In-situ Stress Distribution Analysis of Shunbei Fault-karst Reservoir Based on "Geology-Engineering" Coupling Platform
The Shunbei oilfield is a fault-controlled fracture-vuggy reservoir in carbonate rocks,and hydraulic fracturing is usually used in this type of oilfield to improve the flow performance of the reservoir.In the hydraulic fracturing process,the three-dimensional in-situ stress field is one of the important factors affecting the fracture propagation trajectory.Therefore,the study of the fine spatial distribution of the three-dimensional in-situ stress field is the primary problem to be solved in the hydraulic fracturing process.Aiming at the inaccurate simulation of the spatial distribution of in-situ stress field during hydraulic fracturing of fractured-vuggy carbonate reservoirs,the"geology-engineering"coupling platform was developed.This platform enabled the conversion of geological models into formats compatible with the AiFrac numerical simulation software,facilitating a refined characterization of the three-dimensional in-situ stress field within the reservoir.Based on the three-dimension geological model constructed using corner grid technology,the numerical simulation software was employed to simulate the three-dimensional stress field within the geological formation.This approach enabled the preservation of the intricate structural features of the reservoir while leveraging the computational capabilities provided by the numerical simulation software.Consequently,the integration of the geological model and numerical simulation was achieved.In order to verify the effectiveness of the proposed method,the three-dimensional in-situ stress field of Shunbei oilfield based on the existing in-situ stress measurement data was analyzed and calculated.The results show that faults have a significant impact on the direction and magnitude of the in-situ stress field,mainly in that the scale,dip,strike,and shape of the faults affect the in-situ stress state to varying degrees.The proposed precise simulation method for three-dimensional in-situ stress can effectively study for the stress field distribution of fault-karst reservoir region,interior and intersection area of different faults,internal fractured-vuggy reservoirs and fracture zones,thus providing an important basis for the selection of on-site construction process parameters.
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