Aminu Mohammed Dahiru, Manovic Vasilije
Department of Geology, Modibbo Adama University of Technology, Yola, Nigeria.
Centre for Climate and Environmental Protection, Cranfield University, Bedford, Bedfordshire, MK43 0AL, UK.
Heliyon. 2020 Aug 3;6(8):e04597. doi: 10.1016/j.heliyon.2020.e04597. eCollection 2020 Aug.
Carbon capture and storage (CCS) is expected to play a key role in meeting greenhouse gas emissions reduction targets. In the UK Southern North Sea, the Bunter Sandstone formation (BSF) has been identified as a potential reservoir which can store very large amounts of CO. The formation has fairly good porosity and permeability and is sealed with both effective caprock and base rock, making CO storage feasible at industrial scale. However, when CO is captured, it typically contains impurities, which may shift the boundaries of the CO phase diagram, implying that higher costs will be needed for storage operations. In this study, we modelled the effect of CO and impurities (NO, SO, HS) on the reservoir performance of the BSF. The injection of CO at constant rate and pressure using a single horizontal well injection strategy was simulated for up to 30 years, as well as an additional 30 years of monitoring. The results suggest that impurities in the CO stream affect injectivity differently, but the effects are usually encountered during early stages of injection into the BSF and may not necessarily affect cumulative injection over an extended period. It was also found that porosity of the storage site is the most important factor controlling the limits on injection. The simulations also suggest that CO remains secured within the reservoir for 30 years after injection is completed, indicating that no post-injection leakage is anticipated.
碳捕获与封存（CCS）有望在实现温室气体减排目标方面发挥关键作用。在英国南部北海地区，邦特砂岩地层（BSF）已被确定为一个潜在的储层，能够储存大量的二氧化碳。该地层具有相当良好的孔隙度和渗透率，并且被有效的盖层和基岩所封闭，这使得在工业规模上进行二氧化碳储存成为可能。然而，当捕获二氧化碳时，它通常含有杂质，这些杂质可能会改变二氧化碳相图的边界，这意味着储存操作将需要更高的成本。在本研究中，我们模拟了二氧化碳和杂质（一氧化氮、二氧化硫、硫化氢）对邦特砂岩地层储层性能的影响。使用单水平井注入策略，以恒定速率和压力注入二氧化碳，模拟长达30年的时间，以及另外30年的监测期。结果表明，二氧化碳流中的杂质对注入性的影响各不相同，但这些影响通常在注入邦特砂岩地层的早期阶段出现，不一定会影响长期的累计注入量。研究还发现，储存地点的孔隙度是控制注入极限的最重要因素。模拟结果还表明，注入完成后，二氧化碳在储层内可保持30年安全，这表明预计不会出现注入后泄漏情况。
