川东南A区构造特征与保存条件评价

Tectonic Characteristics and Preservation Condition Evaluation of Area A in Southeast Sichuan

近期川东南盆缘复杂构造带A区W1井测试获高产工业气流,揭示了该区良好的保存条件。本文针对顶底板条件以及构造变形两个影响保存的关键因素,结合岩性、ADS轴面分析法与断面正应力分析技术,详细解剖了A区构造保存条件,认为:① 顶底板岩性致密,封隔性好,上下构造层分层滑脱,顶板滑脱层距页岩气层远,对页岩气层未造成破坏;② 主控断层与最大主应力方向呈大角度相交,断面正应力大,封堵性好;③ 盆缘“断洼”有效,有利于页岩气保存与富集。川东南盆缘复杂构造带可进一步划分为阳春沟段、新场段、丁山–东溪段以及良村段,各段在构造样式和变形强度方面存在一定差异性。

Recently, the W1 well in Area A of the complex structural zone of the southeast Sichuan basin margin obtained high-yield industrial airflow, which revealed the good preservation conditions in this area. In this paper, aiming at the two key factors affecting the preservation of the lithology and structural deformation, combined with lithology, ADS axial surface analysis method and stress analysis technology, this paper analyzes the structural preservation conditions of Area A in detail, and concludes: 1) The top and bottom slate lithology is dense, the sealing property is good, the upper and lower detachment layers do not affect each other, and the detachment layer is far from the shale gas layer, which does not damage to the shale gas layer;2) The main control fault intersects with the maximum principal stress direction at a large angle, and the fault plane has large stress which means the gas is sealed;3) The “depression” of the basin margin is effective, which is conducive to the preservation and enrichment of shale gas. The complex tectonic belt of the southeast Sichuan basin margin can be further divided into Yangchungou, Xinchang, Dingshan- Dongxi and Liangcun, and there are certain differences in structural style and deformation strength.