淮南煤田二叠系沉积相特征及其与烃源岩的关系

在对淮南地区二叠系岩性、矿物和生物化石进行观测研究以及相关地球化学参数测试的基础上，对淮南地区这一时期的沉积相演化特征及其与烃源岩之间关系进行分析。结果表明:淮南地区早、中二叠世时期海水震荡性后退，总体以水下沉积为主，大致可划分为2种沉积亚相:山西组的三角洲沉积和下石盒子组的水下分流河道沉积，又可以进一步细分为前三角洲、泥炭沼泽、分流河道、决口扇、河漫滩等微相，泥页岩在前三角洲和河漫滩相最发育。岩性和显微组分的组成受沉积微环境变化的控制作用明显，“（腐泥组+壳质组）/∑显微组分”以大于等于70%为主，利于生气；有机碳含量则受沉积亚相和沉积微环境的共同控制，山西组泥页岩中有机碳平均质量分数约2.78%，明显高于下石盒子组泥页岩中的1.11%。综合考虑泥页岩累计厚度、有机碳含量及有机质的显微组成等因素认为，研究区山西组和下石盒子组都可作为页岩气的有利勘探层位，尤以“潘集镇-潘集区-泥河镇-平圩镇”这一带最为有利。 

Relationship between sedimentary facies and source rocks of Permian strata in Huainan coalfield

The relationship between sedimentary facies evolution characteristics and hydrocarbon source rocks was analyzed on the basis of observational related test of the geochemical parameters, lithology, minerals and fossils. Seawater retreated in oscillation during Early and Middle Permian Periods in Huainan area, forming mainly underwater deposits. Permian strata in Huainan area can be roughly divided into two subfacies:underwater delta deposits in Shanxi Formation and distributary channel deposits in Lower Shihezi Formation. It can be further broken down into:peat swamp, distributary channel, crevasse splay, flood plain, tidal flat and lagoon microfacies. Among them, shale and coal seam were most generated in former delta and floodplain microfacies. Lithological and microstructure components were significantly controlled by micro environmental change, (exinite plus sapropelinite)/∑macerals is generally greater than 70%, conducive to generation hydrocarbon; organic carbon content jointly controlled by sedimentary subfacies and sedimentary role of microenvironment, organic carbon content of about 2.78 percent on average in the shale of Shanxi Formation was significantly more than that in the shale of Lower Shihezi Formation(about 1.11%), but under the same conditions the organic matter of Lower Shihezi shale may be more conducive to generation hydrocarbon. Considering the factors such as the cumulative thickness of shale, organic carbon content and composition of organic matter, in this region the shale of Shanxi and Lower Shihezi Formation can be used as favorable shale gas exploration layers, in particular the "Panji Town-Panji District-Nihe Town-Pingwei Town" is the most favorable area.