2022 Volume 87 Issue 3 Pages 207-213
In our project, a bio-augmentation field pilot is being planned with utilizing microbial reactions which can convert immovable residual oil into movable methane gas, for the purpose of extracting more hydrocarbon resources from brown oilfields.
In this project, we have already identified the reservoir in which oil degradation microbial communities live. We are planning to transport the formation water which contains the microbial communities to another brown oilfield and injected it into the oil-bearing formations. Considering reservoir temperature and field locations, we selected one domestic brown oilfield as a target field of the project. Reservoir temperature is one of the most important factors because each microbial community has optimal temperature for their metabolisms. In addition, the target field is located close to the microbes bearing reservoir. It will help transporting operations of produced water.
Prior to the field pilot test, the pre-evaluation work was carried out to assess the operational risk in the planned procedures. In the operation, anaerobic condition needs to be maintained to mitigate the risk of oxygen exposure, because our oil degradation microbial communities can survive only under anaerobic condition. Therefore, the pre-evaluation work was conducted mainly focusing on the exposure risk of produced water to air. The workflow consists of several steps, such as temporary preservation of produced water, transportation of produced water, and water injection into the reservoir. In general, the risk of oxygen exposure will increase with the number of operational procedures.
In this article, the results and findings of the pre-evaluation work are introduced.
