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Wellbore Stability Analysis of Gas Drilling in Carboniferous System of Dzungaria Basin
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, IPTC 2013: International Petroleum Technology Conference, Mar 2013, cp-350-00550
Abstract
During drilling operation in carboniferous system of Dzungaria basin, igneous rock was met, which leads to a low penetration rate and long drilling cycle, because of large thickness, high hardness and poor drillability of the igneous rock. Quasi-three axis confining pressure experiment was carried out with the igneous rock core of WUCAN 1 well. Experimental results showed that the igneous rock keeps a brittle fracture even in the confining compression pressure of 40MPa. Based on Mohr- Coulomb failure criterion, one analysis method about the applicability of gas drilling was put forward through comparing maximum principal stress while wellbore instability happened with upper-cover pressure. It can be concluded that gas drilling technology can be applied in carboniferous igneous strata of Dzungaria basin, when embedding depth is less than 6110 meters, which provides theoretical basis on the application of gas drilling technology in deep exploratory wells whose target zone is in igneous strata of carboniferous system of Dzungaria basin.