Packer

摘要

A packer for a well comprises a seal element and seal setting apparatus. The seal setting apparatus is moveable with respect to the seal element in a setting direction to apply a setting force to the seal element to move the seal element from a run-in configuration to a set configuration in which the seal element forms a contact seal with a conduit wall. The packer is arranged such that, in the set configuration, a pressure differential across the packer, which creates a force in the setting direction, will increase the setting force applied by the seal setting apparatus to the seal element to maintain the seal.

主权项

1. A tool for engaging a surrounding surface of a non-round hole, the tool comprising:
an engagement apparatus for engaging the surrounding surface; setting force application means for applying the a setting force; and a plurality of relief devices, each of the relief devices being associated with a corresponding portion of the engagement apparatus, wherein application of the setting force by the setting force application means collectively to the plurality of relief devices causes each relief device to transmit a corresponding force to the corresponding portion of the engagement apparatus causing initial extension of each portion of the engagement apparatus in a corresponding direction towards the surrounding surface until a first portion of the engagement apparatus seals against the surrounding surface, whereupon further extension of the first portion of the engagement apparatus towards the surrounding surface is prevented, and whereupon, as the setting force is increased, the force transmitted by a corresponding first one of the relief devices to the first portion of the engagement apparatus increases until the force transmitted by the first one of the relief devices to the first portion of the engagement apparatus reaches a corresponding pre-determined maximum force, whereupon the first one of the relief devices continues to transmit the corresponding pre-determined maximum force but transmits no more than the corresponding pre-determined maximum force as the setting force application means further increases the setting force applied collectively to the plurality of relief devices.