A natural gas pipeline system (NGPS), as a crucial energy transportation network, exhibits intricate systemic characteristics. Both uncertain disturbances and complex characteristics result in higher requirement of supply safety. The investigation into NGPS resilience addresses the constraints of pipeline integrity and reliability, centering around the vulnerability, robustness, and recovery of an NGPS. Based on a literature review and practical engineering insights, the generalized concept of NGPS resilience is elucidated. The research methodologies of NGPS resilience are classified into three types: indicator construction method, process analysis method, and complex networks method. The practical applications of NGPS resilience research are analyzed, which are based on NGPS operation safety, information safety, and market safety. The ongoing applications and detailed measures are also concluded, which can guide the researchers and engineers from NGPS resilience.

As the lifeline of offshore oil and gas production, a submarine pipeline requires regular safety evaluations with proper maintenance according to the evaluation results. At present, the safety factors based on regional-level commonly used factors in engineering are too many, and this leads to conservative evaluation results with a low acceptance of defects. In this paper, a risk factor evaluation index system for submarine pipeline defects is constructed through an analytic hierarchy process (AHP), and the original safety factors are corrected to achieve accurate evaluations for submarine pipeline safety. By constructing a radial basis neural network (RBFNN), the fast calculation of safety factors for other pipeline defects can be realized. Through comparison, it was found that the values obtained by the machine training were in good agreement with the real values, which reflects the accuracy of the model and provides a basis for the repair of a defective pipeline.

In recent years, with the goal of “carbon peaking and carbon neutralization”, the CO₂ flooding technology in carbon capture, utilization, and storage (CCUs) has been paid great attention to the oil fields. However, the CO₂ flooding of crude oil may produce foams in the oil and gas separation process. In addition, the precipitation of wax components in crude oil might enhance the stability characteristics of these foams and lower the separator’s efficiency. Based on a crude oil depressurization foaming device, the influence of wax crystals on the bursting of oil foam was studied using simulated oil, and the microstructure of the wax crystal and foam liquid film was observed using freeze-etching and microscopic observation. In addition, the gas–liquid interface model of the wax oil was established by a molecular dynamics (MD) simulation to analyze the influence mechanism of wax crystals on foam drainage and gas diffusion among foams in the microlayer. The results show that the precipitation of wax crystals overall reduces the rate of defoaming and drainage and increases the grain diameter of the foam. The formation and growth of the wax crystal-shaped network impede the flow of liquid in the drainage channel and stabilize the foam. Moreover, it impedes the diffusion of CO₂ among foams, inhibiting the bursting of the foams. The results of the combined experiments and MD simulation verify the accuracy and applicability of the molecular model, which further clarifies the effect of wax crystals on foam stability and its mechanism of action on foam film. These findings are a benchmark for the enhancement of defoaming and separation efficiency and a theoretical framework for future study and modeling.