FremgangsmÕte og anordning for bruk ved oppblÕsing av pakning i br°nnboring

PCT No. PCT/CA97/00092 Sec. 371 Date Mar. 26, 1998 Sec. 102(e) Date Mar. 26, 1998 PCT Filed Feb. 10, 1997 PCT Pub. No. WO97/30266 PCT Pub. Date Aug. 21, 1997A system for relieving pressurized fluid entrapped in a annular space between a casing (12) and the surrounding wall (11) of a well bore hole (10) during deployment of a packer exterior (14) of the casing (12) for sealing engagement with the wall (11). When packer (14) is inflated in a zone (17) where fluid is entrapped, such as an intermediate packer between two previously inflated packers (13, 14), the squeeze pressure developed by the inflating packer (14) has been found to be sufficient to prevent effective and lasting sealing of the intermediate packer (14). The present system includes a valve mechanism (35) which is activated by the pressurized fluid providing for inflating the packer (14) to open a passageway (90, 94, 91) to bleed the entrapped fluid into the casing (12) and to then close the passageway (90, 94, 91) as inflation of the intermediate packer (14) is completed.