Patent ID: 6015012
Filing Date: 2000-01-18
Classification: E21B

Abstract:
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; andremoving the lower whipstock from the first casing.