Study of the high resolution sequence stratigraphy of Sha-4 member in Wei-81 fault block，Weicheng oil field

Based on the systematical analysis of drilling, logging data and palaeontology, using continental facies sequence stratigraphy, the high resolution stratig raphic sequence of Sha-4 member in Wai-81 f ault block, Weicheng oil field, was studied. On the basis of the lithological characteristics, tectonic evolution, palaeontology and logging, the Sha-4 member was divided into: 1 three order sequence, 2 systemt racts, 4 parasequencesets, 18 parasequence. The lower Sha-4 member consists of lowstand system tract which mainly developed flood flow depositionract, and upper Sha-4 member consists of trangressive system tract which mainly developed delta deposition tract. The source rocks are the dark grey mudstone of the upper Sha-4 member, and the reservoir is lake delta facies from upper Sha-4 and f lood flow deposition tract from lower Sha-4 member.