BACK PRESSURE VALVE FOR A COMPLETION STRING COMPRISING SAND SCREENS, COMPLETION STRING COMPRISING SAID BACK PRESSURE VALVE, AND METHOD FOR LOWERING SAID COMPLETION STRING

摘要

Herein is described a back pressure valve ( 1) for a completion string (10) comprising sand screens (101), the back pressure valve (1) comprising: - a valve body (2); - a valve seat (7); - a valve head (8) for sealing against the valve seat (7); - a valve stem (4) connected to the valve head (8) for guiding the valve head (8); and - a resilient member (9) arranged around a portion of the valve stem (4); wherein the valve stem (4) is guided by at least two supports (13, 15) which are spaced apart in the longitudinal direction of the valve stem (4), the at least two supports (13, 15) being configured for allowing translation of the valve stem (4) in its longitudinal direction only. Furthermore, a method for using said back pressure valve (1) is described, wherein the method comprises the step of providing the back pressure valve (1) in a completion string.