GB2205879A - Pressure monitoring shut-in tool - Google Patents

Abstract

The pressure monitoring shut-in tool 11 has an elongate body 12 closed at the lower end and adapted at its other end for attachment to a locking device for locating into a wire line landing nipple 16 and having in its wall primary communication ports 13 and secondary pressure monitoring ports 14 and a sleeve 15 is slidably moveable within the body between a lower 'open' position in which fluid can flow through the primary ports 13 and an upper 'closed' position in which such flow is blocked. The sleeve provides a flow passage in communication with the pressure monitoring ports 14, and is biased to the lower 'open' position. The sleeve 15 has a latch mechanism for attachment and detachment of a stinger 10 which is connected to pressure sensing means and which lifts the sleeve 15 by a working pull into the closed position. The latch mechanism is biased against the upward working pull. Due to differential pressure acting on the sleeve when it is in the closed position, the sleeve will remain in the closed position during the shut in measuring procedure and even after release of the stinger. However, with the fluid flowing again through the pressure monitoring ports 14 and sleeve 15, pressure will proceed to equalize and the sleeve 15 will return to its lower open position under its bias when the well pressure is nearing a balanced position. <IMAGE>

Description

PRESSURE MONITORING SHUT-IN TOOL.

The present invention relates to a tool for monitoring the shut-in pressure of oil wells and the like.

It is often necessary to measure the shut-in pressure of an oil well. Existing tools devised for this purpose comprise a down well body having a primary passage through which the oil flows and a secondary passage communicating with a pressure sensor. When the primary passage is closed, the shut-in pressure is then measured via the pressure sensors. This closure is achieved by a sleeve sliding upwards within the body under the pull of a releasably connected stinger. The stinger is however only released by jarring upwards, which is not very effective.

Furthermore since the pressure measurements can take several days, sediment in the static well fluid settles above the tool, blocking the primary passage and preventing the well pressure from equalizing even after the stinger has been released. Positive action is therefore required to achieve the pressure equalisation.

It is an object of the present invention to obviate or mitigate the aforesaid disadvantages.

According to the present invention there is provided, a pressure monitoring shut-in tool for oil wells and the like comprising an elongate body closed at one end, (in use the lower end). adapted at its other end for attachment to a locking device for locating into a wire line landing nipple, and having in its wall primary communication ports and secondary pressure monitoring ports, and a sleeve slidably moveable within the body between a lower 'open' position in which fluid can flow through the primary ports and an upper 'closed' position in which such flow is blocked, the sleeve providing a flow passage in communication with the pressure monitoring ports, the sleeve being biased to the open position, and having a latch mechanism for attachment and detachment of an actuator which is connected to pressure sensing means and which lifts the sleeve by a working pull into the closed position, said latch mechanism being biased against the upward working pull of the actuator which lifts the sleeve into the closed position, and operable to release the actuator only in response to an upward pull in excess of the working pull, said actuator, when installed in the sleeve, closing off the passage of fluid through the pressure monitoring ports and sleeve, and when released re-opening said passage.

Due to differential pressure acting on the sleeve when it is in the closed position, the sleeve will remain in the closed position during the shut in measuring procedure and even after release of the actuator. However, after release of the actuator with the fLuid fLowing again through the pressure monitoring ports and sleeve, pressure will proceed to equalize and the sleeve will return to its lower open position under its bias when the well pressures is nearing a balanced position.

According to a further aspect of the invention there is provided a pressure monitoring shut-in tool used in combination with an actuator both as described in the second preceding paragraph.

In preferred embodiments, latching of the actuator in the sleeve is by co-operating formations of grooves and resilient latch members on facing surfaces of the actuator and sleeve respectively. To provide greater control in releasing the actuator, preferably the sleeve includes an elongate member slidable within the sleeve and having a first platform at its lower end, the upper end of the elongate member having said latch members and being adapted to releasably receive the complementary groove formation of the actuator, the lower end of the sleeve being provided with a second platform above the first platform and a resilient means abutting between the first and second platforms, whereby further upward movement of the elongate member when the sleeve is in the closed position compresses the resilient means until the compression force exceeds the force locking the actuator to the elongate member, and the actuator is released.

Advantageously the elongate member within the first sleeve is slidable on an upstanding rod anchored to the closed end of the shell; and the resilient means is a spring washer stack.

In a preferred arrangement of the invention the latch members are urged into engagement with the groove when they rest on an anchored rise, there being provided a resilient member which cocks in response to the raised members being displaced downwardly from the rise by the weight of the dropped actuator, the force released as the resilient member is uncocked urging the raised members back onto the rise and into engagement with the groove, and the co-operating formations unlocking as the tension in the line of the actuator is increased beyond the working pull, thereby displacing the raised members upwards from the rise.

In particularly preferred embodiment of the invention the groove is provided on a pin of the actuator, the raised members being arcuate segments movable through apertures in the wall of the second sleeve while the rise is formed on the inner surface of the first sleeve. In this embodiment preferably the resilient cocking member is a coiled spring below the second sleeve.

The invention will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a front view of a body of a pressure monitoring tool having its primary exit passage open and a stinger detached therefrom; the shell being anchored down an oil well with the oil well in section; Fig. 2 is a view of the body in Fig. 1, but in section and having the stinger therewithin; Fig. 3 is a view of the body and stinger in Fig. 2 but with the primary passage closed and a secondary passage open.

Fig. 4 is a view of the body and stinger in Fig. 3, but having the stinger detached from the shell: Fig. 5 is an enlarged fragmented view of part of the body showing a locking mechanism and corresponding to Fig. 1; Fig. 6 is a similar view to that of Fig. 5, but having the stinger cocking the locking mechanism and corresponding to Fig. 2; Fig. 7 is a similar view to that of Fig. 6, but having the body and stinger locked together and corresponding to Fig. 3; Fig. 8 is a similar view to that of Fig. 7, but having the stinger unlocked from the body and corresponding to Fig. 4; and Fig. 9 is a front view partly in section of the tip of the stinger.

Referring to Figs. 1 to 4, a stinger 10 associated with a pressure sensor (not shown) is used as an actuator for a pressure monitoring shut-in tool 11 which measures oil-well pressures. The tool 11 comprises a body casing 12 having four primary ports 13 and secondary ports 14. Within the casing 12 is a sleeve 15 acting as a closure means and movable by the stinger 10 from the position shown in Fig. 2, upwards to seal off the primary ports 13 as shown in Fig. 3.

In this mode (Fig. 3) the shut-in pressure of the system is measured.

The tool 11 is installed into a standard wireline landing nipple 16 by means of standard .108" wireline operations, and can be run in in conjunction with any size or make of wireline lock assembly by using an appropriate cross-over. The landing nipple is conjoined with the oil well production tubing 17.

When installed, the tool 11 is held in the open position, allowing fluid to flow through four ports (13) as shown, in Fig. 1 and the secondary ports 14 (not shown in Fig. 1).

The casing 12 itself is elongate and closed at its lower end, which is pointed, for improved fluid flow.

Referring to Figs. 2 to 4, within the casing 12 are provided upper and lower areas 18 and 19 communicating via an annular hole in a separating wall 20. As shown most clearly in Fig. 2, an upper wall 21 of the casing 12 has a throat 22 extending therefrom and an 0-ring 23 mounted on the base of the throat 22 and against the upper wall 21.

The sleeve is in two parts and includes an axially slidable outer sleeve 15a which acts as the closure means for the primary ports 13. The outer sleeve 15a is distributed between the upper and lower areas 18 and 19 and, when the primary ports are open (open mode) Figs. 1 and 2, this sleeve is supported on the separating wall 20 by an annular shoulder 24. A third port 24a is provided in the outer sleeve 15a and communicates with the secondary port 14 in both the open and closed mode via a chamfered annular space 24b located between sealing rings 24c. The upper end 25 of the outer sleeve 15 is enlarged to receive the throat 22 in the closed mode (Figs. 3 and 4).The lower end of the outer sleeve 15 has an annular flange which acts as a first platform 26, while a coil spring 27 is compressed between the bottom of the separating wall 20 and the first platform 26 to bias the outer sleeve downwardly to form the open mode. An inner sleeve 28 which is axially slidable within the outer sleeve 15 has a second circular flange forming a second platform 28a at its lower end and lying below the first platform 26.

Referring to Figs. 5 to 8, the inner sleeve 28 has a plurality of arcuate latch segments 29 movable through apertures (not shown) in the sleeve wall 30. The segments 29 are biased outwards by a resilient means (not shown), but as seen in Figs. 5 and 7 they normally lie in an annular rib 31 formed on the inner surface of the outer sleeve 15a.

If the latch segments 29 are displaced from this rib 31 they will be pushed outwardly under the bias of the resilient means to lie flush with the inner sleeve wall 30 (Figs. 6 and 8). The inner sleeve 28 is axially slidable along an upstanding pole 32 anchored to a base 33 of the shell 12.

In the open mode the inner sleeve 28 is supported on a cocking coil spring 34 between the second flange 28a and shell base 33. A spring washer stack 35 is located between the first and second platforms 26 and 28a. The inner sleeve 28 interlocks with the stinger 10 via a latch mechanism as shown in Fig. 2 and will be described hereinafter.

As seen in Figs. 1 and 4, the stinger 10 has a body 36 around which fins 37 are provided. The bottom end of the body 36 tapers to form a shoulder 38 from which a pin 39 extends. Referring to Fig.9, the pin 39 has a fourth port 40 located between two 0-rings 41 and communicating with an axial passage 42 closed at its upper end. The axial passage 42 communicates with the pressure sensor (not shown). Spaced from the bottom 43 of the pin 39, a circumferential groove 44 is formed having chamfered sides; the bottom 43 itself is conical shaped.

The stinger 10 is operable by a conductor line attached thereto.

The operation of the pressure tool will now be described.

Fig. 1 shows the well liquid flowing through the open primary ports 13 and up the throat 22. In this mode the latch segments 29 are as depicted in Fig. 5. The stinger is dropped into the tool 16 and into the upper end of the sleeve 15. The weight of the stinger 10 and guages (not shown) then displaces the segments 29 from the annular rib 31 as shown in Fig. 6. The flow of liquid through the tool is still via the primary ports 13 as shown in Fig. 2, but the outflow through the secondary ports 14 is now blocked. This downward displacement of the segments 29, however, acts against the cocking spring 34 which together with an upward tug on the stinger 10 causes the segments 29 to ride up the edges of the rib 31 and lock into the annular groove 44 (Fig. 7).In this locked position the stinger 10 can then be pulled upwards with a predetermined working force of eg 150 lbf (33.7N) to haul the inner sleeve 28 and outer sleeve 15 upwards against the bias of spring 27 until the enlarged end 25 of the outer sleeve 15 abuts sealably against the 0-ring 23 (Fig. 3).

This upward displacement now allows communication of the fourth port 40 of the stinger 10, with the secondary port 14 of the casing 12 and the third port 24a of the outer sleeve 15, thereby forming a continuous channel for the well fluid to the axial passage 42 of the stinger 10.

Since this axial passage 42 communicates with the pressure sensor (not shown), the differential pressure of the system is measured and sent as electrical signals up the conductor wire (not shown) to a gauge (not shown) on the surface.

In this sealed position, the outer sleeve 15a is supported on the second platform 28a of the inner sleeve 28, the whole assembly being initially held in position by the tension on the conductor wire (not shown). After a time in the closed mode, the differential pressure of the well will support the sleeve 15 and the tension in the wire can then be slackened. The tool remains in the closed position for up to several days while the pressure is measured.

To release the stinger 10, the stinger line (not shown) is tensioned with a 150 lbf (33.7N) force over the working pull force; that is for example a total force of 300 lbf (67.5N). This additional force slowly compresses the spring wash stack 35 until the compressed force exceeds the force locking together the stinger 10 and inner sleeve 28. When this force is attained, the segments 29 are pulled upwardly from the rib 31 (Fig. 8) thereby moving outwards and releasing the stinger 10 which then shoots out of the body 11 (fig. 4). Thereafter the sleeves 15 and 28 will be held in the sealed position by the differential pressure of the well liquid until the pressure equalizes via the ports 14, 24a and the throat 22. The sleeves 15 and 28 will then return to their starting position (Fig. 2) under the bias of spring 27.

In comparison with previous pressure monitoring tools, the present invention has relatively few moving parts and is simple in its operation and design. The locking mechanism works consistently and therefore as many runs as required can be made. By providing the spring washer stack, more control is obtained over the stinger release.

The release force is built up gradually rather than having to provide a sharp jar to dislodge the stinger. The pressure tool is retrievable by 108" we reline operation and the shell can be fixed to any size of locking nipple.

Further advantages are that the pressure equalizes automatically when the stinger is removed and that any well sediment blocking the primary ports will be blown out as the pressure in the well equalizes.

Claims (12)

CLAIMS.

1. A pressure monitoring shut-in tool fdr oil wells and the like comprising an elongate body closed at one end, (in use the lower end), adapted at its other end for attachment to a locking device for locating into a wire line landing nipple, and having in its wall primary communicating ports and secondary pressure monitoring ports, and a sleeve slidably moveable within the body between a lower 'open' position in which fluid can flow through the primary ports and an upper 'closed position in which such flow is blocked, the sleeve providing a flow passage in communication with the pressure monitoring ports, the sleeve being biased to the open position, and having a latch mechanism for attachment and detachment of an actuator which is connected to pressure sensing means and which lifts the sleeve by a working pull into the closed position, said latch mechanism being biased against the upward working pull of the actuator which lifts the sleeve into the closed position, and operable to release the actuator only in response to an upward pull in excess of the working pull, said actuator, when installed in the sleeve, closing off the passage of fluid through the pressure monitoring ports and sleeve, and when released re-opening said passage.

2. A pressure monitoring shut-in tool as claimed in claim 1 used in combination with an actuator, wherein due to differential pressure acting on the sleeve when it is in the closed position, the sleeve will remain in the closed position during the shut in measuring procedure and even after release of the actuator, but after release of the actuator with the fluid flowing again through the pressure monitoring ports and sleeve, pressure will proceed to equalize and the sleeve will return to its lower open position under its bias when the well pressure is nearing a balanced position.

3. A shut-in tool as claimed in claim 1 or 2, in which latching of the actuator in the sleeve is by co-operating formations of grooves and resilient latch members on facing surfaces of the actuator and sleeve respectively.

4. A shut-in tool as claimed in any one of claims 1 to 3 wherein, to provide greater control in releasing the actuator the sleeve includes an elongate member slidable within the sleeve and having a first platform at its lower end, the upper end of the elongate member having said latch members and being adapted to releasably receive the complementary groove formation of the actuator, the lower end of the sleeve being provided with a second platform above the first platform and a resilient means abutting between the first and second platforms, whereby further upward movement of the elongate member when the sleeve is in the closed position compresses the resilient means until the compression force exceeds the force locking the actuator to the elongate member, and the actuator is released.

5. A shut-in tool as claimed in claim 4, in which the elongate member within the sleeve is slidable on an upstanding rod anchored to the closed end of the shell.

6. A shut-in tool as claimed in claim 4 or 5, in which the resilient means is a spring washer stack.

7. A shut-in tool as claimed in any one of claims 3 to 6, in which the latch members are urged into engagement with the groove when they rest on an anchored rise, there being provided a resilient member which cocks in response to the latch members being displaced downwardly from the rise by the weight of the dropped actuator, the force released as the resilient member is uncocked urging the latch members back onto the rise and into engagement with the groove, and the co-operating formations unlocking as the tension in the line of the actuator is increased beyond the working pull, thereby displacing the latch members upwards from the rise.

8. A shut-in tool as claimed in any one of claims 3 to 7, the groove is provided on a pin of the actuator, the latch members being arcuate segments movable through apertures in the.wall of the elongate member within the sleeve while the rise is formed on the inner surface of the sleeve.

9. A shut-in tool as claimed in claim 7 or 8, in which the resilient cocking member is a coiled spring below the elongate member within the sleeve.

10. A shut-in tool as claimed in any one of claims 3 to 9 in which the sleeve forms an outer first sleeve and the elongate member forms an inner second sleeve.

11. A pressure monitoring shut-in tool substantially as hereinbefore described with reference to the accompanying drawings.

12. A pressure monitoring tool in combination with an actuator substantially as hereinbefore described with reference to the accompanying drawings.