Evaluate the use of low-cost biosurfactants produced from agriculture process waste streams to improve oil recovery in fractured carbonate reservoirs.

University of Kansas (KU),Tertiary Oil Recovery Project, Lawrence, KS
Idaho National Laboratory (INL), Idaho Falls, ID

U.S. oil production has been in steady decline for the past 30 years. Significant effort has been devoted to improving oil recovery by using various secondary and tertiary recovery methods. Although these efforts have resulted in a significant increase in recovery efficiency, almost two-thirds (~350 billion barrels) of the U.S. oil resource still remains stranded and unproduced. Previous research has demonstrated that the injection of surfactants into oil reservoirs can be very effective in mobilizing stranded oil. However, the economics of surfactant injection rarely have been favorable in actual field applications because of the cost associated with high-concentration chemical surfactants.

Results
The INL team produced biosurfactant for this project using Bacillus subtilis 21332 and purified potato starch as the growth medium. The biosurfactant was shown by Fourier transform infrared spectroscopy and high-pressure liquid chromatography to be surfactin. Candidates for benchmark chemical surfactants with molecular structures similar to the biosurfactant were identified and samples obtained.

At KU, rock cores were cleaned with tetrahydrofuran (THF), followed by chloroform, methanol and finally water. Crushed reservoir material was used for static wettability and adsorption testing. The surface area per unit mass was measured, and the crushed rock samples were cleaned using the same sequence of solvents as the cores. Cleaned cores were saturated with Soltrol 130 and Amott wettability tests performed to find the initial wettability.

The wettability change of Lansing-Kansas City field and outcrop material – both clean and aged to an oil-wet state using crude oil – mediated by dilute solutions of commercial anionic surfactant (STEOL CS-330, sodium laureth sulfate) and surfactin was assessed using two-phase separation; water flotation, and Amott wettability tests; and surfactant loss due to retention and adsorption by the rock was determined.

On a molar basis, surfactin is more effective than STEOL CS-330 in altering wettability of crushed Lansing-Kansas City carbonates from oil-wet to water-wet state. Adsorption isotherms of STEOL CS-330 and surfactin on crushed Lansing-Kansas City outcrop and reservoir material showed that surfactin has higher specific adsorption on these oomoldic carbonates. This was confirmed by dynamic adsorption studies on intact cores.

Benefits
The results of this project may lead to a method to significantly increase domestic oil production by recovering previously unrecoverable stranded oil and promote the beneficial reuse of agriculture process waste products. Increased domestic production will reduce the reliance of the United States on imported oil. It will ensure a continued income for operators of established fields and make possible the exploitation of previously uneconomic reserves. In addition, the production of biosurfactant will provide a use for high-BOD (biochemical oxygen demand) agriculture process stream waste, with benefits for both the operators and the environment.

Summary
This three-year research project evaluated the use of low-cost biosurfactants produced from high-starch agriculture process waste streams (e.g., potato or rice process effluents) to improve oil recovery in fractured carbonate reservoirs. Specifically, the project examined the ability of the biosurfactants to effect wettability change that positively affects oil recovery in fractured carbonate rock by accelerating the spontaneous imbibition process during waterflooding.

(December 2008)
Due to lack of available funding, the third year of research work was not funded. The final report,listed below under "Additional Information", documents work completed to 3/31/2007.

Funding
This project was selected in response to DOE’s Oil Exploration and Production solicitation DE-PS26-04NT15450-3D.

$560,000 

$200,000 (26% of total)

NETL - Chandra Nautiyal (chandra.nautiyal@netl.doe.gov or 918-699-2021)
U. of Kansas - Jenn-Tai Liang (jtliang@ku.edu or 785-864-2669)
INEEL – Dr Greg Bala (bala@inel.gov )

Final Project Report [PDF]

Publications 
Liang, J.-T., G.A. Bala, S.J. Johnson, and S.L. Fox, Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs: First Semi-Annual Technical Progress Report. 2005, University of Kansas: Lawrence, KS.

Liang, J.-T., G.A. Bala, S.J. Johnson, and S.L. Fox, Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs: First Annual Technical Progress Report. 2005, University of Kansas: Lawrence, KS.

Liang, J.-T., G.A. Bala, S.J. Johnson, and S.L. Fox, Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs: Third Semi-Annual Technical Progress Report. 2006, University of Kansas: Lawrence, KS.

Eisert, K., Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs, M.S. Thesis, Department of Chemical and Petroleum Engineering. 2006. The University of Kansas: Lawrence, KS

Liang, J.-T., G.A. Bala, S.J. Johnson, S.L. Fox, K. Eisert, and M. Salehi, Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs: Second Annual Technical Progress Report. 2006, University of Kansas: Lawrence, KS.

Salehi, M., S.J. Johnson, J.-T. Liang, S.L. Fox, and G.A. Bala, Wettability alteration of carbonate rock mediated by biosurfactant produced from high-starch agricultural effluents, in 9th International Wettability Symposium. 2006: Bergen, Norway.

Johnson, S.J., M. Saheli, K.F. Eisert, J.-T. Liang, G.A. Bala, and S.L. Fox. Potential for Wettability Alteration in the LKC using Biosurfactants from Agricultural Waste, in Seventeenth Oil Recovery Conference. 2007. Wichita, KS, USA: Tertiary Oil Recovery Project, University of Kansas.

Liang, J.-T., G.A. Bala, S.J. Johnson, S.L. Fox, K. Eisert, and M. Salehi, Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs: Final Technical Progress Report. 2007, University of Kansas: Lawrence, KS.

Johnson, S.J., M. Salehi, K.E. Eisert, J.-T. Liang, G.A. Bala, and S.L. Fox, SPE 106078 Biosurfactants produced from agriculture process waste streams to improve oil recovery in fractured carbonate reservoirs, in SPE International Symposium on Oilfield Chemistry. 2007, Society of Petroleum Engineers: Houston, Texas, U.S.A.