New Insights into Improving the Plugging Effect of Plugging Zone in Fractured Tight Gas Reservoir
Abstract
Lost circulation is one of the problems that impede safe and fast drilling in fractured tight gas reservoir. Based on the numerical simulation and plugging experiments, new insights about improving the plugging effect were proposed in this paper. Fracture was divided into fracture mouth, fracture narrow, and fracture tip. Plugging zones were evaluated which formed at the fracture mouth and fracture narrow, respectively. Experiments results showed that the plugging effect at these two positions is different. The average MPP (Maximum plugging pressure) of the plugging zone formed at fracture mouth was only 5.2MPa, but the average MPP of the plugging zone formed at fracture narrow could reach more than 9.2MPa. Moreover, to reach the same MPP, plugging at fracture narrow needed less lost-circulation materials (LCMs) and lower fluid loss compared with plugging at fracture mouth. This work indicates that plugging at fracture narrow can get a better plugging effect than plugging at fracture mouth, which has been successfully confirmed in HB field in northeast Sichuan Basin.References
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