Ethane-Based Enhanced Oil Recovery: An Innovative and Profitable Enhanced-Oil-Recovery Opportunity for a Low-Price Environment

Abstract

Summary This paper summarizes the current state of the ethane industry in the United States (US) and explores the opportunity for using ethane for enhanced oil recovery (EOR). We show both simulation data and field examples to demonstrate that ethane is an excellent EOR injectant. After decades of research and field application, the use of carbon dioxide (CO2) as an EOR injectant has proved to be very successful. However, there are limited supplies of low-cost CO2 available, and there are also significant drawbacks, especially corrosion, involving its use. The rich gases and volatile oils developed by horizontal drilling and fracturing in the shale reservoirs have brought about an enormous increase in ethane production. Ethane prices have dropped substantially. In the US, ethane is no longer priced as a petrochemical feedstock, but is priced as a fuel. Also, substantial quantities of ethane are currently being flared. Ethane-based EOR can supplement the very successful CO2-based EOR industry in the US. There simply is not enough low-cost CO2 available to undertake all the potential gas EOR projects in the US. The current abundance of low-cost ethane presents a significant opportunity to add new gas EOR projects. The ethane-based EOR opportunity can be summarized as follows: CO2-based EOR works well, and is well-understood. Ethane has more solubility in oil, lower minimum miscibility pressures (MMPs), and better solvent efficiency than CO2. Ethane is operationally simpler than CO2 for EOR. Ethane is now inexpensive, and will likely stay inexpensive. Ethane-based EOR has become a viable option in the Lower 48 (lower 48 states in US). Large volumes of low-cost ethane are available. Recent additions to the growing ethane infrastructure now deliver ethane to locations where ethane-based EOR targets are plentiful.