Methodology and application of shale-reservoir natural fracture modeling based on microseismic monitoring data

Abstract

Fracturing is a key factor for shale oil and gas enrichment and high production. An accurate fracture model can effectively guide shale oil and gas exploration and development. The establishment of a natural fracture model must address the challenges of difficult data acquisition and poor representativeness of data points. To solve these problems, we have developed a method of shale-reservoir natural fracture modeling based on microseismic monitoring data. This method includes three steps. First, we establish an initial natural fracture model based on scale classification, vertical stratification, and genetic classification. Second, the shape and density of the hydraulic fractures are interpreted by microseismic monitoring data to calibrate the initial model of the shale reservoir natural fractures. Third, we verify the rationality of the model by assessment of the fracture porosity and permeability values. The results show that it is possible to calibrate the natural fracture density model using the fracture shape and density as determined by microseismic monitoring. And we predict that an ideal hydraulic fracture network can be formed when the body density of the natural fracturing is greater than 0.3 m2/m3. The crude production of wells is negatively correlated with the development of large-scale structural fractures and positively correlated with small-scale structural fractures. The well trajectory should run through small-scale fracture development sections as much as possible, avoiding large-scale, high-angle fracture areas. This method provides a new approach to model natural fractures in shale reservoirs that has wide applicability and can be used for modeling shale oil and gas reservoirs.