HYDRAULICALLY LOCKED TOOL

Abstract

Disclosed is a downhole tool and method of use. The tool has a sleeve assembly slideable within the tool body under the action of a hydraulic pressure differential. The sleeve assembly has a control collar portion and a first hydraulic reservoir is defined between a first end of the control collar portion and the body, and a second hydraulic reservoir is defined between a second end of the control collar portion and the body. A bleed conduit extending between the first and second hydraulic reservoirs and an electromechanical control valve across the bleed conduit is used to regulate fluid flow along the bleed conduit. The electromechanical control valve may communicate with sensors, by which control systems are transmitted to the control valve.

Claims

1. A downhole tool, comprising: a body having a through bore; a sleeve assembly slideable within the body between a first position and a second position, under the action of hydraulic pressure and/or a biasing arrangement; and the body comprising a control collar portion disposed around the sleeve assembly; wherein a first hydraulic reservoir is defined between the sleeve assembly and the body above a first end of the control collar portion and the body, and a second hydraulic reservoir is defined between the sleeve assembly and the body below a second end of the control collar portion and the body; wherein the control collar portion further comprises; a bleed conduit extending generally longitudinally between the first and second hydraulic reservoirs; and an electromechanical control valve across the bleed conduit configured to regulate fluid flow along the bleed conduit.

2. The tool of claim 1, wherein the first hydraulic reservoir is defined between a first end of the control collar portion and the body and/or wherein the second hydraulic reservoir is defined between a second end of the control collar portion and the body.

3. The tool of claim 1, comprising one or more sensors and/or a wireline in communication with the electromechanical control valve, wherein the electromechanical control valve is operable to open and/or close on detection of a pre-determined control signal or signals by said sensor or sensors or received via the wireline.

4. The tool of claim 3, comprising an accelerometer, wherein the electromechanical control valve is controllable by moving the tool longitudinally and/or rotationally.

5. (canceled)

6. The tool of claim 1, wherein sleeve assembly is resiliently biased towards one or other of the first and second positions, by a resilient biasing member acting between the sleeve assembly and the body.

7. (canceled)

8. The tool of claim 1, further comprising a first tertiary hydraulic reservoir and/or a second tertiary hydraulic reservoir defined, at least in part, between the sleeve assembly and the body above and below the first and second hydraulic reservoirs, respectively.

9. The tool of claim 1, wherein the sleeve assembly is slidable under the action of a hydrostatic pressure differential between the bore an outside of the tool body.

10. The tool of claim 9, wherein the first hydraulic reservoir communicates with the bore and the second hydraulic reservoir communicates with an outside of the body via one or more bleed ports through the body.

11. The tool of claim 8, wherein the sleeve assembly is slidable under the action of a hydrostatic pressure differential between the bore an outside of the tool body; and the second tertiary hydraulic reservoir communicates with an outside of the body.

12. (canceled)

13. The tool of claim 8, when dependent on claim 6, wherein the first tertiary hydraulic reservoir is separated from the first hydraulic reservoir by a first balance piston and/or the second tertiary hydraulic reservoir is separated from the second hydraulic reservoir by a second balance piston.

14. (canceled)

15. The tool of claim 1, wherein the sleeve assembly is slidable between the first and second positions under the action of a dynamic pressure differential along the tool or through a flow restriction within the bore defined by the sleeve assembly.

16.-17. (canceled)

18. The tool of claim 1, wherein movement of the sleeve assembly between the first and second positions may change the tool between a deactivated and an activated condition.

19. The tool of claim 18, comprising one more circulation ports, wherein movement of the sleeve assembly between the first and second positions opens and closes the one or more circulation ports.

20. (canceled)

21. The tool of claim 18, wherein the sleeve assembly is operatively coupled to further downhole apparatus to change the condition of the further apparatus between a deactivated and an activated condition, when the sleeve assembly moves between the first and second conditions.

22. The tool of claim 1, wherein the sleeve assembly is operable to move between the first and second positions and one or more defined third positions, wherein the one or more third positions are optionally defined by closing the electromechanical control valve and hydraulically locking the sleeve assembly in said defined third position.

23. A method of moving a sliding sleeve assembly of a downhole tool between a first position and a second position, wherein a first hydraulic reservoir is defined between the sleeve assembly and a body of the tool above a first end of a control collar portion of the body, and a second hydraulic reservoir is defined between the sleeve assembly and the body below a second end of the control collar portion; wherein the control collar portion comprises a bleed conduit; the method comprising: generating a dynamic pressure differential along the tool or through a flow restriction within the bore defined by the sleeve assembly, and/or generating a hydrostatic pressure differential between the through bore and an outside of the tool; opening a control valve, such as an electromechanical control valve; flowing hydraulic fluid between the first and second hydraulic reservoirs generally longitudinally along the bleed conduit via the control valve; and closing the control valve to hydraulically lock the sleeve assembly in the first or second position.

24. The method of claim 23, comprising issuing a control signal or signals to open and/or close the control valve.

25. (canceled)

26. The method of claim 24, wherein tool comprises an accelerometer in communication with the electromechanical control valve and the method comprises issuing a rotational signal to the accelerometer by rotating the tool.

27. The method of claim 23, further comprising generating the hydrostatic pressure differential by generating a hydrostatic pressure between the bore and an outside of the tool.

28. (canceled)

29. The method of claim 23, wherein the sleeve assembly is operatively coupled to one or more further downhole apparatus, and the method comprises changing the condition of one or more further downhole apparatus between a deactivated and an activated condition, by moving the sleeve assembly between the first and second positions.

Description

DESCRIPTION OF THE DRAWINGS

[0106] Non-limiting example embodiments will now be described with relation to the following drawings in which:

[0107] FIG. 1A shows a cross sectional side view longitudinally through of an upper part of an embodiment of a downhole tool with a sleeve assembly in a first position;

[0108] FIG. 1B shows a cross sectional view of an upper part of an embodiment of a downhole tool with a sleeve assembly in a second position;

[0109] FIG. 2 shows a perspective view of a sleeve assembly of the downhole tool, with the control collar portion omitted for clarity;

[0110] FIG. 3 shows a perspective of the control collar portion of the downhole tool; and

[0111] FIG. 4 shows a perspective cross sectional view of the body of the downhole tool.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENT

[0112] With reference to FIGS. 1A, 1B and 2-4, the downhole tool includes a body 100 and a through bore 102, 102a. The body includes a control collar portion 15, which in the embodiment shown is formed as a separate unit (see FIG. 3) which is secured within the body 100 by a lock key 6, which engages with a recess 31 on the outer surface of the control collar 15.

[0113] A sleeve assembly 200 (shown in perspective view on FIG. 2), consists generally of an upper sleeve 4 threadably coupled to a lower sleeve 8, via respective outer threaded region 19 of the upper sleeve and inner threaded region 20 of the lower sleeve 8. The upper and lower sleeves 4, 8 are provided with hex formations 71, 74 to facilitate such coupling. In alternative embodiments the sleeve assembly may comprise a single sleeve, or a greater number of sleeves.

[0114] A portion 102a of the through bore 102 is defined by the sleeve assembly. The diameter of the bore 102a through the sleeve assembly is less than the diameter of the bore 102 above and below the sleeve assembly defined by the body 100.

[0115] The control collar portion 15 is disposed around a lower region 74 of the upper sleeve 4.

[0116] As shown in FIG. 4, in the embodiment shown, the body 100 includes lower 1, middle 2, and upper 3 sections which are threadably coupled together via conventional male 25 and female 24 pin connectors. For clarity, the upper and lower body sections are omitted from FIGS. 1A and 1B.

[0117] A first hydraulic reservoir 29 is defined between the sleeve assembly 200 and the body 100 above the control collar portion 15 (to the left in FIGS. 1A and B). A second hydraulic reservoir 30 is defined between the sleeve assembly 200 and the body 100 below the control collar portion 15 (to the right in FIGS. 1A and B).

[0118] In the embodiment shown, the first and second hydraulic reservoirs 29, 30 are defined by The upper and lower ends 60, 61 of the control collar portion, adjacent outer surfaces of the upper sleeve 4 and inner surfaces of the body 100. The first and second hydraulic reservoirs are also in part defined by ends of first and second balance pistons, the function of which will be discussed in further detail below

[0119] The sleeve assembly 200 is slidable within the body 100 between a first position, shown in FIG. 1A and a second position, shown in FIG. 1B. In the first position, the upper end 33 of the upper sleeve 4 abuts the lower end 32 of upper body section 3, which functions as an end stop.

[0120] In the second position, a stop shoulder 13 around the upper sleeve 4 encounters an opposing stop shoulder 14 extending from the upper end of the control collar 15.

[0121] The sleeve assembly 200 is spring biased towards the first position shown in FIG. 1A, by a coiled spring 23. The spring is disposed in the first hydraulic reservoir 29 and acts between the upper face 60 of the control collar 15 and a shoulder 204 around the upper sleeve 4.

[0122] The tool also includes a first balance piston 10 and a second balance piston 5. The balance pistons 5, 10 are, in the embodiment shown, slideable in relation to the sleeve assembly 200 and body 100 and accordingly include inner and outer seals 58, 59. It will be understood that the balance cylinders are optional and are omitted in alternative embodiments, and in still further embodiments are fixed in relation to the sleeve assembly.

[0123] A lower end of the first balance cylinder 10 defines the upper end of the first hydraulic reservoir 29. An upper end of the first balance cylinder 10 defines a lower end of a first tertiary hydraulic reservoir 108, between the body and the sleeve 4. The first tertiary hydraulic reservoir communicates with the bore 100 at its upper end, via an annulus defined between the upper sleeve 4 and the upper body section 3.

[0124] The first balance cylinder 10 is slideable along the sleeve 4 between the shoulder 204 and the lower end of the upper body section 3.

[0125] An upper end of the second balance cylinder 5 defines the lower end of the second hydraulic reservoir 30. A lower end of the second balance cylinder 5 defines an upper end of a second tertiary hydraulic reservoir 34. The second tertiary hydraulic reservoir communicates with an outside of the body via bleed ports 11 through the middle body section 2. The lower end of the secondary tertiary hydraulic reservoir 34 is defined by the wiper seal 74.

[0126] The second balance cylinder is slideable along the lower part 74 of the sleeve 4 between an inner shoulder 104 of the middle body section 2, and the lower end face 61 of the control collar 15.

[0127] The body 100 includes fill ports 28, 22 by which the first and second hydraulic reservoirs are filled with hydraulic fluid. The ports are then plugged. The first tertiary hydraulic reservoir 108 is filled with fluid in the bore 100 and the second tertiary hydraulic reservoir 34 is filled with fluid from the wellbore. The balance pistons 5, 10 isolate the first and second hydraulic reservoirs 29, 30 from ingress of unwanted fluids or debris.

[0128] In alternative embodiments (not shown) the hydraulic reservoirs 29, 30 themselves communicate with the bore and outside of the tool respectively. Further embodiments include entirely sealed hydraulic reservoirs.

[0129] FIG. 3 shows the control collar 15 in further detail.

[0130] The control collar portion 15 further comprises a bleed conduit that extends between the first and the second hydraulic reservoirs 29, 30. The bleed conduit is defined in part by apertures extending through the control collar 15 and in part by hydraulic lines.

[0131] The collar has upper and lower flange portions 15a, 15b at the first and second ends of the collar 15. The flange portions 15a, 15b define the respective first and second ends 60, 61 of the collar 15. An upper channel 56 extends through the upper flange portion, and extends from the upper end face 60, exiting at a recess 15c between the flange portions 15a, 15b. Similarly, a lower channel 57 extends through the lower flange portion 15b, extending from the lower end face 61 and exiting to the recess 15c. The upper and lower channels thus communicate with the first and second hydraulic reservoirs 29, 30. Hydraulic lines 53 positioned within the recess 15c are connected by threaded compression couplings 52 to the upper and lower channels 56, 57. The hydraulic lines 53 each also connect to a solenoid valve 51, having a solenoid 54.

[0132] End regions of the bleed conduit are thus defined by the upper and lower channels 56, 57 and an intermediate region of the bleed conduit is defined by the hydraulic lines 53, with the solenoid valve 51 being positioned in the bleed conduit.

[0133] The first and second hydraulic reservoirs 29, 30 each have a minimum and maximum radius and the entire length of the bleed conduit is within the maximum and minimum radii of the reservoirs.

[0134] The solenoid (i.e. electromechanical) valve 51 includes an accelerometer (not shown) and a control system (not shown), by which control over the valve 51 can be effected by way of rotational signals received by the accelerometer, as disclosed herein.

[0135] The control collar 15 also includes a battery pack 55 which communicates with and powers the valve 51. The battery pack is housed within an adjacent recess between the upper and lower flange portions of the collar 15.

[0136] The control collar has a central bore sized to slideably receive the sleeve assembly 200 (and the lower part 74 of the upper sleeve in particular. The flange portions 15a, 15b are sized to be received within the body 100. Seals 58 are provided around the flange portions to seal between the collar 15 and the body 100. Seals 59 are also provided to slideably seal between the control collar 15 and the sleeve assembly 200.

[0137] Movement of the sleeve assembly between the first and second positions will now be described with reference to FIGS. 1A and 1B.

[0138] In use, the tool will be connected to a work string and run into a well.

[0139] The electromechanical control valve is opened by rotating the tool (from the surface, via the work string) to transmit rotational control signals to the accelerometer.

[0140] Fluid is pumped through the work string.

[0141] The section 26 of the bore 102 that is defined by the upper body section 3 above the upper end 33 of the sleeve assembly 200 is of wider diameter than the bore 102b through the sleeve assembly. Fluid flow through the bore 102 to the narrower section 102a defined by the sleeve assembly 200 creates a dynamic pressure differential. Hydrostatic pressure in the bore 102, 102a also increases, resulting in a static pressure differential between the bore and the wellbore outside of the body. When either the static pressure differential, the dynamic pressure differential or their combined effects overcomes the resistance of the spring 23, the sleeve moves towards the second position.

[0142] With the control valve 51 open, hydraulic fluid is able to flow generally longitudinally from the second hydraulic reservoir 30, along the bleed conduit 57, 53, 56 and to the first hydraulic reservoir.

[0143] It should be noted that if the valve 51 is closed, such fluid pumping through the work string (as might be required for other downhole operations, e.g. in relation to other equipment run in on the work string) would not cause movement of the sleeve, since fluid would not be able to flow between the first and second hydraulic reservoirs and the sleeve would be hydraulically locked.

[0144] If, as is typically the case, the balance cylinders are at their upper end stops, or between their upper and lower end stops, fluid is also displaced into the first tertiary hydraulic reservoir 108 and out of the second tertiary hydraulic reservoir 34. One or other of the exchange of fluid between the first and second hydraulic reservoirs and the flow into and out of the first and second tertiary hydraulic reservoirs may be rate limiting (typically the bore may be pumped/pressurised such that flow through the bleed conduit is rate-limiting), such that the movement of the floating balance cylinders 10, 5 independent of the sleeve 4 provides for a degree of damping.

[0145] When the sleeve assembly 200 reaches the second position shown in FIG. 1B (and the balance cylinders 5, 10 are at their lower end stops), the solenoid control valve 51 is closed. This prevents flow of fluid along the bleed conduit and hydraulically locks the sleeve assembly in the second position. With the valve closed, subsequent pressure changes in the bore 100 or the wellbore outside of the tool, which act upon the balance cylinders 5, 10 cannot cause further movement of the sleeve assembly.

[0146] Closure of the control valve can occur automatically, after a predetermined time sufficient for the sleeve to have moved has elapsed since opening. Alternatively, or in addition, further rotational signals can be transmitted to the accelerometer to close the control valve 51. The accelerometer (or optionally further sensors or trip switches) may also be configured to detect landing of the sleeve at the second position. The control valve's control system may be configured to effect closure of the valve under any or all of these circumstances.

[0147] When the control valve 51 is again opened (by rotation of the tool), and pumping/circulation of fluid in the bore 100 has ceased, the spring 23 urges the sleeve back towards the first position shown in FIG. 1A and fluid flows from the second hydraulic reservoir 30 back into the first hydraulic reservoir 29 along the bleed conduit 56, 53, 57.

[0148] Fluid is also drawn into the second tertiary hydraulic reservoir 34 via the bleed port 11.

[0149] Where cessation of pumping causes a negative pressure differential between the outside of the tool and the bore 100, the floating balance pistons 5, 10 can move independently in relation to the sleeve 4 towards their upper end stops, thereby damping motion of the sleeve.

[0150] In use, as discussed above, the total volume of the first and second reservoirs 29, 30 is constant and volume increases of the first tertiary hydraulic reservoir 108 correspond to volume decreases of the second tertiary hydraulic reservoir 34.

[0151] Movement of the sleeve between the first and second positions changes the condition of the tool from a deactivated condition to an activated condition. The embodiment shown is a fluid circulation tool.

[0152] With reference to FIGS. 2 and 4, the sleeve assembly 200 includes an array of sleeve ports 18 which extend through the lower sleeve 8 to the bore 102a. The sleeve ports 18 are separated from the second tertiary hydraulic reservoir 34 by a wiper seal 72 provided with external seals 58 against the body (to which it is fixed, generally as described above in relation to the control collar) and internal deals (not shown) around the lower sleeve 8.

[0153] The lower body section 1 is provided with an array of upwardly oriented circulation ports 7. To either side thereof are positioned internal seals 59, which seal around the sleeve 8.

[0154] When the sleeve is in the first position, the sleeve ports 18 are misaligned with and above the circulation ports 7, and separated therefrom by the internal seals 59a. The seals 59a isolate the bore 102a from the ports 7 and thus the outside of the tool. The circulation tool is in a deactivated condition, when the sleeve is in the first position.

[0155] When the sleeve assembly is in the second position, the sleeve ports 18 are moved into alignment with the circulation ports 7 such that the bore 102a communicates with the outside of the tool via the ports 7, 18 and the circulation tool is in an activated condition.

[0156] In alternative embodiments, the circulation tool can be arranged to be in a deactivated condition when the tool is in the second position.

[0157] In alternative embodiments, the sleeve can be operatively be coupled to additional downhole apparatus, such as cutters or scraper elements that are caused to move outwardly upon movement of the sleeve. For example, an outer surface of the sleeve or an inner face of one or more cleaning elements may be ramped.

[0158] Stabiliser elements may similarly be operatively coupled to a sleeve. In still further embodiments, reamer arms or indeed various further down hole apparatus as known in the art may be connected to the body caused to activate by movement of the sleeve.

[0159] Whilst exemplary embodiments have been described herein, these should not be construed as limiting to the modifications and variations possible within the scope of the invention as disclosed herein and recited in the appended claims.