Patent ID: 8196669
Filing Date: 2012-06-12
Classification: E21B

Abstract:
1. A method of drilling a wellbore into an earth formation, the method comprising a) arranging a drill string and an expandable tubular element coaxially in the wellbore, the drill string having an axially extending fluid passage, the tubular element surrounding the drill string and having a lower end bent radially outward and in axially reverse direction so as to form an expanded tubular section extending around a remaining tubular section of the tubular element, said lower end defining a bending zone of the tubular element, wherein an annular space is formed between the drill string and the remaining tubular section; b) inducing the drill string to further drill the wellbore; c) inducing the bending zone to move in axial direction relative to the remaining tubular section so as to increase the length of the expanded tubular section; d) inducing a stream of drilling fluid to flow into the wellbore via the annular space, and discharging the stream of drilling fluid from the wellbore via the fluid passage of the drill string.