Abstract:
Abstract:To reveal the characteristics of the fault accommodation zone and interpret its control effects on hydrocarbon distribution in the complex fault block oilfield, the authors conducted the study of faults geometry, kinematics and dynamics in Ying 26 block using 3D high-precision seismic data together with oil field geological data, and discovered that it is a typical EW-striking convergent-overlapping and synthetic-overlapping compound fault accommodation zone. The section structural patterns of the west-side major fault (Ying 1 fault) and adjustment faults are of the multiple-stage reverse Y style, and the east-side major faults (Ying 8 fault, Ying 31 fault) and adjustment faults are of the cabbage-appearance style. When the activity of Ying 1 fault became weak, the displacement accommodated Ying 8 fault, Ying 31 fault and adjustment faults, which made the total throw change regularly. The stress field of Ying 26 accommodation zone was complex: the northern part was left-lateral extension-tensional and the southern part was right-lateral extension-tensional. Through the analysis of distribution and source of Ying 26 block structure, characteristics of fault activities and fault sealing properties, the authors recognized the accumulation model of Ying 26 fault accommodation zone. The major fault was an oil source fault which connected the source kitchen and the reservoir, and hydrocarbon migrated during the main hydrocarbon accumulation period, whereas adjustment faults stopped activities in the earlier period, formed fault traps, and became barrier faults. The authors have constructed the reservoir forming model of Ying 26 fault accommodation zone, and pointed out that Ying 13 well, Ying 24 well and Ying 26 well areas are areas favorable for progressive exploration and development.