GB2288197A

GB2288197A - A differential pressure-operated blanking tool

Info

Publication number: GB2288197A
Application number: GB9406870A
Authority: GB
Inventors: Leslie Eric Jordan; John L Schneider
Original assignee: Phoenix Petroleum Services Ltd
Current assignee: Phoenix Petroleum Services Ltd
Priority date: 1994-04-07
Filing date: 1994-04-07
Publication date: 1995-10-11
Anticipated expiration: 2014-04-07
Also published as: GB9406870D0; GB2288197B

Abstract

A differential pressure-operated blanking tool 50 for preventing re-circulation through by-pass tubing of fluid produced from an oil or water well by an electric submergible pump, comprises an elongate body arranged to seal within the by-pass tubing or in the throat of a Y-tool. A passage through the body of the tool allows deployment into the well of logging tools and gauges. Valve means is arranged to open or close the passage in response to the pressure difference developed by operation of the electric submergible pump between pump intake and pump discharge. <IMAGE>

Description

BLANKING TOOLS FOR USE IN OIL WELL BY-PASS SYSTEMS This invention relates to differential pressureoperated blanking valve tools for use in the by-pass systems of oil and other wells being produced by an electrical submergible pump (ESP).

The deployment of an ESP in an oil or water well is common practice, as is the use of an associated by-pass system whereby access is obtained to the well below the ESP in order that a logging tool or gauge may be run into the well adjacent to the reservoir formation for evaluation of the well. Such a logging tool or gauge is lowered into the well on a wireline or coiled tubing and passed through by-pass tubing adjacent to the ESP.

In order that fluid produced by the ESP may flow to the surface it is necessary to close the passage through the by-pass tubing which allows produced fluid to recirculate from the pump discharge to the pump intake.

Traditionally, this passage is closed by the installation of a blanking plug equipped with sealing means which seal in a smooth bore machined in a nipple located at the top of the by-pass tubing and immediately below a Y-tool, thus ensuring that the produced fluid is transferred from the pump discharge to the production tubing extending to surface. A typical blanked off by-pass system is shown diagrammatically in elevation and partial section in Figure A of the accompanying drawings.

Prior to the deployment of a logging tool or gauge into the well below the ESP it is necessary to remove the blanking plug, which is retrieved by lowering a fishing tool into the well on a wireline or coiled tubing, such a tool being capable of latching onto the blanking plug to pull it to the surface. At the completion of well evaluation logging operations it is necessary to replace the blanking plug in the nipple seal bore before fluid can be produced to surface. Thus it is necessary to perform two wireline or coiled tubing operations over and above those required for the deployment of a logging tool or gauge.

The aim of this invention is to alleviate the necessity for these wireline or coiled tubing operations by the replacement of the aforementioned blanking plug with a tool which will automatically close the passage through the by-pass tubing when the ESP is operational and which will automatically open the passage through the bypass tubing when the ESP ceases to operate.

According to the present invention there is provided a differential pressure-operated blanking tool for preventing re-circulation through by-pass tubing of fluid produced from an oil or water well by an electric submergible pump, the tool comprising an elongate body arranged to seal within the by-pass tubing or in the throat of a Y-tool, and having a passage therethrough to allow deployment into the well of logging tools and gauges, and valve means arranged to close the passage in response to the pressure difference developed by operation of the electric submergible pump between pump intake pressure obtaining within the well casing and pump discharge pressure obtaining in the production tubing, and to open the passage on the equalisation of pump intake and discharge pressure when operation of the pump is discontinued.

Preferably, the valve means comprise a rotationallymounted spherical valve having a through-bore which is aligned with said passage when the valve is in the open condition, and actuating means comprising a resilientlyloaded piston which is arranged to be displaced by development of said pressure difference to rotate the spherical valve from the open position to a closed position in which the valve obtrudes the passage, the piston being returnable to its original position under the influence of its resilient loading on removal of the pressure difference.

In order that a logging tool or gauge may be used below the ESP while the pump is operational it is preferable that such a valve be capable of being retained in the open position in order that the wireline or coiled tubing is not damaged and the logging tool or gauge consequently lost into the bottom of the well. This may be achieved by the insertion of a plug arranged to straddle the valve means allowing the wireline or coiled tubing to pass therethrough, and which provides a substantial, but not perfect, seal around the wireline or coiled tubing; the plug is deployed on the wireline or coiled tubing during the well logging operations, thus not requiring a separate wireline or coiled tubing operation, and is removed from the well along with the logging tool or gauge at the completion of the logging operations.

Preferably, the tool according to the invention is arranged to be operated other than automatically, whereby the passage through the tool may be opened or closed mechanically by deployment of another tool deployed into the well by wireline or coiled tubing, the deployed tool being capable of latching into the tool according to the invention to apply a mechanical force to open or close the passage therethrough. Further, it is preferable that, should the closing of the passage through the tool according to the invention not be possible by either automatic or mechanical means, the passage through the tool according to the present invention includes a smooth seal bore into which a blanking plug equipped with sealing means may be deployed using conventional wireline or coiled tubing operational procedures.

It is also preferable that the tool according to the invention be located in the by-pass system such that it is capable of being deployed into the well by conventional wireline or coiled tubing means, and of latching into a selective profile positioned at the top of the by-pass tubing and immediately below the Y-tool, such that in the event of a malfunction it may be retrieved to surface and replaced without the necessity of removing the well completion system. Further, it is preferable that the selective profile into which the invention latches be suitable for the installation of a blanking plug such that the passage through the by-pass tubing may be closed and opened by conventional wire line or coiled tubing operations.

Although the invention may be carried out in a variety of ways one particular embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which Figure 1 is a longitudinal section through part of a by-pass system showing in elevation a differential-pressure operated blanking valve according to the invention installed therein; Figure 2a shows the valve of Fig. 1 on a larger scale and in partial/axial section; and Figures 2b and 2c are end elevations of plugs for use in conjunction with the valve tool of Fig.

2a.

Fig. 1 shows an arrangement whereby a differentialpressure-operated valve tool 50 is assembled into a seal bore profile 32 within a by-pass system such that the exterior of the tool 50 is sealed by elastomeric seals 25 to prevent fluid passage between the outside of the tool 50 and the nipple seal bore profile 32. The seal bore 32 communicates with the exterior of the by-pass system via port 37 such that port 17 in the housing 12 of the tool 50 is connected directly to the pressures pertaining within the well casing 51.

The start-up of an ESP will create a pressure differential between the pump intake areas within the well casing 51 and pump discharge areas within the by-pass system. Whilst these areas are connected via open by-pass tubing, the large volume of fluid pumped will maintain a pressure differential sufficient to generate forces to operate a mechanism within the pressure operated tool 50.

The differential pressure-operated valve tool is shown in more detail in Fig. 2a. A spherical ball 1 is mounted at the end of a sleeve 2 such that it may rotate about pivots 3 located at either side of the spherical ball 1. The end of the sleeve 2 is profiled at 2a such that it will match with the profiled end 4a of an actuating sleeve 4 through which rotation pins 5 are inserted, the pins locating with slots 6 in the spherical ball 1 such that axial movement of the actuating sleeve 4 will cause the spherical ball 1 to rotate about the pivots 3.The spherical ball 1 is provided with a through-bore situated at right angles to the axis of the pivots 3 and angularly situated in relation to slots 6, such that axial movement of the actuating sleeve 4 will cause the throughbore of the spherical ball 1 to rotate from a position in line with the axis of the sleeve 2 to a position in which the through-bore is at right angles to the axis of the sleeve 2. A collar 7 is located within a recess within the sleeve 2 and supported by a spring 8 such that the collar 7 is in constant contact with the spherical surface of the spherical ball 1 and will wipe the spherical surface as the spherical ball 1 rotates about the pivots 3.

The sleeve 2 slides on a spigoted housing 9 in which a seat 10 is located. The sleeve 2 is supported by a spring 11 such that the spherical surface of the spherical ball 1 is maintained above, and not in contact with, the seat 10.

The actuating sleeve 4 is positioned within a stepped bore wIthin a housing 12 and is supported by a spring 13.

The upper end of the actuating sleeve 4 abuts a shoulder 14 within the housing 12 such that the through-bore of the spherical ball 1 is maintained axially aligned to the axis of the sleeve 2. The actuating sleeve 4 is sealed within the housing 12 by elastomeric seals 15 and 16 such that the spring 13 is maintained within an annular space 42 which is sealed to the pressure pertaining within the core of the tool 50 and which is directly connected to pressure external to the tool 50 via a port 17 through the wall of housing 12.

An inner sleeve 18 passes through the bore of the actuating sleeve 4 and is maintained in contact with the spherical surface of the spherical ball 1 by a spring 19.

A stop 20 is screwed into the inner sleeve 18 such that the inner sleeve 18 may not pass upwardly through the actuating sleeve 4.

It can be understood from the above that, on operation of the ESP, the pressure within the tool 50 will exceed the pressure pertaining external to the tool 50, and the actuating sleeve 4 will move so as to reduce the annular space 42 and compress the spring 13. (Pressure obtaining within the tool 50 is communicated to the annular space by the shoulder 14 through ports which are not shown in the drawing.) This movement will cause the spherical ball 1 to turn about pivots 3. During this rotation the spherical surface of the spherical ball 1 is wiped due to the contact between the spherical ball 1 and the collar 7.When the spherical ball 1 has rotated to a position such that the through-bore is at right angles to the axis of the tool 50, the mating profiles 2a and 4a at the ends of the sleeve 2 and actuating sleeve 4 respectively will become enmeshed, and movement of the actuating sleeve 4 be imparted directly to sleeve 2, thus compressing spring 11 until the spherical surface of the spherical ball 1 contacts the seat 10. Such movement imparted to sleeve 2 occurs without further rotation of the spherical ball 1 and the passage through the tool is thus sealed, pressure being sealed via the contact between the spherical ball 1 and the seat 10 and by elastomeric seals 21 and 22 situated within grooves in the sleeve 2.

It can further be understood that when the pressures pertaining within and external to the tool 50 are equalised, the force imparted by the spring 11 will lift the sleeve 2 such that the contact between the spherical ball 1 and the seat 10 is broken; and that the force applied by spring 13 will serve to lift the actuating sleeve 4 so that the spherical ball 1 will rotate about pivots 3 due to the moment transmitted via rotation pins 5, and that the bore through the spherical ball 1 will thus be re-aligned with the axis of the tool 50.

Should the spring forces prove inadequate to move the actuating sleeve 4 the tool may be operated by latching a wireline or coiled tubing-deployed pulling tool (not shown) into profile 23 within the inner sleeve 18 and applying an upward force, compressing spring 19 and bringing stop 20 into contact with the end face 24 and the actuating sleeve 4, thus transmitting said upward force to the actuating sleeve 4; the actuating sleeve 4 moves upwards until the top of the sleeve 4 abuts the shoulder 14 of the housing 12, at which time the through-bore of the spherical ball 1 is aligned to the axis of the tool 50. Additional pulling force is then applied to release the pulling tool as is common wireline or coiled tubing practice.

In another procedure, a blanking plug 38 as shown in Fig. 2 may be seated such that elastomeric seals 39 seal within the seal bore 36 in housing 12, thus preventing the passage of fluid through the tool 50.

Should it prove impossible to operate the tool 50 automatically or mechanically either to open or to close the flow passage through the tool 50, it will be necessary to remove the tool 50 from the well for replacement. This is achieved by latching a wireline or coiled-tubing deployed tool into the profile 26 within fishing neck 27.

Pulling forces will be transmitted through the tool 50 causing the shear pin 30 to shear through, enabling shear ring 28 to move down and the raised finger profile 31 of the lantern collet 29 to flex within the diameter of the nipple seal bore 32; the tool 50 can then be removed from the well. The tool 50 may then be replaced with a similar tool or alternatively with a blanking plug sealing directly into seal bore 32, such a blanking plug being of a type conventional for use in oil well by-pass configurations.

During normal logging operations it is necessary for the flow passage through the tool 50, to remain open although a pressure differential is maintained between the interior and exterior of the tool 50. This may be achieved by installing a plug 33 as shown in Fig. 2c such that elastomeric seals 34 and 35 are positioned within the seal bores 36 and 37 of the tool, thus shielding the actuating sleeve 4 from any increase in pressure applied internally to the tool 50 and at the same time physically preventing the spherical ball 1 from rotating. The plug 33 is hollow to allow the passage therethrough of a wireline or coiled tubing. At the completion of logging operations the plug 33 is removed from the well, the flow passage through the tool 50 remaining open until a pressure differential is developed by operating the ESP.

A hollow plug having a larger bore than the plug 33 may be used to protect the tool 50 when pumping harmful chemicals down the well.

It will be appreciated that the above-described embodiment of the invention affords the following advantages:1. Automatic closure of a flow passage through the by pass system in order that fluid produced from the ESP discharge cannot re-circulate to the pump intake.

2. Automatic opening of the passage through the by-pass system when the ESP is inoperative.

3. Ability to allow the passage through the by-pass system to be opened or closed by mechanical means.

4. Option to use a conventional blanking plug to seal the passage through the by-pass system effectively.

5. Ability to be held in the open position whilst fluid is produced by the ESP such that logging operations may be carried out under such conditions.

6. Ability to be latched or unlatched at will from its position in the completion such that it may be replaced using wireline or coiled-tubing deployed means.

7. Ability to be replaced by a blanking plug using such conventional means.

8. Ability to be used in highly deviated or horizontal wells.

Claims

Claims:

1. A differential pressure-operated blanking tool for preventing re-circulation through by-pass tubing of fluid produced from an oil or water well by an electric submergible pump, the tool comprising an elongate body arranged to seal within the by-pass tubing or in the throat of a Y-tool, and having a passage therethrough to allow deployment into the well of logging tools and gauges, and valve means arranged to close the passage in response to the pressure difference developed by operation of the electric submergible pump between pump intake pressure obtaining within the well casing and pump discharge pressure obtaining in the production tubing, and to open the passage on equalisation of pump intake and discharge pressure when operation of the pump is discontinued.

2. A tool as claimed in Claim 1, in which the valve means comprise a rotationally mounted spherical valve having a through-bore which is aligned with said passage when the valve is in the open condition, and actuating means comprising a resiliently-loaded piston which is arranged to be displaced by development of said pressure difference to rotate the spherical valve from the open position to a closed position in which the valve obtrudes the passage, the piston being returnable to its original position under the influence of its resilient loading on removal of the pressure difference.

3. A tool as claimed in Claim 2, wherein retention means are provided for retaining the valve in the open position when a logging tool or gauge is used below the electric submergible pump in order that the wireline or coiled tubing is not damaged and the logging tool or gauge consequently lost.

4. A tool as claimed in 3, wherein the retention means are provided by a plug, insertable in said tool and arranged to straddle the valve means thereby allowing, in use, the wireline or coiled tubing to pass therethrough.

5. A tool as claimed in 4, wherein the plug is provided with sealing means which provides a substantial, but not perfect, seal around the wireline or coiled tubing.

6. A tool as claimed in any preceding Claim, wherein the passage through the tool is arranged to be openable or closable mechanically by separate deployment of another tool.

7. A tool as claimed in Claim 6, including latching means arranged to receive said another tool thereby allowing a mechanical force to be applied in order to open or close said passage.

8. A tool as claimed in any preceding Claim, wherein the passage includes a substantially smooth seal bore for receiving a blanking plug having sealing means.

9. A well completion system including by-pass tubing to enable access to an oil or water well below an electrical submergible pump, said tubing having a selective profile positioned in the top of said by-pass tubing immediately below a Y-tool, and a tool as claimed in any one of Claims 1 to 8, the arrangement being such that the tool is latchbable in said profile to facilitate retrieval of the tool from the well in the event of a malfunction without the necessity of removing the well completion system.

10. A well completion system as claimed in Claim 9, wherein the profile is suitable for the installation of a blanking plug such that the passage through the by-pass tubing is closable and openable by conventional wireline or coiled tubing operations.

11. A differential pressure-operated blanking tool substantially as hereinbefore described with reference to Figure 1 and Figure 2a of the accompanying drawings.