Reliability analysis and multi-objective optimization of pressure sealing subsystem for in situ pressure-preserved coring

In situ pressure-preserved coring (IPP-Coring) technology is regarded as an exceptionally effective approach for achieving precise exploration and efficient development of deep resources. However, the harsh and complex downhole environments, characterized by high temperature, pressure, and solid phase content, introduce significant uncertainty into the successful implementation of the IPP-Coring operations. To address this issue, this study conducts a reliability analysis and multi-objective optimization of the pressure sealing subsystem of the IPP-Coring tool. Three key factors affecting the reliability of pressure sealing, namely, lifting resistance, total operation time of the spring sleeve, and the adhesion rate of solid phase particles, are identified and systematically analyzed. Corresponding mathematical models are developed to evaluate both the lifting resistance and the total operation time of the spring sleeve. In addition, the adhesion behavior of solid phase particles at critical zones is investigated using the Euler-Lagrange two-way coupling method, and a parametric calculation model is established to correlate the particle adhesion rate with four dimensionless structural parameters. Based on these models, a multi-objective optimization design employing the NSGA-II genetic algorithm is conducted. The optimized design scheme achieves a 59% reduction in particle adhesion and a 50% reduction in lifting resistance under specified conditions, while eliminating interference risks between the pressure controller and the spring sleeve during the rebounding process. Overall, the proposed optimized design scheme offers a promising solution to enhance the success rate of pressure coring technology in deep resources exploration and development. • Three key factors affecting IPP-Coring reliability were identified and evaluated. • A multi-objective optimization strategy was proposed for subsystem design. • An optimization design scheme for the pressure sealing subsystem was developed. • The reliability and performance of IPP-Coring were significantly improved.