数值模拟方法验证光透法监测流体饱和度的有效性：以非均质孔隙介质中的水/气两相流为例

Verification of Effectiveness of Light Transmission Study on Fluid Phase Saturation Using Numerical Modeling Method:Cases of Water-gas Flow in Heterogeneous Porous Media

光透法作为一种安全经济的非侵入监测方法广泛应用于室内砂箱多相流实验中,但该方法在局部空间点上结果的可靠性尚缺乏验证。鉴于当前难以采用实验手段直接进行局部监测点取样验证光透法结果,本文以非均质孔隙介质中的水/气两相流为例,基于砂箱实验开展了数值模拟研究以进行论证。研究表明:(1)模拟结果中气体在非均质含水层中的迁移规律、展布形态和饱和度分布总体上再现了光透法的测量结果。(2)数值模拟和光透法得到的6个局部点饱和度数据在各时刻均拟合较好。同时选取12个时刻共5316个监测点的饱和度数据进行分析,其决定系数达0.94,这表明模拟结果从统计角度较好地验证了光透法在局部点监测上的有效性,两者间的差异主要由人工填砂导致的介质"不均匀"引起。(3)气体总量方面,实测排水值、模拟结果与光透法计算结果均拟合较好。因此数值模拟结果系统地验证了光透法监测流体饱和度的有效性。

Light Transmission Method has been extensively used in phase saturation measurements in porous media due to its non-destructive and non-invasive feature. However doubt about its effectiveness still exists due to the lack of local data validation. Given the fact that it is impossible to obtain local data experimentally, numerical simulation was then developed to verify its effectiveness, in the cases of water-gas flow in heterogeneous porous media. The results show that （1） simulation results agree with the light transmission results in terms of the gas distribution pattern and gas saturation range in the heterogeneous porous media; （2） six local saturation values of light transmission results in time-series graph show good consistency with the simulation results at each moments, meanwhile the analysis of 5316 local saturation data within 12 minutes shows the determination coefficient reaches 0.94 between the simulation results and the light transmission results. The results validate the effectiveness of light transmission method at local points, with the difference being caused by the sandbox packing; （3） the total gas volume calculated by both simulation and the water displacement volume agree with the data by light transmission results. Through these three qualitative and quantitative analyses, this paper verifies the effectiveness of light transmission method in measuring liquid saturation.