Hydraulically actuated pump assembly having mechanically actuated valve means

In a fluid-operated pump assembly for operation downhole in a wellbore, wherein means are provided to convey power fluid from the surface of the ground downhole to the pump assembly, spent power fluid uphole to the surface of the ground, and formation fluid produced by the pump uphole to the surface of the ground;

• the pump assembly having a valve and engine section, and a pump section, all connected together to form said pump assembly;
• with the valve section controlling the flow of power fluid into and from the engine to thereby enable the engine to extract power from the power fluid, and with there being connecting rod means directly by which the engine section drives the pump section to enable the pump to perform the stated function of lifting fluid uphole;
• the improvement comprising:
• said engine section includes an engine cylinder having an engine piston reciprocatingly received therein, said engine piston dividing said engine cylinder into an upper and a lower cylindrical engine chamber;
• a control valve assembly which includes a control rod and a valve element;
• means forming an axial bore within said piston, said control rod being axially aligned and reciprocatingly received within said axial bore such that an annulus is formed therebetween;
• said valve element being reciprocatingly received within said annulus;
• a power fluid flow passageway means extending from the lower engine chamber to said valve assembly and from said valve assembly to said upper engine chamber;
• means connected to said control rod and to the cylinder of said engine for moving said control rod to cause said control rod to reciprocate between two alternant positions in response to reciprocal movement of the engine piston respective to the engine cylinder to thereby cause said valve element to shift between an upper and a lower alternant position;
• said pump section includes a production barrel having a production piston reciprocatingly received therein, said production piston dividing said barrel into upper and lower production chambers;
• said upper production chamber being directly connected to a produced fluid outlet;
• said lower production chamber having means forming an inlet and an outlet so that formation fluid can flow into the inlet and produced fluid can flow through the outlet;
• means connecting said lower engine chamber directly to a power fluid inlet;
• said connecting rod being hollow;
• flow passageway means extending from said valve element, through said engine piston, through the interior of the connecting rod, and into the upper production chamber through which spent power fluid may be exhausted from the upper engine chamber on the upstroke;
• whereby:
• said upper engine chamber is alternately connected to said power fluid source and said upper production chamber while said lower engine chamber is always connected to a power fluid source to thereby cause the engine piston to reciprocate the production piston.

In a fluid-operated pump assembly for operation downhole in a wellbore, including means to convey power fluid from the surface of the ground downhole to the pump assembly and spent power fluid and produced fluid uphole to the surface of the ground;

• said pump assembly having an engine section and a pump section, all connected together to form said pump assembly, said engine section includes a valve section for controlling the flow of power fluid into and from the engine section to thereby enable the engine section to extract power from the power fluid, and with there being connecting means by which the engine section drives the pump section to enable the pump section to perform the stated function of lifting fluid uphole;
• the improvement comprising:
• said engine section includes a cylinder having an engine piston reciprocatingly received therein, said engine piston dividing said cylinder into an upper and a lower cylindrical engine chamber;
• said pump section includes a pump barrel, a production piston reciprocatingly received within said pump barrel, rod means connected to said engine piston and pump piston so that said engine piston reciprocates said pump piston;
• means forming an axial bore within said engine piston, a control rod axially aligned and reciprocatingly received within said axial bore such that an annulus is formed therebetween;
• a valve element reciprocatingly received within said annulus;
• power fluid flow passageway means extending from a power fluid source to said valve element and from said valve element to said upper engine chamber;
• spent power fluid flow passageway means extending from said valve element, through said connecting rod, and to said upper production chamber;
• means by which said control rod reciprocates between two alternant positions in response to reciprocal movement of said engine piston respective to said engine cylinder, to thereby cause said valve element to shift between an upper and a lower alternant position;
• so that said upper engine chamber is alternately connected to said power fluid source and said production fluid outlet;
• to thereby cause the engine piston to reciprocate the production piston.