Plug, and methods for setting and releasing the plug

Abstract

A plug includes a slip actuator for setting and release of slips, and a locking element in contact with the slip actuator. The locking element includes multiple parts with internal threads which constitute an enclosure around threads of a pipe. On the radial outer surface of the locking element are provided resilient elements. When setting the plug, the locking element is capable of sliding over the pipe threads for movement of the slip actuator and setting of the slips, until the locking element comes into engagement with a locking sleeve, fixed relative to the pipe, which prevents rotation of the locking element. When releasing the plug, the locking element is released from the locking sleeve, and the locking element rotates off the pipe threads, and the slip actuator follows the movement of the locking element and releases the slips.

Description

INTRODUCTION[0001]The present invention relates to a plug and to methods for setting and releasing the plug in a well, for example, a hydrocarbon well, as disclosed in the independent apparatus claim and in the independent method claims.BACKGROUND / PRIOR ART[0002]It is common practice to close off the borehole, either temporarily or permanently, by using plugs. The background for this may be that it is desirable, for example, to carry out tests or maintenance in the well. The plugs are usually run down the well using a running tool. When the plug has reached the desired depth in the well, it is secured to the surrounding casing or borehole wall using anchoring elements. The borehole is subsequently sealed, often by using packers which seal the area between the pipe or plug and the borehole wall. The bridge plug shown in U.S. Pat. No. 6,220,348 B1, and the whole running tool, must be pulled out of the well if another operation is to be carried out in the well, which will mean a great ...

AI Technical Summary

Benefits of technology

The invention is described in a series of drawings showing a plug coupled to a running tool and a pipe at different stages of setting. The illustrations show the process of releasing the plug and locking the pipe. The present invention also includes a timer function. The technical effect of the invention is to provide a tool for safely and efficiently setting plugs and plungers in pipes.

Problems solved by technology

The bridge plug shown in U.S. Pat. No. 6,220,348 B1, and the whole running tool, must be pulled out of the well if another operation is to be carried out in the well, which will mean a great deal of extra time and costs.

Known plugs for use in wells have the disadvantage that the plugs require maintenance between each operation.

It is usual to set and release plugs by means of rotation, but it can be difficult to achieve controlled rotation at great well depths.

There are several potential sources of error which make the setting and release hazardous.

One such source of error could be left-hand (anti-clockwise) rotation, which may result in equipment such as drill pipes or plugs being unscrewed from one another.

Up and down movement of the vessel, as a consequence of the rolling of the sea, may inadvertently start the setting.

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