鄂尔多斯西缘羊虎沟组页岩气聚集地质条件分析

Geological Conditions of Yanghugou Formation Shale Gas Accumulation on Western Margin of Ordos Basin

为了研究鄂尔多斯盆地西缘羊虎沟组页岩气成藏潜力，根据泥页岩厚度、有机质类型、有机质丰度与成熟度等因素，从暗色泥页岩地层空间展布特征、构造特征与热事件、生烃能力等方面分析页岩气聚集的地质条件。研究表明，羊虎沟组暗色泥页岩单层最大厚度约30m，区内发育的逆冲推覆构造使地层叠置形成厚的泥页岩层段，泥页岩干酪根以III型为主，II-I型也有发育，TOC平均值为3．25％，R。为l％。4％，这些条件均有利于页岩气聚集成藏。综合分析认为呼鲁斯太南部、乌达及石炭井地区为页岩气聚集最有利的区域。

To study the Yanghngou Formation Shale gas reservoiring potential on the western margin of Ordos Basin, mainly through fac- tors of argillutite thickness, organic matter type, organic matter abundance and maturity, analyzed geological conditions of shale gas ac- cumulation from aspects of spatial distribution and structural features of dark argillutite strata, thermal event and hydrocarbon generat- ing capacity etc. The study has shown that the maximum thickness of single dark argillutite stratum can be about 30m, the developed thrusting nappe structure in the area made strata superimposed into thick argillutite sectors; argillutite kerogen is mainly type III, also some type 1I--I, average TOC 3.25%, Ro 1%-4%, all of these conditions are favorable to reservoiring of shale gas. The comprehensive analysis has considered that the southern Hulstai, Wuda and Shitanjing areas are advantaged areas for shale gas accumulation.