东昆仑山北缘山前构造带的特征及其对油气成藏的意义
Structural characteristics of the northern foreland belt of East Kunlun Mountains and their significance for oil and gas accumulation
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摘要: 东昆仑山北缘山前构造带位于柴达木盆地南部,中新生代以来受东昆仑山和阿尔金断裂双重构造作用的影响,其油气成藏赋存规律尚不十分清楚。结合前人的资料,根据最新的地震资料解释成果,对研究区主要断裂的构造特征、活动性质、时代及其对油气成藏的控制作用进行了研究,认为东昆仑山北缘断裂与东昆仑山隆升、阿尔金断裂活动相关,中新世早期和早更新世末期为2期主要的活动期次,控制了该区生烃凹陷、油气成藏和后期的次生油藏。因此,研究东昆仑山北缘山前构造带的演化规律对寻找同类型油气藏具有重要意义。Abstract: he north foreland of East Kunlun Mountains, located in south Qaidam Basin, has experienced dual events of the uplift of East Kunlun Mountains and the strike-slipping of the Altyn Tagh fault since Mesozoic and Cenozoic period. Controversy still exists concerning the regularity of oil and gas accumulation and storage. Based on the new interpretation of the seismic data and other data as well as studies of the structural characteristics, activity properties and epochs and the control of the main faults over oil and gas resources in the study area, the authors hold that the north edge fault of East Kunlun Mountains was related to the uplift of the Kunlun Mountains and the activity of Altyn Tagh fault. The early stage of Miocene and the last phase of Early Pleistocene were main faulting active stages. This fault not only controlled the formation of hydrocarbon depressions and oil and gas resources but also changed the oil accumulation and formed secondary oil pools. Therefore, it is likely to find the same type oil and gas reservoirs in the Qaidam Basin through the study of the evolution of East Kunlun Mountain fault.