Alhosani Abdulla, Scanziani Alessio, Lin Qingyang, Raeini Ali Q, Bijeljic Branko, Blunt Martin J
Imperial College London, Department of Earth Science and Engineering, SW7 2AZ, London, UK.
Sci Rep. 2020 May 22;10(1):8534. doi: 10.1038/s41598-020-65416-z.
Rapid implementation of global scale carbon capture and storage is required to limit temperature rises to 1.5 °C this century. Depleted oilfields provide an immediate option for storage, since injection infrastructure is in place and there is an economic benefit from enhanced oil recovery. To design secure storage, we need to understand how the fluids are configured in the microscopic pore spaces of the reservoir rock. We use high-resolution X-ray imaging to study the flow of oil, water and CO in an oil-wet rock at subsurface conditions of high temperature and pressure. We show that contrary to conventional understanding, CO does not reside in the largest pores, which would facilitate its escape, but instead occupies smaller pores or is present in layers in the corners of the pore space. The CO flow is restricted by a factor of ten, compared to if it occupied the larger pores. This shows that CO injection in oilfields provides secure storage with limited recycling of gas; the injection of large amounts of water to capillary trap the CO is unnecessary.
要将本世纪的气温升幅限制在1.5摄氏度，就需要迅速在全球范围内实施碳捕获与封存。枯竭油田为碳储存提供了一个现成的选择，因为注入基础设施已经具备，而且提高石油采收率还能带来经济效益。为了设计安全的储存方式，我们需要了解储层岩石微观孔隙空间中的流体是如何配置的。我们利用高分辨率X射线成像技术，研究在高温高压的地下条件下，油湿岩石中石油、水和二氧化碳的流动情况。我们发现，与传统认识相反，二氧化碳并不存在于那些有利于其逸出的最大孔隙中，而是占据较小的孔隙或存在于孔隙空间角落的层中。与占据较大孔隙相比，二氧化碳的流动受到了十倍的限制。这表明在油田中注入二氧化碳可提供安全的储存，且气体再循环有限；无需注入大量水来通过毛细管捕获二氧化碳。
