Patent ID: 7562713
Filing Date: 2009-07-21
Classification: E21B

Abstract:
1. A downhole tool, comprising: a tubular housing defining an annular space; an oil piston disposed inside the annular space; a first member disposed inside the annular space and comprising an orifice; an oil chamber disposed in the annular space defined by the oil piston, the first member and the tubular housing, wherein the oil chamber comprises oil; a sliding element disposed inside the annular space, wherein the first member is located between the oil piston and the sliding element; a second chamber to receive oil communicated through the orifice in response to actuation of the oil piston; a third chamber in fluid communication with the sliding element to receive oil communicated from the second chamber; and a second member between the sliding element and the first member, wherein the second member comprises a port having a rupture disc contained therein and in fluid communication with the third chamber to block all communication of the oil from the second chamber to the third chamber until the second chamber fills with oil communicated from the oil chamber.