WO2021058812A1

WO2021058812A1 - Apparatus for use in establishing a wellhead

Info

Publication number: WO2021058812A1
Application number: PCT/EP2020/077020
Authority: WO
Inventors: William WENANDE
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-27
Filing date: 2020-09-26
Publication date: 2021-04-01
Anticipated expiration: 2022-03-27
Also published as: GB2587803A; GB201913943D0

Abstract

The present invention concerns apparatus for effecting a change in direction during driving of a tubular (2) into a formation to establish a wellhead. The apparatus comprises a drive shoe (3) extendable from within a tubular, the drive shoe having a deflection surface. The apparatus further comprises drive means (5, 6, 7, 8, 9) for extending and retracting the drive shoe relative to the tubular and for rotating the drive shoe relative to the tubular.

Description

APPARATUS FOR USE IN ESTABLISHING A WELLHEAD

Field of the Invention

This invention relates to drilling and well completion operations and provides a tool that is useful to the oil and gas industry for the purpose of establishing a wellhead for example.

More specifically, the present invention relates to the directional adjustment of conductor casings during deployment. In particular, the invention provides an apparatus and a method for active directional adjustment of an offshore conductor casing as it is being driven below the mud-line of the substratum.

Background to the Invention

During the initial stages of drilling, especially at a subsea location, the surface encountered may be typically of a sedimentary deposit character, i.e. relatively soft, unstable, loose and susceptible to movement. In order to stabilise the initial penetration of such a surface for the purpose of subsequent operations, it is known to insert a relatively large diameter casing string referred to commonly as “conductor” casing. The conductor can be driven into the surface at onshore or shallow offshore sites by a pile-driving technique, whilst at deeper locations; the conductor can be delivered on the end of a work string equipped with a reciprocating driving means (pile hammer) and a shoe for assisting the penetration of the surface. The operation may be initiated by a drilling operation e.g. using a drill ahead BHA, in which case the work string would be a drill string. Optionally, the driving of the conductor can be facilitated by fluid-jetting to displace sedimentary material dislodged during the driving operation.

Since very few wells are driven vertically in current practice, there is often a requirement for a deviated or directionally controlled borehole or indeed a number of diverging boreholes. There are numerous proposals for deviated drilling operations by deflecting the drill string after it leaves the conductor. Thus generally, in past practice, it would be usual to deliver the conductor casing directly to initially confront and penetrate the surface, more or less vertically. However, there have been proposals to seek to influence the driving of the conductor to angle it towards a desired direction for the borehole. This is achievable onshore or in shallow locations, but much more difficult to achieve at deep water operational sites where all operations are significantly more challenging.

There is a need to control the angle of entry of the conductor casing especially in a deep water location, since it is via this casing that each subsequent operation is conducted and from which the stability of the well head including support for subsequent borehole casing strings is derived.

Directional drilling of oil and gas production wells has become an established practice in view of the many potential benefits which, inter alia, include: (i) increasing the exposed section length through a reservoir; (ii) bypassing difficult formations that surround a reservoir; (iii) allowing new wells to be drilled in close proximity to existing wells; (iv) increasing the lateral reach of a well; and (v) facilitating the grouping of wellheads closer together with wells diverging through the substrata to predetermined depths and locations around a reservoir.

With particular reference to point (v) above, multi-slot platforms can have 24-60 slots spaced 2-3 metres apart at the surface. Given the natural tendency for driven conductors to deviate and follow the path of least soil resistance, directional control is required to avoid the collision of adjacent conductors. Known techniques for providing such directional control (as described below) can result in dog-legs (i.e. significant changes in angle and/or directional azimuth) resulting in high stresses along the conductor and its connections. Such stresses may exceed the mechanical limits of the conductor or its connections, resulting in a failure and a redundant slot which therefore has to be junked.

Past proposals for influencing the direction of the conductor installation have included suggestions to bend the conductor casing e.g. by passing the conductor casing through formers before deployment from the drilling structure. These early techniques for influencing the extent of deviation of a driven conductor casing typically employed either pre-curved conductor pipes or pipes which were forcibly curved through introducing them via offset guides. More recent solutions utilise drive-shoe members attached to the distal end of the conductor casing, the drive- shoe either having a distal end with an asymmetric surface profile and/or being attached to the conductor casing at a fixed offset angle relative to vertical. Such solutions are disadvantageous insofar as the degree of deviation is often unpredictable and difficult to control once the conductor casing has penetrated the substratum.

More sophisticated solutions employ bevelled drive-shoes connected by hinge means to the distal end of the conductor casing. Devices of this type may utilise shear pins for retaining the central longitudinal axis of the drive-shoe in a coaxial relationship with that of the conductor casing, thus ensuring its vertical insertion into the substratum. Once sub-surface resistive forces impinging on the bevelled surface of the drive-shoe exceed a threshold level, the pivoting motion of the drive-shoe about the hinge causes the shear pin to rupture. Through selection of shear pins with appropriate rupture threshold values, this arrangement allows deviation of the conductor casing to be initiated at a depth below the mud-line. Whilst offering some advantages over early designs, this passive solution is heavily dependent on the accuracy of soil surveys aimed at predicting the depth at which sufficient resistive forces will occur to rupture a given shear pin. Often, shear pins will rupture prematurely with the result that deviation commences at an undesired depth. Moreover, apparatus of this type fails to react predictably where soil characteristics fluctuate below the mud-line, or when passing through areas of disrupted soil (i.e. proximate template wells).

The aforementioned solutions each suffer from the problem that soil strength starts at zero at the mud-line, and increase with depth up to values of 600 psi (~ 42 kg nr²) or higher. Conventional apparatus will typically under perform in the shallow soil, perform close to what is predicted at the mid point, and then begin to over perform in deeper soil having higher soil resistance.

A further suggestion has been to attach an open-ended angled section at the leading end of the conductor which forms an offset or “dog-leg” that is said to influence the direction of the conductor as it is driven into the surface below the mudline.

A still further proposal involves modifying the conductor by provision of a bevel cut partially through a circumferential section of casing, which section is attached to the main body of the casing by a hinge. It is intended thereby that upon driving of the conductor, the bevel section is forced to close, thereby displacing the unhinged end to create an offset leading section which in turn causes the conductor to be deviated at an angle from the axis of the driven main body of the conductor as driving operations below the mudline are continued.

GB2499723B describes an apparatus designed by the applicant for addressing some of these issues. The arrangement in GB2499723B involves a drive shoe connectable to a tubular wherein the drive shoe has a plurality of independently deployable shoe elements offering deflector surfaces to the formation. Whilst this provides an improved apparatus, the applicant has recognised that there is opportunity for further improvements in such an apparatus.

An object of the invention is to provide improvements in or relating to installation of conductor casing, and to provide a tool useful for such a purpose.

Summary of the Invention

According to an aspect of the present invention there is provided apparatus for effecting a change in direction during driving of a tubular into a formation to establish a wellhead, that apparatus comprising a drive shoe extendable from within a tubular, the drive shoe having a deflection surface, wherein the apparatus further comprises drive means for extending and retracting the drive shoe relative to the tubular and for rotating the drive shoe relative to the tubular. In this manner, the apparatus can be used to effectively alter a direction of travel of the tubular.

Preferably, the drive means comprises translation means for translating a linear movement of the drive shoe into a rotation of the drive shoe. In this connection, the translation means can convert a linearly directed motion applied to the drive shoe into a rotation thereof. The drive shoe is preferably rotatable by up to 360 degrees.

Conveniently, the drive means comprises first and second actuators, the first actuator being for moving a drive shoe housing axially relative to the tubular, and the second actuator being for moving the drive shoe linearly with respect to the drive shoe housing, the translation means translating such linear movement of the drive shoe into rotation. In this regard, both actuators can be arranged to apply axially directed forces, which takes advantage of the tubular configuration of the apparatus.

Preferably, the translation means comprises a helical formation which extends around one of the outer surface of the drive shoe and an inner surface of the drive shoe housing. The helical formation may take the form of a groove, track or guide, and affords an effective means for converting axial to rotational motion.

Conveniently, the translation means further comprises one or more drive lugs provided on the other of outer surface of the drive shoe and an inner surface of the drive shoe housing.

Preferably, the one or more drive lugs engage with the helical formation. In this way, an axial movement of the drive shoe is translated also into a rotational movement thereof. Conveniently, the angle of the helix is from 5 to 45 degrees. More preferably the angle of the helix is from 15 to 25 degrees. In certain preferred embodiments the helix angle is 20 degrees.

Conveniently, the first actuator comprises a first hydraulic piston chamber with a first piston reciprocating within the first chamber.

Preferably, the second actuator comprises a second hydraulic piston chamber with a second piston reciprocating within the second chamber.

Conveniently, the drive shoe has a generally solid rod-like configuration with a wedge-like inclined surface which serves as a deflector surface when offered to a formation.

Preferably, the first and second actuators are synchronised for affording rotation of the drive shoe at a desired axial extension of the drive shoe.

Conveniently, the apparatus further comprises sealing means between the drive shoe housing and the tubular, and between the drive shoe housing and the drive shoe for preventing ingress of soil into the apparatus.

According to a further aspect of the present invention there is provided a recoverable tool assembly for directing driving of a tubular into a formation which comprises a tubular and an apparatus as defined above mounted therein, the apparatus further comprising radially deployable grippers for holding the apparatus within the tubular to be driven into a formation.

Further according to a yet further aspect of the present invention there is provided apparatus for effecting a change in direction during driving of a tubular into a formation to establish a wellhead, that apparatus comprising a drive shoe extendable from within a tubular, the drive shoe being housed in a drive shoe housing movably mounted in the tubular, the apparatus further comprising drive means for extending the drive shoe, the drive means comprising first and actuators for moving the drive shoe housing and the drive shoe respectively, the first actuator moving the drive shoe housing linearly with regard to the tubular and the second actuator moving the drive shoe helically with regard to the drive shoe housing, the first and second actuators being synchronized so that the drive shoe can be rotated whilst being maintained at a desired extended axial position relative to the tubular.

With the present invention, a single drive shoe is provided, rather than a multi element drive shoe, thereby reducing the complexity of the apparatus. The drive shoe can be readily orientated at any desired angle and extension relative to the tubular.

According to a further aspect of the present invention there is provided a method of effecting a change in direction during driving of a tubular into a formation to establish a wellhead, using the apparatus or assembly as defined above, the method comprising: positioning the apparatus downhole at the formation; driving the tubular into the formation; and actuating the drive means for extending and retracting the drive shoe relative to the tubular and for rotating the drive shoe relative to the tubular to a desired extension and rotational position of the drive shoe relative to the tubular.

Embodiments of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a view taken through apparatus according to the present invention;

Figure 1a shows a close up view of the end of tubular and drive shoe housing according to the present invention;

Figure 2 shows a view of a drive shoe for use in the present invention; and

Figures 3a to 3h show a series of views illustrating activation of the apparatus of the present invention.

Turning now to the Figures, there is shown in Figure 1 an apparatus 1 for use in directional adjustment of an offshore conductor casing as it is being driven below the mud-line of the substratum. The apparatus is shown mounted within a conventional conductor pipe 2 typically having an inner diameter of 23” (584.2mm). Within the conductor pipe is provided a drive shoe housing 4 which takes the form of a tubular that can moved into and out of the pipe 2 by way of a first actuator in the form of a hydraulic cylinder arrangement 5. Anti-rotation lugs 9 ensure that the drive shoe housing does not twist within the conductor pipe 2 and is simply driven axially to extend from and retract into the conductor pipe 2.

As detailed in Figure 1a, the end of the pipe includes a landing shoulder 10 for the end of the drive shoe housing 4.

Within the drive shoe housing 4 is provided a second actuator in the form of a hydraulic cylinder arrangement 6 which is coupled to drive shoe 3 to move it relative to the drive shoe housing 4. The inner face of the drive shoe housing 4 and the shoe have in this connection a coupling whereby axial movement of the drive shoe 3 within the drive shoe housing 4 results in rotational movement of the shoe 3. In this respect, the coupling between the drive shoe housing and the shoe can take the form of a helical track or guide on one of the drive shoe housing and the shoe which engages with drive lugs provided on the other of the drive shoe housing and shoe.

In the example shown, a helical formation 7 is provided to the outer surface of the drive shoe 3 and drive lugs 8 are provided on the inner face of the drive shoe housing. As such as the drive cylinder urges the shoe 3 to move axially within the drive shoe housing 4, the drive lugs 8 and helical formation 7 engage thereby rotating the shoe. The drive shoe housing is prevented from rotating due to the anti rotation lugs 9 provided between the outer surface of the drive shoe housing and the conductor pipe.

Figure 2 shows the wedge-like inclined face 11 of the drive shoe 3, the helical formation 7 being formed on the cylindrical section of the drive shoe.

Figure 3a to 3d different arrangements for ensuring the face area of the shoe 3 is fully exposed from the end of the conductor pipe, for different rotational orientations of the shoe. For example, in Figure 3a the tool face is at 360 degrees, whilst in Figure 3b the tool face has been rotated by 90 degrees. In order to ensure the face is maintained fully exposed at the end of the conductor pipe, a combination of an extension of the second drive cylinder 6 and a retraction of the first drive cylinder 5 is carried out. The extension of the second drive cylinder hence rotates the drive shoe 3 relative to the drive shoe housing 4, but this also extends the shoe outwardly relative to the drive shoe housing 4. To account for this outward movement of the drive shoe, the first drive cylinder is retracted, in order to maintain the axial position of the drive shoe relative to the conductor pipe 2.

Figures 3c and 3d show further iterations as the shoe is rotated further to 180 degrees and then 360 degrees. As these rotations would further extend the drive shoe axially out from the conductor pipe 2, the first drive cylinder is activated to retract the drive shoe housing 4 by an appropriate amount to ensure the drive shoe is maintained at the desired axial position in relation to the conductor pipe.

Figures 3e to 3h show a corresponding set of rotational iterations of the drive shoe 3, but where the drive shoe is positioned relative to the conductor pipe such that only 50% of the face area of the shoe projects from the end of the conductor pipe 2. In this regard, the first and second drive cylinders can be activated in synchronization in order to maintain a relative axial position of the drive shoe 3 in relation to the conductor pipe 2, at different rotational orientations thereof.

The arrangements shown in Figures 3a to 3h show examples of rotational orientation and axial projection of the drive shoe 3 relative to the conductor pipe 2. It will be understood however that through control of the first and second drive cylinders 5, 6, the rotational orientation and relative axial projection can be adjusted as desired according to requirements. In so doing, the apparatus affords active directional adjustment of an offshore conductor casing as it is being driven below the mud-line of the substratum.

In the example shown, the helix angle of the helical formation is 20 degrees. This affords a mechanical advantage of 2.7 with a force to rotate of 1782 mt. This is based on a shoe having a 23.5” cylinder diameter and a helix length of 5.2 m and a Torque at 660 mt (1 455MMIb) of 3.9 MMft-lb.

The shoe has a 660 mt extend and 500mt retract force at 3500 psi.

A table of alternative possible options for the apparatus is given below:-

The activation of the various components of the apparatus can be controlled using conventional means, and can be controlled automatically by way of suitable downhole sensing apparatus or topside under the control of operators.

Claims

1. Apparatus for effecting a change in direction during driving of a tubular (2) into a formation to establish a wellhead, that apparatus comprising a drive shoe (3) extendable from within a tubular, the drive shoe having a deflection surface, wherein the apparatus further comprises drive means (5, 6, 7, 8, 9) for extending and retracting the drive shoe relative to the tubular and for rotating the drive shoe relative to the tubular.

2. Apparatus according to claim 1, wherein the drive means comprises translation means (7,8) for translating a linear movement of the drive shoe (3) into a rotation of the drive shoe.

3. Apparatus according to claim 2, wherein the drive means comprises first and second actuators (5,6), the first actuator (5) being for moving a drive shoe housing (4) axially relative to the tubular, and the second actuator (6) being for moving the drive shoe linearly with respect to the drive shoe housing (4), the translation means (7,8) translating such linear movement of the drive shoe into rotation.

4. Apparatus according to claim 2 or 3, wherein the translation means (7,8) comprises a helical formation which extends around one of the outer surface of the drive shoe (3) and an inner surface of the drive shoe housing (4).

5. Apparatus according to claim 4, wherein the translation means (7,8) further comprises one or more drive lugs (8) provided on the other of outer surface of the drive shoe (3) and an inner surface of the drive shoe housing (4).

6. Apparatus according to claim 5, wherein the one or more drive lugs engage with the helical formation.

7. Apparatus according to any one of claims 4 to 6, wherein the angle of the helix is from 5 to 45 degrees.

8. Apparatus according to claim 7, wherein the angle of the helix is from 15 to 25 degrees.

9. Apparatus according to any one of claims 3 to 8, wherein the first actuator comprises a first hydraulic piston chamber with a first piston reciprocating within the first chamber.

10. Apparatus according to any one of claims 3 to 9, wherein the second actuator comprises a second hydraulic piston chamber with a second piston reciprocating within the second chamber.

11. Apparatus according to any preceding claim, wherein the drive shoe has a generally solid rod-like configuration with a wedge-like inclined surface which serves as a deflector surface when offered to a formation.

12. Apparatus according to any one of claims 3 to 11, wherein the first and second actuators (5,6) are synchronised for affording rotation of the drive shoe (3) at a desired axial extension of the drive shoe.

13. Apparatus according to any one of claims 3 to 12, further comprising sealing means between the drive shoe housing and the tubular, and between the drive shoe housing and the drive shoe for preventing ingress of soil into the apparatus.

14. A recoverable tool assembly for directing driving of a tubular into a formation which comprises a tubular and an apparatus according to any of claims 1-12 mounted therein, the apparatus further comprising radially deployable grippers for holding the apparatus within the tubular to be driven into a formation.

15. Apparatus for effecting a change in direction during driving of a tubular into a formation to establish a wellhead, that apparatus comprising a drive shoe extendable from within a tubular, the drive shoe being housed in a drive shoe housing movably mounted in the tubular, the apparatus further comprising drive means for extending the drive shoe, the drive means comprising first and actuators for moving the drive shoe housing and the drive shoe respectively, the first actuator moving the drive shoe housing linearly with regard to the tubular and the second actuator moving the drive shoe helically with regard to the drive shoe housing, the first and second actuators being synchronized so that the drive shoe can be rotated whilst being maintained at a desired extended axial position relative to the tubular.

16. A method of effecting a change in direction during driving of a tubular into a formation to establish a wellhead, using the apparatus or assembly of any preceding claim, the method comprising: positioning the apparatus downhole at the formation; driving the tubular into the formation; and actuating the drive means for extending and retracting the drive shoe relative to the tubular and for rotating the drive shoe relative to the tubular to a desired extension and rotational position of the drive shoe relative to the tubular.