Exo-front Facies Sand Body Anatomy Technology Study And Application In The Sazhong Development Area

The development of Daqing Changyuan Saertu oilfields in central depression zone of Songliao Basin has entered the ultra-high water cut stage in which flooding methods coexist such as water flooding, polymer flooding and chemical flooding. The basis of fine adjustment is the accurate understanding of the potential of remaining oil. But the remaining oil distribution is complex, difficult to describe and need to study through a clear understanding of the heterogeneity of the reservoir. The research degree of the heterogeneity of the reservoir depends on the anatomical level of sedimentary sand body. At present, deposition maps used in oil production can only depict the distribution of sedimentary subfacies sandbody and can not characterize the feature of sedimentary microfacies in sand body or achieve the recognition and classification of single sand body and not enough to describe the reservoir heterogeneity clearly.The reservoir of Saertu oilfield is fluvial delta deposition with the development of flood plain subfacies, distributary plain facies, delta front subfacies sedimentary sand body.There are various types of reservoir sedimentary in the Sazhong development area, of which sedimentary sand bodies are representative and the sealed coring and logging data in dense well pattern is rich. Therefore, the Sazhong development area has the conditions of deposition mode research. Using dense well network(well spacing density of 120 /km2) logging data and core data of Duandong development block in Beiyi Area in the central of the Saertu oil field, guided by sedimentology theory, focusing on practical application, study and establish well logging facies mode and sedimentary microfacies combination mode of delta front subfacies sedimentary sandbody, enrich the fine anatomical methods of sedimentary sandbody of sand oilfield on the condition of dense well network and guide the fine reservoir description and remaining oil analysis which provides the geological basis for Gaotaizi reservoir water flooding fine potential tapping in study area and is the effective way to grope water flooding development of sand oilfield in ultra-high water cut stage.