Increasing the volume of oil recovered from oil reservoirs could be an important step in growing the nation’s oil supply and reducing our dependence on imported resources. Depending on the geographical characteristics of a reservoir, over 50 percent of the original oil can be left behind after initial production according to the U.S. Department of Energy’s National Energy Technology Laboratory (NETL). Enhanced oil recovery (EOR) refers to methods that are used to increase the amount of oil recovered from petroleum reservoirs. Typically EOR is employed after primary and secondary methods are exhausted. However, to be viable the cost of the extraction must be kept relatively low.
In order to extract oil, a certain amount of pressure needs to be present. Primary recovery methods exploit the energy naturally present in a reservoir such as gas under pressure or natural water displacing oil downward. Secondary methods usually refer to the use of waterflooding or the injection of water into the reservoir.
Once the initial pressure of a reservoir has been depleted through primary and secondary recovery methods, EOR can be used to increase the yield of a reservoir. Gas flooding is the most commonly used EOR approach because gas, unlike water, is miscible, or has the ability to mix with, oil. Gas flooding refers to the injection of gases into a reservoir to cause miscibility and the efficient extraction of previously trapped residual oil. While not the only viable gas, CO2 is used most often in gas flooding because it’s relatively inexpensive, and has efficient extraction of oil at relatively low reservoir pressures. Injection of CO2 also has the advantage of sequestering a gas that is associated with climate change. According to NETL, CO2 flooding currently produces about 190,000 barrels of oil per day.
As the director of the Gas Flooding Joint Industry Project, Russell Johns has assembled a research team to investigate a wide range of topics related to the issues around gas flooding. The group includes faculty from several universities including Penn State and the University of Texas. The majority of funding for the program comes from industry membership and, in order to ensure the research is highly relevant, the group encourages industry affiliates to provide topics and data for the research. Current member companies are British Petroleum, ExxonMobil, Maersk, Marathon, Occidental, OMV, and Shell.
Johns, professor of petroleum and natural gas engineering at Penn State, initiated this program in 2006 with the goal of generating innovative research in gas flooding and closely related areas as well as recruiting and training graduate students in petroleum engineering for careers in the oil industry. In addition to student recruitment and shared research outcomes, technology transfer is one of the major benefits for gas flooding members. Members have access to an interactive website, annual workshops and meetings, and software toolkits. These toolkits provide members with practical software, which facilitates the dissemination of research results to oil companies as well as providing a platform to store graduate student knowledge.
The group’s research falls into several key areas, including gas flooding processes such as CO2 gas flooding and rich gas flooding, thermodynamics & phase behavior, geo-chemistry, petrophysical properties, and numerical simulation of gas floods.
Current research projects include:
- Development of Miscibility for Various Oils and Injection Mixtures
- CO2 Flooding in Carbonates
- Prediction of the Optimum WAG Performance
- Three-Phase Capillary/Capillary Equilibrium in Oil-Wet Media
- The Effect of Wettability on Three-Phase Relative Permeability During Gravity Drainage
- Foams and Emulsions Stabilized with Nanoparticles for Potential Conformance Control Applications
- Upscaling of Miscible Gas Floods
- Asphalene modeling using the SAFT EOS
- Miscible Gas Flooding in Naturally Fractured Reservoirs
- Analytical Modeling of Three Phase Coning
For more information on the Gas Flooding Joint Industry Project, visit the website, www.energy.psu.edu/gf.