CONTROLLING BACKFLOW PRESSURE DURING RETRIEVAL OF BOTTOM HOLE ASSEMBLY
摘要
A bottom hole assembly in a casing-while-dr tiling operation is retrieved by displacing the fluid in the casing string with a less dense fluid than the fluid in the annulus. The bottom hole assembly moves upward in the casing string in response to an upward force due to the different densities of fluid in the casing string and in the annulus. Displaced fluid flows out of the casing string and through a restrictive orifice of a choke. The flow area of the orifice is varied as the bottom hole assembly moves upward to control the rate at which the bottom hole assembly moves upward.
申请公布号
WO2009143393(A2)
申请公布日期
2009.11.26
申请号
WO2009US44922
申请日期
2009.05.22
申请人
TESCO CORPORATION (US);ERIKSEN, ERIK, P.;MOFFITT, MICHAEL, E.;WARREN, TOMMY, M.
发明人
ERIKSEN, ERIK, P.;MOFFITT, MICHAEL, E.;WARREN, TOMMY, M.