Genetic Mechanism of Overpressure Large Gas Field(Reservoir)——An example from Kuqa depression in Tarim basin

Based on the previous study results,the influence of overpressure on the reservoir-forming factors such as source rock,reservoir and cap rock was analyzed,and the control effect of overpressure on natural gas migration and accumulation was researched.Taking Kuqa depression in Tarim basin as an example,combining with histories of hydrocarbon generation,trap formation and overpressure evolution,the genetic mechanism of overpressure large gas field in Kuqa depression was analyzed.The results show that the overpressure plays a significant role in its formation process by inhibiting the evolution of the Jurassic source rock,improving the quality of the Cretaceous reservoir and enhancing the seal ability of the Paleocene gypsum mudstone cap rock,and provides potential power for the episodic hydrocarbon expulsion and secondary hydrocarbon migration in this area.