Retrievable through tubing tool and method

Abstract

Retrievable window cutting apparatus and method include a whipstock assembly 160 and anchor assembly 10. Whipstock assembly 160 and anchor assembly 10 contract radially inwardly to pass through tubing string T and then expand radially outwardly to operate in casing C. Upper and lower independently moveable slips 24 and 26 engage casing C. Whipstock assembly 160 includes hinge assembly 170 that can be set for operation with a milling assembly 270. Cooperation between shear members in setting tool WSS, working string adaptor 180, hinge assembly 170, and anchor assembly 10 provide for keeping whipstock assembly 160 and anchor assembly 10 in a contracted position for passing downwardly through tubing T, expansion in casing C, and subsequent retrieval through tubing T.

Description

FIELD OF THE INVENTIONThe present invention relates generally to a through tubing assembly operable for cutting a casing window and, more particularly, to apparatus and methods relating to a retrievable through tubing whipstock assembly.DESCRIPTION OF THE BACKGROUNDA whipstock may generally refer to a device inserted in a wellbore that is used for deflecting a drill bit or mill in a direction that is angularly offset with respect to the orientation of the original wellbore so as to establish a new or additional drilling course. In most instances, a whipstock procedure involves setting an anchor and providing an angled whipstock surface supported by the anchor at the desired depth in the wellbore to conduct side track or lateral directional drilling operations through the casing string.It is frequently desired to cut or mill a window in a casing string that also includes therein a smaller diameter tubular string, such as for conducting wellbore fluids, that terminates at a position a...

AI Technical Summary

Benefits of technology

An advantage of the present invention is the elimination of the need to remove a tubing string before milling a window in a casing string below the tubing.

is the elimination of the need to remove a tubing string before milling a window in a casing string below the tubing.

Another advantage of the present invention is ready access to the original casing string after the milling operation.

Problems solved by technology

Removal of the tubular string requires considerable rig time and expense, but is required to permit the entry of a full-bore whipstock assembly into the casing for positioning at the desired depth for then milling or cutting a window in the casing.

However, apparatus and methods have not heretofore existed that permit milling a window in the casing string by passage of a retrievable whipstock assembly through a smaller diameter tubular member, such as a production tubing string positioned within the casing.

Images