A Study On The Geological Model Of Oil Accumulation And The Distribution Of Remaining Oil In Complex Fault Block

With Sha 2 member of the fault block of Tuo 30 in ShengTuo Oilfield as an example, the author studied on aspects of the characteristics of reservoir, established a geological model of the oil accumulation of complex fault block, revealed the distribution of remaining oil. Based on the theory and methods of modern sequence stratigraphy, sedimentology, structure geology, hydrocarbon reservoir geology and reservoir engineering, this study put forth measures and directions of digging remaining oil in view of the geological characteristics and exploitation condition of the oil accumulation, applying multidiscipline information and combining static information with dynamic information. The results and new ideas are as follows:According to the theory of modern sequence stratigraphy, Sha 2 member of the fault block of Tuo 30 were first studied on the division and contrast of high discernible formation sequence. The results had advantages over limits of contrasts between sandbodys. Consequently, formation sequence and reservoir subdivision framework were established accurately, genesis types and sedimentary micro-facie distribution of sandbody units were indicated.The fault distribution and structure characteristics of the fault block were reconfirmed. The sealing degree was firstly evaluated based on the sealing characteristics of the faults transversally and longitudinally, by means of comprehensive assessment of fuzzy mathematics. Sealing models of the faults were developed.The paper disserted in detail micro-textures and filtration characteristics of the reservoir. It is first time that the factors of injecting development affecting on rock physical characteristics of the reservoir and its changing systems were analyzed with respect to rock-facies, according to different periods of injecting development and different sedimentary facies. The author put forward a method of establishing log explanation models with the restriction of geological conditions. The log explanation models for different periods and different sedimentary facies were developed to improve the calculation of reservoir parameters and quantitative evaluation of water flooding beds.The author originally analyzed the characteristics of flow units at different periods of injecting development and established four types of the flow units from many parameters of reservoir, meantime, introduced the remaining oil distribution within the different types of the flow units at the different periods of injecting development and its control factors.From sedimentary microfacies, mini-structure, fault sealing, flow units, reservoir heterogeneity, water-oil displacement experiment with real sandrock, reservoir numerical imitation and injecting and producing relation etc., the distribution characteristics, formation mechanism and controlling factors of the remaining oil in the oil accumulation were revealed in detail and the distribution pattern of them was established. The results have been applied to the fault block of Tuo 30 in ShengTuo Oilfield. As a result, significant economic benefits are brought into play.