GB2504699A - Switchable fluid driving tool - Google Patents

Abstract

A fluid driving tool 10 for connection in a tubular conduit, has a tubular body, an axial throughbore 12 and side wall fluid outlets 93, an internal actuator sleeve 18 moveable under fluid pressure within the axial throughbore from one position to another in order to change the configuration of the fluid driving tool, wherein each position is maintainable by spring force, and the configuration change is achievable by adjusting circulating fluid pressure relative to opposing spring pressure, wherein the respective internal actuator sleeve positions are set by an index patterned surface 50 within the fluid driving tool and a cooperating index pin 60, the internal actuator sleeve 18 housing a flow restriction nozzle device (80, figure 3) with a nozzle outlet (84) directed towards a blind bore (88), and venting fluid through side vent ports (87) when aligned with the fluid outlets (93).

Description

SWITCI-IABLE FLUID DRIVING TOOL

This invention relates to a tool for use in the oil and gas industry, particularly in the drilling and completion of wellbores, for controlling fluid circulation in the performance of wellbore operations. The invention is especially useful in removal of debris and detritus produced during weilbore operations.

Background of the Invention

It is considered desirable in the art of drilling for oil or gas to be able to circulate drilllng fluid at all material times down a drill string. It is also desirable to be able to control circulation to the extent that flow maybe reversed at will, at least in respect of certain parts of a weilbore, for example in proximity to the bottom hole assembly (BHAJ of a drill string to aid recovery of debris and detritus. Furthermore, it is also desirable to direct and control circulation of other fluids during wellbore cleaning operations prior to completion of the well.

Our patents, including US 7 055 605, US 7441 607, US 7416 029, and US 7628 213, illustrate how fluid circulation may be utilised as part of wellbore operations for both cleaning and tool actuation purposes.

The present invention recognises the need for a sub or tool connectable in a drill string that may be used for re-directing or reinstating fluid circulation, notwithstanding the operation of other tools or processes, and provides a reliable fluid driving engine.

Tools which are selectively actuable in a well bore commonly operate by having an element which can be moved relative to the tool when in the well bore. In the circulation tool of US 7 055 605, the element is a sleeve located in the cylindrical body of the tool. When run in the well, the sleeve is held in a first position by one or more shear screws. To actuate the tool, a flow restriction device) typically a drop ball) is released from the surface of the well through the work string to fall or be circulated in fluid to the sleeve. On reaching the sleeve, the ball blocks the flow of fluid through the tool and consequently pressure builds up until the shear screws shear and the sleeve is forced downwards. The movement of the sleeve is then stopped when a lower ledge of the sleeve contacts a shoulder on the internal surface of the tool body.

Though such a tool is useful there remain a number of disadvantages to be overcome. That type of tool is generally limited to one actuable movement If two sleeves are incorporated to overcome this, the shear screws of the second sleeve can operate prematurely under the shock created to shear the shear screws of the first sleeve. Additionally, the reduced bore diameter of the lower part also affects the flow rate achievable through the tool adversely.

One tool which has been developed to operate repeatedly is that disclosed in U.s. 4 889 199. This tool comprises a tubular body having a radial port into which is located a sleeve having a matching radial port The sleeve is slidably mounted and its action controlled from a deformable drop bail biasing the sleeve against a spring.

Initially the spring biases the sleeve to a closed position in which the ports are misaligned. The drop ball causes the sleeve to move to a position where the ports allgn due to a build up of pressure behind the ball) and fluid is discharged radially through the ports. A small steel bail is then dropped into the tool which seals the radial ports and the consequential pressure build up extrudes the deformable ball through the ball seat. The steel ball will drop with the deformable ball and both are retained in a ball catcher at the base of the tool. When the balls drop together the spring biases the sleeve back to the closed position and the tool can be operated repeatedly subject only to availability of sufficient drop balls and the capacity of the ball catcher.

A disadvantage of such a tool is that it requires both a deformable ball and a smaller metal ball to operate. Care must then be taken to ensure the balls are dropped in the correct order. The smaller metal ball must lodge in the second, radial, outlet in order to stop flow and thus the tool is restricted to having a single radial port Therefore, there remains a need to design tools which are not complex) are easy to use, do not interfere with other tools and are reliable in use.

A particular demand exists in the industry for a higher standard of recovery of debris and detritus arising from wellbore operations prior to completion.

Typically) a tool for this purpose will be included in a drill string or work string for use when required.

Our patent US 6453 996 describes a clean up tool for use in a well bore, the tool comprising a tool body defining a first and second liquid passage which each communicate with a venturi chamber, wherein the first and second liquid passages are each associated with an inlet for receiving well fluid into the tool, wherein the tool body further comprises a discharge passage associated with one or more outlets, wherein the discharge passage also physically communicates with the venturi chamber and is adapted to allow the expulsion of fluid out of the tool body in a radial or near radial direction from the tool body.

Our further patent US 7 992 636 describes a tool for use in retrieving debris from a well wherein fluid is circulated into an annulus defined between the tool and a well borehole wall.

Typically the known tools are designed to be set before run in to the well bore in a "ready for use" or "on" mode, i.e. the tool is set up to induce reverse circulation immediately when fluid is pumped through it.

Summary of the Invention

We have now designed an improved fluid driving tool which can be repeatedly switched off and on indefinitely and is of simple and reliable design. According to the present invention, the tool is provided with relatively movable cooperating components one of which has an index pattern and the other has an index pin presented to follow the index pattern. The movable cooperating components may be an actuator sleeve mounted within a tubular body of the tool. Suitably, the actuator sleeve has the index pattern defining a track consisting of differing sizes of slot, e.g. sequential short and long travel slots, interconnected by ramps for receiving the index pin mounted in the side wall of the tubular body of the tool.

Since the index pattern is endless, the index pin may be moved around the track in an indefinitely repeatable cyclic pattern to progressively advance the index pin from one slot to the next at each relative movement of the components in one direction around the tool. The relatively moveable components are moveable under the influence of fluid pressure changes applied to the tool and countered by an opposing spring force. In this way the configuration of the tool can be repeatedly switched from one configuration to another. This allows the tool to be switched from a configuration permitting fluid flow through the tool to a configuration where flow fluid is diverted outside the tool and back. The tool can be set up originally in either flow through [normal circulation) or flow diversion (locallsed reverse circulation in the proximity of the tool) as a matter of choice, and its switchable operation thereafter by means of circulating fluid pressure changes easily allows the required configuration to be changed from one to the other repeatedly. This tool provides for reverse circulation of fluid below the tool, whilst regular or "forward circulation" occurs above the tool.

The unique index pin for this application has a stepped shank wherein the nose has a relatively shorter length than normal and is adapted for ease of use in a short travel slot whilst the remainder of the shank of the pin is stepped out to provide a shoulder, flange or head of greater width than the nose which serves as a bearing surface for the thrust of a strong return spring used to move the pin out of the slots and over the ramps of the track when fluid pressure upon the sleeve is reduced.

More than one pin may be used) for example at diametrically opposed positions if two are used, or at some other spacing interval around the track if more than two are used. Four index and orientation pins may be conveniently used in various embodiments of the invention.

The use of the index pin and track combination allows both actuation and configuration changes in respect of axial and rotational movements) for example for the purpose of aligning fluid ports (actuation for operational use] or occluding same (revert to flow through). The track is configured to have alternate long and short slots allowing long and short strokes of axial displacement, e.g. the short stroke displacement may be half that of the long stroke, for a sleeve component of the tool with a progressive rotational movement. In this way the tool components can be

S

rotationally and axially re-configured indefinitely. This also means that the tool can be set up for run in selectively in "flow through" or "reverse circulation" operational modes. The set up configuration is easily changed in use by a sequence of pressure changes experienced by the tool) which may be effected for example by delivery of a flow restrictor to the tool. WO 2011/146836 A2, incorporated herein by reference) describes hydraulic actuation of a downhole tool assembly) for example by cycling the drilling fluid rate without requiring delivery of a flow restrictor like a ball, dart etc. An axial piston assembly is configured for axial reciprocation in the tool) with a helical compression spring configured to bias the piston assembly in the uphole direction towards an under-reamer body. In exemplary embodiments described therein the tool assembly makes use of the differential pressure between an internal flow channel and the annulus to selectively actuate and deactuate certain tool functionality. Such a piston assembly can be used in embodiments of the presently disclosed tool assembly.

According to a preferred construction) the present tool is biased to a first configuration by spring loading, e.g. by use of a spring housed within the tool. A disc spring is preferably used for this purpose. Disc springs comprise frusto-conical discs or coned/dished washers [often called Belleville washers and hence "Belleville springs"] stacked together in alternate inverted orientations to form an elongate resilient device adapted to be loaded in an axial direction. They are preferred for use in coping with high loadings because they are found to be subject to relatively small deflections, in comparison with other types of axially loaded springs such as helical or coil types, which nevertheless could be used in this invention due to confinement within the tool.

The configuration of the tool may be changed by the mud pump operator through fluid pressure changes by providing within the tool, or in close operative connection with the tool, an area against which pressure may be developed. Whilst it is possible to design the tool such that significant increases in fluid pressure alone are sufficient to effect a displacement of a sleeve or another moveable component within the tool (c.L WO 2011/146836 A2 above)) one may form a valve seat adapted to receive an obturator or flow restrictor device such as a dart or ball introduced from above the tool, for example from the surface or otherwise from a release mechanism in the string above the tool. A ball may fall or be carried to the seat in circulation fluid and when seated thereon restricting flow sufficiently to create an increase of pressure upon the seat. A dart would be pumped in the circulation fluid to the site of use. By restricting or obstructing flow through the tool for a sufficient period this allows a high pressure to be developed behind the flow-restrictor device.

This pressure can be utilised to displace a component, such as an actuating sleeve) operatively associated with the means for facilitating the high pressure build up such as a dart or ball in combination with a suitable stop shoulder or seat adapted to cooperate with the dart or ball in effecting a pressure build up.

In order to achieve the sequential switching capability the flow restrictor (dart, ball or plug) or the receiving surface may be deformable to allow a further pressure change to be used to blow the flow restrictor clear of the receiving surface to restore unrestricted fluid flow. A suitable flow control valve assembly is described in our patent publication WO 2005 106 186 Al. The flow restrictor may be caught in a "ball catcher" or capture zone within the tool or string assembly which is configured to allow fluid flow past the restrictor e.g. in adjacent by-pass channel(s) located around and either side of the capture zone.

In a suitable arrangement, fluid flowing through the tool may be directed through a bore restriction to accelerate the fluid flow locally, induce local reverse flow, and improve entrainment of debris or detritus in the circulation fluid, which fluid may then be vented to the annulus above the tool and at the same time at least some of the debris or detritus may be captured in a screen, chamber or magnetic tool associated with the tool.

A bore restriction configured to perform in use as a venturi within the tool has a tapered inlet feeding into a tubular outlet nozzle mounted concentrically within a sleeve, which may comprise a blind bore provided with side outlet channels for re-directing fluid flow into the annulus below the tool. The part of the tool or sub housing the nozzle may comprise a single axially directed nozzle delivering fluid to a plurality of side ports e.g from 3 to 8, suitably 4 or 6, preferably 4 ports arranged radially or near radially to initiate and sustain reverse circulation. The side ports direct fluid flow through the side channels feeding into the annulus below the tool.

This arrangement enables provision of a fluid driving engine to be coupled with other tools in the string, e.g. magnetic fishing tools for debris and detritus, filters for improving welthore operations etc. S Those in the art understand reverse circulation in this context to be a description of flow wherein fluid received through the string in the fluid driving engine is accelerated in the nozzle creating a local reduction in pressure ahead of the nozzle which has the effect of drawing fluid inwards towards the nozzle from below the tool. It is observed that below the tool, the fluid flow passes down through the annulus and returns internally bringing any sand, debris) metallic particles or the like detritus upwards where it may be collected from the reverse circulated fluid in filters, baskets or debris chambers or by magnetic tools mounted on the string.

The nozzle may be incorporated in a removable device which may be mounted within the sleeve using self-retaining press-fit fasteners, e.g. a slotted tubular spring or roll pin such as a Bissell pin.

In an embodiment, the tool of this invention is assembled into operational relationship with various associated tools incorporating magnets, filters and debris recovery chambers and run on the end of a work string near the BI-IA to create a localized reverse circulation flow path to pick up and trap small pieces of debris (e.g. sand, scale etc] and remove them from the well.

The invention further provides a method of cleaning a well, comprising running a fluid driving tool of the invention on a work string into the well, delivering fluid under pressure to the tool to effect a configuration change in the tool, wherein the configuration change is selectively one of (i) re-configuring the tool to create a localized reverse circulation flow path near the end of the work string to pick up and trap small pieces of debris (e.g. sand, scale etcj and remove them from the well, and (ii) re-configuring the tool for normal circulation throughout the work string.

The invention will now be further described by way of example with reference to the accompanying drawings.

B

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a part cross-sectional side view of the upper part of a downhole tool in a first position according to an embodiment of the present invention; Fig. 2 is a pan cross-sectional side view of the lower part of a downhole tool in a first posilion according o an embodiment of the present invention; Fig. 2a is a cross-sectional axial view at A -A of the lower part of the downhole tool illustrated in Figure 2; and Fig. 3 is an enlarged part cross-sectional side view of an internal nozzle component required for operational use of the tool and outlet slots accessing the annulus below the tool.

Reference is made w Figure 1 of the drawings which illusraes a downhole tool, generally indicated by reference numeral 10, according w an embodiment of the present invention. The tool 10 is a fluid circulation modifying tool, capable of producing enhanced fluid flow when located in a well bore (not shown) as part of a drill or work string depending upon the wellbore operation requiring the enhanced fluid flow to be produced. The operation may require debris and detritus removal in the circulation fluid in which case the tool provides a wellbore scavenger engine further details of which are given below.

Tool 10 comprises a cylindrical body having at an upper end 14 (Fig. 1), a conventional box section and at a lower end 24 (Fig. 2), a conventional pin section for connection of the tool in a work string (not shown). In the embodiment shown the body has a centra' bore 12 of generally uniform diameter in so far as fluid flow is concerned. However, within the tool are located operational components some of which introduce bore restrictions or alternate flow paths within the bore of the tool same to be more specifically discussed hereinbelow.

The tool 10 is controlled and actuated by providing and restricting flow of circulation fluid. A valve assembly 16 using a separate restrictor element, for example a ball) dart or plug (not shown) which can be released in the string from above the tool, e.g. from within the string or from the surface, into the circulation fluid to fall or be carried to the valve assembly is the means for initiating an operating cycle for the tool 10 and for changing one configuration of the tool to another. Alternatively, a flow-restricting dart [not shown] may be pumped down in the circulation fluid to be captured in the tool for a sufficient period to permit an actuation of a configuration change to be effected.

The valve seat assembly 16 is mounted within an axially displaceable sleeve 18 located in an upper section of the tool 10. The valve seat assembly has a bell inlet for directing a ball, dart or plug towards a resilient seat 17 adapted to resist passage of a ball, dart or plug up to a pre-determined pressure whereupon it temporarily deforms to allow the ball, dart or plug to squeeze through. Sleeve 18 has upper and lower bypass ports 11, 13 respectively arranged around the circumference of the sleeve 18 and providing access to a fluid bypass channel 15 defined between an outer surface of the sleeve 18 and an inner surface of the central bore 12. This by pass channel 15 allows flow around an interior "ball catcher" section 19 when required.

The sleeve 18 also has defined on an external surface thereof an infinite track 50 around the sleeve and consisting of short slots 52, long slots 54, and respective upper and lower guide ramps 56, 58, and apexes 51, within which track an index pin 60 travels when urged to do so under either axial fluid pressure in one direction or counter pressure from a bias spring 70 [Fig.2]. The developed circumference of the track SO is illustrated in Fig. 1, and 4 x pins 60 are shown at rest in the long slots 54 which configuration corresponds to the open throughbore [flow through tool] configuration.

The index pin 60 fixed through a sidewall of the tool has a stepped shank wherein the nose 62 has a relatively shorter length than the remaining length of the shank and is adapted for ease of use in a short travel slot whilst the remainder of the shank of the pin is stepped out to provide a shoulder, flange or head 64 of greater width than the nose 62 the side wall 66 of which serves as a bearing surface for the thrust of a strong return spring 70 used to move the sleeve such that the pin is pushed out of the slots and over the ramps SB of the track when fluid pressure upon the sleeve is reduced. When pressure is applied, the sleeve moves downwards such that the pin 60 eventually encounters the ramps 56 and rests in apex 51.

Referring now to Fig. 3, within a lower section of the sleeve 18 is mounted a flow restriction nozzle device 80 comprising an inlet 82 of gradually decreasing diameter S converging towards a tubular body 83 with a nozzle outlet 84 directed down the bore of the tool and defining within the sleeve 18 a short annular passage 85 between a port 86 in the sleeve 18 and a blind bore 88 terminating in plug 89.

The nozzle device may be removably mounted within the sleeve using self-retaining press-fit fasteners, e.g. Bissell pins 81.

The nozzle device 80 is configured for fluid flow around or through the nozzle device according to a selected configuration setting of the tool either for flow through the tool [open throughbore 12), or operationally actuated for use (restricted flow through the tool with external fluid venting) in a wellbore operation such as facilitating recovery of debris and detritus in the circulation fluid.

Thus [referring again to Fig. 1) fluid leaving the by-pass channel 15 passes through the tool beneath the track SO, and in an optional run-in hole configuration flows through by-pass ports 41 leading to an annular by-pass channel 45 (Fig. 2) around the lower section of the sleeve 18 and back into the continuation of the bore 12 through the tool.

The lower section of the sleeve 18 terminates in an upset thicker section 90 (Fig. 3) within which transversely directed lower vent ports 87 are formed and having axial by-pass channels 92 for through flow in an optional run-in configuration. The vent ports 87 are alignable with outer vent ports 93 when the tool is actuated and reconfigured to displace the sleeve 18 axially under circulation fluid pressure. The lower vent ports 87 together with the outer vent ports 93 define slots in the tool allowing flow access to the annulus external to and below the tool.

The lower section of the sleeve 18 (Fig. 2) abuts a further axially displaceable support sleeve 20 housing a strong compression spring 70. The spring in this embodiment is a disc spring i.e. it comprises a stack of Belleville washers arranged in alternate inverted orientations to form a durable return spring capable of withstanding high loadings. The spring loading is reacted against a spring reaction plug 22 fixed at the lower end of the tool.

In use of the tool 10, the index and configuration pin(s) 60 fixed in the tool sidewall S are set in the track 50 at the surface such that in this selected run-in configuration) the sleeve 18 is positioned for through flow only in that the lower vent ports 87 are not aligned with the external vent ports 93, and the return spring 70 holds the sleeve 18 in its uppermost position within the tool 10 wherein the index pin lies in the longer slot 54.

When a wellbore operation is to be conducted with requires use of the fluid driving engine (use of the venturi nozzle device 80 within the tool] to modify the fluid circulation) a ball (not shown] is released in the string and in due time it seats upon the valve seat 17 restricting flow within the tool. Continued application of fluid pressure to the now occluded valve seat 17 with trapped ball axially displaces sleeve 18 downwardly, overcoming bias of return spring 70, and initiating a configuration change whereby fluid flow through the tool is changed.

During this configuration change the sleeve is depressed such that the index pin contacts the ramp 56 at its extremity of travel out of the slot 54 and thereby in addition to the relative axial displacement of the pin 60 and sleeve 18, a relative rotational movement about the longitudinal axis of the tool is urged upon the sleeve 18 by contact with the pin 60 and terminated as the pin 60 contacts the apex 51.

Continued application of elevated fluid pressure drives the ball through, thereby relieving pressure upon the spring 70 somewhat, and allowing its counter pressure to displace the sleeve 18 in reverse such that the relative movement of the pin 60 is towards the ramp 58, and hence locked positively into the shorter slot 52. At this configuration of pin(s) with respect to track 50, the lower vent ports 87 are aligned with the external vent ports 93 allowing flow out into annulus below the fluid driving engine towards the bottom hole assembly (not shown]. At the same time this change of configuration of sleeve 18 also blocks flow through by-pass channel 45, preventing flow through internal by-pass channels 92.

Bringing the lower vent ports 87 into registry with the external vent ports 93, simultaneously seals off the annular by-pass channel 45 causing fluid to enter the tapered inlet 82 tubular body 83 of the nozzle device 80 to emerge more rapidly from the nozzle outlet 84 into the blind bore 88 wherefrom the accelerated fluid can only exit via the vent ports 87, 93 to promote fluid circulation external to the tool and inducing reverse circulation. An observed effect of this configuration change is that there is an induced reduced pressure below the tool which sucks debris, detritus, sand etc. from around the bottom hole assembly upwards towards the tool with the reverse circulated fluid. In this way appropriately mounted filters, baskets and magnetic fishing tools (not shown] provided on the string can be used to capture the debris, detritus, sand etc. whilst fluid is re-directed into the annulus above the tool and circulated out normally.

When the wellbore operation is completed and normal circulation is to be restored another ball is delivered to the tool, allowing pressure up as before to overcome spring pressure, and advancing the pin(s) to the next long slot 54, whereupon the sleeve 18 becomes axially displaced and the lower vent ports 87 and the external vent ports 93 become misaligned again, and the venturi by-pass channel 45 is re-opened allowing flow through the internal by-pass channels 92, whereby normal circulation flow through the tool and string is re-established.

This operation can be repeated for as long as flow restrictors such as balls or darts or plugs (when used] can be accommodated in a catcher. In embodiments where increased pressure applied to tool surfaces alone are relied upon, without needing delivery of a separate flow restrictor, the number of cycles would be infinite.

Claims (10)

1. Claims 1. A fluid driving tool comprising a tubular body adapted for connection in a work string, having an axial throughbore and fluid outlets in a side wall of the tubular body, and an internal actuator sleeve moveable within the throughbore from an initial position defining a first configuration of the tool and another position defining another configuration of the tool, wherein each configuration is realised by compressive force of fluid delivered through the tool and each position is maintained by spring force, and the transition from one configuration to the next is achieved by delivering sufficient fluid pressure to overcome the spring force, and thereafter reducing the fluid pressure to allow the spring to hold the next position, wherein the sleeve has at one end a surface upon which pressure can be applied and at the other end a blind bore with adjacent side ports alignable with the fluid outlets in the side wall for fluid communication in a selected configuration of the tool, and not so aligned in another configuration, and the sleeve is movable with respect to the tubular body according to guidance from an index pin engaged with an index patterned surface within the tool, the sleeve housing a flow restriction nozzle device with a nozzle outlet directed towards the blind bore.
2. 2. A fluid driving tool as claimed in claim 1, wherein the index patterned surface is a grooved track defined in external surface of the sleeve for directing configuration changes by means of series of slots of differing sizes interconnected by ramps for guiding the index pin which is mounted in a side wall of the tubular body of the tool.
3. 3. A fluid driving tool as claimed in claim 1 or claim 2, wherein the index pin has a stepped shank defining a short nose and a head of greater width than the nose, a side area of which serves as a bearing surface.
4. 4. A fluid driving tool as claimed in any one of claims 1 to 3, wherein multiple mutually spaced index pins are used in the tool, preferably four.
5. 5. A fluid driving tool as claimed in any one of the preceding claims wherein the tool is biased to a first configuration by use of a spring housed within the tool, said spring being selected from the group consisting of coil, helical and disc springs.
6. 6. A fluid driving tool as claimed in claim 5, wherein the spring is a disc spring formed from coned discs (Belleville spring).
7. 7. A fluid driving tool as claimed in any one of the preceding claims wherein the flow restriction nozzle device comprises a single axially directed nozzle delivering fluid to a plurality of side vent ports in an upset region of the sleeve alignable in one configuration of the tool to direct fluid through corresponding outer vent ports in a side of the tubular body into an annulus below the tool; the upset region having axial by-pass channels for through flow in another configuration of the tool.
8. 8. A fluid driving tool as claimed in any one of the preceding claims, wherein the flow restriction nozzle device is incorporated in a removable device mounted within the sleeve using self-retaining press-fit fasteners.
9. 9. A work string comprising a fluid driving tool as claimed in any one of the preceding claims wherein the fluid driving tool is assembled into operational relationship with various associated tools incorporating magnets, filters and debris recovery chambers provided near to the bottom hole assembly.
10. 10. A method of cleaning a well, comprising running a fluid driving tool as claimed in any one of claims 1 to 9 on a work string into the well, delivering fluid under pressure to the tool to effect a configuration change in the tool, wherein the configuration change is selectively one of (i) re-configuring the tool to create a localized reverse circulation flow path near the end of the work string to pick up and trap small pieces of debris (e.g. sand, scale etc) and remove them from the well, and (ii) re-configuring the tool for normal circulation throughout the work string.