Assessing the feasibility of enzyme technology for the biodegradation of polymers used in hydraulic fracturing operations

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Hydrocarbons, such as the methane, ethane and propane found in natural gas, are recovered from reservoirs deep under the ground. In some cases, the hydrocarbon can be accessed relatively easily by drilling a series of wells into a reservoir. The hydrocarbons readily move from the reservoir into the wells where they are collected. These are known as conventional reservoirs. However, in some cases the gas does not easily move into a well, and thus simply drilling the well is not sufficient. These unconventional reservoirs require more work to recover the hydrocarbons. One approach that has been taken to free the hydrocarbons is called hydraulic fracturing. In this approach, liquids are pumped at high pressure down a well and into the reservoir rock causing it to crack. Fracturing the reservoir in this manner facilitates the movement of hydrocarbons. Once the liquid is removed, the freed hydrocarbon can enter the well and be collected. The liquid used in fracturing typically contains polymers, such as polyacrylamide, which help in the process. However, one problem that arises is that residual polymer often remains in the fractures, accumulating over time, preventing the hydrocarbon from flowing into the well. Thermal and chemical approaches have been evaluated to break down this polymer, but they are inefficient, expensive, and can result in toxic by-products. In this project, we propose to use a biological approach to degrade the polymers. Our preliminary results suggest that there are microbes in nature that contain enzymes which can naturally break down these polymers. Our aim here is to identify and grow these microbes, and then evaluate if their enzymes can break down specific polymers to harmless products under reservoir conditions. We will create these conditions in a novel device that we will design and construct. If successful, this project will have great benefit to Canada. Increased hydrocarbon production from unconventional reservoirs will have a positive economic impact. This project will also result in the training of individuals in new multidisciplinary areas. Finally, it will show that academia and industry can collaborate to develop environmentally friendly, biology-based solutions to problems in the oil and gas industry.