Division of exploration units and its significance in mature exploration region：a case study in Dongying Sag

It is very difficult to explore with structural unit in mature exploration regions.According to exploration and production practices,the concept and the division method of exploration unit in mature region were proposed,and were used to guide geologic study,well arrangement and input-output ana-lysis.In Yanjia-Yong'an region of the northern steep slope of the Dongying Sag,a case study was carried out in the nearshore subaqueous fan lithologic reservoir from the upper Es⁴ to the lower Es³.The relationship between geologic conditions and exploration capabilities was analyzed with "exploration unit".The key problems were pointed out so as to guide exploration and improve efficiency.