台北凹陷西部差异逆冲推覆体系与油气聚集规律

台北凹陷西部构造活动晚期形成的差异逆冲推覆体系与该区构造格架的定型、油气的运聚具有十分密切的关系, 该体系所产生的近东西向逆冲断裂体系和南北向走滑断裂体系将西部地区分割为若干棋盘格式构造块体。东西向逆冲断裂体系起到阻断油气、控制油气成排成带分布的作用; 南北向走滑断裂体系起到沟通深部油气, 使之进行垂向运移和分隔、封堵油气, 形成油气藏块体的作用, 西部地区主要含油气层段砂层的沉积厚度变化较大, 从而使平移断层错断砂体产生砂、泥对接成为可能, 在侧向岩性尖灭或砂体不连通等因素的配合下, 平移断层与岩性共同作用构成了台北西部构造- 岩性油气藏形成要素。根据差异推覆体系与油气分布规律, 凹陷中部断褶带和北部山前逆冲推覆背斜及断阶带具有广阔的勘探前景。

Hydrocarbon accumulation and related differential thrust system in western Taibei Sag

Differential thrust system formed in late period of tectonic activity in western Taibei Sag has a close relationship with structural framework, hydrocarbon migration and accumulation in this area. Near east-west direction thrust fault system and north-south direction strike-slip fault system divide the western area into several chess-board structural blocks. East-west direction thrust fault system obstructs oil/gas and controls hydrocarbon distribution, while north-south direction strike-slip fault system plays a role in communicating deep oil/gas, which makes the vertical migration and seals oil/gas to form reservoir block. The depositional thickness of the main hydrocarbon bearing sands varies greatly, which makes the joint of the sand and mud possible. Both the strikeslip fault and lithologies are responsible for the forming of structural-lithologic reservoirs in western Taibei, with the influence of lateral lithological pinchout or disconnected sand body. According to differential thrust system and hydrocarbon distribution rules, a great exploration potential is predicted in faulted fold zone in the middle sag and thrust anticline and fault bench in piedmont of northern sag.