This Small Business Innovation Research (SBIR) Phase I project will develop a new class of environmentally-friendly and sustainable biopolymer-based chemistries that can be modified and applied in oil and gas production operations. These new chemistries take advantage of the availability of natural polymers such as guar as a feedstock. It already has been demonstrated that guar and other biopolymers may be modified by adding other chemical groups to create ?green? polymer molecules with a broader range of solution properties. These may include the ability to have a self-thickening or gelling effect. Such fluids are applied in oil and gas wells to block selectively movement of subsurface water, thereby increasing hydrocarbon production. This sustainable technology would replace a competing chemical method based on using (not green) synthetic polymers.
The broader/commercial impacts of this research are research breakthroughs that will have immediate and profound commercial potential for the target application of increasing the volume of oil produced in mature oil fields. The DOE estimates these fields in the U.S. have over 350 billion barrels of oil remaining in place that is not now recoverable economically. A new method that will produce some of this trapped oil cheaply with an environmentally-friendly chemical will be extremely attractive to the domestic energy industry. Besides the immediate target application for the oil and gas industry, the same types of new environmentally-friendly chemistries should find uses in other industries.
PI: Patrick Shuler Awardee: ChemEOR, Inc. Award Number: 1047290 Award Expires:06/30/2011 Program Officer Name: Anthony Walters Program Officer Email Address: awalters@nsf.gov Program Officer Phone Number: (703)292-8772 Outcomes Report The objective of this study is to develop a new class of environmentally-friendly and sustainable biopolymer-based chemistries that can be applied as conformance control agents in oil and gas production operations. This project takes advantage of available commercial and experimental natural polymers such as guar and hydroxyl ethyl cellulose (HEC), and their hydrophobically modified (hm) variations. The project strategy was to use natural polymer based products as source of "green" materials. It was hoped that these modified polymers would exhibit properties that make them suitable as environmentally-friendly thickeners for aqueous treatment fluidsused in oil field applications. These sought after desirable aqueous solution properties include a spontaneous association and self-gelling effect in order to block high permeability, high water flow channels. This physical selective blocking effect forces the injection water following the chemical treatment to penetrate into lower permeability areas of the reservoir previously not swept, thereby promoting increased oil production. This sustainable technology would replace a competing chemical method based on using (environmentally less favorable) synthetic polymers such as those from the polyacrylamide type of chemistry. The first experiments included preparing samples for each candidate material to encompass a wide range of salt content in the make-up brine. Viscosity values measured by a Brookfield viscometer examined their behavior versus time. None of these samples exhibited the sought after self-thickening, pontaneous increase in solution viscosity. One positive outcome is that some of these bio-polymers have good tolerance to high saline brines, such as may occur in oil and gas operations. Thus some of these materials might have a technical fit as thickeners for oil field treatment fluids that contain high concentrations of salts such as sodium or calcium chloride. A second series of experiments focused on the interaction of salt solutions containing these materials with different refined and crude oils. Because these materials include hydrophobic groups, it is possible these may add some surfactant nature to the molecule. Thus we tested for reduced interfacial tension (IFT) and rapid emulsification of the oil into the aqueous phase. This would represent additional mechanisms to mobilize and produce additional oil from a reservoir contacted with this chemical fluid. However, the observed IFT and phase behavior did not exhibit these features. Instead our fluids generally created viscous or gel-like oleic phases. This behavior would not be expected to be helpful towards increased oil recovery.
