杭锦旗地区山西组沉积相及其演化特征

Sedimentary facies and its evolution characteristics of Shanxi Formation in Hangjinqi area

通过详细观察杭锦旗地区30余口取心井岩心,对岩石类型、沉积构造等沉积相识别标志进行了分析。杭锦旗地区山西组发育三角洲平原亚相,可进一步划分出主分流河道、次分流河道、洼地、泥炭沼泽等微相。根据研究区及邻区130余口探井各小层的砂体厚度统计,以及井间沉积微相的对比研究,系统编制了杭锦旗地区山西组不同小层的沉积相平面分布图。研究表明:山西组沉积期受北部和东北部物源的影响,分流河道具由北向南的相带展布特征;不同时期受古地貌和物质供给差异的影响,分流河道微相的发育位置和规模存在差异。研究成果为杭锦旗地区的进一步开发评价提供了重要的地质依据。

Based on the detailed observation of about 30 drilling cores in Hangjinqi area, the classification of lithologic types, sedimentary structure and signs of equivalent sedimentary facies are analyzed. The Shanxi Formation in the study area is divided into delta sedimentary facies, and it is further subdivided into microfacies of main distributary channel, secondary distributary channel, depressions and peat swamp. Based on the statistics of sand body thickness of each sublayer and the comparative study of cross-well sedimentary microfacies in more than 130 exploration wells in the study area and adjacent areas, the sedimentary facies plane distribution maps of different sublayers of Shanxi Formation in Hangjinqi region are systematically compiled. The study shows that the sedimentary period of Shanxi Formation was affected by the north and northeast provenances, and the distribution characteristics of the distributary stream are from north to south. Under the influence of paleogeomorphology and material supply, the development position and scale of distributary channel are different in different periods. The results provide an important geological basis for the evaluation of lithologic traps and further development in the Hangjinqi area.