Abstract

After decades of research and field application, the use of CO2 as an enhanced-oil-recovery (EOR) injectant has proved very successful. However, there are limited supplies of low-cost CO2 and significant drawbacks to its use, especially corrosion.

Simulation data and field examples demonstrate that ethane is an excellent EOR injectant. The rich gasses and volatile oils developed in the United States shale reservoirs have caused an enormous increase in ethane production. Ethane in the US is no longer priced as a petrochemical feedstock but as a fuel, and substantial amounts of ethane are being flared.

Ethane-based EOR can supplement the very successful CO2-based EOR industry. There simply isn’t enough low-cost CO2 available to undertake all of the potential US gas-EOR projects. The current abundance of low-cost ethane presents a significant opportunity to add new gas-EOR projects in the US and elsewhere.

To summarize the ethane-based EOR opportunity:

1. CO2-based EOR…