Importance

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Abstract

A zone isolating and testing apparatus comprising an isolation tool and a downhole flow control means and a method of using such apparatus. The zone isolating and testing apparatus is particularly useful for testing zones during reverse circulation drilling using concentric drill string such as concentric drill pipe or concentric coiled tubing. The isolation tool of the zone isolating and testing apparatus comprises an expandable packer means and is adapted to connect to concentric drill string near the drilling means and be in fluid communication with the concentric drill string. The downhole flow control means of the zone isolating and testing apparatus comprises at least two valves, one for closing off the annular conduit between the inner tube and outer tube of the concentric drill string and the other for closing off the inner conduit of the inner tube. The downhole flow control means is also adapted to connect to concentric drill string near the drilling means and be in fluid communication with the concentric drill string. During testing, the isolation tool seals off the annular passage between the concentric drill string and the walls of the wellbore and the downhole flow control means seals off either the annular conduit or the inner conduit of the concentric drill string.

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First Claim