Development of alkane solvents enhanced steam + flue gas processes for enhancing heavy oil recovery from post-CHOPS reservoirs

对于加拿大西部储量巨大的稠油油藏，最常见的生产工艺是带砂冷采稠油（CHOPS），由于虫孔的产生和泡沫油的流动，这种工艺通常只能回收5-15%的原始含油。因此，在常规的蒸汽热采油技术和溶剂型非热采油技术都存在局限性的情况下，在这些后chop油藏中需要高效的后续提高采收率（EOR）技术。在实践中，通常由80-88% N2和12-20% CO2组成的烟气可以作为一种有效的非混相剂，通过N2提供的自由气机制和CO2提供的增溶机制来提高稠油采收率。本研究的总体目标不仅是研究通过烷烃/水溶性溶剂增强蒸汽+烟气回收工艺提高后排油油藏稠油采收率的适宜性和适用性，同时最大限度地减少环境足迹，而且还评估在枯竭地质地层中安全储存二氧化碳的可能性。随着直接接触蒸汽发生（DCSG）工艺（即浸没燃烧汽化器（scv））的成功开发，这使得未经处理的油田采出水能够以高效率和低成本直接转化为高质量的蒸汽和清洁的烟气。随着烷烃/水溶性溶剂的加入，新提出的烟气辅助热采技术和优化的SCV操作参数将扩展到目标后chops油藏的试点测试中。拟议的研究有可能为上游石油和天然气工业提供可行的技术，通过利用烟道气体和热能，同时最大限度地减少淡水的使用，并减少甲烷和二氧化碳的排放，从而有效地从后chop油藏中回收重油。这也将有助于加拿大成为一个技术资源中心，重点是烟气的使用、稠油储层的EOR技术和二氧化碳储存。

As for the enormous heavy oil reserves deposited in Western Canada, the most common production process is the cold heavy oil production with sand (CHOPS) which can typically recover only 5-15% of original-oil-in- place due to both wormhole generation and foamy oil flow. As such, efficient follow-up enhanced oil recovery (EOR) techniques are required in these post-CHOPS reservoirs where both conventional steam-based thermal recovery techniques and solvent-based non-thermal recovery techniques find their limits. In practice, flue gas that typically consists of 80-88% N2 and 12-20% CO2 can be used as an efficient immiscible agent for enhancing heavy oil recovery through a free gas mechanism provided by N2 and a solubilization mechanism provided by CO2. The overall objective of this proposed research is to not only investigate the suitability and applicability for enhancing heavy oil recovery from the post-CHOPS reservoirs through the alkane/water-soluble solvents enhanced steam + flue gas recovery processes while minimizing environmental footprint, but also evaluate the possibility of safely storing CO2 in the depleted geological formations.With the successful development of direct contact steam generation (DCSG) processes referred to as the submerged combustion vaporizers (SCVs), this allows directly converting the untreated oilfield produced water into high-quality steam together with clean flue gas at high efficiency and low cost. With addition of alkane/water-soluble solvents, the newly proposed flue gas-assisted thermal recovery techniques with the optimized SCV operating parameters will be extended to the pilot tests in the targeted post-CHOPS reservoirs. The proposed research has the potential of providing the upstream oil and gas industry with viable techniques for efficiently and effectively recovering heavy oil from post-CHOPS reservoirs by taking advantages of both flue gas and thermal energy while minimizing freshwater usage as well as mitigating CH4 and CO2 emissions. This will also help Canada to become a technology resource centre, focusing on the usage of flue gases, EOR techniques for heavy oil reservoirs, and CO2 storage.