Petroleum resource development is a significant contributor of greenhouse gas emissions to the atmosphere. A potential source of emissions may result from stray gas migration. However, its contribution to overall emissions and potential groundwater contamination is unknown, and quantification of flow and dissolution of stray gas is required. The environmental expression of stray gas was investigated using an intermediate-scale (150 × 150 × 2 cm³), two-dimensional flow cell packed in both homogeneous and heterogeneous sand configurations allowing for visualization and measurement of gas movement, collection of aqueous samples, and real-time measurement of gas fluxes escaping the surface of the sand. Results show that gas is transported to the surface of the system via varying dominant discontinuous conduits for flow dictated by geology, leading to surface expression that can be greater or less than the leakage rate of gas. This suggests that surface expression is not directly indicative of the expanse and magnitude of stray gas migration leaks. It was found that 35–39% of the methane was released to the aqueous phase and 61–65% to the atmosphere. The results underscore that subsurface characteristics and gas flow are the key drivers for the overall expression of stray gas in unconsolidated sand aquifers.

中文翻译：

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杂散气体迁移影响的中级实验室研究：瞬态气体流量和表面表达。

石油资源开发是温室气体向大气排放的重要因素。杂散气体迁移可能导致潜在的排放源。但是，它对总排放量和潜在的地下水污染的贡献尚不清楚，因此需要对流量和散逸气体的溶解进行量化。使用中等规模（150×150×2 cm ³）研究了杂散气体的环境表达），二维流动池装在均质和非均质砂配置中，可实现可视化和气体流动测量，收集水样以及实时测量逸出砂表面的气体通量。结果表明，气体是通过变化的支配不连续管道传输到系统表面的，这些管道是由地质条件决定的，从而导致表面表达大于或小于气体的泄漏率。这表明表面表情并不能直接表明杂散气体迁移泄漏的范围和大小。发现35-39％的甲烷释放到水相中，而61-65％释放到大气中。