Downhole inflatable packer pump and testing apparatus
First Claim
1. A downhole pump comprising:
- case means attachable to a lower testing string portion and defining a pumping chamber therein;
mandrel means connectable to an upper testing string portion for mutual rotation therewith and rotatable within said case means, said mandrel means comprising cam means thereon and said case means and said mandrel means defining a piston chamber therebetween;
piston means disposed in said piston chamber and having cam follower means thereon for following said cam means and reciprocating said piston means with respect to said case means in response to rotation of said mandrel means with respect to said case means;
diaphragm means sealingly positioned between said piston chamber and said pumping chamber and preventing fluid communication therebetween, whereby fluid movement in said pumping chamber is responsive to fluid movement in said piston chamber and;
pressure equalizing means for equalizing a hydrostatic fluid pressure in said pumping chamber with a hydrostatic fluid pressure in said piston chamber.
2 Assignments
0 Petitions
Accused Products
Abstract
A downhole inflatable packer pump for use in a testing string. The pump includes an upper mandrel rotatably disposed in a case. The upper mandrel includes a pump cam with a cam slot thereon. A piston cavity is defined between the case and inner mandrel in which a single, sleeve-type piston is reciprocably disposed. A cam roller on the piston engages the cam slot, and as the inner mandrel rotates, the piston is reciprocated. A diaphragm sealingly separates the piston chamber from a pumping chamber. Inlet and outlet check valves with annular resilient lips allow fluid flow into the pumping chamber from the well annulus and out of the pumping chamber into an outlet chamber in communication with the lower portion of the testing string. The piston chamber is filled with a lubricating oil, and pumping action of the reciprocating pump piston causes movement of the oil which is transmitted to the pumping chamber through the diaphragm. An equalizing chamber allows equilization of hydrostatic pressures between the piston chamber and the well annulus. A pressure limited is included for limiting a pressure differential between the pumping chamber and the well annulus to a predetermined level. Fluid from the pumping chamber is not directly bypassed to the well annulus.
43 Citations
18 Claims
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1. A downhole pump comprising:
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case means attachable to a lower testing string portion and defining a pumping chamber therein; mandrel means connectable to an upper testing string portion for mutual rotation therewith and rotatable within said case means, said mandrel means comprising cam means thereon and said case means and said mandrel means defining a piston chamber therebetween; piston means disposed in said piston chamber and having cam follower means thereon for following said cam means and reciprocating said piston means with respect to said case means in response to rotation of said mandrel means with respect to said case means; diaphragm means sealingly positioned between said piston chamber and said pumping chamber and preventing fluid communication therebetween, whereby fluid movement in said pumping chamber is responsive to fluid movement in said piston chamber and; pressure equalizing means for equalizing a hydrostatic fluid pressure in said pumping chamber with a hydrostatic fluid pressure in said piston chamber. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A downhole pump assembly comprising:
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an outer case defining a longitudinally central opening therethrough and having a lower end adapted for attachment to a lower testing string portion, said outer case defining; inlet passageway means for providing communication between said central opening and a well annulus; and outlet passageway means for providing communication between said central opening and said lower testing string portion; an upper mandrel comprising;
an upper end adapted for attachment to an upper testing string portion;a lower end rotatably disposed in said central opening of said case such that a generally annular, downwardly opening piston chamber is defined between said upper mandrel and said case; and a cam on said lower end; and a generally annular piston reciprocably disposed in said piston chamber; a cam follower on said piston and engageable with said cam for reciprocating said piston in response to relative rotation between said upper mandrel and said case; a lower mandrel disposed in said central opening below said upper mandrel such that a generally annular, upwardly opening pumping chamber is defined between said lower mandrel and said case, said pumping chamber being adjacent said inlet and outlet passageway means, said lower mandrel having a fixed operating position with respect to said case; an annular diaphragm sealingly disposed between said piston chamber and said pumping chamber and preventing fluid communication therebetween; an inlet valve disposed across said inlet passageway; an outlet valve disposed across said outlet passageway; and a volume of fluid filling said piston chamber; wherein, as said upper mandrel is rotated with respect to said case, said piston is reciprocated in said piston chamber and generates fluid movement therein, thus causing a corresponding reciprocation of said diaphragm such that upward movement of said diaphragm results in fluid from said well annulus being drawn into said pumping chamber across said inlet valve and downward movement of said diaphragm results in fluid in said pumping chamber being discharged therefrom across said outlet valve. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A downhole testing tool for use on a testing string in a well annulus and having a central flow passageway therethrough, said tool comprising:
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a tester valve; a pump defining a piston chamber and a pumping chamber therein and comprising; a reciprocating piston positioned in said piston chamber; diaphragm means sealingly separating said piston chamber and said pumping chamber, said diaphragm means being flexibly responsive to movement of said piston; and hydrostatic equalizing means for equalizing hydrostatic fluid pressure in said pumping chamber with hydrostatic fluid pressure in said piston chamber to prevent rupture of said diaphragm means; a packer positionable in said well annulus above a formation to be tested, said packer being inflatable by said pump into sealing engagement with said well annulus and deflatable by upward movement of said testing string; and a porting sub positionable adjacent said formation for allowing well fluid flow therethrough into said central flow passageway during a testing operation. - View Dependent Claims (16, 17, 18)
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Specification