Piston and valve assembly

A downhole hydraulically actuated pump assembly comprising a main body within which there is formed an engine chamber and a production chamber;

• an engine piston reciprocatingly received within said engine chamber and dividing said engine chamber into a hydrostatic chamber and a power chamber;
• passageway means formed through said main body through which fluid can flow into and out of said hydrostatic chamber in response to reciprocation of said engine piston;
• a pump plunger reciprocatingly received within said production chamber, means connecting said plunger to said piston to impart reciprocal movement into said plunger, production inlet valve means by which formation fluid can flow into said production chamber, production outlet valve means by which produced fluid can be forced from said production chamber;
• a control rod means axially aligned with said engine piston and said hydrostatic chamber, said control rod is stationary respective to said main body, a valve sleeve concentrically arranged respective to said control rod, means mounting said valve sleeve within said piston for reciprocation between two alternant positions in response to the relative location of the control rod respective to the piston;
• means forming a first flow path which extends axially through said control rod, through said valve sleeve, and into said power chamber whereby power fluid effected within said control rod forces said piston to stroke uphole when said sleeve is in one alternate position;
• means forming a spent power fluid flow path which extends from said power chamber into said piston, through said valve sleeve and into said hydrostatic chamber so that spent power fluid can be exhausted from said power chamber when said valve sleeve is in the other alternant position;
• whereby power fluid forces said piston to stroke uphole and thereafter hydrostatic pressure forces said piston to stroke downhole, thereby reciprocating said plunger and causing formation fluid to flow through said production chamber in response to reciprocal action of said pump plunger.

A single action long stroking hydraulically actuated downhole pump having a main body within which there is formed a cylindrical bore;

• an engine and a pump plunger reciprocatingly received within the cylindrical bore;
• said piston and plunger being spaced apart and rigidly connected to one another in axially aligned relationship respective to one another and to the main body cylindrical bore;
• said plunger having opposed faces and forming part of said cylindrical bore into a production chamber, a blind passageway formed through said piston which terminates in spaced relationship respective to one face of the plunger, a valve control rod axially aligned respective to said piston and plunger, said rod terminates in spaced relationship respective to the blind end of the blind passageway;
• a valve sleeve reciprocatingly received within said engine, means by which the sleeve is urged to reciprocatingly move into one of two alternate positions in response to relative movement between the piston and the control rod;
• said piston divides the cylindrical bore into a power chamber and a hydrostatic chamber, flow passageway means by which well fluid can flow into and out of said hydrostatic chamber thereby effecting a hydrostatic force on one end of the piston;
• passagway means extending through the control rod, into an annulus formed between the control rod and the blind passageway, into said sleeve, through part of the piston, and into said power chamber whereby said sleeve is moved into one alternant position to cause power fluid to flow into the power chamber and force the piston to stroke uphole;
• means forming an exhaust passageway from said power chamber into said piston, into said sleeve, and through said piston to said hydrostatic chamber so that spent power fluid can flow from said power chamber, through said piston, into said hydrostatic chamber, where spent power fluid can exit the pump main body and co-mingle with production fluid and flow to the surface of the earth;
• inlet and outlet check valve means associated with said production chamber by which formation fluid is forced to flow into said production chamber, through the outlet check valve, and uphole to the surface of the earth.