CONTROL OF SEQUENCE OF STRATA OVER RESERVOIR HETEROGENEITY OF THE CHANG SIX OIL FORMATION IN NORTHERN SHAANXI
Du Chunyan, Zheng Rongcai (Chengdu University of Technology, China)
The Chang six oil formation consists of a suite of thin interbedded sandstone and mudstone. Its reservoir heterogeneity is very strong, and especially the seam heterogeneity is the most serious. This is obviously influenced by the base level up and down changings, pore space variation and sediment alimentation. Through analysing the relationship between the course of base level up and down cycles of high resolution sequence strata and the reservoir physical behavior, six heterogeneity models of different sedimental microfacies are founded. This paper discusses the up deepening and shallowening unsymmetric and symmetric short term base level cyclic sequences and their control over the characters of reservoir heterogeneity.