GB2256664A

GB2256664A - Hanger lock

Info

Publication number: GB2256664A
Application number: GB9211446A
Authority: GB
Inventors: James Brown Mason
Original assignee: SEABOARD LLOYD Ltd
Current assignee: SEABOARD LLOYD Ltd
Priority date: 1991-05-29
Filing date: 1992-05-29
Publication date: 1992-12-16
Also published as: GB9111509D0; GB9211446D0

Abstract

Locking apparatus is provided for looking a hanger 1 in a wellhead 2 and comprises a primary lock 7 comprising an annular series of segments 16 held by an expansion ring 17, and an actuator member 9 for the primary lock. During the operating movement of the actuating member 9 the hanger 1 is positively locked on its seating 3 in the wellhead by virtue of the primary lock 7 being urged against the hanger 1 by the actuator, the operating movement being completed at the set position when the lock segments 16 move radially into a groove 8 on the wellhead 2 to lock the hanger. The primary lock 7 and the actuator member 9 preferably have operating surface portions 7A-7C/13-15 precluding axial load transfer between these items in the set position. <IMAGE>

Description

t'HM GER LOCK" The present invention relates to apparatus for locking casing and tubing hangers into a wellhead.

Hangers are utilised in oil, gas and petrochem installations to facilitate support of a tubular string by a wellhead, to this end the hanger being mounted on a suitable support surface in the wellhead via an integral metal seal while the tubular string is also carried by the hanger.

It is an object of the present invention to provide apparatus for positively locking casing and tubular hangers into their respective wellheads while maintaining a downward loading on to the metal seal of the hanger.

According to the present invention apparatus for locking a hanger in a wellhead comprises annular form primary locking means radially movable from a free position to a location cooperating with the wellhead defining a set position; and an actuating member movable in an operating movement to shift the primary locking means from said free position to said set position; the arrangement being such that the hanger is positively locked on its seating in the wellhead via the primary locking means during said operating movement of the actuating member.

Preferably the actuating member is adapted to be moved by a running tool, second locking means being provided to lock the running tool to the actuating member while release means serve to free the second locking means when the primary locking means is in said set position.

Preferably the actuating member includes frusto-conical surface means co-operating with corresponding surfaces on its loading means during the operating movement.

In the set position, the primary locking means are preferably located in an annular groove on = wellhead. The primary locking means can comprise an annular serIes of indivIdual segments permitting the primary rimary locking means to extant and contract radially, and an expandable locating ring is preferably provided received by said segments to maintain the structural integrity of the primary locking means.

Preferably the frusto-conical surface means of the actuator member comprises vertically spaced first and second frusto-conical surfaces. Said first and second surfaces can be spaced by a cylindrical surface and the inner periphery of the primary locking means can include a corresponding cylindrical portion.

In a preferred embodiment, the inner periphery of the annular primary locking means includes spaced cylindrical surface portions, the arrangement being such that in the set position, contact between the primary locking means and the actuating member is substantially solely through said cylindrical surface portions.

Preferably the top of the primary locking means includes a frusto-conical surface with its apex upwards, while the annular groove in the wellhead includes a corresponding conical surface longable with said top frusto-conical surface.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings wherein Fig 1 shows a sectional side-view of a tubing hanger in position in a wellhead and including the locking system of the present invention, the locking system being shown in the locking or set condition; Fig 2 shows to a larger scale the detail of the locking system on the ready to be set but free condition; Fig 3 shows the actuating member of the locking system in part sectional side view and to a larger scale; Fig 4 shows a plan view of the actuating member; and Fig 5 shows a side view of the load ring segment of the lock system vo a larger scale and indicating the forces which apply In the set position ofsthe locking system.

Pe-errin to the drawings, a hanger 1 is located in a wellhead 2, a metal seal surface 3 in the wellhead 2 serving as a seating surface for the hanger 1 while the hanger 1 carries seal rings 15. The hanger 1 serves to support a casing or tubing string (not shown) by means of the upper tube being screwed to the hanger at threading 4.

Apparatus 6 provides a system for positively locking the hanger 1 in the wellhead 2 and comprises a split-load ring device 7 which is capable of expanding and contracting radially whereby the device 7 can move from a free position (Fig 2) to a set position (Fig 1) where it extends into an annular groove 8 in the wellhead 2 for locking of the hanger 1, the device 7 bearing against an annular support surface 1A of the hanger. Radial movement of the device 7 is effected by an actuator ring 9 of the apparatus 6 the bottom end 9A of which ring 9 can move into an annular recess 1B in the hanger.

The floor 1C of the recess serves as an abutment for the end 9A to limit the operating movement of the actuator ring 9.

For operating movements of the actuator ring 9, the ring 9 is coupled to a running tool 10 via a running tool lock 11 (shown in detail in Figs. 3 and 4).

The lock 11 is in the form of a spring urged pin, and it is arranged that the tool 10 can be freed from the ring 9 only when the device 7 is in the set position shown in Fig 1; to this end an actuating key 12 on the hanger 1 reacts with the spring urged pin to free the lock 11 when the device 7 has reached the set position. The pin of the lock 11 moves completely into an axial groove 9B (Fig. 4) in the freed position.

The actuator ring 9 includes vertically spaced frustoconical operating surfaces 13, 14 with a cylindrical surface 15B between the surface 12, 13, a further cylindrical surface 15A being located above the surface 14, while the inner periphery of the device 7 is complementary profiled with a frusto-conicai surface 7A and spaced cylindrIcal surfaces 7B, 7C (see Fig 5) on each side of the surface 7A.Further, the top of the device 7 carries an upwardly facIng frusto-conlcal surface 7D cc-operating with a similar surface 8A of the groove 8. Secifically, the device 7 comprises an annular series of in~-idual segments 16 which are held in position by a resilient metal split-ring 17 at the periphery of the device 7 and located in grooves in the segments 16. The segments 16 are placed in position by passing through respective apertures in the hanger 1, a lip 16A on each segment 16 engaging a shoulder 5 of the hanger 1 to limit inward movement of the segment.A conduit device 20A is provided for a control line (not shown) or lines which extends in the wellhead 2 for downhole operations.

Operation With the hanger 1 landed in the wellhead 2, the running tool 10 loads the actuating ring 9 causing it to move in a downwards direction so that surfaces 13 and 14 of the ring activate the split ring device 7 into the groove preparation 8 of the wellhead 2. Only when the ring 9 and device 7 are in the fully set position (Fig 1) does the actuating key 12 free the lock tool 11 to allow the running tool 10 to be retrieved.

As will be observed, the hanger 1 is positively locked on the surface 3 of the wellhead at all times during the operating movement of the actuating ring 9.

A further feature of the apparatus 6, is that the design of the interacting surfaces of the split-ring device 7 and the actuating ring 9 ensures that any upward loading on the device 7 will be transferred to a resultant horizontal reaction on the actuating ring 9 so that any tendency for upward movement of the hanger 1 will be removed.

In particular, referring to Fig 5, upward loading (arrow L) on the device 7 due for example to formation pressure on the hanger 1, causes a normal force FL to be created at the interface 7D/8A of the device 7 and the groove 8, and this force FL resolves into a horizontal force component FH due to the frusto-conical interface. However, in the set position contact between the device 7 and the actuating ring 9 is solely between the cylindrical surface portions 7B, 7C of the device 7 and the cylindrical surfaces 15A, 15B of the actuating ring 9, the frustoeconical surface portions 14, 7A being free, 5 that the horizontal force FH is not resolved into any upward force on the ring thereby avoiding any tendency for upward movement of the hanger 1.

A grub screw 22 is provided in the actuating ring 9 and is engagable with the hanger to stop movement of the actuator unit prior to running of the tool, the screw being released when running is to occur.

Claims

CLAIMS.

1. Apparatus for locking a hanger in a wellhead comprising annular form primary locking means radially movable from a free position to a location co-operating with the wellhead defining a set position; and an actuating member movable in an operating movement to shift the primary locking means from said free position to said set position; the arrangement being such that the hanger is positively locked on its seating in the wellhead via the primary locking means during said operating movement of the actuating member.

2. Locking apparatus as claimed in claim 1, wherein the actuating member is adapted to be moved by a running tool, second locking means being provided to lock the running tool to the actuating member while release means serve to free said second locking means when primary locking means is in said set position.

3. Locking apparatus as claimed in claim 1 or 2, wherein the actuating member includes frusto-conical surface means cooperating with corresponding surfaces on the primary locking means during the operating movement.

4. Locking apparatus as claimed in claim 2, wherein the second locking means comprise a spring urged pin.

5. Locking apparatus as claimed in any one of the preceding claims, wherein in the set position, the primary locking means are located in an annular groove on the wellhead.

6. Locking apparatus as claimed in any one of the preceding claims, wherein the primary locking means comprise an annular series of individual segments permitting the primary locking means to expand and contract radially.

7. Locking apparatus as claimed in claim 6, wherein an expandable locating ring is provided and received by said segments to maintain the structural integrity of the primary locking means 7).

8. Locking apparatus as claimed in claim 6 or 7, wherein the segments are insert through individual apertures In the hanger so as to be engagable by the actuating member.

9. Locking apparatus as claimed in any one of the receding claims, wherein the primary locking means and the actuating member are arranged to preclude the generation of an axial load between the primary locking means and the actuating member when an axial load is applied on the primary locking means in the set position.

10. Locking apparatus as claimed in claim 3, wherein the frusto-conical surface means of the actuator member comprises axially spaced first and second frusto-conical surfaces.

11. Locking apparatus as claimed in claim 10, wherein said first and second surfaces are spaced by a cylindrical surface and the inner periphery of the primary locking means includes a corresponding cylindrical portion.

12. Locking apparatus as claimed in claim 11, wherein the inner periphery of the annular primary locking means includes spaced cylindrical surface portions, the arrangement being such that in the set position, contact between the primary locking means and the actuating member is substantially solely through said cylindrical surface portions to preclude the generation of axial loads between the primary locking means and the actuating member in said set position.

13. Locking apparatus as claimed in claim 5, wherein the top of the primary locking means includes a frusto-conical surface, with its apex upwards, while the annular groove in the wellhead includes a corresponding conical surface engagable with said top frusto-conical surface.

14. Locking apparatus as claimed in any one of the preceding claims, wherein means are provided to limit radial inward movement of the primary locking.

15. Locking apparatus for locking a hanger in a wellhead substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

15. Locking apparatus as claimed in any one of the preceding claims, wherein means are provided to limit the operating movement of the actuating member.

16. Locking apparatus for locking a hanger in a wellhead substantially as hereinbefore described with reference to and as illustrate In the accompanying drawings.

Amendments to the ctebns have been fled as folioos 1. Apparatus for locking a hanger in a wellhead comprising annular form primary locking means radially movable from a free position to a location co-operating with the wellhead defining a set position; and an actuating member movable in an operating movement to shift the primary locking means from said free position to said set position; the arrangement being such that the hanger is positively locked on its seating in the wellhead via the primary locking means during said operating movement of the actuating member, the inner periphery of said annular locking means including a first surface portion and a second tapering surface portion extending radially inwardly from said first surface portion, the actuating member having a corresponding working surface including a first working portion for reaction with said second tapering surface portion of the locking means during said operating movement of the actuating member to place the locking means in the set position, and a second surface portion for engagement with said first surface portion of the locking means in said set position.

2. Locking apparatus as claimed in claim 1, wherein said first and second surface portions comprise cylindrical surfaces and in the set position, contact between the primary locking means and the actuating member is substantially solely through cylindrical surfaces to preclude the generation of axial loads between the primary locking means and the actuating member in said set position.

3. Locking apparatus as claimed in claim 1 or 2, wherein the actuating member is adapted to be moved by a running tool, second locking means being provided to lock the running tool to the actuating member while release means serve to free said second locking means when primary locking means is in said set position.

4. Locking apparatus as claimed in any one of the preceding claims wherein said first working portion of the actuating member comprises frusto-conical surface means co-operating with the tapering surface portion of the primary locking means during the operating movement 5. Locking apparatus as claimed in claim 3, wherein the second locking means comprise a spring urged pin.

6. Locking apparatus as claimed in any one of the preceding claims, wherein in the set position, the primary locking means are located in an annular groove on the wellhead.

7. Locking apparatus as claimed in any one of the preceding claims, wherein the primary locking means comprise an annular series of individual segments permitting the primary locking means to expand and contract radially.

8. Locking apparatus as claimed in claim 7, wherein an expandable locating ring is provided and received by said segments to maintain the structural integrity of the primary locking means.

9. Locking apparatus as claimed in claim 7 or 8, wherein the segments are inserted through individual apertures in the hanger so as to be engagable by the actuating member.

10. Locking apparatus as claimed in claim 4, wherein the actuator member comprises axially spaced first and second frusto-conical surfaces one of which defines said first working poriton.

11. Locking apparatus as claimed in-claim 10 wherein said first and second frusto-conical surfaces are spaced by a cylindrical surface portion, and the inner periphery of the locking means comprises spaced cylindrical surface portions which are radially off-set and one of which defines said first surface portion, said tapering surface portion linking said off-set cylindrical surface portions.

12. Locking apparatus as claimed in claim 6, wherein the top of the primary locking means includes a frusto-conical surface, with its apex upwards, while the annular groove in the wellhead includes a corresponding conical surface engagable with said top frusto-conical surface.

13. Locking apparatus as claimed in any one of the preceding claims, wherein means are provided to limit radial inward movement of the primary locking means.

14. Locking apparatus as claimed in any one of the preceding claims, wherein means are provided to limit the operating movement of the actuating member.