Ecophysiology of Thermophilic Clostridia in Tight Rock Unconventional Oil Reservoirs

世界上相当大比例的石油储量被困在紧密结合的富有机质页岩中，这些页岩具有极低的孔隙度，通常被称为致密岩非常规（TRU）储层。加拿大绝大多数TRU地层位于阿尔伯塔省和不列颠哥伦比亚省的沉积盆地内，其特征是高温，例如超过60摄氏度。通过水平钻井与水力压裂相结合，可以实现TRU油藏的高收益采油。水力压裂是一种新兴技术，依赖于向深层页岩储层注入大量水。尽管在生产策略上与传统油田有很大不同，但TRU生产设施也会遇到类似的问题，比如有毒硫化氢的产生，以及由于微生物活动不受控制而导致的上层设施腐蚀。在热储层中，微生物群落及其活动的影响仍然知之甚少。该项目将与雪佛龙加拿大公司合作，研究在TRU裂缝地层中适应极端温度、盐度和压力的嗜热盐孢子形成梭状芽孢杆菌。主要目标是在了解深层TRU油藏中这些细菌的生存情况以及它们对流动管线和上层设施温度下降的反应的基础上，为雪佛龙提出微生物控制建议。该项目还将调查反排水和采出水的循环利用如何影响微生物活动和相关有害代谢物的产生。生成的信息可以更好地预测雪佛龙加拿大公司TRU作业的潜在有害影响，从而提出针对特定油藏的处理和回收建议，并为这些重要资产的风险管理和决策提供信息。在TRU油藏预期产量增加的背景下，该项目通过保护这一新兴行业免受微生物在油气行业中众所周知的陷阱和危害，为加拿大提供了巨大的经济、社会和环境效益。

A considerable proportion of the world's petroleum reserves are trapped within tightly bound organic-rich shale rocks with extremely low porosity, commonly referred to as tight rock unconventional (TRU) reservoirs. A large majority of the TRU formations in Canada are situated within the sedimentary basins of Alberta and British Columbia, and are characterized by high temperatures e.g. above 60 degrees Celsius. Profitable oil recovery from TRU reservoirs is achieved by horizontal drilling combined with hydraulic fracturing, an emerging technology that relies on injection of extremely large volumes of water into the deep shale reserves. Although very different from conventional oil fields in terms of production strategies, TRU production facilities encounter similar problems such as unwanted production of toxic hydrogen sulfide and corrosion of topsides facilities stemming from uncontrolled microbial activity. In hot TRU reservoirs, the impact of microbial communities and their activities remain poorly understood. In collaboration with Chevron Canada, this project will investigate thermohalophilic spore-forming Clostridia adapted to the extreme temperature, salinity and pressure within fractured TRU formations. The primary goal is to advance microbial control recommendations for Chevron based on understanding the survival of these bacteria in deep TRU reservoirs and their response to decreasing temperatures in flowlines and topsides facilities. The project will also investigate how recycling of flowback and produced water impacts microbial activity and associated production of deleterious metabolites. Information generated will enable better prediction of potential deleterious effects in Chevron Canada's TRU operations, leading to reservoir-specific treatment and recycling recommendations, and informed risk management and decision-making for these important assets. In the context of increasing production anticipated from TRU reservoirs such as these, the project offers great economic, social and environmental benefits to Canada by safeguarding this nascent industry from the pitfalls and harms that microorganisms are well known for in the oil and gas sector.