川东南地区区域构造特征及圈闭类型与气藏分布关系

THE REGIONAL TECTONO—STRUCTURAL FEATURES AND TRAP TYPES IN SOUTHEASTERN SZECHUAN AND THEIR RELATIONS WITH THE DISTRIBUTION OF GAS POOLS

童崇光 张亮鉴

Tong Congquang Zhang Liangjian

成都地质学院

Chengdu College of Geology

四川川东南断褶区分布有大量的扭动构造圈闭,其中有些圈闭已获得大量的天然气。本文根据卫星照片的解译,结合物探、占井及区域构造资料,按板块构造理论,对四川盆地形成机制,川东南区域构造特征及圈闭类型与气藏分布的关系进行了探讨。从而指出了有利的含气圈闭在空间、时间上分布的规律性。对估计含油气远景和寻找新的油气田提出了新的领域。

Interpretation of Landsat images has indicated four westeastward hidden fractures and nine concealed structural traps, some of which are proved to be gas pools.There is evidence that a major hidden fracture exists below the high, steep, narrow anticlinal belt. since the late paleozoic time, as a result of the mutual subduction and collision of the Indian-Australian plate, the Asian plate and the Pacific plate, large amount of wrench series have developed within Szechuan Basin. These fracture series of horizontal displacement have involved the creeping of the low volocity beds or the upper mantles and the deep seated beds as well as the activation of the magma, resulting in strong faulting and folding and deformation of the crust. The horizontal displacements of several deep fractures that are located between Huaying Shan and Qian Jiang have given rise to large amount of torsionanticlinal traps in the sedimentary cover. At the time of the formation of these traps, the primary and secondary hydrocarbons migrated to and accumulated in these traps, while hardly any gas pools occurred in the high, steep, narrow anticlinal belt due to its poor conditions for gas preservation. Therefore the low anticlines and/or the hidden structural traps are essentially the sites for gas accumulation. The gas pools are rather dispersed both geographically and stratigrap-hically and the traps are poorly filled.

https://doi.org/10.11781/sysydz198103155