SEDIMENTARY SYSTEM AND STRUCTURAL GENESIS OF KONGDIAN FORMATION IN JIYANG DEPRESSION

The Jiyang Depression, one of the main petroliferous basins in eastern China with fairly complex geological structures, is the most typical area for petroliferous basin study. Based on the seismic and drilling data, this paper studies the structural control on the sedimentary systems of Kongdian Formation which is the main reservoir. The Kongdian Formation is characterized by typical early continental strike-slip and extensional fault basin with fast-accumulated episodic filling of multisource. Alluvial fan and fan delta are the two main types of sandy sedimentary system. Gypsum salt, limestone and rhythmic-bedding mudstone in dry playa are distributed in deep sags. Three types of steep slope boundaries share the common characteristics of nearshore sediments, but differ in horizontal and vertical distribution of sedimentation. Compared with steep slope boundaries, the sedimentary facies of gentle slope boundary are relatively simple with underdeveloped alluvial fan and nearshore subaqueous fan, wide facies belts and farther-transported sediments.