Over the last decade, there has been tremendous success is developing and producing unconventional oil resources such as the Bakken and Eagle Ford; however, flaring produced gases from these fields has become a problem that needs to be addressed. In many instances, pipeline infrastructure is not in place to transport gas away from the wells.
One possible solution is to reinject the produced gas back into the formation, which has numerous positive benefits. It has the potential to increase oil recovery from unconventional reservoirs because of the strong likelihood to achieve miscibility with reservoir oil. Furthermore, unlike flaring, the injected gas will be available for sales once gas gathering pipelines become available. Gas reinjection also should mitigate environmental concerns associated with greenhouse gas emissions.
We evaluated the recovery potential along with the costs of reinjecting gas to determine the economic value of this process. A dual-porosity, compositional flow simulator was used to model the gas injection process into a well surrounded by producers and to determine the amount of incremental oil and gas produced. We calculated the net economic value of the process by including the cost of gas compression and fuel gas for injection.
We have concluded that oil production rates can be significantly increased, and the economics of the process is very positive. Additionally, significant volumes of gas can be recycled, which alleviates environmental concerns of gas flaring and improves resource efficiency. As a result, we recommend pilot testing the gas injection process to assess the commercial application of the proposal.