Key Technologies for the Safe Drilling of Fractured Carbonate Gas Reservoirs in the Shunbei Oil and Gas Field

In order to solve the problems created by the coexistence of overflow and circulation lost during drilling through fractured carbonate gas reservoirs in the Shunbei Oil and Gas Field and to ensure drilling safety, a technical solution was worked out by means of analyzing the causes of the coexistence of overflow and lost circulation in fractured carbonate gas reservoirs. According to this solution, the first thing to do is to temporarily block fractures that prevent gas invasion into the wellbore, and in the case of gas influx, it is necessary to control the amount of gas influx and the speed of gas channeling to ensure drilling safety. Based on this, tje key technologies for the safe drilling of fractured carbonate gas reservoirs involves integrating temporary blocking technology for fractured reservoirs, using MPD and implementing high temperature gas-block plugging. First, the temporary blocking technology for fractured gas reservoirs should be used to prevent gas from entering the wellbore. In case of gas influx occurs in the bottom hole, MPD should be used to control the influx amount, while high temperature gas-block plugging should be adopted to reduce the speed of gas channeling if the gas is found in the wellbore. After the application of such key technologies in the fractured carbonate gas reservoir in the Shunbei Oil and Gas Field, the coexistence of overflow and circulation lost was solved and drilling speed was increased and the drilling safety ensured.