Delicate Reservoir Description Research On The Chang 10 Member Of Yanchang Formation Of G52 Area In An'sai Oilfield, Ordos Basin

The content of delicate reservoir description research includes analysis of precise depositional microfacies and reservoir heterogeneity, reservoir comprehensive evaluation,three-dimensional geological modeling and reservoir simulation.The aim is to understand reservoir more accurately and figure out of residual oil distribution under the ground, delicate reservoir description research has become a important way to deepening geology research and residual oil distribution research.Chang10 Member of Yanchang Formation, Upper Triassic of G52 area in An'sai oilfield is first found as a low permeability reservoir in 2007.There are some problems in this area.The major problems in the study area include well with high water-bearing,difficulty determined production pressure differential,serious reservoir heterogeneity and large capacity differences between the north and south of the G52 area.Furthermore,it is hard to determine a reasonable production pressure and though to make a comprehensive management,because of complex condition of seepage underground,highly dispersed distribution of residual oil,in addation to the above problems.A multi-disciplinary combination method was used to solve the problems and the contradict existing in G52 area. The geological research in this paper include stratigraphic fine division and correlation, depositional microfacies, secondary interpretation of logging curves, reservoir delicate description and Comprehensive evaluation and other approaches. According to the theory of modern sequence stratigraphy, ChanglO member was studied on the division and contrast of high discernible formation sequence. Consequently,formation sequence and reservoir subdivision framework were established accurately,genesis types and sedimentary micro-facie distribution of sandbody units were indicated.The low critical boundary of lithology,physical quality and hydrocarbon-bearing property of the reservoir is determined,in the basis of secondary interpretation of logging curves.The paper disserted in detail petrological characteristics and spatial structure of the reservoir.The reservoir heterogeneity was also meticulously researched based on the detailed explanation of reservoir parameters.Rich geological knowledge base and a three-dimensional geological model which include Sedimentary microfacies, porosity, permeability,oil saturation and other properties for the ChanglO reservior is established under limited condation of depositional facies and geological charateristics,via geostatistics and stochastic simulation by using the Petrel geological model software,based on a combination of multi-disciplinary approaches,in considerating different geological revervoir variables.Numerical simulation and residual oil distribution is studied in this paper after outlined the geological model.Finally, this paper put forward the reasonable injection-production ratio, repeat fracturing and adjust the water flooding and other development schemes, which lays a robust theory and practical foundation for hydrocarbon exploitation and development of An'sai oil field in the future.