| 摘要 |
An apparatus for closing a reverse circulation passage and opening a crossover fluid passage in a gravel packing service tool which sets a well packer comprises a closure means for closing the reverse circulation passage and an opening means for opening the crossover fluid passage in response to an axial lifting force on the service tool. The closure means is preferably an automatic closure valve having a sleeve with a substantially cylindrical bore and a radially disposed upper surface; and a substantially cylindrical rod and piston assembly moveable within the bore, the assembly including a partial axial fluid flow passage and a connecting radially disposed fluid port whereby fluid flowing within the fluid flow passage flows outwardly of the piston through the port when the port is in an open position axially away from the radially disposed outer surface and resilient damper means restraining movement of the piston within said bore and maintaining the port in the open position under relatively low fluid pressure conditions. C-56113 |
