柴达木盆地基底构造特征及其控油意义

Characteristics of Basement Structures and Their Controls on Hy-drocarbon in Qaidam Basin

基于岩性、重力、磁场和大地电磁测深资料，分析了柴达木盆地的基底构造特征。柴达木盆地是在印支运动之后的总体挤压构造应力场的背景下形成的，基底构造发育。沿北西方向受祁连山与昆仑山相向挤压对冲的控制，发育了祁连南缘断裂、柴北缘断裂、葫北─陵间─达霍断裂、Ⅺ号断裂和昆北断裂等区域性断裂构造；沿北东东─北东方向受阿尔金构造带的强烈影响，发育了阿南断裂、塔尔丁─鱼卡断裂和格尔木一锡铁山断裂。两组方向的基底构造的复合叠加对盖层沉积建造的发育和展布起着重大控制作用，致使柴达木中、新生代盆地具有北西－南东向分带，北东－南西向分区的特点，并且直接或间接地控制了侏罗纪、第三纪和第四纪油气资源的形成、分布和聚集成藏。

Based on the information from lithology, gravity, magnetic field and magnetotelluric depth measurement and on analyses Of basement structural characteristics in Qaidam basin, the study shows that the basin was shaped with-in the stress field of compressional structures following indo-China movement, in which well-developed faults were brought about. And Qilian southern marginal fault, Qaidam northern marginal fault, Hubei -Lingjian_ Dahuo fault, No. Ⅺ fault and Kunlun northern fault are confirmed along NW distribution and controlled by a compressive inter-ramping effect between Qilian moutains and Kunlun Moutains; while along NEE-NE direction, the development Of A'nan fault, Tardin-Yuka fault and Germu-Xitieshan fault occurred due to intensive influences of Arkin structural belt. These two varied basement structures in orientation when composite and superimposed each other could have a major significance for controlling the development and distribution of caprock sedimentation constructions, resulting in the fact that at Qaidam's Mesozoic and Cenozoic basins have zonations with NW-SE strike and segments along NE-SW direction, which may, in a direct or indirect sense, control the formation, distribution and accumulation or reservoir of hydrocarbon resources in Jurassic, Tertiary and Quaternary.