Productivity prediction model and applicability analysis of self-cleaning and after-effect perforation technology

Conventional shaped-charge perforation completion for low-permeability oil and gas reservoirs faces persistent challenges, namely compaction damage zones, high seepage resistance, and reduced productivity. To address these issues, two novel perforation techniques are proposed: self-cleaning perforation and after-effect body perforation. Analytical productivity prediction models for both methods are developed on the basis of the Joshi model, and their reliability is rigorously verified. Furthermore, dynamic numerical simulations of the perforation process are carried out, and the simulation results are validated against surface experiments. With the maximization of the productivity ratio as the optimization objective, the applicability and sensitivity of each technique to reservoir physical parameters are systematically investigated through orthogonal experimental design, employing level k values and range coefficient R. The results indicate that the maximum deviation between the productivity prediction model and actual field data is 6.73%, while the discrepancy between dynamic simulations and experimental measurements is 7.74%. In terms of applicability, self-cleaning perforation exhibits favorable performance under porosity conditions of 15%-25%, confining pressure of 10-20 MPa, and elastic modulus of 2.4-3.6 GPa; in contrast, after-effect body perforation demonstrates superior performance at porosity of 5%-15%, confining pressure of 20-40 MPa, and elastic modulus of 3.6-14.5 GPa. Both techniques perform comparably when compressive strength ranges from 20 to 60 MPa. Sensitivity analysis of reservoir physical parameters reveals the following order of influence for self-cleaning perforation: confining pressure > compressive strength > porosity > elastic modulus; for after-effect body perforation, the order is: compressive strength > porosity > confining pressure > elastic modulus. This study provides theoretical guidance for the application of these two techniques in low-permeability reservoirs and holds significant implications for oil and gas well stimulation.