SYSTEM FOR SEALING THE INTERSECTION BETWEEN A PRIMARY AND A BRANCH BOREHOLE

摘要

A system for sealing the intersection between a primary borehole and a branch borehole comprises a primary casing section which in use is located in the primary borehole in the region of the branchpoint and a branch casing section which is secured to the primary casing section and is located in the branch borehole. The primary casing section is a tubular which defines a slant surface which intersects a central axis of the tubular at an acute angle, so that the primary casing section can be pressed towards the branchpoint by means of a hollow whipstock or other wedge-shaped element.