| 摘要 |
<p>A downhole pressure activated device and a method of operating a tool (21) downhole by applying pressure are described. The device comprises a chamber (18) which has a fluid port for communication between the chamber (18) and downhole fluid located outwith the device. The fluid port preferably comprises a check valve (17) and a fluid flow restrictor (15) connected in parallel, where preferably, the check valve (17) permits fluid flow into the chamber (18) and substantially prevents reverse flow. The chamber (18) is provided with a pressure transmission means (14, 14a, 40) by which a pressure in the chamber (18) greater than that in the downhole fluid is capable of being applied to a tool (21) to be operated by the device.</p> |
