Downhole producing pump

Claim 2

A downhole piston pump for producing well liquids from a subsurface reservoir involving a piston adapted to reciprocate within a cylinder, immersed in said reservoir, said piston being provided with a traveling valve, the improvement which comprises a multiplicity of inlet ports in free and open communication with said reservoir, disposed in said cylinder wall throughout the area between the lower extremity of said wall and the location of the bottom of the piston at the top of its upstroke, means opening said ports in response to initiation of movement of the piston in an upward direction and actuated by the weight of the column of produced liquid being delivered by said pump for closing said ports in response to initiation of movement of the piston in a downward direction and means to prevent communication between said inlet ports and the space above said piston.

Claim 3

A downhole piston pump as defined in claim 1 wherein said last named means comprises a piston skirt extending thereabove to cover said inlet ports during the lower portion of the piston stroke.

Claim 4

A downhole piston pump as defined in claim 1 wherein said ports extend through in the lateral sidewall of the cylinder.

Claim 5

A downhole piston pump as defined in claim 1 wherein said cylinder is arranged to reciprocate axially within a limited predetermined path to effect opening of said ports at one extremity of its path of reciprocation and to effect closure thereof at the other extremity of its path.

Claim 6

A downhole piston pump as defined in claim 1 which includes outlet port means located in the upper part of said cylinder above the piston and means in response to the opening of said inlet ports for actuating the outlet port to open and close with the said inlet ports.

Claim 7

A downhole piston pump for producing well liquids from a subsurface reservoir comprising a piston adapted to reciprocate coaxially within a cylinder adapted to be immersed within said reservoir and being provided with a travelling valve, said cylinder comprising inner and outer coaxially disposed barrels relatively movable in an axial direction, a multiplicity of inlet ports passing thru said barrels and in free and open communication with said reservoir, means to effect relative movement of said barrels in an axial direction between open position in which said inlet ports on the inner and outer barrels are in registration, and closed position where each inlet port is closed by the imperforate wall of the opposite barrel, said ports being distributed in the wall of said cylinder throughout the area between the lower extremity thereof and the lower part of the piston at the upper end of its stroke, sleeve means on said piston adapted to limit opening of said ports to the space below said piston and means to shift said barrels to inlet port open position in response to initiation of upward movement of the piston said last named means being actuated by the weight of the column of produced liquid being delivered by the pump for closing said ports in response to initiation of movement of the piston in a downward direction.

Claim 8

A downhole piston pump for producing well liquids from a subsurface reservoir comprising a piston adapted to reciprocate coaxially within a cylinder adapted to be immersed within said reservoir and being provided with a travelling valve, said cylinder comprising inner and outer coaxially disposed barrels relatively movable in an axial direction, a multiplicity of inlet ports passing thru said barrels and in free and open communication with said reservoir, means to effect relative movement of said barrels in an axial direction between open position in which said inlet ports on the inner and outer barrels are in registration, and closed position where each inlet port is closed by the imperforate wall of the opposite barrel, said ports being distributed in the wall of said cylinder throughout the area between the lower extremity thereof and the lower part of the piston at the upper end of its stroke, sleeve means on said piston adapted to limit opening of said ports to the space below said piston and means to shift said barrels to inlet port open position in response to initiation of upward movement of the piston said last named means being actuated by the weight of the column of produced liquid being delivered by the pump for closing said ports in response to initiation of movement of the piston in a downward direction.

Claim 9

A downhole piston pump as defined in claim 6 wherein said last named means is adapted to shift said barrels relatively to inlet port closed position in response to initiation or movement of piston in a downward direction.