底水气藏型储气库注采渗流规律实验

为深入研究底水气藏型储气库在多周期注采过程中的气-水两相渗流规律,以辽河油田S6储气库储层岩心为研究对象,开展多周期升压—卸压渗透率应力敏感性评价、多周期模拟注采气-水相渗特征评价实验,并结合扫描电子显微镜观察进行微观结构分析。结果表明:研究区渗透率应力敏感性较低,多周期升压—卸压后渗透率有低幅度下降;随着气-水互驱次数的增加,束缚水饱和度和残余气饱和度分别下降和上升,而后逐渐趋于平衡;多周期循环注采导致微裂缝生成和微粒运移,微裂缝强化渗流能力占主导地位,含气饱和度、气相渗透率逐渐升高并逐渐趋于平衡,与实际运行中储气库前期扩容、后期逐渐平衡规律一致。研究结果对合理配置注采参数和区域内新兴储气库建设提供技术指导。

Test on the Seepage Pattern in Injection and Production of Gas Storage in Bottom-water Gas Reservoir

In order to further study the gas-water seepage pattern of gas storage in bottom-water gas reservoir during multi-cycle injection and production, the reservoir core in S6 gas storage, Liaohe Oilfield was sampled to evaluate the stress sensitivity of permeability in multiple cycles of pressure boosting and relief, test the gas-water seepage characteristics in multiple cycles of injection and production simulation, and analyze the microstructure in combination with observation by scanning electron microscope. According to the results, the stress sensitivity of permeability in the study area was low, and the permeability was decreased to a low extent after multiple cycles of pressure boosting and relief; after gas-water mutual flooding was conducted for many times, the irreducible water saturation was decreased while the residual gas saturation increased, and then both gradually reached a balance; the multi-cycle injection and product caused micro-cracks and particle migration, the micro-cracks played a dominant role in enhancing seepage capacity, the gas saturation and gas permeability were gradually increased and tended to balance, which was consistent with the law of storage expansion at the early stage and gradual balancing in the later stage in the actual operation. The results of the study provide technical guidance for the reasonable configuration of injection and production parameters and the construction of new gas storage in the area.