Modular subsurface lift engine

A modular subsurface lift engine, comprising:

• an upper valve housing adapted to connect to a production tubing supported by a wellhead of a cased well bore, the upper valve housing having an upper valve seat and an upper valve for controlling a flow of produced fluid through the subsurface lift engine during a down-stroke thereof;
• an upper crossover sleeve connected to a bottom end of the upper valve housing;
• an upper transition sleeve connected to a bottom end of the upper crossover sleeve, the upper transition sleeve having an upper crossover tube that is connected to a bottom of a transition travel limiter, the crossover sleeve extending through a central passage in a bottom of the upper transition sleeve;
• at least one subsurface lift engine module connected to a bottom end of the upper transition sleeve and comprising a modular cylinder sleeve, a modular cylinder piston that reciprocates within the modular cylinder sleeve, and a modular cylinder tube connected to a lower side of the modular cylinder piston and extending through a passage in a modular cylinder sleeve bottom wall of the modular cylinder sleeve;
• and
• a lower crossover sleeve having a lower valve housing with a lower valve seat and a lower valve for controlling a flow of produced fluids through the subsurface lift engine during an up-stroke thereof, the lower crossover sleeve being adapted to connect to a production packer that isolates an annulus of the cased well bore surrounding the modular subsurface lift engine from an annulus of the cased well bore below the production packer.

A modular subsurface lift engine, comprising:

• at least one subsurface lift engine module adapted to be connected end-to-end to other subsurface lift engine modules, each subsurface lift engine module comprising:
• a modular cylinder sleeve having an open top end, a cylinder sleeve bottom wall with a central passage therein, and at least two cylinder sleeve ports adjacent the cylinder sleeve bottom wall to provide fluid communication through the modular cylinder sleeve with a modular cylinder lift chamber;
• a modular cylinder piston with a modular piston seal that provides a high-pressure fluid seal between an inner wall of the modular cylinder sleeve and the modular cylinder piston, the modular cylinder piston having an upper travel limiter and a lower travel limiter to limit travel of the modular cylinder piston in the modular cylinder sleeve;
• a modular cylinder tube connected to the bottom travel limiter of the modular cylinder piston and extending through a high pressure fluid seal in the central passage in the modular cylinder bottom wall, the modular cylinder tube having at least two modular cylinder tube ports that provide fluid communication through a sidewall of the modular cylinder tube with a modular cylinder pump chamber above the modular cylinder piston in an adjacent lower modular cylinder sleeve;
• an upper valve housing adapted to connect a production tubing supported by a wellhead of a cased well bore, the upper valve housing having an upper valve seat and an upper valve for controlling a flow of produced fluids through the subsurface lift engine during a down-stroke thereof;
• an upper crossover sleeve connected to a bottom end of the upper valve housing;
• an upper transition sleeve connected to a bottom end of the upper crossover sleeve, the upper transition sleeve having a bottom end connected to the at least one lift engine module, and further having an upper crossover tube that is connected to a bottom end of an upper transition travel limiter that reciprocates within the upper transition sleeve, the upper crossover tube extending through a central passage in a bottom of the upper transition sleeve;
• and
• a lower crossover sleeve having a lower valve housing with a lower valve seat and a lower valve for controlling a flow of produced fluid hydrocarbons through the subsurface lift engine during an up-stroke thereof, the lower crossover sleeve being adapted to connect to a production packer that isolates the subsurface lift engine from an annulus of the cased well bore below it, the production packer supporting a production tubing that extends downwardly through the cased hydrocarbon well to fluids in the cased well bore.