Research On Seismic Prediction Method Of Fractured-cavity Carbonate Reservoirs

Carbonate reservoirs play an important role in the global oil and gas resources.Fractured-cavity carbonate reservoirs are widely developed in the Tarim Basin in northwestern my country,and their production is extremely high.They have become the main production pillar oil and gas reservoirs in my country.Therefore,carbonate reservoir prediction research has important economic value.Compared with traditional sandstone oil and gas reservoirs,the diagenesis of carbonate rocks leads to the diversification of fractured-cavity reservoir spaces,strong reservoir heterogeneity,significant spatial separation of each reservoir type,and obvious differences in oil and gas accumulation in different structural segments..Relying only on seismic inversion methods can no longer meet the requirements of reservoir prediction.It is necessary to comprehensively use a variety of reservoir prediction methods for comprehensive evaluation,describe reservoirs from different aspects,and meet the requirements of fine reservoir description.In this thesis,the Ordovician carbonate rocks in the Shunbei study area are mainly "fracture-cave" reservoirs controlled by strike-slip faults,and the fracture and cave reservoirs are predicted according to their differences.Use seismic attributes such as coherence,curvature and maximum likelihood to detect fractures in the target interval in the study area,and conduct applicability analysis to optimize fracture prediction methods suitable for this work area,and determine the spatial distribution of fracture reservoirs;Amplitude contrast attributes and two impedance inversions,model-based inversion and constrained sparse pulse inversion,are used to compare and optimally predict cave reservoirs,and determine the spatial distribution of cave reservoirs in the target interval;The oil and gas accumulation in structural sections is quite different.The oil and gas detection method based on matching and tracking fluid activity attributes is used to determine the oil and gas distribution characteristics of the target interval,and compare it with the fracture-cave results to evaluate the oil and gas potential of the reservoir.A set of reservoir prediction methods suitable for fracturedcavity carbonate rocks are formed through the analysis of practical application effects.Based on the results of fractured-cavity reservoirs and oil and gas detection,the accumulation model of the target interval in the study area was clarified,and the favorable target reservoirs of the Ordovician carbonate "fracture-cave type" reservoir were evaluated,so as to provide a basis for subsequent exploration.and production guidance.