库车坳陷克拉2气藏异常压力成因分析

异常地层压力的成因是油气成藏过程研究的重要内容。通过分析气层气体压力-温度-比容（p-T-C）状态以及应力的分配机制对库车坳陷克拉2气藏的异常地层压力成因进行了分析，并使用R-K-S真实气体方程计算了克拉2气藏气体聚集造成的压力。结果表明，克拉2气藏气体聚集（充注）形成了气藏现今约59.54 MPa的流体压力，占整个地层压力异常的57.12%。气体和岩石压缩系数的巨大差异导致应力分配机制不符合线性关系，而与应力变化范围内的岩石和气体压缩系数积分比有关。计算了喜山中、晚期以来构造应力在克拉2气藏的分配，其中约10.6MPa的剩余压力来源于构造挤压，为不足气藏剩余压力的42.4%。克拉2气藏超压的主要成因为充气作用，其次为构造挤压作用。

Abnormal pressure origin analysis of Kela 2 gas pool in Kuqa depression of Tarim basin

The genesis of abnormal pressure in petroliferous basins is important for studying mechanism of hydrocarbon reservoir.On the basis of analysis of p-T-C state and allotment of stress between rock and gas on gas pool,the mechanism of abnormal pressure in Kela 2 gas pool was discussed.The calculation results obtained from R-K-S gas state equation show that more than 59.54 MPa formation pressure,which is 57.12% of gas pool's abnormal pressure in Kela 2 nowadays,was derived from gas accumulation.The allotment of stress between rock and gas doesn't coincide linear relation,which is resulted from great difference of compression factor between them.It is related to the integral ratio of compression factor between rock and gas.The calculation results show that only 10 MPa,less than 42.4% excess pressure of gas pool, is derived from tectonic compression in Kela 2 gas pool.So the mainly controlling factor of overpressure is gas accumulation.Tectonic compression is the secondly contributing factor on overpressure.