Wireline pump

Abstract

The present invention relates to a wireline pumping assembly (1) for being introduced in a wellbore (60) or a casing (61) and submerged in well fluid. The wireline pumping assembly extends in a longitudinal direction (50) and is adapted for connection with a wireline. Furthermore, the wireline pumping assembly comprises a pump section (2) comprising a tubular pump housing (20) providing a pump chamber (210); one or more inlets (21) provided in a lower part of the tubular pump housing; a first valve (22) for opening and closing the inlet; a plunger (23) being slidingly disposed in the pump chamber, the plunger comprising a second valven (242) controlling a flow of fluid from a first compartment (202) of the pump chamber below the plunger to an second compartment (203) of the pump chamber above the plunger; a pump rod (26) operably connected to the plunger and extending from the plunger through the tubular pump housing; and one or more outlets (27) provided in an upper part of the tubular pump housing. The wireline pumping assembly further comprises a linear actuator (40) arranged in association with the tubular pump housing for driving the pump rod, whereby, when the wireline pumping assembly is at least partially submerged into the well fluid, well fluid is drawn into the tubular pump housing through the one or more inlets, forced through the second valve of the plunger, and expelled through the one or more outlets in the upper part of the tubular pump housing, wherein the linear actuator comprises a tubular stroker cylinder (4) comprising one or more piston housings (47), one or more piston elements (46) slidingly disposed in the piston housing to divide the piston housing into a first chamber (41) and a second chamber (42), a stroker shaft (45) operably connected to the piston element and for connection with the pump rod to provide reciprocation of the plunger, a pump (5) for alternately supplying hydraulic fluid under pressure to the first chamber and the second chamber of the tubular stroker cylinder to reciprocate the piston element in the tubular stroker cylinder, and an electrical motor (6) for driving the pump. Furthermore, the invention relates to a use of the wireline pumping assembly, a method of initiating a well using a wireline pumping assembly and a method of optimising an initiation operation.

Dependencies are inferred from the claim text.