Quantitative investigation into the relationship between the fracture geometry and the well production during near-wellbore temporary plugging and diverting fracturing

Abstract

During near-wellbore temporary plugging and diverting fracturing (NWTDF), the old fractures can be plugged, and the new fractures can be generated and propagated along the direction perpendicular to the old fractures. The fracture geometry after NWTDF determines the stimulated volume and the well productivity. Studying the quantitative relationship between fracture geometry and well production during NWTDF is of great significance for NWTDF optimization. Based on the large-scale true tri-axial fracturing equipment, this work carried out the fracture propagation experiments of NWTDF. The experiment results confirmed the feasibility of forming diversion fractures by plugging the old fractures. The extended finite element method obtained the overall fracture geometry under various conditions. Moreover, based on the propagation pattern of fracture geometries, a reservoir seepage model was established and applied to predict oil well production. The results show that: (1) The fracture diversion radius (FDR) significantly affects well production. When the diversion radius increases from 20 m to 110 m, the well production increases by 17.2%. (2) When the FDR increases from 20 m to 50 m, the area of the pressure sweep region increases by about 7.5%; when the FDR increases to 80 and 110 m, the degree of the area and the productivity uplift is not apparent. There is an optimal value of the FDR. (3) Well productivity significantly increases with diversion frequency, while when it reaches 9, the degree of the well productivity uplift is small. The diversion frequency should be optimized to obtain a desirable stimulated volume. The research results provide a theoretical basis for the optimization design of NWTDF.