文南油田开发中后期沉积微相精细研究

重新认识处于开发中后期油藏的沉积环境、沉积微相及其特征，建立准确的储集层模型，对于查明剩余油分布和挖掘剩余油潜力、提高采收率具有重要的现实意义。通过对东膜凹陷文南油田沙二下亚段古生物特征、地球化学特征、沉积构造特征、储集层岩性特征、粒度特征等方面的综合分析，认为其沙二下亚段为干旱炎热气候条件下的间歇性涨缩浅湖环境下发育的浅水三角洲和滨浅湖沉积体系；划分出三角洲前缘水下分流河道、水下溢岸砂、水下天然堤、水下分流间湾、前三角洲砂泥、滨浅湖泥等6种沉积微相类型；分析各沉积微相特征，指出水下分流河道砂体储集物性最好，水下送岸砂次之。图5表1参13

The fine studies of depositional micro-facies on the middle-post development stages in Wennan Oilfield

For a reservoir on the middle post development stages, a fine study about micro facies is very important for modeling a proper reservoir, getting a proper knowledge of remaining oil distribution and improving oil recovery rate. Based on the basis of comprehensive analyses of the features of the paleontology, geochemistry, depositional structure, petrology and granularity, the depositional environment of the sub zone of No.2 member of the Shahejie Formation in age of Paleogene could be identified as an intermission fluctuating shore shallow lake under a drought weather. The depositional facies should be swallow delta sedimentary system. A few of type of micro facies are marked off, such as underwater channel, overflow bank sands, and so on. The nature of the micro facies are described, it is clearly that the physical and storage properties of reservoirs, taken a sequence from the best to the worse, are underwater channel, overflow bank sands, respectively.