Patent ID: 8613317
Filing Date: 2013-12-24
Classification: E21B,F04B

Abstract:
1. A method, comprising: supplying a hydraulic pressure via a hydraulic fluid to a positive displacement pump of a downhole tool to actuate a two-stroke piston, having a first head positioned in a first cylinder and a second head positioned in a second cylinder, to displace other fluid at least partially through the downhole tool, wherein the first head divides the first cylinder into a first pump chamber and a first fluid chamber and wherein the second head divides the second cylinder into a second pump chamber and a second fluid chamber; moving the piston in a first stroke direction by supplying the hydraulic fluid to the first pump chamber; detecting a pressure increase caused by the piston abutting an inner wall of the first cylinder to foreclose a volume of the first fluid chamber; actuating a valve, in response to detecting the pressure increase, to reverse the direction of the piston by supplying the hydraulic fluid to the second pump chamber.