Abstract: An assembly, mountable below a whipstock, for engagement into an anchor packer is disclosed which has a valve member as a principal component. The assembly is stabbed into the anchor packer in a manner that isolates the main wellbore from the lateral to be created using the whipstock. An equalization feature facilitates the stabbing in of the assembly into the anchor packer. Upon concluding the stabbing in, the equalization opening closes and locks in the closed position. Thereafter, the lateral is created by milling a window (in the case of a cased wellbore) and drilling the lateral. Liners may be used within the lateral and are insertable by use of the whipstock. At any desired time when production is to resume from below the whipstock, the valve member is actuated while the anchor packer remains in position to hold the whipstock. The valve member can be actuated by mechanically shifting a sleeve or by dissolution with chemical attack of a dissolvable plug or by other techniques.

Abstract: A retrievable packoff assembly for temporarily sealing a well pipe and anchoring equipment at a subsurface location within the pipe. The assembly is connected to a tubular actuation tool which is manipulated from the surface to position the assembly at a subsurface well location, set the assembly and then release from the set assembly. Right-hand tool rotation sets the assembly, releases the tool, and is subsequently employed to reengage and unset the assembly for retrieval to the surface. A bypass flow passage in the assembly is controlled by a sliding sleeve valve which is automatically closed by the right-hand tool rotation during setting and release and automatically reopened by tool rotation occurring during retrieval of the assembly. Flow through both the assembly and the bypass is confined within the actuation tool. A control flow passage in the apparatus is sealed by a retrievable blanking plug which may be removed to permit passage of equipment through the anchored assembly.

Abstract: A downhole valve 10 opens or closes a bypass (12,13) in response to the pressure of the fluid in the valve. The valve housing body 14 is adapted for fluid communication with a tubular within a well bore. The valve bypass may be repeatedly cycled from open to closed position by selectively raising and lowering the fluid pressure. A replaceable flow restriction 18 in the valve is sized to produce a desired flow-induced pressure drop across the valve to cycle the valve with fluid flow. Differential sealing areas (11c and 15,16) are provided to cycle the valve by varying the static fluid pressure in the valve. According to the method, a flowing fluid pressure drop induced by fluid flow through the valve is used to change the state of the valve, and a subsequent change in hydrostatic fluid pressure or fluid pressure is used to return the valve to its original state.