Fracture prediction and main controlling factors analysis of tight carbonate gas reservoir:take the Sinian Dengying Formation of G Gas Field in Sichuan Basin as an example
The controlling factors of fracture development in tight carbonate reservoir in G Gas Field of Sichuan Basin are unclear.Considering the difference of lithologic elastic-brittleness,the fracture devel-opment characteristics and fracture formation stages of single well are analyzed,and the stress field nu-merical simulation is carried out to establish the stress field,energy and fracture parameters calculation model.Combined with the multi-phase fracture superposition algorithm,the reservoir fractures of Dengying Formation in G Gas Field are predicted and the main controlling factors of fracture develop-ment are clarified.The results show that the fractures in Dengying Formation of G Gas Field are multi-stage and diverse,mainly high-angle and half-filled tension-shear fractures.The top of the fold and the fault affected area in the middle of the study area are the dominant development zones of carbonate frac-tures,the fracture density is 1.10-2.30 strips per meter,and the fracture opening is greater than 1.5 mm.The fracture development degree of mudstone is weak,the fracture density is less than 0.50 strips per meter,and the fracture opening is less than 0.4 mm.The fracture development of mudstone inter-layer is generally lower than that of carbonate rock,it has poor regularity.The fracture development conforms to the fault-fold-fracture symbiosis model.The scale and distribution of fractures are con-trolled by lithology,fault and structural morphology in carbonate reservoir.This result is helpful to im-prove the fracture prediction of the same type of tight carbonate reservoir and improve the development plan of the reservoir.
tight carbonate rockfracture predictionmain controlling factorsstress field simulationDengying FormationG Gas FieldSichuan Basin
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