Research on Nuclear Magnetic Resonance Displacement Experiment on Gas–Water Mutual Drive Based on Rock Physical Property Differences

This study addresses the impact of rock physical property differences on the displacement efficiency during the multi-cycle gas–water mutual drive process in water-driven gas storage reservoirs. Utilizing multi-cycle gas–water displacement core experiments and high-pressure nuclear magnetic resonance (NMR) technology, we systematically investigate the relationship between rock physical properties and gas–water flow dynamics. By measuring and dynamically monitoring changes in gas–water distribution within the core, we focus on the effects of differences in permeability, porosity, and pore structure on the non-uniformity and displacement efficiency during the gas–water mutual drive process. The results demonstrate that rock heterogeneity significantly reduces the displacement efficiency, particularly in low-permeability layers where pore structure heterogeneity exacerbates the uneven flow of gas and water, leading to a notable decline in displacement efficiency. Moreover, the impact of micropore structure on displacement efficiency has also been validated. These findings provide important experimental data and theoretical foundations for evaluating and demonstrating the gas–water mutual drive efficiency in water-driven gas storage reservoirs, which is crucial for enhancing gas storage recovery and long-term stability.