【摘要】 鄂尔多斯盆地中部气田奥陶系马家沟组属蒸发边缘海相地层 ,其风化壳是中部气田的主要产气层段。该层中广泛发育毫米级、厘米级的溶斑 ,这些溶斑的产状、大小、成分以及溶孔内的充填物十分复杂 ,有的具多期充填 ,充填物为石膏、石英、方解石、白云石、高岭石、黄铁矿等多种矿物。溶斑中下半部残留的岩石经溶蚀后的白云石晶粒形成的渗流砂示底构造十分明显。研究表明 ,溶斑的形成不仅具有适宜的岩相古地理环境和其复杂的生成演化史 ,而且与原始沉积以及不同地史阶段的岩溶作用相关。更多还原

【Abstract】 The weathering crust of Majiagou Formation in Ordovician of Changqing Gasfield in Ordos Basin is the major pay zone with the evaporated marginal sea facies. Solution spots and holes with millimeter and centimeter size are developed and its occurrence, composition and fillings in the holes are very complex. Some of them have multi-stage fillings such as gypsum, quartz, calcite, dolomite, kaolinite and pyrite,and so on. The lower part of the solution hole remains dolomite crystalline just like geopetal structure of vadose sands in the clastic rock. As shown, the solution spots are formed not only with suitable lithofacies, paleogeographic environment and complexed evolutional genetic history, but also the karstification related to original deposit and different geologic historical stages.更多还原