GB2490534A

GB2490534A - A reaming device with a locking cutter

Info

Publication number: GB2490534A
Application number: GB1107504.1A
Authority: GB
Inventors: Alan Mackenzie
Original assignee: MACKENZIE DESIGN CONSULTANTS Ltd
Current assignee: MACKENZIE DESIGN CONSULTANTS Ltd
Priority date: 2011-05-05
Filing date: 2011-05-05
Publication date: 2012-11-07
Anticipated expiration: 2031-05-05
Also published as: GB2490534B; GB201107504D0

Abstract

A hole opener or reamer (10), for use in a downhole environment to enlarge a drilled hole, comprises an opener body (12) that includes a retention member (14) coupled therewith to retain a cutter (16) relative to the opener body. The retention member and the opener body cooperate with one another to define a locking chamber (18, figure 3a) that lies therebetween. The locking chamber confines movement of a locking member (26, 42) received therein relative to the opener body. The locking member includes one or more actuator members (28, 48), which may be screws, to move the locking member relative to the opener body. The locking member and one of the opener body and the retention member include formations that are cooperable with one another to drive the retention member and opener body into engagement upon movement of the locking member relative to the opener body caused by operation of the or each said actuator member to inhibit movement of the retention member relative to the opener body and thereby securely retain the cutter relative to the opener body.

Description

A HOLE OPENER

The invention relates to a hole opener for use in a downhole environment, and particularly a downhole environment in the oil and gas exploration and production industries, to enlarge a drilled hole.

Hole openers are typically mounted in a drill string directly above a drill bit and normally enlarge the drilled hole by a factor of two or more. A conventional hole opener comprises an opener body which has one or more retention members coupled therewith each of which retains a cutter relative to the opener body. Typically the cutter is a rotatable cutter, such as a rotating roller cone cutter, but a fixed cutter, i.e. a non-rotating cutter, may also be used.

In one form of conventional hole opener the or each retention member is fixedly secured to the opener body by welding.

The manufacture of such hole openers is challenging because complex and critical welding procedures must be adhered to in order to maintain mechanical integrity of the join between retention member and opener body without degrading the parent material or materials from which the retention member and opener body are formed.

These difficulties are exacerbated because of the large mass and size of the components to be welded. Also, necessary mechanical tolerances for the fit of subsequent components are difficult to maintain because of the shrinking and distortion arising from the welding and any subsequent remedial heat treatments.

A further, major drawback of welded hole openers is management of cracking during initial welding and subsequent maintenance operations, in which re-welding is often required. Such welding procedures induce stresses in the parent materials which cause cracks to form in and between the welded components. Such cracks cause the hole opener to fail and so limits the operational life of the entire tool.

There is, therefore, a need for a robust hole opener which is easy to manufacture and has an extended operational life.

According to an aspect of the invention there is provided a hole opener, for use in a downhole environment to enlarge a drilled hole, comprising an opener body including a *1 retention member coupled therewith to retain a cutter relative to the opener body, the retention member and the opener body cooperating with one another to define a locking chamber lying therebetween, the locking chamber confining movement of a locking member received therein relative to the opener body, the locking member including one or more actuator members to move the locking member relative to the opener body, the locking member and one of the opener body and the retention member including mutually engageable formations cooperable with one another to drive the retention member and opener body into engagement with one another on movement of the locking member relative to the opener body caused by operation of the or each said actuator member to inhibit movement of the retention member relative to the opener body and thereby securely retain the cutter relative to the opener body.

The provision of a locking member that is cooperable with one of the opener body and the retention member to drive the retention member and the opener body into engagement with one another obviates the need to weld these components to one another, and so simplifies manufacture of the hole opener and avoids the creation of operational-lifetime-limiting cracks in the hole opener.

In addition, the inclusion of mutually engageable formations on the locking member and one of the opener body and the retention member imparts a degree of mechanical advantage to the force generated by the or each actuator member to drive the retention member and the opener body into engagement with one another. As a consequence the retention member and opener body are driven together, and hence held together, with a greater force than is achievable by the actuator or other mechanical fastener acting alone. Holding the retention member and opener body together using such a high force results in a robust hole opener that has a high tolerance to adverse operating conditions.

Furthermore, the provision of a locking chamber in which the locking member is received protects the locking member from external loading and abrasion applied to an exterior of the hole opener, and so reduces the risk of the locking member becoming damaged during operation of the hole opener. As such the operational lifetime of the hole opener is further increased.

Preferably the retention member and the opener body cooperate with one another to define first and second locking chambers lying therebetween, the first locking chamber receiving and confining a first locking member and the second locking chamber receiving and confining a second locking member.

The inclusion of first and second locking chambers and associated locking members introduces a degree of redundancy into the securing of the retention member relative to the opener body, and so helps to ensure that the retention member (and associated cutter) remains securely fastened to the opener body in the unlikely event that either of the locking members fails.

Optionally the first and second locking chambers have different configurations. Having locking chambers with different configurations reduces the likelihood of both the locking members failing through the same fault mode, e.g. adverse loading and/or excessive vibration.

In a preferred embodiment of the invention the first locking chamber is defined by a male formation extending from one of the retention member and the opener body and a female formation lying in the other of the retention member and the opener body. The inclusion of male and female formations assists in assembly of the hole opener of the invention since they help to define the manner in which the retention member and the opener body to fit together In another preferred embodiment of the invention the male and female formations additionally cooperate with one another to restrict relative movement between the retention member and the opener body in a lengthwise direction. Such an arrangement allows the retention member to be held in a desired position relative to the opener body before the retention member and the opener body are secured to one another.

Restricting relative movement between the retention member and the opener body also assists operation of the locking member to drive the retention member and opener body into engagement with one another.

Optionally each of the male and female formations is inclined at an angle to the lengthwise direction of the corresponding retention member and opener body. Arranging the male and female formations such a manner assists in assembly of the hole opener since the retention member may be readily engaged with the opener body, while providing a desired restriction in relative lengthwise movement between the retention member and the opener body.

In a further preferred embodiment of the invention one of the male and female formations includes a formation chamfer which defines one of the mutually engageable formations cooperable to drive the retention member and the opener body into engagement with one another. Such a chamfer is readily manufacturable white providing a desired degree of mechanical advantage to operation of the or each actuator member associated with the first locking member.

The formation chamfer may further define an undercut. The inclusion of such a feature assists in locating the first locking member relative to corresponding male or female formation.

In a still further preferred embodiment of the invention the first locking member includes a first locking chamfer that is mutually engageable with the formation chamfer to drive the retention member and the opener body into engagement with one another. Such a first locking chamfer is readily formable in the first locking member and provides optimal cooperation with the formation chamfer.

Optionally the hole opener includes a plurality of first locking chambers each with a corresponding first locking member. Having a plurality of first locking chambers increases the force with which the retention member and the opener body are driven into engagement with one another, and hence reduces the likelihood of the retention member becoming separated from the opener body.

Preferably the second locking chamber includes a chamfered wall defined by at least one of the opener body and the retention member. Such a chamfer is readily manufacturable and provides a desired degree of mechanical advantage to operation of the or each actuator member associated with the second locking member.

The chamfered wall may define an undercut. The inclusion of such a feature assists in locating the second locking member within the second locking chamber.

In another preferred embodiment of the invention the second locking member includes at least one second locking chamfer that is mutually engageable with a corresponding chamfered wall to drive the retention member and the opener body into engagement with one another. Such a second locking chamfer is readily formable in the second locking member and provides optimal cooperation with the corresponding chamfered wall.

The or each locking member may include an aperture passing therethrough to permit the actuator member to protrude from the locking member in order to effect movement of the locking member relative to the opener body. Such an arrangement helps to ensure that the or each locking member is operated in a controlled manner.

Optionally the or each actuator member is or includes a screw that is threadedly received in the aperture which is threaded in a corresponding manner to the screw. Such a screw, that preferably but not necessarily is a grub screw, may readily be accessed and operated from an exterior of the hole expander using an elongate tool.

Preferably the retention member includes a shaft element extending therefrom to receive the cutter. This allows the retention member to protect the shaft element from the inner wall of a, e.g. a downhole bore, as well as helping to prevent the shaft element from becoming dislodged from the retention member.

The shaft element may extend into and be received by the opener body. Such an arrangement secures the shaft element at both ends, and so provides for a robust cutter assembly.

In a further embodiment of the invention the shaft element is inclined at an angle to the lengthwise direction of the retention member. Such a feature assists in the assembly of the hole opener while helping to inhibit movement of the cutter radially outwards relative to the opener body.

There now follows a brief description of a preferred embodiment of the invention, by way of non-limiting example, with reference being made to the accompanying drawings in which: Figure 1 shows a partially-exploded perspective view of a hole opener according to a first embodiment of the invention; Figure 2 shows an elevational view from a first side of the hole opener shown in Figure 1; Figure 3(a) shows a cross-sectional view through section B-B of Figure 2 Figure 3(b) shows an enlarged view of a portion of Figure 3(a); Figure 4 shows a front elevational view of the hole opener shown in Figure 1; Figure 5(a) shows a cross-sectional view through section D-D of Figure 4; Figure 5(b) shows an enlarged view of a portion of Figure 5(a) in a first configuration; and Figure 5(c) shows an enlarged view of a portion of Figure 5(a) in a second configuration.

A hole opener according to a first embodiment of the invention is designated generally by the reference numeral 10.

The hole opener 10 includes an opener body 12 which has three retention members 14 coupled therewith, each of which retains a cutter 16 relative to the opener body 12.

In the embodiment shown each of the retention members 14 is equally spaced radially from one another about the opener body 12. Other embodiments of the invention (not shown) may include fewer than three or greater than three retention members 14, and the retention members 14 need not necessarily be equally spaced radially from one another.

is The cutter 16 is a rotatable cutter, and in particular a rotatable cone cutter. Other types of cutter 16 may be included in the hole opener 10 of the invention, including fixed cutters which do not rotate relative to the opener body 12.

Each retention member 14 cooperates with the opener body 12 to define first and second locking chambers 18, 20 lying therebetween. In particular, in the embodiment shown, each retention member 14 and a corresponding portion of the opener body 12 cooperate with one another to define six first locking chambers 18 that are arranged in respective pairs which lie on either side of each retention member 14. The retention member 14 and the opener body 12 also cooperate to define three second locking chambers 20 each of which is associated with a given retention member 14.

In other embodiments of the invention the or each retention member 14 and the opener body 12 may cooperate with one another to define a different number and/or arrangement of first and second locking chambers 18, 20. Preferably, however, in the case of a plurality of respective first and second locking chambers 18, 20 the respective groups of first and second locking chambers 18, 20 are arranged symmetrically with respect to the corresponding retention member 14 so as to help ensure uniform loading of the retention member 14.

Each first locking chamber 18 is defined by a male formation 22 extending from a respective retention member 14 and a female formation 24 lying in the outer body 12. In other embodiments of the invention (not shown) the male formation 22 may extend from the opener body 12 and the female formation 24 may lie in the associated retention member 14.

The male and female formations 22, 24 cooperate with one another to restrict relative movement between the retention member 14 and the opener body 12 in a lengthwise direction L. in particular, in the embodiment shown, the male and female formations 22, 24 are inclined at an angle of approximately 45° to the lengthwise direction L, and so relative movement between a given retention member 14 and the opener body 12, once the male and female formations 22, 24 are engaged with one another, is restricted to movement at an angle of approximately 45° to the lengthwise direction L. In other embodiments of the invention the male and female formations 22, 24 may extend at a different angle to the lengthwise direction L of one or both of the retention member 14 and the opener body is 12.

Each first locking chamber 18, so defined by the cooperating male and female formations 22, 24, receives a corresponding first locking member 26 and confines the movement of the first locking member 26 relative to opener body 12.

Each first locking member 26 includes a first actuator member 28 to move the first locking member 26 relative to the opener body 12.

Each first locking member 26 and a corresponding portion of the opener body 12 include mutually engageable formations which, in the embodiment shown, are respectively defined by a first locking chamfer 30 formed on the first locking member 26 and a formation chamfer 32 formed in the female formation 24.

Other embodiments of the invention may include a mutually engageable formation formed in the female formation 24 of a given retention member 14, or formed on a male formation 22 of one of a given retention member 14 or the opener body 12. In any such embodiments the formation chamfer 32 may additionally define an undercut.

Each first locking member 26 includes a first aperture 34 which passes therethrough to permit the corresponding first actuator member 28 to protrude from the first locking member 26.

More particularly the first actuator member 28 is a first screw 36, and specifically a first grub screw, that is threadedly received in the first aperture 34 which is itself threaded in a corresponding manner to the first screw 36.

Each second locking chamber 20 includes a first chamfered wall 38 defined by the opener body 12 and a second chamfered wall 40 defined by a corresponding retention member 14.

Other embodiments of the invention (not shown) may include a second locking chamber 20 having only one such chamfered wall defined by either the opener body 12 or the retention member 14.

In any of the aforementioned embodiments the or each chamfered wall 38, 40 may define an undercut.

Each second locking chamber 20 receives a second locking member 42 and confines movement of the second locking member 42 relative to the opener body 12.

Each second locking member 42 includes two second locking chamfers 44, each of which is mutually engageable with the corresponding first or second chamfered wall 38, 40.

Each second locking member 42 also includes a pair of second apertures 46, each of which passes therethrough to permit a corresponding second actuator member 48 to protrude from the second locking member 42. In the embodiment shown the second actuator member 48 is a second screw 50, and more particularly a second grub screw, that is threadedly received in the corresponding second aperture 46 which is itself threaded in a corresponding manner to the second screw 50.

The aforementioned chamfers, i.e. the first and second locking chamfers 30, 44, the formation chamfer 32, and the first and second chamfered walls 38, 40 include mating surfaces that are aligned to cause movement of the corresponding first or second locking member 26, 42 relative to each of the opener body 12 and the retention member 14.

One or more of the mating surfaces may include formed thereon one or more bind-promoting features that promote binding with the other mating surface. One example of a bind-promoting features is a pattern of grooves formed in the said mating surface.

Each retention member 14 includes a shaft element 52 that extends therefrom to rotatably receive the corresponding cutter 16. Each shaft element 52 extends at an angle to the lengthwise direction L of the corresponding retention member 14 which corresponds to the angle at which the male and female formations 22, 24 extend relative to the lengthwise direction L, i.e. approximately 45° in the embodiment shown. Each shaft element 52 also extends into and is received by a tapered hole 54 formed in the opener body 12.

In use each first locking member 26 is slidably received between the corresponding male and female formations 22, 24 of a respective first locking chamber 18 as a given retention member 14 is slidably engaged with the opener body 12.

Each first actuator member 28, i.e. first screw 36, is operated by rotating it within the corresponding first locking member 26. Such rotation may be effected by means of an elongate tool (not shown) which has an engagement formation that is configured to mate with the first screw 36, and which is able to access the screw 36 via a first access passage 56 formed in the opener body 12.

Rotation of each first screw 36 causes it to protrude from the corresponding first locking member 26 which, in turn, effects movement of the first locking member 26 relative to the opener body 12. In particular, the first locking chamber 18 is configured in such a manner that the aforementioned rotation of each first screw 36 causes each first locking member 26 to move radially outwards relative to the opener body 12.

The mutually engageable formations of the first locking chamfer 30 and the formation chamfer 32 cooperate with one another to drive the corresponding retention member 14 and the opener body 12 into engagement with one another. In particular, in the embodiment shown, the first locking chamfer 30 and the formation chamfer 32 cooperate with one another to clamp a portion of the retention member 14 between the first locking member 26 and the opener body 12, as shown in Figure 3(b).

In this manner a predetermined torque that is applied to each first actuator member 28, i.e. each first screw 36, is amplified by the mechanical advantage generated by the cooperating first locking chamfer 30 and formation chamfer 32 into a higher clamping force that is applied to the retention member 14.

In a similar manner each second locking member 42 is slidably received in the corresponding second locking chamber 20, preferably before a corresponding retention member 14 is slidably engaged with the opener body 12. Each retention member 14 includes a cutaway portion 60 to facilitate such assembly of the second locking member 42.

Each second actuator member 48, i.e. second screw 50, is operated by rotating it within the corresponding second locking member 42. Such rotation may again be effected by a suitable elongate tool (not shown) which is able to access the second screw 50 via a respective second access passage 58 formed in the opener body 12.

Rotation of each second screw 50 causes it to protrude from the corresponding second locking member 42 which, in turn, moves the first locking member 42 from a first unlocked configuration, as shown in Figure 5(b), to a second locked configuration,as Is shown in Figure 5(c). In a similar manner to the first locking chamber 18, the second locking chamber 20 is configured such that the aforementioned rotation of each second screw 50 causes each second locking member 42 to move radially outwards relative to the opener body 12.

The mutually engageable formations of each of the two second locking chamfers 44 and the corresponding chamfered wall 38, 40 cooperate with one another to drive the corresponding retention member 14 and the opener body 12 into engagement with one another. More specifically, in the embodiment shown, the mutually engageable formations cooperate with one another to drive respective male formations 22 of a given retention member 14 against the corresponding female formation 24 of the opener body 12 to clamp the retention member 14 against the opener body 12, as partially illustrated in Figure 5(c).

A predetermined torque that is applied to each second actuator member 48, i.e. each second screw 50, is amplified by the mechanical advantage generated by the cooperating second locking chamfers 44 and first and second chamfered walls 38, 40 into a higher clamping force that is applied to the retention member 14.

Clamping each retention member 14 relative to the opener body 12 in each of the manners set out above inhibits movement of the given retention member 14 relative to the opener body 12 and thereby securely retains each cutter 16 relative to the opener body 12.

Claims

CLAIMS: 1. A hole opener, for use in a downhole environment to enlarge a drilled hole, comprising an opener body including a retention member coupled therewith to retain a cutter relative to the opener body, the retention member and the opener body cooperating with one another to define a locking chamber lying therebetween, the locking chamber confining movement of a locking member received therein relative to the opener body, the locking member including one or more actuator members to move the locking member relative to the opener body, the locking member and one of the opener body and the retention member including mutually engageable formations cooperable with one another to drive the retention member and opener body into engagement with one another on movement of the locking member relative to the opener body caused by operation of the or each said actuator member to inhibit movement of the retention member relative to the opener body and thereby securely retain the cutter relative to the opener body.
2. A hole opener according to Claim I wherein the retention member and the opener body cooperate with one another to define first and second locking chambers lying therebetween, the first locking chamber receiving and confining a first locking member and the second locking chamber receiving and confining a second locking member.
3. A hole opener according to Claim 2 wherein the first and second locking chambers have different configurations.
4. A hole opener according to Claim 2 or Claim 3 wherein the first locking chamber is defined by a male formation extending from one of the retention member and the opener body and a female formation lying in the other of the retention member and the opener body.
5. A hole opener according to Claim 4 wherein the male and female formations additionally cooperate with one another to restrict relative movement between the retention member and the opener body in a lengthwise direction.
6. A hole opener according to Claim 4 or Claim 5 wherein each of the male and female formations is inclined at an angle to the lengthwise direction of the corresponding retention member and opener body.
7. A hole opener according to any of Claims 4 to 6 wherein one of the male and female formations includes a formation chamfer which defines one of the mutually engageable formations cooperable to drive the retention member and the opener body into engagement with one another.
8. A hole opener according to Claim 7 wherein the formation chamfer further defines an undercut.
9. A hole opener according to Claim 7 or Claim 8 wherein the first locking member includes a first locking chamfer that is mutually engageable with the formation chamfer to drive the retention member and the opener body into engagement with one another.
10. A hole opener according to any of Claims 2 to 9 includes a plurality of first locking chambers each with a corresponding first locking member.
11. A hole opener according to any of Claims 2 to 10 wherein the second locking chamber includes a chamfered wall defined by at least one of the opener body and the retention member.
12. A hole opener according to Claim 11 wherein the chamfered wall defines an undercut.
13. A hole opener according to Claim 11 or Claim 12 wherein the second locking member includes at least one second locking chamfer that is mutually engageable with a corresponding chamfered wall to drive the retention member and the opener body into engagement with one another.
14. A hole opener according to any preceding claim wherein the or each locking member includes an aperture passing therethrough to permit the actuator member to protrude from the locking member in order to effect movement of the locking member relative to the opener body.
15. A hole opener according to Claim 14 wherein the or each actuator member is or includes a screw that is threadedly received in the aperture which is threaded in a corresponding manner to the screw.
16. A hole opener according to any preceding claim wherein the retention member includes a shaft element extending therefrom to receive the cutter.
17. A hole opener according to Claim 16 wherein the shaft element extends into and is received by the opener body.
18. A hole opener according to Claim 16 or Claim 17 wherein the shaft element is inclined at an angle to the lengthwise direction of the retention member.
19. A hole opener generally as herein described with reference to and/or as illustrated in the accompanying drawings.