赤水地区二叠系、三叠系构造期次探讨

GENETIC MODEL OF PERMIAN-TRIASSIC STRUCTURES IN CHISHUI AREA

赤水地区二叠系、三叠系是该区最主要的产气层,由于对其构造形成期次不清楚而长期制约了赤水地区的油气勘探工作。在收集整理大量资料的基础上,总结出赤水地区二叠系、三叠系储层构造是在四川盆地形成的大环境下形成的,其东西向构造形成时间早于南北向构造,早期的东西向构造是由于黔中古隆起向北的构造挤压力作用形成的;晚期的近南北向构造则是受四川盆地东部边缘北西向构造作用力在南端的派生应力作用形成的。东西向构造(特别是东西向大断层)在近南北向构造运动晚期,由于受南西西向构造应力作用而产生逆时针平滑剪切活动。

The Permian and Triassic are the most important gas-producing formations in Chishui area,Guizhou province.The exploration of reservoirs in this area has been confined for a long time because the understanding of structure formulation and evolvement are unclear.Based on the analyses of large amount of data,main research results are proposed.The structures of the Permian and Triassic in Chishui area developed under the background of development of Sichuan basin.The E-W-trending structures formed earlier and the N-S-trending structure later.The earlier E-W-trending structures formed because of the structural compaction pressure of the Qianzhong palaeohigh to north while the later N-S-trending structures formed by the south induced stress action of the westnorthern structural stress in the east boundary of Sichuan basin.The E-W-trending structures (especially,great E-W-trending faults) generated anticlockwise smooth shearing activity in the N-S structural movement stage due to the W-S-trending structural stress action.