Abstract: A wellhead hydraulic drive unit to operate various styles of downhole pumps, including a hydraulic cylinder having a piston positioned therein for reciprocation within the cylinder; hydraulic fluid supply conduits contained within the hydraulic cylinder and fluidly communicative with the piston such that hydraulic fluid flowing through the hydraulic fluid supply conduits produces reciprocation of the piston within the hydraulic cylinder, a ram within the cylinder and operably connected to the piston, the ram having a bore; and production tubing inserted through the bore of the ram for enabling well fluid to be discharged from the well, wherein the hydraulic fluid supply conduits are radially offset from a longitudinal axis of the cylinder and the ram is oppositely radially offset from the longitudinal axis of the cylinder.

Abstract: The present invention provides a wellhead hydraulic drive unit to operate various styles of downhole pumps, which is installed as an integral part of a wellhead thereby eliminating the need for a stuffing box. The wellhead hydraulic drive unit comprises a hollow hydraulic cylinder having a piston positioned therein, a hydraulic fluid supply attached to the hydraulic cylinder for raising the piston within the hydraulic cylinder, a hollow ram slideably received within the inner wall of the hydraulic cylinder and connected to the piston for reciprocation in response to the piston; and a production tube inserted through the ram for enabling well fluid to be discharged from the well.

Abstract: The present invention provides a wellhead hydraulic drive unit to operate various styles of downhole pumps, which is installed as an integral part of a wellhead thereby eliminating the need for a stuffing box. The wellhead hydraulic drive unit comprises a hollow hydraulic cylinder having a piston positioned therein, a hydraulic fluid supply means attached to the hydraulic cylinder for producing reciprocation of the piston within the hydraulic cylinder, a hollow ram means slideably received within the inner wall of the hydraulic cylinder and connected to the piston for reciprocation in response to the piston; and a production tube means inserted through the ram means for enabling well fluid to be discharged from the well.

Abstract: An apparatus and method for pumping fluids in a wellbore. The apparatus includes a pipe string in the wellbore extending between a wellhead end and a production end, the pipe string defining an interior fluid path. A swivel device is connected into the pipe string so that an upper portion of the pipe string rotates relative to a lower portion thereof. A lower connector connects the lower portion with a stator of a rotary pump such that a fluid pumped by the pump is conducted through the interior fluid path of the pipe string. An upper connector connects the upper portion with a rotor of the rotary pump such that rotation of the upper portion rotates the rotor and thus pumps the fluid. The method includes rotatably supporting the upper portion in the wellbore at the wellhead end, connecting the lower portion with the stator, connecting the upper portion with the rotor, positioning the pump in the wellbore and rotating the upper portion in order to rotate the rotor to pump the fluid.