NO346836B1

NO346836B1 - Orientation system for directional drills and method for orientation or re-orientation of a direction drill

Info

Publication number: NO346836B1
Application number: NO20200812A
Authority: NO
Inventors: Thomas Bjørgen
Original assignee: Devico As
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2023-01-23
Also published as: NO20200812A1

Description

Orientation system for directional drills and method for orientation or re-orientation of a directional drill

The present invention is related to an orientation system for directional drills, according to the preamble of claim 1.

The present invention is also related to a method for orientation or re-orientation of a directional drill according to the preamble of claim 7.

The present invention is especially related to the use of a retrievable inner assembly for controlling the orientation system for orientation or re-orientation of the directional drill.

Background

A directional drill is a type of rock drill where the drill bit is pointed or pushed in a controlled direction. A wireline system is used to retrieve core samples and/or orientation instrumentation from the directional drill.

To achieve deflection the directional drill has a device or system that controls the direction the drill bit is oriented. Some systems rely on a mechanical anti-rotation device that grips into the borehole wall by the force of pistons, springs, drilling fluid or other. An example of such anti-rotation device is known from US6516900 B1, describing a directional drill using a restriction to build up pressure inside the anti-rotation device. The pressure expands a packer assembly that again acts on a system gripping the borehole wall. Connected to the anti-rotation device is a deflection system, while a driveshaft system rotates freely inside the anti-rotation device. The driveshaft system is connected to the drill string at the upper end and the drill bit at the lower end.

In order to set the drilling direction of the directional drill, the anti-rotation device and deflection assembly must be rotated and set in an orientation corresponding to the planned drilling direction before drilling can be initiated. In order to achieve this a system that connects the stationary part (anti-rotation device and deflection assembly) with the rotating part (drill string and drill bit) is needed.

An early version of such orientation system consists of a share pin. As the directional drill or device is lowered into the borehole, the stationary and rotating parts are connected by a metallic pin. Upon arrival at the bottom of the borehole, the orientation is measured, and the directional drill is rotated according to the planned orientation. As the anti-rotation device is activated and drilling initiated, the shear pin will break and allow relative rotation between the two parts. This system is still in use today in whipstocks and other one-time direction tools. However, it does not allow for the orientation to be checked or adjusted and is such not suitable for continuous directional systems where the directional drill remains at the bottom of the hole for a long duration of time.

In US6516900 B1 the orientation system consists of a drill fluid pressure operated piston system that opens to allow relative rotation at high pressure and closes at low pressure. This system is suited for continuous directional drills but has the disadvantage of requiring accurate pressure readings while also being challenging to use in drill hole conditions without fluid return where the pressure inside the directional drill cannot be lowered to the required level.

Another system, as described in patent application NO20171838 A1, uses a one-way clutch system between the stationary and rotating part. As the drill string is rotated in the drilling direction (clockwise), relative rotation between the two parts are allowed, while when rotated in the opposite direction (anti-clockwise), the two parts locks together by the clutch. This system is also suited for continuous directional drills but has major disadvantages in deeper or high torque holes where the anti-clockwise rotation may cause drill string threads to open and prevent re-orientation.

In WO2005100734 A1 is described a system for directional drilling within a wellbore including a drill string having an upper portion, a lower portion, a bent motor coupled to the lower portion, and a drill bit coupled to the bent motor, as well as a clutch assembly disposed between the upper portion and lower portion. The clutch assembly is operable to disengage the upper portion and lower portion of the drill string and allowing the upper portion to rotate while the lower portion does not rotate.

It is thus a need for an orientation system for directional drills and a method for orientation or reorientation of a directional drill solving the issues of the mentioned prior art systems.

Object

The main object of the present invention is to provide an orientation system for directional drills and a method for orientation or re-orientation of a directional drill partly or entirely solving the drawbacks and lacks of prior art solutions.

An object of the present invention is to provide an orientation system and method enabling the use of a retrievable inner assembly for activation and deactivation of the orientation system.

It is an object of the present invention to provide an orientation system and method enabling both initial orientation and re-orientation at any time.

An object of the present invention is to provide a robust and accurate orientation system and method for directional drills.

It is an object of the present invention to provide an orientation system and method that are not affected by ground water level or pump and pressure gages.

A further object of the present invention is to provide an orientation system and method not requiring rotation in opposite direction as the drilling rotation.

Further objects of the present invention will appear from the following description, claims and attached drawings.

The invention

An orientation system for directional drills according to the present invention is defined by the technical features of claim 1. Preferable features of the system are described in the dependent claims.

A method for orientation or re-orientation of a directional drill according to the present invention is defined by the technical features of claim 7. Preferable features of the method are described in the dependent claims.

An orientation system according to the present invention comprises a lock and release coupling assembly arranged in a directional drill that is controllable by a retrievable inner assembly.

The lock and release coupling assembly is adapted to be activated in the absence of a retrievable inner assembly preventing relative movement between stationary and rotating parts of the directional drill and deactivated when the inner assembly is present in the directional drill allowing relative rotation between stationary and rotating parts of the directional drill.

According to the present invention, the lock and release coupling assembly comprises a first coupling member and a second coupling member adapted for mutual engagement.

According to the present invention, the first coupling member is arranged movable in longitudinal direction of the directional drill into engagement with the second coupling member and out of engagement with the second coupling member and vice versa.

In accordance with the present invention the lock and release coupling assembly comprises at least one pretension device providing a pretension force on the first coupling member. According to one embodiment of the present invention, the at least one pretension device holds the first coupling member in engagement with the second coupling member with a pretension force.

According to the present invention, the lock and release coupling assembly comprises a deactivation assembly or member connected to the first coupling member for transferring axial movement of the retrievable inner assembly onto the first coupling member. According to one embodiment of the present invention, the axial movement of the deactivation assembly or member in the directional drill moves the first coupling member out of engagement with the second coupling member.

In accordance with a further embodiment of the present invention the lock and release coupling assembly comprises a tubular shaft adaptor adapted for allowing the first coupling member to move axially in the lock and release coupling assembly and preventing it from rotation in the lock and release coupling assembly.

According to one embodiment of the present invention, the first and second coupling members are provided with splines or teeth at engaging surfaces thereof, wherein the conical splines or teeth are inclined in opposite directions.

According to a further embodiment of the present invention, to maximize the contact area and secure smooth and accurate engagement, the splines or teeth are designed with a conical shape. A high spline tooth count further improves engagement and secures high accuracy.

In accordance with a further embodiment of the present invention, the first and second coupling members are provided with at least one corresponding projection and/or at least one recess at engaging surfaces thereof.

The first coupling member is thus loosely mounted to the shaft coupling/shaft adaptor where it is allowed to move axially to compress the spring, but not rotate.

Accordingly, by the present invention is achieved a robust and accurate orientation and reorientation system for directional drills.

The first coupling member is designed to allow a slight tilting to compensate for any misalignment between the first and second coupling member engagement surfaces and thereby securing correct and full contact between them.

The orientation system is controlled by absence or presence of the retrievable inner assembly in the directional drill. When the retrievable inner assembly is locked in place inside the directional drill, the orientation system according to the present invention is deactivated to allow relative rotation between the stationary and rotating parts.

As the retrievable inner assembly lands and locks in place in the directional drill, the first coupling member via the deactivation assembly or member is pushed forwards and the at least one pretension device is compressed. The retrievable inner assembly is preferably locked in place by latch means known from standard wireline core drilling technology. The first and second coupling members are now disengaged, and orientation system deactivated.

When the retrievable inner assembly is retrieved from the directional drill, the orientation system is activated due to the pretension force in the at least one pretension device that moves the first coupling member back into engagement with the second coupling member locking the stationary and rotating parts again.

As the first and second coupling member are engaged and the orientation system activated, the stationary part of the directional drill will rotate along with the drill string. The drill string may now be rotated slowly by the drilling machine until the correct drill bit deflection orientation has been achieved.

After the desired orientation is achieved the retrievable inner assembly can be inserted into the directional drill, disengaging the first and second coupling members, thus deactivating the orientation system and allow drilling with relative rotation between the stationary and rotating parts of the directional drill.

The present invention is also related to a method for orientation or re-orientation of a directional drill by using the orientation system according to the present invention.

A method according to the present invention for orientation or re-orientation of a directional drill provided with an orientation system as described above, comprises introducing a retrievable inner assembly into the directional drill and using the retrievable inner assembly to apply an axial movement of a first coupling member in relation to a second coupling member via a deactivation assembly or member deactivating the orientation system and allowing relative rotation between stationary and rotating parts of the directional drill, and retrieving the retrievable inner assembly from the directional drill and using at least one pretension device providing a pretension force applying axial movement of the first coupling member into engagement with the second coupling member activating the orientation system and preventing relative rotation between stationary and rotating parts of the directional drill.

In a further embodiment of the method according to the present invention, the method comprises retaining the orientation system in activated position by a pretension force.

According to a further embodiment of the present invention, the method comprises, in activated position, using a drilling machine to rotate the directional drill to correct drill bit deflection orientation.

The method according to the present invention comprises using the pretension force of at least one pretension device to apply an axial movement of a first coupling member in relation to a second coupling member of the orientation system to achieve engagement of the first and second coupling member and activation of the orientation system.

The orientation system according to the present invention solves the known issues with prior art.

The orientation system according to the present invention can be used for both initial orientation and re-orientation at any time.

A further advantage with the present invention is that the orientation system is not affected by ground water level, pump and pressure gages, and does not require rotation in opposite direction as the drilling rotation.

Further preferable features and advantageous details of the present invention will appear from the following example description, claims and attached drawings.

Example

The present invention will below be described in further detail with references to the attached drawings, where

Fig.1 is a principle drawing of a directional drill according to prior art,

Fig.2 is a principle drawing of a retrievable inner assembly according to prior art,

Fig.3 is a principle drawing of a directional drill according to the present invention,

Fig.4a-b are principle drawings of a lock and release coupling assembly for an orientation system according to the present invention,

Fig.5a-e are principle drawings of a second embodiment of a lock and release coupling assembly for an orientation system according to the present invention,

Fig.6a-b are principle drawings of a third embodiment of a lock and release coupling assembly for an orientation system according to the present invention, and

Fig.7a-b are principle drawings of a fourth embodiment of a lock and release coupling assembly for an orientation system according to the present invention,

Reference is now made to Figure 1 illustrating an example of a directional drill 10 according to prior art, wherein the directional drill 10 comprises numerous parts in the longitudinal direction forming the directional drill 10, also referred to as a bottom hole assembly. The directional drill 10 comprises, in order from below and up, a foremost diamond drill bit 20 with a reamer 30, drive shaft connection assembly 40, a thrust bearing assembly 50, a lower outer tube 60, a deflection assembly 70, an upper outer tube 80, stabilizer assembly 90, rotation preventing device 100, an optionally magnetic orientation assembly 150 and an orientation and connector assembly 200. The thrust bearing assembly 50, lower outer tube 60, deflection assembly 70, stabilizer assembly 90, rotation preventing device 100 and optional magnetic orientation assembly 150 being arranged for accommodating an inner drive shaft 110 (shown e.g. in parts in Fig. 6a-c and 7a-c) for driving the drill bit 20, wherein the drive shaft 110 is transferring feed and rotation forces from a drill rig onto the drill bit 20.

The rotation preventing device 100, shown in Figure 1, is e.g. formed by a packer pipe 101 including a packer housing having at least one pressure pad or packer element 102, lower 103 and upper 104 end pieces, respectively, and front 105 and rear 106 stuffing boxes, respectively. Accordingly, the rotation preventing device 100 is provided with sealings and connections at both sides thereof enabling arrangement into the directional drill 10. The at least one pressure pad or packer element 102 of the rotation preventing device 100 is arranged for, at activation, to extend out of the packer pipe 101 and into engagement with a borehole wall for locking rotation of the rotation preventing device 100, as well as parts of the directional drill 10 between the orientation and connector assembly 200 and the drill bit 20, in relation to the borehole wall, the rotation preventing device 100 being arranged to be displaced axially along the borehole wall during drilling. The at least one pressure pad or packer element 102 is/are arranged to be pressed outward to the borehole wall by means of fluid pressure from a valve assembly 600 of a retrievable inner assembly 300 when supplied with drilling fluid into the valve assembly 600/directional drill 10.

The drill bit 20 may be a full-face drill bit or arranged for drilling a bore core. The drive shaft 110 as well as the function of such a directional drill 10 is well described in prior art, such as e.g. in NO316286B1, the enclosure of which is included herein by reference, and need no further description herein. A drill bit for drilling a bore core is shown in NO316286B1.

Reference is now made to Figure 2 showing a principle drawing of a retrievable inner assembly 300 suitable for use in the present invention. The retrievable inner assembly 300 comprises numerous parts in the longitudinal direction. The retrievable inner assembly 300 according to the shown embodiment comprises, in order from top and downwards, a head assembly 400 comprising a spear head 401 for connection of the retrievable inner assembly 300 to a wireline with a quick snap connection (not shown), an optional instrumentation assembly 500 and a valve assembly 600. The retrievable inner assembly 300 is well known for a skilled person and requires no further description herein.

Reference is now made to Figure 3 showing a principle drawing of a directional drill 10 according to the present invention. According to the present invention, the directional drill 10 comprises an orientation system comprising a lock and release coupling assembly 700 arranged in the directional drill 10 above the rotation preventing device 100, which lock and release coupling assembly 700 is adapted to be activated and deactivated by a retrievable inner assembly 300. According to the present invention, when the retrievable inner assembly 300 is locked in place inside the directional drill 10, the orientation system is deactivated to allow relative rotation between stationary and rotating parts of the directional drill 10. When the retrievable inner assembly 300 is retrieved from the directional drill 10, the orientation system is activated and locks the stationary and rotating parts of the directional drill 10 to allow orientation of the directional drill 10.

Reference is now made to Figs. 4a-b showing simplified principle drawings of a lock and release coupling assembly (LRCA) 700 for the orientation system according to the present invention, wherein Fig.4a is a cross-sectional view of the LRCA 700 in a locked position and Fig.4b is a crosssectional view of the LRCA 700 in an unlocked position. According to the present invention, the LRCA 700 is adapted to be activated in the absence of a retrievable inner assembly 300. The LRCA 700 according to the present invention comprises first 720 and second 760 coupling members adapted for mutual engagement. When a retrievable inner assembly 300 is inserted into the directional drill 10, it according to the present invention, engages one of the coupling members of the LRCA 700 via a deactivation assembly 730 for transferring axial movement of the retrievable inner assembly 300 on one of the coupling members 720, 760 of the LRCA 700, which in the shown embodiment is the first coupling member 720 and thus moves the first 720 and second 760 coupling members out of engagement with each other.

To ensure that the first 720 and second 760 coupling members are engaging each other when the retrievable inner assembly 300 is not present in the directional drill 10, the LRCA 700 is provided with a pretension device 750, such as a spring, providing a pretension force on one of the coupling members 720, 760, in the shown embodiment the first coupling member 720, such that in the absence of the retrievable inner assembly 300 in the directional drill 10, the pretension device 750 will move the first coupling member 720 axially into engagement with the second coupling member 760.

Accordingly, in initial state, without a retrievable inner assembly 300 in the directional drill 10, the LRCA 700 is in a locked position/state wherein the pretension force ensure engagement of the first 720 and second 760 coupling member, as shown in Fig. 4a. The orientation system is thus in an activated state, wherein relative movement between stationary and rotating parts of the directional drill 10 is prevented.

When a retrievable inner assembly 300 is inserted into the directional drill 10 and lands on the deactivation assembly 730, as shown in Fig. 4b, the deactivation assembly 730 is pushed/moved axially and pushes/moves the first coupling member 720 axially and out of engagement with the second coupling member 760. When the retrievable inner assembly 300 is locked in the directional drill 10, the LRCA 700 is thus in an unlocked position/state, wherein the orientation system is deactivated allowing relative rotation between the stationary and rotating parts of the directional drill 10 and thus allow drilling with relative rotation between the stationary and rotating parts of the directional drill 10.

Reference is now made to Figs.5a-e showing principle drawings of a second embodiment of the lock and release coupling assembly (LRCA) 700 for the orientation system according to the present invention, the LRCA 700 comprising numerous parts in the longitudinal direction forming the LRCA 700. Fig.5a is a cross-sectional view of the LRCA 700 in a locked position, Fig.5b is a cross-sectional view of the LRCA 700 in an unlocked position, Fig.5c is an exploded view of the LRCA 700, Fig.5d is principle drawing of an inner spline ring and Fig.5e is a principle drawing of an outer spline ring.

According to the second embodiment of the LRCA 700, it comprises a tubular shaft coupling 710 with a first and second end, provided with interior threads 711 at a section facing the first end and exterior threads 712 at a section facing the second end. The tubular shaft coupling 710 is formed by sections in longitudinal direction thereof with different interior and exterior diameter, namely first, second, third and fourth sections. The first section extends with a first interior and first exterior diameter in longitudinal direction from the first end, which first section has an inner diameter larger than the inner diameter of the remaining section for accommodating components of the LRCA 700, further described below, and an external diameter corresponding to the external diameter of other components of the directional drill 10. The tubular shaft coupling 710 extends in longitudinal direction from the first section with a second section having a second interior diameter and second exterior diameter, wherein the second interior and second exterior diameter are smaller than the interior and exterior diameter of the first section, respectively.

The tubular shaft coupling 710 further extends in longitudinal direction with a third section with a third exterior diameter that is smaller than the exterior diameter of the second section and with an interior diameter as the second section. The tubular shaft coupling 710 further extends in longitudinal direction with a fourth section with a fourth exterior diameter that is smaller than the exterior diameter of the third section and with an interior diameter as the second and third section. Accordingly, the tubular shaft coupling 710 is provided with a stepped interior diameter and a multistepped exterior diameter from an initial (larger) diameter to a final (smaller) diameter. The purpose of the stepped exterior and interior diameter will be further described below. The exterior threads 712 is a part of the fourth section facing the second end.

The LRCA 700 further comprises a first coupling member 720 (inner coupling member), which in the second embodiment is formed by a main body 721, which in the second embodiment is mainly tubular, with a first and second end. The first coupling member 720 is at the first end provided with a conical spline ring 722 arranged around the exterior circumference thereof.

The LRCA 700 further comprises a deactivation assembly 730 comprising a sliding sleeve 731 adapted for movable arrangement in longitudinal direction interior in the first section of the tubular shaft coupling 710. The deactivation assembly 730 further comprises longitudinally extending release bolts 732 in engagement with the sliding sleeve 731 at a first end and in engagement with the first coupling member 720 at a second (other) end.

The tubular shaft coupling 710 is provided with longitudinally extending through holes 713, extending from the interior of the first section and ending in longitudinally exterior recesses 714 in the fourth section of the tubular shaft coupling 710 adapted for accommodating the mentioned release bolts 732.

The mentioned release bolts 732 is at the second end thereof, i.e. the end facing the sliding sleeve 731, extending through a sealing house 715 mounted interior in the first section of the tubular shaft coupling 710 and into engagement with the sliding sleeve 731.

The LRCA 700 further comprises a tubular shaft adaptor 740 with an interior diameter adapted the exterior final diameter of the tubular shaft coupling 710, wherein the tubular shaft adaptor 740 is provided with interior threads 741 adapted the exterior threads 712 of the tubular shaft coupling 710, for detachable attachment of the two parts.

Exterior surface of the tubular shaft adaptor 740 is formed by two sections of different exterior diameter, wherein the section facing the tubular shaft coupling 710 has a smaller exterior diameter than the section facing away from the tubular shaft coupling 710.

The first coupling member 720 has an interior diameter adapted the section of the tubular shaft adaptor 740 facing the tubular shaft coupling 710 for movable arrangement in longitudinal direction thereof. The conical spline ring 722 of the first coupling member 720 is formed by conical splines or teeth 723 extending with expanding height in their longitudinal direction from the first end of the first coupling member 720 and a distance towards the second end of the first coupling member 720, i.e. extending with expanding height from the mentioned first end.

In the second embodiment, the first coupling member 720 is further provided with interior projections 724 extending from the interior circumference of the mentioned first end and a distance towards the centre of the mentioned first end of the first coupling member 720. The shape and size of the projections 724 is adapted the mentioned longitudinal recesses 714 of the tubular shaft coupling 710, thus allowing the first mentioned coupling member 720 to move in longitudinal direction of the tubular shaft coupling 710, while rotation is prevented. The mentioned projections 724 also provides contact surfaces for the mentioned release bolts 732 extending in longitudinal direction of the tubular shaft coupling 710.

The LRCA 700 further comprises a helical spring 750 arranged enclosing the section of the tubular shaft adaptor 740 with the smallest exterior diameter. One end of the mentioned helical spring 750 is in engagement with rear end the mentioned first coupling member 720, i.e. at the opposite side of side with the spline ring 722, and at the other end in engagement with a distance or stop ring 751 for the helical spring 750.

The LRCA 700 further comprises a second coupling member 760 (outer coupling member), which in the second embodiment is formed by a mainly tubular body 761 with a first and second end. The second coupling member 760 is at the first end provided with a conical spline ring 762 arranged around interior circumference thereof. The second coupling member 760 is formed by first and second sections in longitudinal direction thereof with different interior and exterior diameter. The first section is extending in longitudinal direction from the first end with a first interior and first exterior diameter, where the inner diameter is adapted the exterior diameter of the second section of the tubular shaft coupling 710 for arrangement to the tubular shaft coupling 710 and an exterior diameter corresponding to the external diameter of other components of the directional drill 10. The second section is extending in longitudinal direction from the first section and to the second end with an exterior diameter smaller than the exterior diameter of the first section and thus form an annular recess at exterior surface of the second coupling member 760, the purpose of which will be described in more detail below.

The conical spline ring 762 is provided with conical splines or teeth 763 extending with their longitudinal direction with expanding height from the interior surface of the second coupling member 760 in longitudinal direction from the second end, i.e. extending with expanding height a distance from the second end towards the first end. Accordingly, the conical spline ring 762 exhibit an opposite shape than the conical spline ring 722 of the first coupling member 720 and the two spline rings 722, 762 are thus adapted each other.

The interior diameter of the second section of the second coupling member 760 is smaller than the interior diameter of the first section, but larger than the interior diameter formed by the splines or teeth 763 of the spline ring 762.

The LRCA 700 further comprises an outer tube 770 having a first and second end, the outer tube 770 is adapted to enclose parts of the tubular shaft adaptor 740. The outer tube 770 comprises a stepped interior diameter in longitudinal direction decreasing from a first end to a second end via three sections, namely first, second and third sections. The interior diameter of the first section extending in longitudinal direction from the first end is adapted the exterior diameter of the annular recess of the second coupling member 760 for arrangement thereon, wherein the outer tube 770 and second coupling member 760 are provided with corresponding attachment means, such as screws and holes or corresponding threads, for fixation of the two parts together. The interior diameter of the first section has an extension in longitudinal direction that allows the first coupling member 720 to move a required distance in longitudinal direction of the LRCA 700.

The second section extends in longitudinal direction of the outer tube 770 with a second interior diameter from the first section, wherein the second interior diameter is smaller than the interior diameter of the first section. The interior diameter of the second section is adapted to enclose the section of the tubular shaft adaptor 740 with the smallest exterior diameter and with the spring 750 and first coupling member 720 arranged thereon, i.e. the part of the first coupling member 720 without the spline ring 721, with a spacing to allow the spring 750 to compress and decompress freely as well as allowing the first coupling member 720 to move a required distance in longitudinal direction.

The third section extends in longitudinal direction of the outer tube 770 with a third interior diameter from the second section and to the second end of the outer tube 770, wherein the third interior diameter is smaller than the second interior diameter. The interior diameter of the third section is adapted to enclose the section of the tubular shaft adaptor 740 with the largest exterior diameter with a spacing therebetween.

The outer tube 770 is further at the second end provided with interior threads 771 for arrangement to adjoining components of the directional drill 10.

In the spacing between the outer tube 770 and the section of the tubular shaft adaptor 740 with the largest exterior diameter, as well as in the spacing between the second coupling member 760 and the second section of the tubular shaft coupling 710, are preferably arranged at least one radial bearing 780.

Accordingly, at assembly of the LRCA 700, the second coupling member 760 will be fixed while the first coupling member 720 will be loosely arranged to the shaft coupling 710 and thus movable in longitudinal direction, while prevented from rotation, wherein the first coupling member 720 due to the pretension force of the spring 750 will be in engagement with the second coupling member 760 when not subject to exterior affection by a retrievable inner assembly 300, further described below.

The use of conically shaped spline rings 722, 762 on the engaging surfaces of the first 720 and second 760 coupling members results in maximum contact area and further ensures smooth and accurate engagement. Further, by using a high spline or tooth count one further improves engagement and secures high accuracy.

It will be preferable that the first coupling member 720 is designed to allow a slight tilting to compensate for any misalignment between the first 720 and second 760 coupling member engagement surfaces and thereby securing correct and full contact between them.

Reference is now made to Fig. 5a, showing a principle drawing of the LRCA 700 in a locked position/state. Accordingly, in initial state, without a retrievable inner assembly 300 in the directional drill 10, the LRCA 700 is in a locked position/state wherein the spring 750 holds the movable first coupling member 720 in engagement with the second coupling member 760 with a pretension force. The orientation system is thus in an activated state, wherein relative movement between stationary and rotating parts of the directional drill 10 is prevented.

As the first 720 and second 760 coupling members are engaged and the orientation system activated, the stationary parts of the directional drill 10 will rotate along with the drill string. The drill string may now be rotated slowly by a drilling machine until the correct drill bit deflection orientation has been achieved.

Reference is now made to Fig. 5b, showing a principle drawing of the LRCA 700 in an unlocked position/state. When a retrievable inner assembly 300 is inserted into the directional drill 10 and lands on the deactivation assembly 730, the deactivation assembly 730 is pushed/moved axially and pushes/moves the first coupling member 720 axially and out of engagement with the second coupling member 760. When the retrievable inner assembly 300 is locked in the directional drill 10, the LRCA 700 is thus in an unlocked position/state, wherein the orientation system is deactivated allowing relative rotation between the stationary and rotating parts of the directional drill 10 and thus allow drilling with relative rotation between the stationary and rotating parts of the directional drill 10.

Reference is now made to Figs. 6a-c showing a third embodiment of an LRCA 700 comprising numerous parts in the longitudinal direction forming the LRCA 700, wherein Fig. 6a is a principle drawing of the LRCA 700 in locked position, Fig. 6b is a principle drawing of the LRCA 700 in an unlocked position and Fig.6c is an exploded view of the LRCA 700.

The LRCA 700 according to the third embodiment of the present invention is forming a clutch system. The LRCA 700 comprises a tubular shaft coupling 710 and an outer tube 770 as for the second embodiment. The tubular shaft coupling 710 is provided with interior threads 711 at a first end and exterior threads 712 at a recessed part of the exterior surface at a second end.

The LRCA 700 further comprises a tubular shaft adaptor 740 formed by a first and second section with different interior and exterior diameter. The first section extends in longitudinal direction from a first end of the tubular shaft adaptor 740 with a first exterior diameter and first interior diameter and wherein the first section is provided with interior threads 741 at a part of the interior surface facing the first end. The second section of the tubular shaft adaptor 740 extends in longitudinal direction of the tubular shaft adaptor 740 with a second exterior and second interior diameter from the first section to a second end of the tubular shaft adaptor 740. The exterior and interior diameters of the second section have a smaller diameter than the exterior and interior diameters of the first section, respectively. The second section is further provided with exterior longitudinally extending teeth or splines 742 at a part of the second section extending a distance from the first section. The purpose of the longitudinally extending splines or teeth 742 will be further described below. The second section is further provided with recessed interior threads 743 at the part of the second section closest to the second end adapted for arrangement to the drive shaft 110 of the directional drill 10 via corresponding exterior threads of the drive shaft 110.

The LRCA 700 further comprises a first coupling member 720 (inner coupling member) formed by a main body 721, which is this embodiment is ring-shaped, with a first and second end. The main body 721 is in the third embodiment provided with interior longitudinally extending splines or teeth 724 adapted the exterior longitudinally extending splines or teeth 742 of the tubular shaft adaptor 740. The first coupling member 720 is accordingly arranged movable in longitudinal direction of the tubular shaft adaptor 740, but rotation about the tubular shaft adaptor 740 is prevented. The first coupling member 720 is further at the exterior circumference thereof provided with at least two projections 725, in the shown embodiment arranged diagonally about the exterior circumference of the main body 721. The purpose of the at least two projections 725 will be further described below.

The LRCA 700 comprises, as the second embodiment, a deactivation assembly 730 comprising a sliding sleeve 731 adapted for movable arrangement in longitudinal direction interior in the tubular shaft adaptor 740. The deactivation assembly 730 further comprises longitudinally extending release bolts 732 in engagement with the sliding sleeve 731 at a first end and in engagement with the first coupling member 720 at a second (other) end. The mentioned release bolts 732 extend from the sliding sleeve 731 in the tubular shaft adaptor 740 and via through holes 744 in the tubular shaft adaptor 740 to/into engagement with the first coupling member 720.

The LRCA 700 further comprises a second coupling member 760 (outer coupling member) integrated in an outer tube 770 at the end of this facing the tubular shaft adaptor 740 and tubular shaft coupling 710. The second coupling member 760 comprises in the third embodiment at least two projections 764, in the shown embodiment arranged diagonally at interior circumference of the outer tube 770, wherein the spacing between the at least two projections 764 is adapted the shape and size of the projections 725 of the first coupling member 720.

The LRCA 700 further comprises, as the second embodiment, an helical spring 750 arranged enclosing the upper end of the drive shaft 110 and restricted by a spring sleeve or spring stopper 751 arranged on the drive shaft 110 at one end and in engagement with the first coupling member 720 at the other end, which spring 750 provides a pretension force acting on the first coupling member assembly 720. The spring sleeve or spring stopper 751 is e.g. arranged to the drive shaft 110 by means of corresponding threads.

The outer tube 770 is at the second end provided with interior threads 771 (see Fig.5a-c), as in the second embodiment, for arrangement to an adjoining components of the directional drill 10.

Reference is no made to Fig. 6a, showing a principle drawing of the LRCA 700 in a locked position/state. Accordingly, in initial state, without a retrievable inner assembly 300 in the directional drill 10, the LRCA 700 is in a locked position/state wherein the spring 750 holds the movable first coupling member 720 in engagement with the second coupling member 760 with a pretension force. The orientation system is thus in an activated state, wherein relative movement between stationary and rotating parts of the directional drill 10 is prevented.

As the first 720 and second 750 coupling members are engaged and the orientation system activated, the stationary parts of the directional drill 10 will rotate along with the drill string. The drill string may now be rotated slowly by a drilling machine until the correct drill bit deflection orientation has been achieved.

Reference is now made to Fig. 6b, showing a principle drawing of the LRCA 700 in an unlocked position/state. When a retrievable inner assembly 300 is inserted into the directional drill 10 and lands on the deactivation assembly 730, the deactivation assembly 730 is pushed/moved axially and pushes/moves the first coupling member 720 axially and out of engagement with the second coupling member 760. When the retrievable inner assembly 300 is locked in the directional drill 10, the LRCA 700 is thus in an unlocked position/state, wherein the orientation system is deactivated allowing relative rotation between the stationary and rotating parts of the directional drill 10 and thus allow drilling with relative rotation between the stationary and rotating parts of the directional drill 10.

Reference is now made to Figs. 7a-c showing a fourth embodiment of an LRCA 700 comprising numerous parts in the longitudinal direction forming the LRCA 700, wherein Fig. 7a is a principle drawing of the LRCA 700 in locked position, Fig. 7b is a principle drawing of the LRCA 700 in an unlocked position and Fig.7c is an exploded view of the LRCA 700.

The LRCA 700 according to the fourth embodiment of the present invention is forming a mechanical lock system. The LRCA 700 comprises a tubular shaft coupling 710 and an outer tube 770 as for the second and third embodiments. The tubular shaft coupling 710 is provided with interior threads 711 at a first end and exterior threads 712 at a recessed part of the exterior surface at a second end.

The LRCA 700 further comprises a tubular shaft adaptor 740 having a first and second end, which tubular shaft adaptor 740 is provided with a stepped interior and exterior surface formed by sections with different interior and exterior diameter. In the shown embodiment, the tubular shaft adaptor 740 comprises three sections, namely first, second and third section, with different interior and exterior diameter. The first section extends in longitudinal direction from the first end of the tubular shaft adaptor 740 with a first exterior diameter and first interior diameter, wherein the first section is provided with interior threads 741 adapted for arrangement to the tubular shaft coupling 710 via the exterior threads 712 thereon. The second section of the tubular shaft adaptor 740 extends in longitudinal direction of the tubular shaft adaptor 740 with a second exterior and second interior diameter from the first section, wherein the exterior and interior diameters of the second section are smaller than the exterior and interior diameter of the first section, respectively. The third section extends in longitudinal direction of the tubular shaft adaptor 740 with a third exterior diameter and third interior diameter, wherein the exterior and interior diameters of the third section are smaller than exterior and interior diameters of the second section, respectively. The third section is further provided with interior threads 743 at the part of the third section facing the second end adapted for arrangement to drive shaft 110 of the directional drill 10 via corresponding exterior threads of the drive shaft 110.

The tubular shaft adaptor 740 is further provided with oblong holes 745 arranged in the third section of the tubular shaft adaptor 740, wherein the longitudinal direction of the oblong holes 745 coincides with the longitudinal direction of the tubular shaft adaptor 740. The purpose of the oblong holes 745 will be further described below.

The LRCA 700 further comprises a first coupling member 720 (inner coupling member) comprising a main body 721, in the shown embodiment mainly tubular, having a first and second end. The first end is extending in circumferential direction with a curved profile in longitudinal direction of the main body 721 and thus forming a recess 726 in circumferential direction ending in a mainly perpendicular wall 727. Accordingly, the first end of the main body 721, i.e. the recess 726, extends in circumferential direction with a decreasing longitudinal length from top of the perpendicular wall 727 to the bottom of the perpendicular wall 727.

Interior diameter of the main body 721 is adapted the exterior diameter of the third section of the tubular shaft adaptor 740 for arrangement thereon. The main body 721 is further provided with through holes 728 in circumferential direction thereof adapted the oblong holes 745 arranged in the tubular shaft adaptor 740.

The LRCA 700 further comprises a deactivation member 730, which in the fourth embodiment comprises a tubular muleshoe centralizer 733 with a first and second end. The tubular muleshoe centralizer 733 is adapted to be accommodated in the tubular shaft coupling 710 and tubular shaft adaptor 740. According to the present invention the deactivation member 730 is arranged axially movable in the tubular shaft coupling 710 and tubular shaft adaptor 740. The muleshoe centralizer 733 is close to the second end provided with threaded holes 734 in circumferential direction, which threaded holes 734 are adapted the through holes 728 of the first coupling member 720 and the oblong holes 745 of the tubular shaft adaptor 740.

The deactivation member 730 further comprises attachments screw 735 for fixating the first coupling member 720 to the muleshoe centralizer 733 via the oblong holes 745. Accordingly, the first coupling member 720 is arranged movable in longitudinal direction of the LRCA 700 to the extent of the oblong holes 745 in longitudinal direction.

The LRCA 700 further comprises a second coupling member 760 (outer coupling member), which in the fourth embodiment is formed by a main body 761 with a first and second end. The second coupling member 760 is at a part of the exterior surface facing the second end provided with recessed exterior threads 765 adapted for attachment to the outer tube 770 via corresponding interior threads 772 at a first end thereof. The second coupling member 760 is further provided with an interior projection 766, arranged a distance from the first end and with a shape and size adapted the perpendicular wall 726 of the first coupling member 720.

The muleshoe centralizer 733 is further provided with a stepped exterior surface adapted the interior diameter of the tubular shaft coupling 710, tubular shaft adaptor 740 and second coupling member 760 for accommodation of the muleshoe centralizer 733 therein. According to the present invention it is formed an annular spacing 736 between the tubular shaft coupling 710 and the muelshoe centralizer 733 wherein an helical spring 750 is arranged enclosing the muleshoe centralizer 733. The spring 750 provides a pretension force on the muleshoe centraliser 733 and thus the first coupling member 720 fixed thereto.

The outer tube 770 is at the other end provided with interior threads 771 for arrangement to adjoining components of the directional drill 10.

Reference is now made to Fig. 7a, showing a principle drawing of the LRCA 700 in a locked position/state. Accordingly, in initial state, without a retrievable inner assembly 300 in the directional drill 10, the LRCA 700 is in a locked position/state wherein the spring 750 holds the movable first coupling member 720 in engagement with the second coupling member 760 with a pretension force. The orientation system is thus in an activated state, wherein relative movement between stationary and rotating parts of the directional drill 10 is prevented.

As the first 720 and second 750 coupling members are engaged and the orientation system activated, the stationary part of the directional drill 10 will rotate along with the drill string. The drill string may now be rotated slowly by a drilling machine until the correct drill bit deflection orientation has been achieved.

Reference is now made to Fig. 7b, showing a principle drawing of the LRCA 700 in an unlocked position/state. When a retrievable inner assembly 300 is inserted into the directional drill 10 and lands in the deactivation member 730, in this case the muleshoe stabilizer 733, the deactivation member 730 is pushed/moved axially and pushes/moves the first coupling member 720 axially and out of engagement with the second coupling member 760. When the retrievable inner assembly 300 is locked in the directional drill 10, the LRCA 700 is thus in an unlocked position/state, wherein the orientation system is deactivated allowing relative rotation between the stationary and rotating parts of the directional drill 10 and thus allow drilling with relative rotation between the stationary and rotating parts of the directional drill 10.

The fourth embodiment requires a rotational movement to ensure that the LRCA 700 is in a locked position/state after being in the unlocked position/state.

The technical features of the described embodiments may be combined or modified to provide other embodiments within the scope of the attached claims.

The above described embodiments only show some few examples of how a retrievable inner assembly 300 according to the present invention may be used to activate and deactivate the orientation system by axially moving the first 720 and second 760 coupling member out of engagement or into engagement by insertion or retrieval of the retrievable inner assembly 300, respectively.

Claims

1. Orientation system for directional drills (10), comprising a lock and release coupling assembly (700) arranged in the directional drill (10), the lock and release coupling assembly (700) comprising first (720) and second (760) coupling members adapted for mutual engagement, wherein the first coupling member (720) is movable in longitudinal direction of the directional drill (10) into and out of engagement with the second coupling member (760) and vice versa,

characterized in that the lock and release coupling assembly (700) comprises a deactivation assembly or member (730) connected to the first coupling member (720) and at least one pretension device (750) arranged to the first coupling member (720),

wherein the lock and release coupling assembly (700) is adapted to be activated in the absence of a retrievable inner assembly (300) in the directional drill (10) by the at least one pretension device (750) providing a pretension force applying axial movement of the first coupling member (720) into engagement with the second coupling member (760) preventing relative movement between stationary and rotating parts of the directional drill (10), and deactivated when a retrievable inner assembly (300) is present in the directional drill (100) by the deactivation assembly or member (730) transferring axial movement of the retrievable inner assembly (300) onto the first coupling member (720) and moving the first coupling member (720) out of engagement with the second coupling member (760) and allowing relative rotation between the stationary and rotating parts of the directional drill (10).

2. Orientation system according to claim 1, characterized in that the at least one pretension device (750) is a spring.

3. Orientation system according to claim 1, characterized in that the lock and release coupling assembly (700) comprises a tubular shaft adaptor (740) adapted for allowing the first coupling member (720) to move axially in the lock and release coupling assembly (700) and preventing it from rotation in the lock and release coupling assembly (700).

4. Orientation system according to claim 1, characterized in that the first (720) and second (760) coupling members are provided with conical splines (723, 763) or teeth at engaging surfaces thereof, wherein the conical splines (723, 763) or teeth are inclined in opposite directions.

5. Orientation system according to claim 1, characterized in that the first (720) and second (760) coupling members are provided with at least one corresponding projection (725, 764, 766) and/or at least one recess (726) at engaging surfaces thereof.

6. Orientation system according to claim 1, characterized in that the deactivation member (730) is a tubular muleshoe centralizer (733).

7. Method for orientation or re-orientation of a directional drill (10) provided with an orientation system comprising a lock and release coupling assembly (700) comprising first (720) and second (760) coupling members, adapted for mutual engagement, wherein the first coupling member (720) is movable in longitudinal direction of the directional drill (10) into and out of engagement with the second coupling member (760) and vice versa, characterized by introducing a retrievable inner assembly (300) into the directional drill (10) and using the retrievable inner assembly (300) to apply an axial movement of the first coupling member (720) in relation to the second coupling member (760) via a deactivation assembly or member (730) deactivating the orientation system and allowing relative rotation between stationary and rotating parts of the directional drill (10), and retrieving the retrievable inner assembly (300) from the directional drill (10) and using at least one pretension device (750) providing a pretension force applying axial movement of the first coupling member (720) into engagement with the second coupling member (760) activating the orientation system and preventing relative rotation between stationary and rotating parts of the directional drill (10).

8. Method according to claim 7, characterized by retaining the orientation system in activated position by a pretension force.

9. Method according to claim 7, characterized by, in activated position, using a drilling machine to rotate the directional drill (10) to correct drill bit deflection orientation.