塔里木盆地库车拗陷现今异常高压分布特征及其成因

Analysis of current of abnormal high pressure distribution characteristicsistic and discuss which cause of formation in Kuqa depression of Tarim basin

为了恢复库车拗陷现今流体动力场,根据实测地层压力资料,研究了库车拗陷现今异常高压在纵向和平面上的分布特征.结果表明:该区纵向上在2 km深度以内地层压力基本正常,大多数为静水压力,在部分构造带出现异常高压,且超压与膏盐岩、膏泥岩的发育关系明显;平面上超压大部分分布在库车前陆逆冲带,塔北隆起几乎为静水压力.研究认为,欠压实作用和构造挤压作用是克拉2气田超压成因的重要因素.

In order to recover present hydrodynamic field of Kuqa depression,based on measurement of fluid pressure data,the characteristic of abnormal high pressure both in vertical and horizontal distribution is studied in Kuqa Depression.Results show that that fluid pressure is normal at the vertical depth of less than 2 kms,the fluid pressure being hydrostatic pressure,and the abnormal high pressure come forth at the depth of more than 2 kms.At the same time,the abnormal high pressure is closely related to the development of anhydrocks,salt beds and gypsum mudstone caprock;abnormal high pressure is mostly distributed in obduction zone.The northern uplift in Tarim basin is mostly hydrostatic pressure.A conclusion is arrived at that undercompaction and tectontic compression are two important factors for Kela-2 gas field's overpressure.