构造挤压对库车坳陷异常地层压力的影响

Influence of Tectonic Compression on the Abnormal Formation Pressurein the Kuqa Depression

库车坳陷异常高压呈东西向带状分布,中部克拉苏-东秋-迪那构造带的地层压力系数在2.0以上,往南北两侧递减。异常高压的分布和古近系的膏盐岩分布密切相关,巨厚的膏盐层盖层是形成异常高压的重要条件。喜马拉雅晚期强烈的构造挤压作用是库车坳陷异常高压形成的主要因素,地层压力和过剩地层压力与最大构造主应力之间具有较好的相关性,构造抬升对该区异常高压形成的影响较小。异常高压对油气藏的形成和保存有十分重要的作用,它是库车坳陷形成大型油气藏的必要条件。

Abnormal high pressure is distributed in a E-W-stretching zone in the Kuqa depression. The formation pressure coefficient is above 2. 0 in the middle part of the Kelasu - Dongqiu - Dina structural zone, and it decreases northwards and southwards from the centre. The distribution of abnormal high pressure is relative to Eogene gypsolith and salt layers. Huge gypsolith and salt layers are the important condition for the formation of abnormal high pressure. Tectonic compression at the late stage of the Himalayan Orogeny is the main factor of the formation of the abnormal high pressure in the Kuqa depression. The formation pressure and residual formation pressure have good relations with the maximum tectonic principal stress. The influence of tectonic uplift on the formation of the abnormal high pressure is relatively small. Abnormal high pressure has a very important effect on the formation and preservation of oil and gas reservoirs and is a necessary condition for formine larse oil and gas reservoirs in the Kuqa depression.