塔里木盆地库车坳陷油气成藏的若干特征

Some characteristics of oil and gas accumulation in the Kuqa depression,Tarim basin

库车坳陷发育2大类6套烃源岩,生气强度大,为库车坳陷天然气成藏提供了充足的气源;构造运动派生出的一系列断裂,沟通了深部的气源岩,为天然气往储集层运移提供了有力的通道;受多种因素的影响,库车坳陷油气相态的分布很不均一;库车坳陷发生过多期成藏,但最重要的是最后一期成藏,气藏的形成均比较晚;库车坳陷以生气为主,部分油藏或油气藏是残余油藏或油气藏,是天然气大量散失的结果;库车坳陷和吐哈盆地保存条件的差别导致吐哈盆地倾油,库车坳陷倾气。

There exist6sets of hydrocarbon source rocks with a great gas generation potential in the Kuqa depression,which provide plenty of gas for gas accumulation in the depression.Tectonic movements gener-ated a series of fractures,which get the deep gas source rocks connected and provide good conduits for the migration of natural gas from deep source rocks to reservoirs.Due to the influence of many factors,the phase states of oil and gas in the Kuqa depression are of very uneven distribution.Multiple phases of petroleum accumulation occurred in the Kuqa depression,but the last phase was the most important.Gas accumulation occurred relatively late in the Kuqa depression.The Kuqa depression mainly yields gas;how-ever,a part of oil deposits or oil and gas deposits are residual ones,which is the result of diffusion of large amounts of gas.Because of the difference in preservation conditions between the Kuqa depression and the Turpan-Hami basin,the Kuqa depression is gas-prone while the Turpan-Hami basin is oil-prone.