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 is disclosed. 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. The downhole flow control means of the zone isolating and testing apparatus comprises two valves, one for closing off the annulus between the inner tube and outer tube of the concentric drill string and the other for closing off the inner space of the inner tube. The downhole flow control means is also adapted to connect to concentric drill string near the drilling means. During testing, the isolation tool seals off the annulus between the concentric drill string and the walls of the wellbore and the downhole flow control means seals off either the annulus between the inner tube and outer tube of the concentric drill string or the inner space of the inner tube of the concentric drill string.

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First Claim