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上三叠统延长组长6油层组是鄂尔多斯盆地大路沟地区重要的勘探开发目的层。文章依据野外露头、岩心、测井及相关测试资料,对大路沟地区三叠纪长6期的沉积类型、沉积微相特征及时空演化进行了系统分析。结果表明:大路沟地区三叠纪长6油层组发育三角洲沉积体系,主要包括三角洲平原亚相和三角洲前缘亚相,缺前三角洲亚相;分流河道和水下分流河道砂为储集层骨架砂体;长6油层组各微相经历了从三角洲前缘、三角洲平原到混合载荷高弯度河的沉积演化过程。同时对长6油层组各小层沉积微相的时空展布特征进行了分析,认为油气聚集受沉积微相的控制,三角洲前缘亚相的水下分流河道微相和三角洲平原亚相的分流河道微相是砂岩储层分布和发育的最有利相带,也是今后勘探开发的方向。
The Upper Triassic Yanchang Formation 6 oil layer group is an important exploration and development target layer in the Daluogou area of the Ordos Basin. Based on the outcrops, cores, well logs and related test data, the paper systematically analyzes the sedimentary types, sedimentary microfacies and temporal and spatial evolution of the Chang 6 Triassic in Daluogou area. The results show that the Triassic Chang 6 reservoir in the Daluogou area developed deltaic sedimentary system, including delta subfacies and delta front subfacies, lack of anterior delta subfacies, distributary channel and submarine distributary channel sand as reservoir skeleton Sand body. The microfacies of the Chang 6 oil layer experienced the sedimentary evolution from the delta front to the delta plain to the mixed caverns. At the same time, the spatial and temporal distribution characteristics of sedimentary microfacies in each layer of Chang 6 oil layer are analyzed. It is concluded that the hydrocarbon accumulation is controlled by sedimentary microfacies, the distributary channel microfacies in the delta front subfacies and the distributaries in the delta plain River microfacies are the most favorable facies belt for the distribution and development of sandstone reservoirs, and also the direction of exploration and development in the future.