereby controlling fluid flow
through the test string and capable of trapping a sample of the
fluid therein;
said power section means further comprising:
a substantially cylindrical outer housing assembly having a bore
therethrough;
an inner barrel assembly concentrically located within said housing
assembly and forming a plurality of annular chambers therebetween,
said inner barrel assembly having a substantially open unrestricted
bore therethrough;
a valve sleeve assembly slidably located on said housing assembly
and having a plurality of ports through the wall thereof, some of
said ports being capable of fluidically communicating with a
plurality of ports through the wall of said housing;
said sleeve assembly arranged to be pressure balanced against
buoyancy of said testing string and said sleeve assembly further
adapted to move in response to reciprocation of said testing string
to align some of said ports in said sleeve assembly with said ports
in said housing in one position of said sleeve assembly; and in a
second position of said sleeve assembly to prevent flow through
said housing assembly ports;
supplemental pressure annular floating piston means located in
sealing engagement between said housing assembly and said inner
barrel assembly and having fluid communication with said housing
assembly ports, said piston means capable of sliding movement
between said housing assembly and said barrel assembly;
spring biasing means located between said outer housing assembly
and said inner barrel assembly blow said supplemental pressure
annular floating piston means and arranged in springing engagement
therewith;
said spring biasing means comprising an inert gas chamber;
second annular floating piston means slidably and sealingly located
within said chamber;
pressurized inert gas within said chamber between said supplemental
piston means and said second annular floating piston means; and
mechanical spring means abutting said second annular piston
means;
power piston means slidably and concentrically located within said
housing assembly in abutting relationship with said spring biasing
means and reacting in conjunction with said second annular floating
piston means by way of hydraulic fluid sealingly emplaced between
said power piston means and said second annular floating piston
means; said power piston means arranged to receive annulus fluid
through a second plurality of ports through the wall of said
housing assembly and adapted to react in longitudinal movement
against said spring biasing means in response to fluidic pressure
applied to said annulus fluid, said power piston means having a
differential pressure area thereon; and
pull mandrel means located slidably within said housing assembly
and arranged to move in response to longitudinal movement of said
power piston means; said pull mandrel means adapted to engage said
sampler means and transfer longitudinal movements thereto.
2. The sampling apparatus of claim 1 further comprising:
inert gas filler valve means located in said housing assembly;
inert gas chamber isolation valve means located in said
housing;
hydraulic impedance means located in said housing between said
second annular floating piston means and said power piston means in
said hydraulic fluid and arranged to dampen movements of said power
piston means; and
check valve means in communication with said hydraulic fluid and
located in parallel with said impedance means and adapted to bypass
said impedance means upon longitudinal movement of said power
piston means in response to said spring biasing means.
3. The sampling apparatus of claim 1 wherein said sampler means
further comprises:
a cylindrical external sampler housing assembly having a bore
therein and adapted to be securedly attached to said power section
housing assembly;
an upper, inner housing extension member fixedly attached to the
interior of said external sampler housing, located concentrically
therein, and having an open axial bore therethrough;
a lower inner housing extension member fixedly attached to the
interior of said external sampler housing located concentrically
therein, coaxial with said upper extension member, and having an
open axial bore therethrough;
valve mandrel means slidably located within said upper and lower
extension members and said sampler housing assembly and forming a
sample chamber therein;
valve coupler means located concentrically within said sampler
housing, attached to said valve mandrel means, and adapted to be
securedly engaged with said pull mandrel means in said power
section means;
first port means in said valve mandrel means comprising two sets of
ports through the wall thereof;
second port means through the wall of said upper extension member
and arranged to communicate with one set of ports in said first
port means in one position of said valve mandrel means within said
housing assembly; and
third port means through the wall of said lower extension member
and arranged to communicate with the other set of ports in said
first port means simultaneously with said communication between
said second port means and said first port means.
4. The sampling apparatus of claim 3 further comprising:
drain valve means in said sample chamber, said drain valve means
including:
a drain port through the wall of said upper extension member;
plug means threadedly engaged in said upper extension member,
aligned coaxially with said upper extension member, and threadedly
engaged in the bore thereof so as to block said drain port in a
first position thereof;
said plug means further adapted to be selectively moved out of
blocking engagement with said drain port; and
said drain port having drain conduit attachment means therein.
5. The sampling apparatus of claim 3 further comprising:
safety lock-closed means, said lock-closed means including:
limit-stop sleeve means frangibly attached to said valve coupler
means and arranged to abut said power section means in a first,
open position of said valve mandrel means;
a concentric inner sleeve attached to said lower extension member
located concentrically within said valve mandrel means;
a plurality of prop-arms hingedly attached to said inner sleeve
between
said inner sleeve and said valve mandrel means and arranged to
swing out in propping relationship below said valve mandrel means
upon shearing of said limit-stop sleeve means in response to
extreme upward movement of said valve coupler means; and
spring actuation means between said prop-arms and said inner sleeve
arranged to move said prop-arms out into propping relationship
below said valve mandrel means upon sufficient movement upwards of
said valve mandrel means to clear said spring actuation means.
6. A sampler apparatus for use in a test string in an oil well
comprising:
a power section having a central bore therethrough, which
comprises;
a piston responsive to fluid pressure in the annulus exterior to
the test string such that increases in said annulus pressure will
move said piston in a first longitudinal direction,
means engaged with said piston for biasing said piston in order
that said piston will move in a second longitudinal direction
opposite to said first direction when said annulus pressure
increases are removed,
means for supplementing said biasing means with hydrostatic
pressure in the annulus as the apparatus is lowered into the well,
and
means having an open position and a closed position for selectively
isolating said supplementing means such that hydrostatic pressure
in the annulus while said isolating means is in the open position
will actuate said supplementing means, and increases in the annulus
pressure subsequent to the closing of said isolating means will
move said piston in the first direction against said biasing means,
and
a sampler section removably attached to said power section and
having a central bore therethrough communicating with said central
bore of said power section, which comprises;
means removably attached to said piston for transferring movements
of said piston, and
two valves in said sampler section spaced apart to form a sample
chamber therebetween, both valves being actuated by said movement
transferring means to open when said piston moves in the first
longitudinal direction thereby allowing formation fluid to flow
through said central bores, and to close when said piston moves in
the second longitudinal direction thereby trapping a sample of
formation fluid in said sample chamber,
said valves further having a fail safe position wherein said valves
are closed when the annulus pressure increases above a
predetermined level thereby moving said piston and said valves by
the action of said movement transferring means in the first
longitudinal direction to a fail safe position.
7. The apparatus of claim 6 wherein said piston comprises an
annular tubular piston arranged within said power section to abut
said biasing means, said piston attached to said movement
transferring means and adapted to receive said applications of
increased annulus pressure.
8. The apparatus of claim 6 wherein said isolating means is
remotely shifted to the opened or closed position by manipulations
of the test string.
9. The apparatus of claim 6 wherein one valve of said sampler
section controls fluid communication between said sample chamber
and said communicating central bores through the sampler section
and the power section, wherein said second valve of said sampler
section controls fluid communication between said sample chamber
and the test string, and wherein said valves are actuated by said
movement transferring means to open and close simultaneously in
response to longitudinal movements of said piston.
10. The apparatus of claim 6 wherein said sampler comprises a means
for locking said valves in the closed fail safe position when said
movement transferring means has moved said valves to the fail safe
position in response to movement of said piston under the influence
of overpressure in the annulus.
11. The apparatus of claim 6 wherein said biasing means comprises a
pressured inert gas filled chamber forming an inert gas spring
within said power section arranged to bias against said piston as
said piston moves in the first longitudinal direction.
12. The apparatus of claim 11 wherein said supplementing means
comprises a floating annular piston adajcent said inert gas spring
and exposed on one side to the pressurized inert gas of said gas
spring, and exposed on a second side to the hydrostatic pressure in
said annulus, and free to move in response to said hydrostatic
pressure to further pressurize said inert gas.
13. The apparatus of claim 12 wherein said isolating means
comprises a valve between said second side of said floating piston
and said annulus which when open allows fluid communication between
said floating piston and said annulus, and when closed blocks fluid
communication between said floating piston and said annulus.
14. The apparatus of claim 12 wherein said floating annular piston
comprises spaced apart, axially aligned sleeve pistons and oil
located in the space between said sleeve pistons.
15. The apparatus of claim 11 wherein said biasing means further
comprises a mechanical spring arranged to work in conjunction with
said inert gas spring to further bias said piston in said second
longitudinal direction.
16. The apparatus of claim 15 with said power section having a
spring chamber containing said mechanical spring between said
piston and said inert gas spring, said power section further
comprising:
a fluid conduit communicating said spring chamber with said inert
gas filled chamber;
an oil cushion in said spring chamber wherein a portion of said oil
is displaced from said spring chamber through said fluid conduit
and into said gas filled chamber as said piston is moved in the
first longitudinal direction; and
a floating annular piston slidably located in said inert gas filled
chamber exposed on one side to said pressurized inert gas and on a
second side to said displaced oil.
17. The apparatus of claim 16 wherein said fluid conduit contains
hydraulic impedance means for impeding the rate of oil displacement
from said spring chamber to said inert gas filled chamber to
thereby dampen movements of said piston in the first longitudinal
direction.
18. An oil well testing sampler for controlling the flow of well
fluids through the conduit of a test string in a well bore, and for
trapping a sample of well fluids therein; said sampler
comprising:
a cylindrical outer housing assembly;
upper and lower inner cylindrical housing members, both having a
plurality of ports through the walls thereof, said members being
longitudinally spaced apart and located concentrically within and
connected to said outer housing assembly so as to provide an
annular space between each inner housing member and said outer
housing assembly;
a cylindrical sampler mandrel having an upper set of a plurality of
ports and a lower set of a plurality of ports through the wall
thereof, said sampler mandrel slidably located concentrically
within said inner housing members and spanning the space between
said inner housing members to form an annular sample chamber
between said outer housing assembly, said sampler mandrel, and said
upper and lower inner housing members; and
a pull mandrel having a plurality of longitudinal flow channels
along a portion of the sides of said pull mandrel, said pull
mandrel extending from one end of said outer housing assembly
between said outer housing and one of said inner housing members
and being linked to one end of said sampler mandrel through
longitudinal slots in said one of said inner housing members;
said pull mandrel, when connected to an actuating tool in said test
string, moving said sampler mandrel from
a closed position wherein said upper set and lower set of ports of
said sampler mandrel do not communicate with the ports in said
upper and lower inner housing members;
to an open position wherein said upper set and lower set of ports
of said sampler mandrel communicate respectively with the ports in
said upper and lower inner housing members with one set of
communicating ports additionally communicating with said flow
channels in said pull mandrel and with the other set of
communicating ports additionally communicating with the annular
space between the second of said inner housing members and said
outer housing assembly, and
to a second closed position wherein said upper set and lower set of
ports of said sampler mandrel do not communicate with said ports in
said upper and lower inner housing members.
19. The sampler of claim 18 further comprising safety means for
locking said sampler mandrel in said second closed position after a
predetermined force from said actuating tool.
20. The sampler of claim 19 wherein said safety means comprises a
sleeve frangibly attached to said pull mandrel for abutting the
tool string to which said sampler is attached, hinged prop arms
retained in the annular space between one of said inner housing
members and said outer housing assembly while said sampler is in
said initial closed or said open position, and
means for biasing said prop arms in locking engagement with said
sampler mandrel when said sampler mandrel moves to said second
closed position.
21. The sampler of claim 20 wherein one of said inner housing
members has a drain port adapted for attachment of a drain conduit
therein, said sampler further comprising:
a removable plug, threadably engaged in said inner housing member
for blocking fluid communication through the central bore of said
cylindrical inner housing member; said removable plug adapted to
block said drain port in one position, and to allow fluid
communication through said drain port in a second position.
22. The sampler of claim 21 further comprising a spool valve
through the wall of said outer housing assembly and communicating
with the annular space between said second inner housing member and
said outer housing assembly; said spool valve having a first
position for allowing fluid flow from the conduit of said test
string into said sampler, and a second position for allowing the
draining of fluids trapped within said outer housing assembly
through the walls of said outer housing assembly.
Description
BACKGROUND OF THE INVENTION
This invention is directed towards testing of oil wells and is
specifically advantageous in offshore and underwater wells.
After an oil well has been encased and cemented it usually becomes
desirable to test the formations penetrated by the wellbore for
possible production rates and general potential of the well. In
doing so, a test string containing several different types of tools
is utilized to determine the productivity of the well. These tools
may include a pressure recorder, a sample chamber, a closed-in
pressure tester, an hydraulic jar, one or more packers, a
circulating valve, and possibly several other tools.
The testing procedure requires the opening of a section of the
wellbore to atmospheric or reduced pressure. This is accomplished
by lowering the test string into the hole on drill pipe with the
tester valves and sample chamber closed to prevent entry of well
fluid into the drill pipe. With the string in place in the
formation, packers are expanded to seal against the wellbore or
casing to isolate the formation to be tested. Above the formation
the hydrostatic pressure of the well fluid is supported by the
upper packer. The well fluid in the isolated formation area is
allowed to flow into the drill string by opening the tester valve.
Fluid is allowed to continue flowing from the formation to measure
the ability of the formation to produce. The formation may then be
"closed in" to measure the rate of pressure buildup. After the flow
measurements and pressure buildup curves have been obtained,
samples can be trapped and the test string removed from the
well.
Previously the method used to open and close the necessary valves
and chambers in the tool string involved physical manipulations of
the string either in vertical reciprocation or rotational motion or
a combination of both. Another method involved use of heavy bars or
balls dropped down the string to actuate certain tools in the
string.
All of these methods suffer thee serious disadvantage of requiring
movement of or within the drill pipe. This is especially
disadvantageous in offshore drilling because of the danger of drill
pipe separation or blowout during the period the blowout preventer
rams are removed from the drillpipe during the manipulation of the
string or dropping of objects down the pipe.
One means of operating tools in the testing string without
manipulation of the pipe which has proven very successful involves
the use of annulus pressure operated testing tools. Examples of
these tools include the annulus pressure responsive (APR) safety
sampler disclosed in U.S. Pat. No. 3,664,415, the APR disc valve
disclosed in U.S. Pat. application Ser. No. 224,755 filed Feb. 9.
1972, now U.S. Pat. No. 3,779,263, and the APR circulating valve
disclosed in U.S. Pat. application Ser. No. 288,187 filed Sept. 11,
1972, all assigned to the assignee of this application, Halliburton
Company.
While this family of annulus pressure operated testing and sampling
tools offers substantial advancements over the mechanically
operated tools previously discussed, the present invention
discloses a second generation APR tool having even further
advantages over those of the first generation.
Use of the above-mentioned first generation APR tool string
requires a fairly accurate knowledge, either empirical or
calculated, of the bottomhole conditions in the well immediately
prior to running the required tests. This is because the inert gas
chamber in these tools which serves as a spring biasing means must
be charged at a predetermined pressure and volume to offset the
hydrostatic pressure and temperature at bottomhole and still retain
sufficient springing action to allow the tool to operate in
response to surface applications of hydraulic pressure on the
annulus fluid and to close the tool upon release of the applied
annulus pressure. In the case of fairly deep wells, this requires
the charging of the inert gas spring chamber to extremely high
pressures, on the order of 10,000 psi and above, on the ground
before going in the hole, which pressures require extra thick
chamber walls and other precautionary measures for safety's
sake.
The present invention overcomes these disadvantages by providing a
tool which can be charged with inert gas at a relatively low
pressure level on the ground and then utilizes hydrostatic pressure
to supplement this pressure as the tool travels down the borehole,
so that when the APR tool reaches the bottom of the hole there will
be sufficient pressure in the tool gas chamber to provide a
springing action above the pressure established by hydrostatic
forces and gas expansion due to the high temperature rise. As the
tool is removed from the well, hydrostatic supplementary pressure
is gradually removed from the tool.
The tool of this invention, in addition to serving as a testing
tool and sampler, also operates as a safety valve in case the drill
string parts or leaks or other emergency arises which takes the
weight off of the string. The tool also provides a lock-closed
feature which automatically closes the tool in case of a large
pressure rise in the casing. Furthermore, it features a full-open
drill-pipe bore from ground surface to the sampler depth.
This invention achieves its objectives by the use of multiple
floating piston means, and multiple gas chambers in conjunction
with shuttle valves and pressure balanced valves.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 provides a schematic, vertical, elevational view of an
offshore test site, illustrating a testing string disposed in a
submerged well and intersecting a submerged formation;
FIG. 2 illustrates an enlarged, vertically sectioned, fragmentary
elevational view of a well head portion of the assembly of FIG. 1,
located on a floating vessel or work station, and a submerged well
head portion having an annulus pressure responsive system;
FIGS. 3a through 3h when joined along common lines a--a through
g--g, provide an enlarged, vertically sectioned, "right-side only"
view of the power section of the APR tools;
FIGS. 4a through 4d when joined along common lines a--a through
c--c, provide an enlarged, vertically sectioned, "right-side only"
view of the separable sampler of the APR tool; and
FIG. 5 is an elevational side view of the pull mandrel yoke.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 schematically illustrates a representative offshore test
operation.
As shown in FIG. 1, a floating drilling vessel or work station 1 is
anchored or otherwise secured in position over a submerged well
site 2. Submerged well site 2 comprises a bore hole 3, the interior
of which may be lined by a casing string 4 in a conventional
fashion.
Wellbore 3, and usually casing 4, intersect a formation 5 whose
productivity is to be tested.
Where casing 4 intersects formation 5, at area 3a, perforations
will usually be provided to ensure fluid communication between the
formation 5 and the interior 6 of the wellbore 3.
At the submerged "mud-line" a submerged wellhead installation 7 may
be provided. Installation 7 may be provided with a variety of
blow-out preventer mechanisms of both the partial closing and
"blind" type, the structure and operation of which are generally
shown in FIG. 2 of United States Manes et al., U.S. Pat. No.
3,646,995 filed Dec. 8, 1969, and assigned to the assignee of the
present application.
As will be understood, submerged wellhead 7 may also comprise any
of several conventional "off the shelf" submerged wellhead units
now available.
A marine conductor 8 extends upwardly from wellhead 7 to floating
work station 1 and may be laterally supported on deck means 9 of
work station 1, generally as schematically shown in FIG. 2. The
upper end of conductor 8 may pass slidably through a gimbal
connection on deck 9. Such an arrangement, known in the art,
provides lateral support for conductor 8 while permitting wave
action induced, vertical movement of station 1 relative to the
conductor. Conductor slip joints might also be used to accommodate
wave action.
A testing string 10 is manipulated at work station 1 by
conventional hoisting means 11, conventionally operated from a
derrick-like structure 12A, as shown in FIG. 1. The usual control
head, manifold and swivel arrangements may be provided in the upper
end of string 10 to permit conventional circulation of fluid
through the testing string and rotary testing string
manipulations.
This hoisting means, in conjunction with conventional rotary table
slip means would be employed to threadably interconnect sections of
the test string 10 and lower the test string 10 through the marine
conductor 8 and casing 4 to the general disposition shown in FIG.
1.
As shown in FIG. 2, test string 10 will be disposed in slidable but
sealing engagement with a wellhead seal 12. Wellhead seal 12 may
comprise a conventional flow head or circulating head mounted on a
wellhead closure 13 and defining a transverse annular barrier
extending across the upper end of marine conductor 8. As will thus
be appreciated, elements 13 and 12 cooperate to provide a seal
between the upper end of marine conductor 8 and the exterior of the
conduit or test string 10.
A pressuring fluid supply conduit 14, possibly a conventional,
safety valve controlled, mud or "kill" line may extend from site 1,
downwardly along the exterior of conductor 8, and intersect the
wellhead 7 below its blowout preventers, generally as shown in FIG.
2. Such a "kill" line would usually be attached to the exterior of
conductor 8 and would communicate with the upper interior of casing
4. Conduit 14 extends to a conventional "mud pump" 15 on floating
site 1. Pump 15 is used to impart pressure to fluid, possibly of a
conventional drilling mud nature, contained within and
substantially filling the annular void or space 16 surrounding the
conduit string 10, and disposed between the string 10 and casing 4
beneath the wellhead 7.
String 10 may include the following components, disposed in
consecutively downwardly spaced relation:
ITEMS REFERENCE NUMERAL ______________________________________
Upper conduit string extending to floating work site 1 (threadedly
interconnected conduit sections) 17 Hydraulically operated, conduit
string test tree 18 Intermediate conduit portion 19 Torque
transmitting pressure and volume balanced slip joint 20
Intermediate conduit portion imparting packer setting weight to
lower portion of string 21 Circulating valve 22 Intermediate
conduit portion 23 Upper pressure recorder and housing 24 Valving
and sample entrapping mechanism 25 Lower pressure recorder and
housing 26 Packer mechanism 27 Perforate "tailpipe" providing fluid
communication between interior of conduit string 10 and formation 5
28 ______________________________________
As shown in FIG. 1, with the testing string 10 installed in
position, the packer 27 will have been manipulated to expanded
condition so as to provide a seal between the conduit string 10 and
the bore hole wall 4. Packer 27 may desirably be of the type shown
in Anderson et al., U.S. Pat. Nos. 3,584,684 and 3,702,634, filed
June 2, 1969, assigned to the assignee of the present
application.
This packer mechanism is operated in response to rotary and linear
manipulations of the conduit string as described in the aforesaid
Anderson et al. patents, with sufficient operating weight or
movement being transmitted through the string by virtue of the
presence of such weight providing elements in the string as the
conduit means 21. Such weight is desirable in a testing string of
this nature because of the expansible and contractible character of
the torque transmitting, but telescoping, slip joint coupling 20.
With the weighting elements included in string 10 below coupling
20, downward or upward movment of the conduit string, during its
installation, will be effectively transmitted through the string to
the operating components of the packer mechanism 27.
After setting of the packer has been initiated, the slip joint 20
will be disposed in a partially contracted condition, the weight of
upper elements 17 and 18 of string 10 will be supported by closed
blowout preventer rams in wellhead 7, and the drilling vessel 1
will be free to move up and down in relations to the upper end of
test string 10. The manner of effecting packer setting as above
indicated and the manner in which wellhead rams provide upper test
string support by engaging test tree associated abutment means is
fully described in the aforesaid Manes et al. patents.
During the packer setting, the slip joint 20 effectively isolates
wave action induced force from being transmitted through the upper
portion of string 10 to the packer 27, as described in the
aforesaid Manes et al. patents. The slip joint 20 also permits some
tolerance in the extent of downward movement of the upper conduit
string portion, after initiation of packer setter, required to
"seat" test tree abutment means on the closed rams in wellhead
7.
Since the slip joint 20 permits the upper end of the string 10 to
be seated on, i.e., supported by, wellhead 7, it permits the string
10 to be disconnected from fully supported relation with the
hoisting mechanism of the vessel 1 and thus isolated from wave
actions acting on this vessel. Even if string 10 should remain
supported by this hoisting mechanism, the telescoping action of the
slip joint would prevent the transmission of wave actions to the
portion of string 10 below the slip joint.
With the testing string 10 manipulated so as to "seat" or expand
the packer 27, the expanded packer will provide a seal between the
conduit string 10 and the casing or bore hole wall 4, defining the
closed lower end of annular void or space 16. With this
arrangement, annular space 16 will be effectively isolated from the
interior of the conduit string 10 and from the formation 5. In the
embodiment described, the closed rams in wellhead 7, upon which
test tree abutment means is seated, will provide an annular closure
in wellbore 3, defining a closed upper end of annulus 16. Thus,
with annulus 16 filled with fluid, such as mud, line 14 will serve
to convey pressurized fluid to annulus 16 and increase its
pressure, depending on the height of line 14 and the pressure of
fluid it conveys.
Even if the support rams in wellhead 7 should not define an annulus
seal at wellhead 7, the annular cavity above wellhead 7 between
string 10 and casing 4 will be filled with fluid, possibly mud.
This body of fluid will define an upper extension or portion of
annulus 16, sealed at its upper end by means 12 and 13.
Indeed, in certain circumstances, it may be desirable for the
entire weight of the portion of conduit string 10 above slip joint
20 to be supported by hoist mechanism 11, with slip joint 20 being
partially contracted to absorb wave action and the rams of wellhead
7 open. This arrangement would provide an annulus 16 extending from
packer 27 to conductor closure 13. Pressurizing of such an
elongated annulus 16 could be effected by a pressurizing line 14
communicating with the interior of the conductor 8 at the elevation
of the vessel 1.
The test tree mechanism 18 incorporated in the conduit string may
comprise the safety mechanism described in the aforesaid Manes et
al. patent, assigned reference numeral 801 in the Manes et al.
patent, and commercially available from Otis Engineering
Corporation, Post Office Box 34380, Dallas, Texas 75234. This
mechanism 18 comprises an hydraulically operable valve assembly for
selectively closing off or opening the interior passage of the
string 10 in the vicinity of the submerged wellhead installation 7.
The mechanism 18 is designated by Otis Engineering Corporation as a
retrievable "subsea test tree," the structure and function of the
apparatus being described in greater detail in the aforesaid Manes
et al. patent.
The slip joint mechanism 20 may desirably comprise a pressure and
volume balanced slip joint of the type described in Hyde U.S. Pat.
No. 3,354,950. The Hyde slip joint comprises an extensible and
contractible, telescoping coupling in the conduit string 10, which
coupling is pressure and volume balanced, telescoping in nature,
and operable to effectively minimize or eliminate the transmission
of wave action induced force acting on the upper portion of the
conduit string 10 and the floating vessel 1 from being transmitted
through the conduit string 10 to the packer 27 and the valving and
sample entrapping mechanism 25.
With this basic disposition of components, a valving mechanism
included in the device 25 may be operated so as to close the
longitudinally extending interior passage of the conduit string 10,
open this passage, or close the passage so as to entrap a sample of
formation fluid with the body or conduit means portion of the
mechanism 25.
As the valving elements of the mechanism 25 are manipulated, the
pressure recorders 24 and 26, disposed respectively above and below
the mechanism 25, will continuously record the pressure of
formation fluid at these sites in the conduit string, in a well
recognized fashion.
During the testing operation, or during the removal of the testing
string, or during its installation, it may be desirable to effect a
circulation of fluid between the interior of the conduit string and
the annular space 16. Such circulation of fluid is permitted by the
circulating valve 22, which normally is disposed in a closed
condition. Valve 22 may comprise a ratchet-type annulus pressure
operated sleeve valve such as that disclosed in U.S. Pat.
application, Ser. No. 288,187 in the names of John C. Holden and
Gary Q. Wray, also assigned to the assignee of this
application.
As is often done, from a safety standpoint, the testing string 10
may include a jar mechanism, anticipating the possibility that
release of the packer 27 may be impeded for a variety of
operational reasons. An effective jarring mechanism which may be
utilized for this purpose, and which may be incorporated in the
test string above the packer 27, and beneath the recorder 26,
comprises an hydraulic jarring mechanism of the type generally
featured in Barrington U.S. Pat. No. 3,429,389, or of the type
featured in Barrington U.S. Pat. No. 3,399,740.
As a further safety feature, the test string 10 may include a
"safety joint" incorporated between the jarring mechanism and the
packer 27. A safety joint uniquely suitable for such incorporation
is featured in Barrington U.S. Pat. No. 3,368,829. The safety joint
would permit the testing string to be disconnected from a stuck
packer assembly and removed to the work site.
While the arrangements heretofore described afford the unique
advantage of an open or unobstructed interior of string 10
extending downwardly from vessel 1 to mechanism 25, it might be
desirable, at times, to utilize additional passage blocking, safety
equipment. Thus, as described in the aforesaid Manes et al. patent,
the lower end of the slip joint 20 might be connected with a test
string, passage controlling, reciprocation responsive safety valve,
designated item 12 in the Manes et al. disclosure.
Under certain conditions, the packer 27 may not be attached to the
test string 10. For example, a drillable test packer could be
previously set by a "wire line" and the test string later lowered
and coupled with the packer via a probe or "stinger" carried by the
test string. Such an arrangement is generally described in Evans et
al. U.S. Pat. No. 3,423,052.
With the overall installation and test string having been generally
described and various alternatives discussed, it now becomes
appropriate to consider the general operating characteristics of
this invention as reflecting in the structure and operating
characteristics of the valving and sample entrapping mechanism
25.
DETAILED POWER SECTION CONSTRUCTION
The sampling mechanism 25 essentially comprises two sections, the
power section 30 and the separable sampler section 40.
The power section 30 which occupies the upper part of the mechanism
is shown in detail in FIGS. 3a through 3h. This section, beginning
at the top, has an upper adapter 301 having internal threads 302 at
the top for connecting in the drill string and external threads 303
on a reduced diameter skirt 304 at the bottom for attachment to the
power section 30. Attached to threads 303 is the hydrostatic
pressure balanced port valve assembly 305 utilized to prevent the
bouyancy of the tool from closing the hydrostatic pressure ports
306 when entering the well fluid. Assembly 305 comprises a
cylindrical upper housing 307 atached to a cylindrical lower
housing 308, a cylindrical piston mandrel 309 slidably located
within outer housings 307 and 308, and coil compression spring 310.
Ports 306 pass through the wall of housing 308.
Inner piston mandrel 309 comprises a cylindrical sleeve having an
integral annular external piston shoulder 311 and external splines
312 located thereon. Piston shoulder 311 has annular seal grooves
313 on its outer surface for receiving O-ring seals 314 therein.
Upper housing 307 has an enlarged inner chamber 315 for sealingly
receiving piston shoulder 311 in slidable relationship therein.
Housing 307 furthermore has internal splines 316 for engaging with
external splines 312 of mandrel 309 to prevent rotation of mandrel
309 within housings 307 and 308. Cylindrical mandrel extension 309a
contains one or more ports 320 through the wall.
One or more pressure balancing ports 317 pass through the wall of
upper housing 307 and allow annular fluid under hydrostatic
pressure to communicate with the upper face 318 of piston shoulder
311.
The buoyancy induced by hydrostatic pressure on the tool is
equivalent to the hydrostatic pressure times the cross-sectional
area. Thus, the bouyancy trying to push mandrel 309 upward in
housings 307 and 308 is equivalent to the hydrostatic pressure
times the cross-sectional area of mandrel 309 indicated by
reference arrows as A.sub.3. The effective counter balancing
downward force arises from hydrostatic pressure acting on piston
face 318 and is calculated by multiplying hydrostatic pressure
times the area of this face. Since this is a circular annular area
it is calculated as the area of the outer circle A.sub.1, minus the
area of the inner circle A.sub.2. For ideal balancing condition
therefore (A.sub.1 - A.sub.2) = A.sub.3. To overcome friction
forces and other incidental factors, (A.sub.1 - A.sub.2) should be
slightly greater than A.sub.3 or, as in this situation, a coil
compression spring 310 can be used to further bias against
telescoping together of mandrel extension 309a and housing 308. In
the outermost extended position of mandrel extension 309a in
housing 308, ports 306 are lined up vertically with ports 320. In
case rotation has occurred and lateral misalignment of the two sets
of ports occurs, an annular groove 319 is located around the
exterior of extension 309a to intersect all of ports 320 and
provide continuous fluid communication between the two sets of
ports regardless of horizontal rotation.
Lower housing 308 has seals 321 therein to seal against mandrel
extension 309a and prevent fluid communication therebetween. Upper
adapter 301 has internal seals 322 to seal against mandrel 309, and
mandrel extension 309a has external seals 323 above and below ports
320 to prevent fluid communication between mandrel extension 309a
and lower housing 308 around the port area.
The void areas between seals 314 and seals 321 are initially at
atmospheric pressure and therefore allow a pressure differential to
form across piston 311 from hydrostatic pressure acting on piston
face 318. Atmospheric pressure has access to these areas through
ports 324 in mandrel 309. The void spaces between seals 321 and
seals 323 are at hydrostatic pressure from fluid entering one or
more ports 391 in the wall of lower housing 308. Circular seal 325
is located between the upper and lower housings to prevent fluid
leakage therebetween.
Below assembly 305 is located the upper inert gas chamber floating
piston assembly 326 having two slidable floating pistons 327 and
328 located therein. These two pistons are annular cylinders each
having internal and external seal means 329. The piston chamber is
formed by cylindrical external housing member 330 which is fixedly
attached to the lower end of mandrel extension 309a. Located
concentrically within housing 330 and pistons 327 and 328 is a
cylindrical uppermost inner barrel 331 which sealingly engages
mandrel extension 309a through seals 332a and sealingly engages an
orifice member 333 through seals 332b to form a fluid tight chamber
334 around pistons 327 and 328.
Annular fluid access to chamber 334 is accomplished through ports
306 and 320. A fluid cushion of oil 335 is maintained between
pistons 327 and 328 and held there by seals 329. Below the lower
piston 328 is an inert gas such as nitrogen compressed under
predetermined pressure.
Upper orifice member 333 is a cylindrical extension of housing 330
having a reduced inner diameter forming an inward extending thicker
section 333a. The thicker wall area serves to provide material
through which pass one or more orifice channels 336 communicating
with lower gas chamber 337. Member 333 also has an inner shoulder
333b on which is seated inner barrel 331 and an upper intermediate
inner barrel 338. Seals 339 prevent fluid communication between the
orifice member 333 and housing members 330 and 340.
Upper intermediate barrel 338 is sealingly engaged with upper
orifice member 333 and a lower orifice member 343 by seal means
341a and 341b respectively.
Lower orifice member 343 is similar in construction to upper member
333 and has one or more orifice channels 342 communicating lower
gas chamber 337 with the inert gas filler chamber 344.
It should be noted that uniform sections of chambers 334 and 337
have been broken out in order to shorten the drawings and
facilitate understanding of the invention.
Gas filler chamber 344 is formed by an outer housing connector 345
having a cylindrical configuration, and a lower intermediate inner
barrel 346. In the annular space between connector 345 and barrel
346 is a valve piston 347. Connector 345, piston 347 and barrel 346
cooperate to provide an inert gas filler assembly 353 for the
apparatus. Connector 345 has a gas filler port 348 and a pump
actuating port 349. Piston 347 is an annular sleeve type piston
concentrically and slidably located between housing 345 and barrel
346. It has an enlarged diameter 351 at the top containing circular
seals 350, and a lesser diameter section 352 comprising the lower
approximately two-thirds of the piece.
The enlarged end 351 acts as a differential pressure area so that
when an actuating fluid or quasi fluid such as oil or grease is
pumped under pressure through port 349 a resultant force upward
will be applied on the piston.
In the position shown, the filler valve assembly 353 is in a closed
position. Lower section 352 of the piston covers gas filler port
348 and circular seals 354a and 354b above and below the port
prevent leakage of the inert gas between the piston and the
housing. When it is desirable to open the filler port to either add
more inert gas or to drain inert gas, plug 355, which is threadedly
secured in actuating port 349, is removed and fluidic pressure is
applied through the port to piston shoulder 351. A convenient
method of applying this pressure is by means of a common grease
gun, such as mechanics use, with an attachment for connecting into
port 349. Upon application of sufficient pressure across
differential pressure area 351, piston 347 will move upward in
response to the hydraulic force on it. This will move seals 354b
upward past filler port 348 until the lower end of the piston
clears the port. The inert gas can then be inserted into the port
whereupon it flows to the various chambers in the tool. Piston 347
has a sufficiently large inner diameter to allow the inert gas to
flow between the piston and the inner barrel 346.
When filling is completed, pressure on the actuating fluid is
released at port 349 and the internal pressure of the inert gas
which has been injected into the tool will force piston 347 back
downward, closing off and sealing the filler port 348 by locating
seals 354a and 354b above and below the port.
Plug 355 can then be replaced in pumping port 349 to protect that
port against sediment and well fluids and a similar plug 356 can be
placed in the filler port 348 to likewise protect it and further
seal it off against gas leakage. It should be noted that the
smallest inner diameter of housing connector 345 at 357 is large
enough to allow the inert gas to pass downward between the
connector and inner barrel 346.
Located immediately below housing connector 345 is shuttle valve
assembly 360. This comprises a sliding cylindridal piston mandrel
358 concentrically located within housing member 359, which is
attached to housing connector 345, with piston mandrel 358
encircling inner barrel 346. Piston mandrel 358 is a cylindrical
sleeve having an upper skirt 358a and a lower skirt 358c divided by
an annular piston shoulder 358b. Mandrel 358 has sufficiently large
inner diameter throughout to provide a flow space between it and
inner barrel 346.
Located concentrically around upper skirt 358a is an upper
cylindrical sleeve spacer 361 to limit upward travel of mandrel 358
by abutment with lower end of housing connector 345 and shoulder
358b of mandrel 358. Spacer 361 has seals 362a and 362b on its
outer and inner surfaces to seal against housing 359 and mandrel
358 respectively. Lower cylindrical spacer sleeve 363 is located
below piston shoulder 358b, encircling lower skirt 358c, and having
seals 363a on its exterior and 363b on its interior surfaces to
seal against housing 359 and mandrel skirt 358c respectively.
Mandrel shoulder 358b has circular seals 358d thereon to seal
against housing member 359. Lower spacer sleeve 363 limits downward
movement of mandrel 358 by abutment with shoulder 358b and inner
housing extension 364 which is concentrically located inside
housing member 359, and indirectly attached thereto by means of
connecting member 365. Extension 364 is a cylindrical sleeve type
member having an upper skirt portion 364a with enlarged inner
diameter to accomodate the lower end of mandrel skirt 358c, a
stepped inner shoulder 364b to accommodate the lower end of inner
barrel 346, and inner ridge 364c to limit downward movement of the
inner barrel.
Extension 364 has seals 366a to seal against housing 359, seals
366b and 366c to seal against mandrel skirt 358c, and seals 366d to
seal against inner barrel 346.
Housing 359 has a pump-open port 367a and a pump-closed port 367b
through the wall thereof communicating with the inner mandrel 358
and spacer sleeves 361 and 363. When not in use, these two ports
are filled with protector plugs 368a and 368b respectively.
Mandrel 358 has a relief port 369a and communication port 369b
through the wall of skirt 358c. In the open position, as shown in
FIG. 3e, port 369b aligns vertically with port 370a and annular
groove 370b which passes circumferentially around the inner surface
of extension 364 intersecting port 370a. This alignment allows
communication of inert gas from the upper part of the tool, through
the space 371a between mandrel 358 and barrel 346 to the lower part
of the tool via the annular space 371b between housing member 359
and inner housing extension 364.
If it becomes desirable to remove the upper portion of power
section 30 from the lower portion, the connecting member 365 may be
detached from housing member 359 and extension 364 by unscrewing
the threads therebetween. To prevent loss of the inert gas held in
the upper portion, mandrel 358 is moved downward to close ports
369b and 370a off from one another. This is accomplished by
removing plug 368b from port 367b and attaching a fluid pressure
means, such as a common grease gun, to the port 367b and applying
pressure thereto. This pressure will operate on piston shoulder
358b to force it downward until abutment of spacer sleeve 363 on
extension 364 occurs. Upper spacer 361 moves upward in response to
the fluidic pressure. Lower skirt 358c moves down across port 370a
and groove 370b thereby blanking them off, and seals 366b and 366c
prevent any leakage along skirt 358c through port 370a. In the
closed position, the mandrel 358 is in a balanced position and will
be held closed by seal friction so that the pressure source can be
removed and protector plug 368b replaced in port 367b. When it
becomes desirable to reconnect the inert gas supply from the upper
portion of the tool to the lower portion, for instance after the
lower portion has been reattached to the upper portion, both plugs
368a and 368b are removed and a pressure source is connected to
opening port 367a. When pressure is applied to the port it works
against piston 358b to move mandrel 358 back to its uppermost
position whereupon ports 369b and 370a are realigned and
communication is achieved therethrough. Plug 368b is removed to
prevent back-pressure buildup above piston 358b due to fluid which
normally would be trapped there were port 367b not opened.
Port 369a in skirt 358b is provided to allow inert gas to drain
from beneath lower spacer 363 and piston shoulder 358b when the
mandrel is moved downward to close the valve assembly. This
prevents a gas trap from forming below the mandrel and allows
easier downward movement thereof.
Immediately below housing connecting member 365 is the lower
floating piston assembly comprising an external housing member 372
attached to connecting member 365 and being a cylindrical tubular
piece. Located concentrically within housing 372 is a floating
annular piston sleeve 373 having external seals 373a and internal
seals 373b located thereon. Lowermost inner barrel 374 is an
elongated cylindrical tubular mandrel located concentrically within
connecting member 365 and piston 373 and sealingly engaged with
member 365 by seals 374a.
Inert gas which passes through ports 369b, 370a, and annular space
371b, is communicated to lower piston chamber 375a through port 376
in connecting member 365 and into annular space 376a between member
365 and inner barrel 374. Piston 373 provides a sealing barrier
between the inert gas in chamber 375a and the oil cushion in
chamber 375b. Seals 373a provide sealing engagement with the
interior surface of housing 372 and seals 373b provide sealing
engagement with inner barrel 374.
Located below chamber 375b is an inner annular shoulder 372a in
housing 372 through which passes an oil filler port 372b having a
removable plug therein. An annular passage 377a communicates from
chamber 375b to an inner annular recess 377b in shoulder 372a. An
impedance metering rod channel 377c communicates from recess 377b
to metering mandrel 378 having therein an axial orifice 378a
opening up into spring chamber 379. Metering rod 380 is located
within channel 377c to provide hydraulic impedance to oil flow
therethrough.
Diametrically opposite channel 377c in shoulder 372a is relief
bypass channel 381 shown in dashed lines, having a ball and spring
type check valve assembly 382 in the spring chamber end thereof and
communicating with annular recess 377b. Furthermore, annular
shoulder 372a contains an inner annular recessed portion 372c about
inner barrel 374, which is in communication with a second filler
plug 381a.
Seals 374b between shoulder 372a and barrel 374 prevent fluid
leakage between these two elements. Spring chamber 379 is formed by
metering mandrel 378 in conjunction with a lower external
cylindrical housing 383 and cylindrical bottom adapter 384 attached
to housing 383. The inner wall of spring chamber 379 comprises
inner barrel 374 to which is attached power piston 385 and
cylindrical tubular sampler pull coupler 386. Barrel 374, power
piston 385, and coupler 386 move as a single unit in sliding
relationship inside external housing members 365, 372, 383, and
cylindrical adapter 384. Coil spring 387 is disposed around barrel
374 and between metering mandrel 378 and power piston 385, and
works in comparison to bias the power piston towards its lowermost
position as shown in FIG. 3h. Power piston 385 is a cylindrical
sleeve having a raised annular piston shoulder 385b, seals 385a and
lower skirt 385c.
Power piston seals 385a on piston shoulder 385b provide sealing
engagement with inner wall of housing 383, and seals 384a provide
sealing engagement between pull coupler 386 and adapter 384.
Pull coupler 386 and adapter 384 have threads 388 and 389 thereon
to allow attachment of the separable sampler shown in FIGS. 4a
through 4d.
Housing 383 has one or more annulus pressure actuating ports 390
through the wall thereof to communicate fluid pressure from the
annulus area to the power piston shoulder 385b which acts as a
differential pressure area between the annulus pressure and a the
internal inert gas pressure.
OPERATION OF THE POWER SECTION
The power section illustrated in FIGS. 3a through 3g is charged
with a relatively low pressure of inert gas in chamber 334 and is
then placed in the testing string by threading the upper end in
FIG. 3a into the conduit or next upper tool in the string. The
sampler section 40 is attached to the power section at the lower
end and the remainder of the test string, including a packer
mechanism, is attached to the lower end of the sampler section.
While the string is being lowered into the hole, the weight of the
string below the power section applies tension to the power section
which tension telescopes the port valve assembly 305 into its most
extended position as shown in FIGS. 3a and 3b.
As the string is lowered, any bouyancy arising from the fluid in
the well which naturally tends to push the string back upward, is
counterbalanced by allowing hydrostatic fluid pressure to react
through ports 317 and down against differential pressure area
318.
When the string is in the correct position in the well, the packer
is expanded against the borehole by known conventional methods
thereby anchoring the lower end of the string against further
movement. Then the string is allowed to move further down by the
weight of the upper string, thereby telescoping assembly 305 inward
which is a result of housings 307 and 308 moving downward over
internal mandrel 309.
During the descent of the power section in the borehole, because of
the tension on the assembly 305, annulus pressure access ports 306
and 320 remain in vertical alignment with peripheral groove 319
guaranteeing fluid communication therebetween. Annulus pressure
increases proportionately to the depth of the tool in the well
fluid. The increasing annulus pressure arising with the descent of
the tool acts through ports 306 and 320 and down between barrel 331
and mandrel extension 309a to upper piston 327. A hydraulic fluid
is located between pistons 327 and 328 to provide a better seal
between the annulus fluid above piston 327 and the inert gas below
piston 328. The annulus pressure acting on piston 327 is
transferred via the hydraulic fluid to piston 328 which moves
downward with piston 327 to compress the inert gas in chamber 334.
This process occurs until the tool reaches bottomhole whereupon the
inert gas will then be at hydrostatic pressure of the annulus
fluid.
When the string reaches location, the above mentioned packer is set
and weight is set down on the packer thereby moving housing 308
downward over mandrel extension 309a, moving ports 306 out of
alignment with ports 320 and sealing off the inert gas chamber from
further hydrostatic pressure of the annulus fluid.
At this point the power section may be remotely actuated by
applying fluidic pressure to the annulus fluid, which increased
pressure acts through ports 390 and upward against power piston
shoulder 385b thereby moving piston 385 upward while compressing
coil spring 387 and inert gas in chamber 375a through abutment with
hydraulic fluid between piston 385 and floating piston 373. Upon
release of the applied pressure on the annulus fluid, the biasing
action of spring 387 and inert gas above piston 373 acts on piston
385 moving it back downward into its at-rest position.
Movement upward of piston 385 is transferred to the sampler section
40 by way of pull coupler 386 which is fixedly secured to piston
385 and to the pull coupler connector section 438 of the sampler
section.
When it is desirable to remove the tool from the hole, applied
pressure on the annulus fluid is released, the packer is released,
and the string is pulled upward. This once again extends port valve
assembly 305, aligning ports 306 with ports 320, and allows the
supplemental hydrostatic pressure acting on pistons 327 and 328 to
drain off as the tool comes out of the hole and hydrostatic
pressure of the annulus fluid decreases in proportion to the
decreasing tool depth.
THE SAMPLER SECTION
The separable sampler 40 is shown in detail in FIGS. 4a through 4d.
FIG. 4a shows in phantom the lower end of the power section 30 and
illustrates how the power section 30 and sampler section 40 are
joined.
Sampler section 40 consists basically of a stationary housing
assembly 401, a pull mandrel assembly 402 and a valve mandrel
assembly 403.
Housing assembly 401 consists of a cylindrical tubular upper
external housing 404, intermediate housing 405, and lower housing
406, as well as threaded assembly connector collars 407 and 408,
upper and lower drain valve heads 409 and 410, and upper and lower
flow port sleeves 411 and 412.
The three external housings 404, 405 and 406 are joined together by
means of connector collars 407 and 408 to form a substantially
cylindrical elongated tubular member.
Upper connector collar 407 has an inner threaded section 413 which
receives upper flow port sleeve 411 in fixedly attached
relationship therewith. Sleeve 411 is a tubular, cylindrical,
slotted sleeve having a longitudinally extending slot 414 through
the wall thereof. Also passing through the wall of sleeves 411 and
412 are two sets of one or more flow ports 415 and 457. Circular
seals 416 are located in annular recesses in the internal bore wall
of sleeve 411. Fixedly attached to the upper end of sleeve 411 is
the upper drain valve head 409 which is a relatively thick-walled
tubular member having a large exit port 417 passing through the
wall thereof. Head 409 has a restricted axial bore 418 passing
longitudinally therethrough. The inner wall of bore 418 has annular
seal means 419 located in recesses therein.
A solid cylindrical plug means 420 is sealingly engaged within bore
418 of head 409 and threadedly held therein by annular adapter
421.
Upper end 422 of plug 420 is polygonal-shaped to allow a wrench to
be applied thereto in order to rotate plug 420 in head 409.
Counterclockwise rotation of plug 420 results in axial movement
outward of plug 420 in head 409 and sufficient movement outward
will result in the lower end 423 of plug 420 clearing exit port 417
so that fluid within the central bore of sampler section 40 may
flow outward through port 417. Seals 419 and 419a prevent fluid
flow between plug 420 and the inner bore wall of head 409 until
plug end 423 moves outward past port 417.
The construction and orientation of the lower flow port sleeve 412,
lower drain valve head 410, and lower head plug 424 are very
similar to that of the upper port sleeve 411, upper head 409, and
plug 420 as described above, but in an inverted orientation
thereto. The operation, function, and purpose of these lower
elements are substantially identical to the aforementioned upper
ones. Plug 424 serves as a valve member to cover or uncover exit
port 425 in lower head 410 by threaded conjunction with annular
adapter 426. Plug 424 has a polygonal head 427 and engages seal
means 428 above port 425 in the inner bore of head 410. Seals 429
in plug 424 provide sealing engagement with plug 424 below port
425.
In addition, lower head 410 has fixedly attached at the upper end
thereof, a tubular lock-closed sleeve 430 with biasing spring 431
located thereon in conjunction with one or more prop arms 432
swingably attached to sleeve 430 at their lower ends. The function
and purpose of sleeve 430, biasing spring 431, and prop arms 432
will be more particularly described later in conjunction with the
operation of the sampler section. Sleeve 430, in conjunction with
sleeve 412, serves to form an extended annular slip space 433
therebetween.
The pull mandrel assembly 402 comprises an elongated pull mandrel
yoke 402a having a cylindrical limit-stop sleeve 434 frangibly
attached exteriorly thereto by shear pins 441 in telescopic
arrangement. Pull mandrel assembly 402 is slidably arranged
concentrically within upper external housing 404 and has a lower
expanded elongated yoke section 435 passing slidably and
concentrically in relatively close relationship between housing
404, head 409 and sleeve 411. Located above yoke section 435 is
necked tubular section 436 having a reduced diameter and one or
more ports 437 through the wall thereof. Integrally attached to
section 436 is the pull coupler connector section 438 having an
intermediate diameter and having internal threads 439 therein for
attaching to the power section pull coupler 386. Likewise, upper
housing 404 has internal threads 440 at its upper end for engaging
adapter 384 of the power section 30.
Mandrel yoke 402a and limit-stop sleeve 434 are located so that
yoke 402a has approximately two inches of travel from its lowermost
position as illustrated, to its uppermost position whereupon
limit-stop sleeve 434 is abuttingly engaged with the lowermost end
of adapter 384 thereby, under normal operating conditions,
preventing any further upward movement of the mandrel assembly 402
within housing 404.
Valve mandrel 403 consists of an elongated, tubular, cylindrical
piece having enlarged upper section 442 and lower section 443
joined together by attachment to a reduced-diameter, solid central
section 444.
Near the lower end of section 442 and near the upper end of section
443 are short, tapered frusto-conical wall sections 445 and 446
respectively, having a plurality of flow ports therethrough
numbered 447 and 448 respectively.
Upper section 442 is slidably located within collar 407 and sleeve
411 and sealingly engaged therewith and has an inner bore 449
communicating through ports 447 to an annular chamber area 450
formed by the concentric arrangement of the external housing 405
and the reduced central section 444. Chamber 450 also communicates
with the inner bore 455 of lower section 443 through ports 448 in
conical wall 446.
One or more linkage pins 451 are securedly imbedded in the wall of
upper section 442 and pass radially through one or more slots 414
in the upper flow port sleeve 411. Pins 451 extend far enough
through slots 414 to be securedly engaged with the arms of pull
mandrel yoke 402a. Slots 414 and pins 451 are designed to allow
pins 451 to slide freely through slots 414 in a longitudinal, axial
direction yet prevent any significant angular rotation therein.
Furthermore, it should be noted that upper and lower sections 442
and 443 of valve mandrel 403 have a plurality of ports 453 and 454
respectively through the wall thereof, circumferentially spaced
thereon, and arranged to communicate with annular grooves 452 and
456 out in the inner bore wall of flow port sleeves 411 and 412.
Grooves 452 and 456 are located so that they intersect flow ports
415 and 457 to allow fluid communication therethrough when ports
453 and 454 are axially aligned therewith, even though ports 453
may be peripherally non-aligned with ports 415, and ports 454 may
be peripherally non-aligned with ports 457.
In the lowermost position of valve mandrel 403, with respect to
housing assembly 401, ports 415 and 457 are sealed off from bores
409 and 455 and chamber 450 by the blocking position of the upper
and lower sections of the valve mandrel 403.
When mandrel 403 moves to its uppermost position, ports 415 and 457
are aligned axially with ports 453 and 454 respectively. Fluid flow
is then possible throughout the entire length of the apparatus by
flowing through inner bore 458 of the pull mandrel assembly,
through ports 437, between the arms of yoke 402a, through ports 415
and 453, through bore 449, ports 447, bore 450, ports 448, bore
455, and through ports 454 and 457 into bore 459 which communicates
with the lower part of the string through well conduit attached to
the lower end 460 of housing 406.
FIG. 5 illustrates the construction of pull mandrel yoke 402a
having one or more arms 461 which pass downward outside of sleeve
411 and are pinned to valve mandrel 403 by pins 451. The preferred
embodiment herein utilizes two yoke arms diametrically opposed one
from the other to thereby provide sufficient pull strength which is
balanced across the diameter of the yoke, and also allow the
greatest open area to fluid flow between the yoke arms.
Additionally, a spool type relief valve 462 is located through the
lower end 460 of lower housing 406. This valve is designed to allow
the operator to drain off high pressure well fluids and/or gases
which may become trapped in bore 459 between the closed sampler
chambers 449, 450, and 455 and the closed valve below the sampling
mechanism 25.
Valve 462 consists of a cylindrical outer housing 463 having two or
more ports 464 through the wall thereof, with a threaded spool
assembly 465 sealingly engaged therein. In the illustrated position
the valve is closed but does allow flow around it along bore 459.
After the sampler has been filled and closed and it is desired to
drain off the hazardous fluids trapped in bore 459, a conduit (not
shown) can be threadedly attached in threaded opening 466 of
housing end 460 and the polygonal upper end 467 of spool assembly
465 can be turned counterclockwise with a common wrench. This
rotates the spool outward by action of threads 468 on the spool
with threads 470 on annular adapter 469 located securely in housing
end 460. Continued rotation of spool assembly 465 will move the end
471 of the spool past ports 464 and allow the trapped fluid to flow
therethrough and out threaded opening 466 into the drain conduit
(not shown).
Operation of the separable sampler section 40 occurs in the
following manner. A sufficient annulus pressure increase acting on
the power section 30 of the sampler mechanism 25 results in an
upward movement of pull coupler 386. In the orientation of the
sampler section 40 as illustrated, the sampler chamber is initially
closed to fluid flow therethrough and no flow can occur through the
conduit string.
Upward movement of the pull coupler 386 pulls the pull mandrel
assembly 402 upward with it until limit-stop sleeve 434 abuts the
bottom end of adapter 384. In this position the sampler is fully
opened and flow can occur therethrough and throughout the conduit
string. The sampler can be held open by continuous application of
the actuating pressure on the annulus fluid. In the open position,
pull mandrel assembly 402, working through pins 451, have pulled
the valve mandrel assembly 403 upward until ports 415 are aligned
with ports 453 which simultaneously aligns ports 457 with ports
454, which alignment provides an open flow path through the sampler
as previously described.
When it is desired to cease flow tests and begin pressure buildup
tests or trap a sample, actuating pressure is released from the
annular fluid which allows the inert gas and spring biasing means
in the power section to move the pull coupler 386 back to its
initial position thereby moving the valve mandrel assembly 403 back
downward, closing off flow ports 415 and 457.
A sample of the well-fluid which was flowing through the open
sampler will automatically be trapped in bores 449 and 455 and in
annular chamber 450.
After the desired tests have been completed and the sample has been
trapped, the test string is removed from the hole and the separable
sampler section 40 may be removed from the power section and
replaced by an empty one if desired. Before the sampler is removed
from the string, though, it is often desirable to remove trapped
formation fluids from the void area below the sample chamber which
can be accomplished by the use of a conduit attached to threaded
opening 466 and manipulation of spool valve 462 as previously
described.
After the sampler section 40 is removed from the string it can be
shipped to the lab for testing. At the lab, the upper and lower
external housings 404 and 406 can be unscrewed from the apparatus
and set aside to expose the drain ports 417 and 425. Only one such
drain port need be exposed although both can be if so desired. The
sample is removed from the sample chamber by attaching a drain
conduit (not shown) into the enlarged threaded portion 472 or 473
of drain ports 417 or 425 respectively.
Then threaded plug 420 or plug 424 is screwed out of the end having
the drain conduit connected therein until the end of the plug
clears the drain port 417 or 425, whichever the case may be, and
the trapped fluid is allowed to exit from the sample chamber.
In addition to providing structural integrity of the sampler
section as well as serving to connect the sampler to the power
section and the conduit string, upper and lower housings 404 and
406 also serve as protective shields over the sample drain port
assemblies during transportation of the sampler from the field to
the lab.
As previously noted, the sampler incorporates a further safety
feature designed to move the sampler section into a lock-closed
position should the well suddenly become overpressured and threaten
to blow out through the annulus.
The sudden overpressuring of the annulus fluid will act upon the
power section to provide an increasingly greater upward pulling
force on the pull mandrel assembly 402 until finally, at a
predetermined maximum annulus pressure, shear pins 441 in limit
stop sleeve 434 will be sheared thereby allowing the pull mandrel
yoke 402a to pull the valve mandrel 403 an additional distance
upward thereby pulling the bottom end 474 of the mandrel clear of
the hinged prop arms 432. At this instant the biasing springs 431
force arms 432 radially outward behind end 474 of the valve mandrel
thereby preventing any reverse movement of the mandrel back
downward.
This additional increment of upward movement of valve mandrel 403
upon shearing of pins 441 results in moving of ports 453 and 454
out of alignment with ports 415 and 457 thereby closing off any
further flow through the sampler. Prop arms 432 serve to keep the
valve mandrel in this upward lock-closed position. Seals 475 and
476 located in annular recesses in the outer surface of valve
mandrel lower section 443 are located so that in the lock-closed
position they straddle the flow port 457 and prevent fluid leakage
thereby. Seals 477 and 478 located on lower section 443 above ports
454 serve to prevent fluid leakage thereby when the sampler is in
its initially closed and open-flowing orientations.
SUMMARY AND ADVANTAGES OF THE APPARATUS
The sampler mechanism disclosed herein is particularly advantageous
for use in wells wherein it is highly desirable to operate tools in
the string without resorting to any physical manipulation of the
drillpipe such as reciprocation or rotation.
This mechanism provides an annulus pressure operated sampler which
is very versatile in that it can be utilized in deep hot holes
where the exact pressure and downhole temperature are not shown. By
the use of this tool these conditions need be determined only
approximately.
Furthermore, the sampler mechanism does not require a high pressure
inert gas charge in the spring biasing chamber to overcome the high
hydrostatic pressure at bottomhole but instead can be charged at
relative low pressures at the surface and then utilizes the
hydrostatic pressure as it goes in the hole to supplement the inert
gas chamber pressure and serve as a biasing-closed means.
In addition, this mechanism employs a safety sampler that is
separable from the power section and which can be opened and closed
an indefinite number of times by actuation of the power section.
The sampler can be removed from the string and sent to the lab with
the sample intact and another dry sampler inserted in its place and
the test string returned to the hole or taken to another job right
away.
Use of this mechanism obivates the need for a power section for
each sampler and allows a testing crew to operate almost
indefinitely with only one power section and as many sampler
sections as needed.
Also the sampler section of this mechanism provides an easily
accessible yet protectively shielded drain port mechanism. It also
features a lock-closed safety feature that closes and locks the
sampler flow ports when an undesirable high pressure condition
arises in the annulus.
The sampler section provides a means of draining off formation
fluids trapped between the sampler and tools below it in the
string. This provides a clean spill-free access and method to drain
these usually flammable and always dirty contaminants.
Although a specific preferred embodiment of the present invention
has been described in the detailed description above, the
description is not intended to limit the invention to the
particular forms or embodiments disclosed herein, since they are to
be recognized as illustrative rather than restrictive and it will
be obvious to those skilled in the art that the invention is not so
limited. For example, it would be possible to utilize a varying
number of floating pistons in the power section 30, or different
spring biasing means than those disclosed as coil springs. Where
the porting is disclosed as allowing the supplementary hydrostatic
pressure to enter near the top of the power section and actuating
annulus pressure to enter near the lower end of the power section,
it is obvious that one could reverse the orientation of various
tool parts and obtain a reversal of the porting arrangement
disclosed herein. The invention is declared to cover all changes
and modifications of the specific example of the invention herein
disclosed for purposes of illustration, which do not constitute
departures from the spirit and scope of the invention.
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