Simulation of the Tectonic Stress Field and Multiparameter Quantitative Prediction of Fractures in Ultradeep Carbonate Reservoirs

The exploration and development of ultradeep carbonate oil and gas reservoirs are constrained by complex tectonic evolution and heterogeneous reservoir characteristics. In particular, the control mechanism of strike-slip fault zones on fracture systems is still unclear, which limits the accuracy of reservoir sweet spot prediction. In this work, the Ordovician carbonate reservoirs in the Fuman oilfield, Tarim Basin, were taken as examples. With the strike-slip fault belt as the research object, this study focused on the distribution pattern and quantitative prediction methods of fractures under the tectonic background of the main fracturing period. Integration of geological, geophysical, and mechanical properties enables an innovative multiparameter fracture prediction method, developed through structural stress field modeling for ultradeep carbonate strike-slip fault systems. First, single-well rock mechanics parameters are obtained from well logging data, which are then used in combination with borehole wall caving and induced fractures to construct a single-well geomechanical evaluation system. Second, on the basis of the combination of well and seismic attributes, the high-precision inversion of 3D rock mechanics parameters is realized through the multivariate nonlinear mapping relationship between seismic attributes and rock mechanics parameters. Then, the seismic interpretation fracture system, core tectonic analysis and well logging data were integrated to establish a finite element geometric model, and the geometric centroid assignment method was used to model the heterogeneity of reservoir geomechanics. Finally, the boundary load conditions were determined, a numerical simulation of the finite element stress field was carried out to investigate the distribution characteristics of the tectonic stress field during the main fracturing period, the rock fracture criterion was optimized, and a multiparameter quantitative prediction of fractures was carried out to investigate the distribution pattern of fractures in the strike–slip fault system in the study area. The approach developed in this study offers valuable insights for predicting fractures within ultradeep carbonate strike-slip fault systems across diverse geological settings.