Petroleum engineers need real-time understanding of the dynamic information of reservoirs and production in the development process, which is essential for the fine description of oil and gas reservoirs. Due to the non-invasive feature of electromagnetic waves, more and more oil and gas reservoirs have received attention to capture the development dynamics with electrical resistance tomography (ERT). By measuring the distribution of resistivity on the surface, the ERT can offer information on the subsurface media. The theory and foundation of the ERT technology are presented in this study in the context of monitoring oil and gas reservoir growth dynamics. The characteristics of ERT technology are analyzed, and the progress of ERT application in the development of monitoring dynamics in terms of residual oil distribution, detection of water-driven leading edge, and monitoring of fractures during hydraulic fracturing is reviewed, as well as the progress of ERT technology optimization, including forward and inverse algorithms. This review aims to promote further application of ERT in the field of reservoir dynamics monitoring because of its important engineering significance as well as its academic value in terms of improving production efficiency and reducing risk.

To improve oil displacement efficiency under deep reservoir conditions, foam flooding technology represents a critical strategy through the establishment of a stable, long-lasting foam system. A central challenge in this application is to characterize the evolution dynamics of foam under extreme reservoir conditions such as high temperature and salinity. In this study, a performance evaluation experiment of foams generated by different types of surfactants was carried out by using the Waring-blender method. The foam stability characteristics were analyzed on the basis of foam volume, half-life of the liquid solution, and the foam comprehensive index and other related parameters. Based on the microscopic action mechanism of gas-liquid interface, the change pattern of foam performance with concentration, salinity and the coordinated action of core-shell particles were investigated. Both candidate surfactants exhibited good resistance to temperature and salinity. Among them, one surfactant demonstrated superior overall performance, with the foam comprehensive index reaching its peak at an optimal mass concentration of 0.5%. In high-salinity environments, the synergistic interaction between core-shell particles and surfactant molecules significantly enhances foam stability. In particular, the combination of this surfactant with core-shell particles at a mass fraction of 0.5% resulted in a notably higher foam comprehensive index, suggesting its strong application potential. This study quantitatively analyzes the synergistic stability effects of salinity, core-shell particles and surfactant, and reveals the synergistic stability mechanism of salt ion compression electric double layer and particle interface adsorption, providing important theoretical guidance for the development and application of deep reservoir foam flooding. Document Type: Original article Cited as: Xu, Z., Ding, G., Tao, L. Shi, W., Bai, J., Dang, F. Foam stabilization mechanism of core-shell particles: Insights from the gas-liquid interface theory. Capillarity, 2025, 16(1): 5-17. https://doi.org/10.46690/capi.2025.07.02

Although waterflooding treatment assisted by traditional viscosity reducer yields additional oil recovery, this increments in production sometimes cannot meet the production requirements. To solve this problem, it is necessary to analyze and understand the flow mechanism of heavy oils in the waterflooding process assisted by the viscosity reducer. This study employed an etched glass micro-model to visualize the flow behavior of heavy oils under assistance of a novel multi-functional viscosity reducer with the condition of high temperature and ultra-heavy oil. The water flooding and novel viscosity reducer flooding experiments were carried out, and the state and shape of the remaining oil phase were observed from the global perspective and the microscopic local perspective in the etching micro-glass. Results show that the viscosity reducer solution can not only greatly reduce viscosity of heavy oil but also decrease oil-water interface tension. In the waterflooding process, the continuous oil group and long oil slug are the main characteristics of remaining heavy oil in the reservoir. By waterflooding with the new viscosity-reducer, the remaining oils exist as short slug and droplet, and 3 times wider flooding area for fluid-flow was observed than conventional waterfloodings.