US 6,015,012 A · In-situ polymerization method and apparatus to seal a junction between a lateral and a main wellbore

Abstract

An improved method and apparatus for sealing a junction between a central and lateral wellbore is provided. In a broad aspect, the method of the present invention includes installing a polymerizable sealing sleeve within a first casing in a central wellbore at a junction between the first casing and a second casing in a lateral wellbore. After the sealing sleeve has been installed and allowed to cure, a milling tool is used to mill a window through a sidewall of the sealing sleeve and flush with the inner diameter of the second casing. The sealing sleeve may be used alone to establish a primary seal, or in combination with cement or other sealing substance, as used heretofore in prior art sealing methods, as a back-up seal. The sealing sleeve of the present invention may be provided with at least one orienting means to enable the second casing to be located and to direct a well tool thereinto.

Claims26

Dependent claims

A method of sealing a junction between a central wellbore having a first casing and at least one lateral branch wellbore comprising the steps of:

running and setting a lower whipstock in the first casing;
running and setting a window mill pilot in the first casing;
milling a window in the first casing;
drilling a lateral branch wellbore through the casing window out from the central wellbore;
removing the window mill pilot from the first casing;
running and setting an upper whipstock in the first casing adjacent and above the lower whipstock;
running a second casing into the first casing, through the casing window, and into the lateral branch wellbore such that a stub portion of the second casing extends from the lateral branch wellbore through the casing window and into the first casing;
milling the stub portion of the second casing flush with an inner diameter of the first casing;
retrieving the upper whipstock from the first casing;
running and installing an in-situ polymerizable sleeve in the first casing adjacent the junction of the first and second casings;
running and setting a window remill pilot inside the in-situ polymerizable sleeve adjacent the junction of the first and second casings;
milling a window in the in-situ polymerizable sleeve;
retrieving the window remill pilot from inside the in-situ polymerizable sleeve;
and
removing the lower whipstock from the first casing.

12 more elements

Dependencies are inferred from the claim text.

In-situ polymerization method and apparatus to seal a junction between a lateral and a main wellbore

Life of this patent

In-situ polymerization method and apparatus to seal a junction between a lateral and a main wellbore

Life of this patent

Abstract

Claims26