Analysis method of cluster perforating tubing strings trafficability in horizontal wells for unconventional reservoirs

The feasibility of a normal perforating operation depends on the perforating tubing string, which is the main component of the cluster perforating tool for the exploration and development of unconventional oil&gas reservoirs. To improve the efficiency of cluster perforation in horizontal wells, a passing capability analysis model for the tubing string in a wellbore was established, thereby generating complex equations with coefficients that are solved via geometric analyses and the beam-column theory. This model was based on a comprehensive consideration of the friction between the downhole tools and the borehole wall, fluid resistance, wellbore geometric constraint, pump thrust, axial tension, tool variable cross-section, tension of cable head, and tool elastic deformation. Based on field test data, the pass-through capacity of “1 bridge plug + 4 cluster perforating gun string” in the X206 well and the main factors affecting pass-through ability were analyzed to test the validity of the model. The model presented in this paper can provide an effective tool for analyzing the design and operation of a cluster perforating string.