GB2525148A

GB2525148A - Method and apparatus for transmitting torque through a work string when in tension and allowing free rotation with no torque transmission when in compression

Info

Publication number: GB2525148A
Application number: GB1401460.9A
Authority: GB
Inventors: Martin Klaus Alios Isolde Horn
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-28
Filing date: 2014-01-28
Publication date: 2015-10-21
Anticipated expiration: 2034-01-28
Also published as: GB2525148B; GB201401460D0

Abstract

A system enables rotational torque to be transmitted from above a tool box connection 1 to below a tool pin connection when in tension by engaging a hexagonal torque bushing 3 with a hexagonal profiled section on an internal barrel 7. The system further enables no rotational torque to be transmitted from above the tool box connection 1 to below the tool pin connection when in compression by engagement of the hexagonal torque bushing 3 with a cylindrical profiled section of the internal barrel.

Description

METHOD AND APPARATUS FOR TRANSMITTING TORQUE THROUGH A

WORK STRING WHEN IN TENSION AND ALLOWING FREE ROTATION WITH

NO TORQUE TRANSMISSION WHEN IN COMPRESSION

DESCRIPTION

BACKGROUND OF THE INVENTION

The object of the present invention is to provide an apparatus and a method for using the apparatus, which enables rotational torque to be transmitted from above the tool to below the tool when in tension and stroked fully open, whilst enabling no torque to be transmitted from above the tool to below the tool when in compression and stroked partially or fully closed.

The present invention is for use in the oil industry, particularly for "cf 15 cementing operations on offshore oil rigs within a work string.

CV) A work string component such as the present invention is made up 0 as pad of a number of components attached together via connections. The present N-invention has connections which enable it to be made up to any work string. (J 20

Casing strings are run and cemented into oil wells to facilitate deeper drilling operations to continue. If preferable an inner work string is sometimes run into the casing to facilitate more optimal cementing operations.

The inner work string may be attached to the base of the casing string via a threaded connection which requires rotational torque to be transmitted through the string to make up the connection and to break out the connection.

In the case of certain subsea wellhead systems it is required to provide rotational torque to attach components above the inner work string to the casing. In this instance it is required to provide free rotation below these components after the inner work string has been connected to the base of the casing string.

The requirement described dictates a need for a work string component which provides rotational torque when in tension but allows free rotation above the tool without torque transmission when in compression in a partially or fully stroked closed position.

SUMMARY OF THE INVENTION

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the present invention assembly in tension in a stroked open position.

Figure 2 shows the present invention assembly in compression in a stroked partially closed position. C?)

0 Figure 3 shows the inner barrel embodiment of the present invention N-shown in figures 1 and 2, (\J 20 Figure 3a shows an orthographic projection of the end of the inner barrel.

Figure 4 shows the polished bore receptacle assembly as well as the hexagonal torque bushing of the present invention shown in figures 1 and 2.

Figure 4a shows an orthographic projection of the hexagonal torque bushing.

DETAILED DESCRIPTION OF THE INVENTION

Generally, an apparatus and a method for using the apparatus, which enables cementing operations to be carried out with an inner work string is disclosed.

A typical cementing operation of a casing string involves pumping of the fluid cement slurry down the internal diameter of the casing string, which exits the base of the casing and returns up the annulus of the casing string. Once sufficient fluid cement slurry has been pumped, a displacement fluid is pumped behind the cement slurry which forces cement slurry out of the internal diameter of the casing string, leaving said displacement fluid internally and said cement slurry externally to the casing string. By use of a smaller diameter inner work string within the casing string, a smaller volume of displacement fluid is required to place all of the cement slurry in the annulus and thereby optimises the cementing operation.

Wth subsea wellhead systems used on offshore oil wells, a running tool is required to be connected to the top of the casing string when running conductor (first casing string for structural support of the rest of the oil well) and surface casing (second casing string run with the wellhead on the top). This running "cf 15 tool creates a point of fixity for the inner work string resulting in an uncertainty of the length of the inner work string. The present invention provides means of an internal CV) barrel Fig. 3 which can stroke relative to a polished bore receptacle Fig. 4, providing 0 compensation for a discrepancy between casing string and inner work string length.

N

(\J 20 During the pumping of a fluid cement slurry an upward force is experienced at the base of the inner work string which unless connected would drive the connection out of the base of the casing string. This is overcome by threading a connection on the base of the inner work string which engages the base of the casing string. This threaded connection is made up as the inner work string is run into the casing string and it interacts with the base of the casing string. The present invention is at the top of the inner work string in tension and in a stroked open position. Rotational torque can be transmitted through the present invention as the box connection 1 is rotated from above, transmitting torque through the polished bore receptacle 2 and hexagonal torque bushing 3. The hexagonal torque bushing 3 engages with the hexagonal profile section of the internal barrel 6 which transmits rotational torque into the cylindrical profile section of the internal barrel 7 and through the pin connection 8. Confirmation of the successful mating of the threaded connection at the base of the inner work string with the base of the casing string can be confirmed by means of attempting to pull the inner work string and creating additional tension in the inner work string. The running tool of the casing string can then be lowered into position at the top of the casing string, in turn causing the present invention to undergo a compressional force and stroking partially closed as the internal barrel head 5 rides up internally within the polished bore receptacle 2. The running tool is required to be rotated to engage the top of the casing string which can be achieved without rotating the inner work string as the hexagonal torque bushing 3 is rotating around the cylindrical profile section of the internal barrel 7, therefore no engagement of the internal barrel Fig. 3 with the upper section of the present invention Fig. 4 is established.

The casing string is then run to the required depth using additional pipe, and cementing operations are performed through the additional pipe and inner work string to place cement slurry in the annulus of the casing string. The fluid cement slurry is pumped internally through the inner work string as well as through the present invention which provides pressure containment with a seal stack cf 15 assembly 4 mounted around the internal barrel head 5.

CV) Following successful cementing operations, the running tool is 0 removed from the top of the casing string by applying rotational torque. This N-rotational torque is experienced at box connection 1, the polished bore receptacle 2 (\J 20 and the hexagonal torque bushing 3 of the present invention. This rotational torque is not experienced by the internal barrel Fig. 3 or the inner work string underneath the pin connection 8 as the hexagonal torque bushing 3 is rotating around the cylindrical profile section of the internal barrel 7 therefore there is no engagement.

Once the running tool is removed and raised the present invention experiences a tensile force due to the base of the inner string still being engaged at the base of the casing string via the threaded connection. This tension in the present invention strokes open the tool and engages the hexagonal torque bushing 3 with the hexagonal profile section of the internal barrel 6. Rotational torque can now be transmitted through the string from above which will provide rotational torque through the inner work string and disengage the threaded connection at the base of the inner work string.

In a preferred embodiment, the material of the tool body, is steel. Of course, the tool box connection 1, polished bore receptacle 2, hexagonal torque bushing 3, internal barrel head 5, hexagonal profile section of inner barrel 6, cylindrical profile section of inner barrel 7 and pin connection 8 could be made of other materials, such as X56, [80, P110, 3135, V150 (various grades of steel). The seal stack assembly 4 can be any polymer or steel material to provide hydraulic sealing whilst the internal barrel Fig. 3 is in various positions within the polished bore receptacle 2.

Although the invention has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only and that the claims are not limited to those embodiments.

Those skilled in the art will be able to make modifications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims.

CO

N (4

Claims

CLAIMS1. A system which enables rotational torque to be transmifted from above the tool box connection (1) to below the tool pin connection (8) when in tension and stroked fully open to provide engagement of a hexagonal torque bushing (3) with a hexagonal profiled section of the internal barrel (6), whilst enabling no rotational torque to be transmitted from above the tool box connection (1) to below the tool pin connection (8) when in compression and stroked partially or fully closed to engage a hexagonal torque bushing (3) with a cylindrical profiled section of the internal barrel (7).CON (4Amended claims have been filed as follows:-CLAIMS1. A system which enables rotational torque to be transmitted from above a tool box connection (1) to below a tool pin connection (8) when in tension and stroked fully open to provide engagement of a hexagonal torque bushing (3) with a hexagonal profiled section of an internal barrel (6), whilst enabling no rotational torque to be transmitted from above the tool box connection (1) to below the tool pin connection (8) when in compression and stroked partially or fully dosed to engage the hexagonal torque bushing (3) with a cylindrical profiled section of the internal barrel (7). C) C) c'J