The United States has enormous oil resources. For every barrel of oil produced, two barrels are left behind. Most oil remaining is hard to lift because it is locked in complex geological structures and bypassed by conventional technologies. Additionally, for every barrel of oil produced, about seven to nine barrels of water are also produced. Therefore, excess water production is a major issue that leads to early well abandonment and unrecoverable hydrocarbon for mature wells.

Surfactants have been designed to increase oil recovery for both sandstone and carbonate reservoirs. Aqueous solutions of surfactant are injected to porous media of the reservoirs where the oil is trapped by capillary force. This technology is called surfactant flooding. Reservoir heterogeneity is the most important reason for low oil recovery and early excess water production. Gel treatments have been widely applied as a cost-effective method to correct reservoir heterogeneity, and thus to reduce excess water production during oil production. Conventional in-situ bulk gels have been widely used for this purpose. A mixture of polymer and cross-linker is injected into target formation and reacts to form a gel that fully or partially seals the formation under reservoir conditions. A new trend in gel treatments is to use preformed particle gel, because particle gel technology can avoid disadvantages caused by in-situ bulk gel, such as lack of gelation time control and uncertainty of gelling due to shear degradation

Recently, it has been found that preformed particle gel does not form filtration cake on low permeable zones or areas, and that surfactants have significant influence on swollen particle gel strength prepared by surfactant brine solution. This invention provides a novel enhanced oil recovery method called forced imbibition in which the mixture of particle gel and surfactant significantly improves the injectivity of the particle gels. The filtrated solution will be forced to enter into the oil zones or areas in mature oilfields to reduce the remaining oil saturation.

File Number: 10MST011 

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Case Manager: Eric Anderson (ericwa@mst.edu)