Study Of Sedimentary Characteristics And Reservoir Evaluation Of Chenjia Fault Zone

With many years of exploration and development by various oil fields in our country, large structural reservoirs have now basically gone through exploration. In recent years, proportion of structural-lithological reservoir and lithological reservoir in proven annual reserves tends to increase year by year. It has become a common view among oil explorers to search for structural-lithological reservoir and lithological reservoir inside and beside source rock in the periphery of oil-gas rich depressions.Liaohe Depression is rich of oil and gas in Eogene,and West Depression has gone through 40 years of exploration and development with proven reserves of nearly 1,400,000,000t. With exploration developing in depth, lithological reservoir has become key concern of next step. In order to explore reservoir-forming style of lithological reservoir in the periphery of Chenjia Sag, we start from basin modeling and integrate studies of source rock, reservoir, cap rock, migration condition, trap condition and preservation condition etc. Finally, the goal of resource evaluation and exploratory discovery is achieved.In this study, sequential formation framework is established using regional geological formation unification and paleontological information. Accurate structure interpretation is conducted using drilling data and 3-D seismic data supplemented by high-precision synthetic seismic records. Fault structure characteristics of different intervals are confirmed. Sedimentary characteristics of this area are studied using seismic and drilled well data. In terms of significant lateral sand variation and close relation between sand and reservoir in this area, drilling data and reservoir inversion technology are used to study reservoir distribution. By studying structures, sands, cores, formation testing and reservoir-forming rule etc, reservoir distribution rule and geological control factors in the work area are identified.Through study it is concluded that S3 and S4 intervals in Chenjia Fault Zone of Chenjia Sag are favorable targets of lithological reservoir. Large amount of carbonate reservoirs such as micritic dolomite and shaly dolomite are deposited in S4 interval of this area resulting in special lithological reservoir of dolomites. S3 interval is mainly composed of steep-coast fan delta deposits. Source area is Central Uplift in the east. Sands gradually decrease from east to west. There are favorable reservoir-forming belts near Chenjia Fault Zone, and reservoir petrophysical property is good. This study investigates reservoir-forming rule of lithological reservoir in Chenjia Fault Zone and provides clear guidance for next step exploration.