鄂尔多斯盆地中南部马五1-2亚段岩相古地理特征及其对储层的影响

为探讨岩相古地理环境对储层的影响，以鄂尔多斯盆地中南部马五_1-2亚段为例，综合利用岩芯观察及薄片鉴定、多矿物测井解释模型以及单因素分析多因素综合作图法等多种方法，对研究区岩相、岩相古地理特征进行了研究，并结合测井解释储层厚度的分布特征及实际天然气产量数据分析了岩相古地理环境对储层分布的影响。分析结果表明，研究区马五_1-2亚段岩石类型主要包括白云岩（泥晶白云岩、膏盐溶蚀角砾白云岩、溶蚀角砾泥晶白云岩、溶蚀角砾含灰粉晶白云岩、灰云岩、含膏云岩、含泥含灰云岩、泥云岩）、石灰岩（云灰岩、含泥云灰岩）以及部分蒸发岩（石膏岩、盐岩）。岩相古地理环境以蒸发台地和局限台地亚相为主，蒸发台地亚相包括云坪和含膏云坪微相，局限台地亚相包括膏盐湖、膏湖和含膏湖微相。岩相古地理环境在一定程度上影响储层分布，蒸发台地亚相中的云坪微相、含膏云坪微相以及局限台地亚相中的部分含膏湖微相、膏湖微相均是储层发育的有利区域。

Characteristics of Lithofacies Paleogeography and Its Effect on the Majiagou Submember 51-2 Reservoir in the Central-southern Ordos Basin

In order to investigate the effect of lithofacies paleogeography on the reservoir, the lithofacies and lithofacies paleogeography characteristics of the Majiagou submember 5_1-2 in the central-southern Ordos Basin were studied by various methods, including core observation, thin sections identification, and multi-mineral logging interpretation, as well as single factor analysis and multi factor comprehensive mapping. Then the effect of lithofacies paleogeography on the reservoir was analyzed by combining with reservoir distribution, which we obtained by logging interpretation and the data of actual gas production. The result shows that the main rock types of the Majiagou submember 5_1-2 mainly include dolostone (dolomicrite, gypsum and salt corrosion breccia dolomicrite, karst breccia dolomicrite, karst breccia calcitic crystal powder dolostone, calcitic dolostone, gypsiferous dolostone, argillaceous calcitic dolostone, and argillaceous dolostone) and limestone (dolomitic limestone and argillaceous dolomitic limestone), as well as partial evaporite (gypsum and halite). The lithofacies paleogeography environment mainly includes the evaporate platform, which can be divided into dolomitic flat and gypsiferous dolomitic flat, as well as a restricted platform, which can be divided into salt lake, gypsum lake, and gypsiferous lake. The reservoir can be affected by lithofacies paleogeography to some extent. Dolomitic flat and gypsiferous flat, as well as partial gypsiferous and gypsum lake are all the favorable areas for the reservoir.