Patent ID: 6668932
Filing Date: 2003-12-30
Classification: E21B

Abstract:
A method of isolating a junction between a first wellbore and a second wellbore extending outwardly from the first wellbore, the method comprising the steps of:providing an elongated assembly including an outer generally tubular structure and an inner generally tubular structure, a first flow passage being formed through the inner structure and a second flow passage being formed between the inner and outer structures; sealing a first longitudinal portion of the assembly within a first interior sealing area of the first wellbore uphole of the junction, and sealing a second longitudinal portion of the assembly within a second interior sealing area of a selected one of (1) a portion of the first wellbore downhole from the junction and (2) a portion of the second wellbore, in a manner such that the assembly sealingly straddles the junction with the first and second flow passages being isolated from the non-selected wellbore portion; and flowing fluid, via one of the first and second flow passages, through the assembly between the sealing areas while returning circulation of the fluid, via the other one of the first and second flow passages through the assembly between the sealing areas.