| The Chang 6 reservoir of Yanchang Formation is the main producing pay of Ansai Hei Shanliang oil field, which has been entered a period of stabilized produetion of waterflood development in 2004. The research on the characteristics and control factors of the reservoir and remaining oil is the key to improve oil recovery. This study guided by theories of reservoir sedimentology, logging geology, petroleum geology and reservoir development geology, based on analysis of drilling, logging and laboratory experiments results and the results of other researchers. The research purpose is to increase the production and oil recovery of region of interest.The principal producing formation of Hei Shanliang region is Chang 62-1, Chang 62-2, Chang 63 reservoir, which belong to the delta-front facies. In the light of the characteristhcs of source bed, fault and center of subsidence, we can find the factor that the migratory direction of oil in this region is from northwest to southeast. The distribution of oil reservoir is controlled by lithologic character, migration area, precipitation facies and structural setting. So the type of reservoir is lithologic deposit. It developed three vertical main oil layer and several oil sheet. The motivating force of oil is expansion and dissolved gas which lead to the lack of producing energy, so we must take measures of waterflood development to improve the present situation.Basing on the geological and technological factors, three kinds of flood effectiveness had been divided. The main factors influencing the remaining oil distribution are reservoir microtectonics, sand body geometry, reservoir heterogeneity(which include of in layer heterogeneity, interlayer heterogeneity and areal heterogeneity) and development program.According to the classification of remaining oil, the exploration and injection-production strategy adjustment scheme had been put forward from the view of plane and vertical. |
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