Lower-Cost Methods for Enhanced Oil Recovery Via Surfactant Flooding

DE-FC26-01BC15362

Program
This project was selected in response to DOE's Oil Exploration and Production solicitation DE-PS26-01NT41048 (focus area: Enhanced Oil Recovery, or EOR). The goal of the solicitation was to promote innovative methods for cost-effective surfactant flooding.

Project Goal
The goal of this project was to identify new, potentially more cost-effective surfactant formulations for Improved Oil Recovery (IOR). The project emphasized searching for surfactants that can reduce the interfacial tension (IFT) between surfactant solutions and oil to ultra-low levels and at a low cost.

Performer
California Institute of Technology
Pasadena, CA

Project Results
The project used a combined experimental and theoretical approach to identify new surfactant chemistries for IOR. These newer products (not available commercially during previous intense research in chemical EOR more than two decades ago) offer performance advantages such as less sensitivity to salinity and temperature for low IFT.

Benefits
This project benefits the industry by identifying a wider spectrum of surfactant products that may be useful for IOR. Having these alternatives offers more choices and more competition (resulting in lower costs) for an oil company that is selecting a surfactant for IOR.

The state and the public benefit of this research is that it provides further impetus for the industry to practice chemical IOR and thereby increase domestic oil supply. There also is a general benefit because the project approach is a successful example for other researchers to follow where complementary chemical molecular-level simulation studies are synergistic with the experimental chemistry investigation and thus produce better results.

Background
This 3-year project began in September 2001 as an effort to identify more cost-effective surfactants for IOR. The motivation for this study is that the oil industry had a history from the previous "boom" period of the late 1970s and early 1980s of developing chemical IOR in the laboratory and having moderately successful technical field tests. However, its economics prevented widespread commercial deployment of the technology, due in large part to the high cost of the chemicals required for the process.

The project did identify promising new candidate formulations (based on alkyl polyglycosides [APG] and alkyl propoxy sulfate [APS] surfactants). These more recently available products offer key technical advantages and may in fact be more economical in future commercial applications.

Project Summary
Significant accomplishments for this project include:

• Completion of a literature review to assemble current and new surfactant IOR ideas.
• Development of new atomistic-level MD (molecular dynamic) modeling methodologies to calculate IFT rigorously from first principles.
• Exploration of less computationally intensive meso-scale methods to estimate IFT, Quantitative Structure Property Relationship, and cohesive energy density calculations.
• Experiments screened many surfactant structures for desirable low-IFT and solid-adsorption behavior.
• Further experimental characterization of the more promising new candidate formulations (based on APG and APS) offer new choices of materials to incorporate into IOR chemical formulations.

Current Status (May 2005)
Since the formal completion of the project, work continues on multiple papers and publications that will document additional details of this effort to the public domain. For example, there will be a paper presented at the 2005 SPE Fall Meeting concerning the performance of the APS surfactants. Also, experiences gained during the execution of this project were helpful in writing additional chemical IOR proposals and securing further funding from DOE in this technical area. There have been 4 presentations at American Chemical Society meetings.

These images illustrate the linkage between the experimental and theoretical efforts of the project. The graphic on the left is a photograph of the image seen in an instrument that measures IFT (spinning drop tensiometer). The graphic on the right is an image taken from a computer simulation showing a surfactant interacting with its alcohol co-surfactant at an oil-water interface.

Publications
Final Report: Lower-Cost Methods for Improved Oil Recovery (IOR) via Surfactant Flooding, DOE Project: DE-FC26-01BC15362, October 2004.

Iglauer, S., Wu, Y., Shuler, P.J., Blanco, M., Tang, Y., and Goddard III, W.A., "Alkyl Polyglycoside Surfactants for Improved Oil Recovery," SPE/DOE 89472, presented at the 2004 SPE/DOE 14th Symposium on Improved Oil Recovery, Tulsa, OK, April 17-21, 2004.

Jang, S.S., Lin, S.T., Maita, P.K., Blanco, M., Goddard III, W.A., Shuler, P.J.,and Tang, Y., "Molecular Dynamics Study of a Surfactant-Mediated Decane-Water Interface: Effect of Molecular Architecture of Alkyl Benzene Sulfonate," Journal of Physical Chemistry B, 108, 12130-12140, 2004.

Project Start: September 18, 2001
Project End: September 17, 2004

Anticipated DOE Contribution: $720,230
Performer Contribution: $180,058 (20% of total)

Contact Information
NETL - Paul West (paul.west@netl.doe.gov or 918-699-2035)
California Institute of Technology - William Goddard (wag@wag.caltech.edu or 626-395-2731)