| 摘要 |
A pressure-compensation system is in fluid communication with the annular space between the body of the packer or plug and the inflatable element. The compensation system responds to thermally induced pressure load changes within the wellbore by allowing fluid to escape from beneath the inflated element when increases in fluid temperature in the wellbore increase the pressure under the element. The system additionally supplies fluid behind the element should the wellbore fluids decrease in temperature, thus lowering the pressure under the inflatable element. When the packer 12 is expanded pressure passes along passage 18 to move piston 48. This moves until it contacts piston 60. Fluid in cavity 54 is vented via ports 70. If there is a further pressure increase due to a temperature rise piston 48 moves piston 60. This causes fluid in chamber 72 to pass along passage 74 and through one way valve 90. The fluid is accomodated by movement of piston 88. If there is a temperature fall fluid can pass along passage 90 and through one way valve 100 to move pistons 60 and 48 to push fluid into the packer. |
