Patent ID: 8291986

Claim:
A tubular portion apparatus for securing and sealing to an existing wellbore tubular in an oil or gas well, the apparatus comprising: a first sidewall thickness part having a first sidewall thickness and a fully circular outer surface; a second sidewall thickness part having a second sidewall thickness, wherein the second sidewall thickness part is located at each end of the first sidewall thickness part; and a tapered part located between each end of the first sidewall thickness part and the respective second sidewall thickness part; wherein the first sidewall thickness is less than the second sidewall thickness; and the tapered part has a wall thickness gradually increasing from the first sidewall thickness to the second sidewall thickness; and at least one annular seal provided on the outer surface of the tubular portion in a region of the respective tapered part; wherein, in use, the tubular portion is radially expanded whereby the first sidewall thickness part is expanded prior to the expansion of the second sidewall thickness part upon pressurised fluid being applied to an interior of the tubular portion, and wherein the tubular portion comprises a substantially uniform outer diameter prior to expansion thereof.