Abstract:

At present,there are few studies on the influence of medium and low water saturation on the capacity of free gas storage.Therefore, this study simulates the multi?round gas injection?soaking?production process through laboratory experiments; The laboratory experiment was carried out to simulate the process of multi?round gas injection?well soaking?production. Combined with the mathematical model and numerical simulation results, the research shows that the reservoir capacity increases with the increase of injection?production rounds, but the increase after single?round injection?production decreases rapidly.When the initial water saturation is higher than 50%, the increase of water saturation is beneficial to the reconstruction of gas storage, but the increase of injection?production capacity and storage capacity is relatively slow in the early stage of reservoir construction. When the initial water saturation is increased from 50% to 85%, the gas saturation is reduced by about 9.27% after 6 injection?production cycles. When the injection?production cycles are increased to 20,30,50 cycles, the free gas storage capacity is increased by about 0.51%,3.33%,6.61%, respectively. The research results are expected to provide reference for the evaluation of injection?production capacity and storage capacity of reservoir?type gas storage.

Key words: Free gas storage capacity, Injection?well soaking?production, Water saturation, Injection and extraction times, Volumetric method

摘要：

针对目前中、低含水饱和度对自由气库容量影响的研究较少的问题，开展室内实验模拟了多次注气?焖井?采气实验，并根据相似原理,利用实验数据建立了自由气库容量与初始含水饱和度、注采次数的量化表征模型。结果表明，自由气库容量随注采次数的增多而增大，但单次注采后的增幅快速降低；含水饱和度（初始含水饱和大于50%）的提高有利于油藏改建储气库，但是建库初期的注采能力和库容提高相对缓慢；当初始含水饱和度由50%提高到85%时，经过6次注采后，含气饱和度降低幅度约9.27%，而当注采次数分别增至20、30、50时，自由气库容量增加幅度分别为0.51%、3.34%、6.61%。研究结果可为油藏型储气库的注采能力及库容评价提供借鉴。

关键词: 自由气库容量, 注气?焖井?采气, 含水饱和度, 注采次数, 容积法