Valving system for a downhole hydraulically actuated pump

1. A hydraulically actuated downhole pump comprising:

a power piston vertically reciprocated in a power cylinder;

a reversing valve carried with said power piston and serving, when in a first position, to direct fluid flow to force said piston upwardly in said cylinder and in a second position to provide bypass fluid flow to cause said piston to move downwardly in said cylinder;

a pilot valve carried by said power piston and having an upper and a lower position and serving when in said lower position to direct fluid flow to move said reversing valve from said first to said second position;

a probe fixedly secured relative to said cylinder and configured to move said pilot valve to said lower position when said piston reaches an upper limit of travel, wherein said probe includes a downwardly extending essentially closed conduit at its upper end and except for at least one orifice to control flow of hydraulic fluid as said piston reaches said upper limit of travel;

a pump cylinder in fixed and in coaxial relationship to said power cylinder;

a pump piston reciprocated within said power cylinder;

a pump rod interconnecting said power piston and said pump piston; and

valves actuated in response to movement of said pump piston to cause pumping of fluid.

2. A hydraulically actuated downhole pump according to claim 1 including a reversing valve spool within said reversing valve and a pilot valve spool within said pilot valve, and wherein said reversing valve spool and said pilot valve spools are structurally uncoupled from each other.

3. A hydraulically actuated downhole pump according to claim 2 wherein said reversing valve is controlled in part by hydraulic action initiated by said pilot valve spool.

4. A hydraulically actuated downhole pump according to claim 3 wherein said reversing valve spool is controlled in part by a momentary change of positions of said pilot valve spool.

5. A hydraulically actuated downhole pump according to claim 1 wherein said reversing valve and said pilot valve are housed in a tubular engine mandrel in tandem coaxial relationship.

6. A hydraulically actuated downhole pump responsive to hydraulic pressure from fluid supply tubing that extends from the earth's surface, the pump having a piston vertically reciprocal between a top position and a bottom position in a cylinder, and an engine, formed as a part of said piston, to force fluid from an underground formation to the earth's surface upon upward movement of the piston and to permit fluid bypass as the piston moves downwardly in the cylinder said engine including:

a reversing valve carried with the pump piston having a first position and a second position, means in said first position to open passageways to direct fluid pressure from the fluid supply tubing to force the piston upwardly in the pump cylinder to said top position and when in said second position to open a flow channel to cause the piston to move downwardly;

a pilot valve carried with the pump piston having an upper and a lower position, the pilot valve having means to control flow passageways to hydraulically move said reversing valve from said first position to said second position; and

an actuator probe within an upper portion of said pump having a downwardly extending essentially closed conduit at its upper end except for at least one orifice to control flow of hydraulic fluid as said engine approaches said top position and arranged to receive and move said pilot valve from said upper to said lower position when the piston reaches an upward travel limit and thereby cause said reversing valve to move from said first to said second position to thereby reverse the direction of travel of the piston to the downward direction.

7. A hydraulically actuated downhole pump according to claim 6 including a vertically positionable reversing valve spool within said reversing valve and a vertically positionable pilot valve spool, and wherein said reversing valve spool and said pilot valve spool are structurally independent of each other.

8. A hydraulically actuated downhole pump according to claim 7 wherein said reversing valve is controlled in part by hydraulic action initiated by positions of said pilot valve spool.

9. A hydraulically actuated downhole pump according to claim 8 wherein the position of said reversing valve spool is controlled in part by a momentary change of positions of said pilot valve spool.

10. A hydraulically actuated downhole pump according to claim 6 wherein said reversing valve and said pilot valve are in tandem coaxial relationship and housed in a tubular engine mandrel.

11. A hydraulically actuated downhole pump according to claim 6 wherein said engine includes an essentially square combined upper pilot valve body and a lower reversing valve sleeve defining an upper and a lower axial central passageway;

a plurality of spaced flow control openings in said reversing valve sleeve;

a first longitudinal passageway communicating from an opening in said upper central passageway of said pilot valve body with said lower central passageway above said flow control openings;

a second longitudinal passageway below said opening from said first longitudinal passageway communicating said upper central passageway of said pilot valve body with the bottom of said reversing valve sleeve;

said pilot valve being reciprocable to substantially open and close flow through said first and second longitudinal passageways;

said reversing valve being reciprocable to substantially open and close flow through said flow control openings in said reversing valve sleeve as a function of a position of said pilot valve.