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DEGRADABLE NANO COMPOSITE PREFORMED PARTICLE GELS AND THEIR APPLICATION IN ENHANCING OIL RECOVERY

Detailed Technology Description

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*Abstract

In one aspect of the invention, a new and improved nanocomposite crosslinked hydrogel to increase the oil recovery rate from mature or abandoned reservoirs is described. According to this invention, the inventive nanocomposite includes the crosslinked PPGs swelled in brine solution with gel to solution ratio of 0.01 wt% to 1.0 wt%, preferably 0.05 wt% to 0.8 wt%, more preferably 0.1 wt% to 0.5 wt%. The crosslinked nanocomposite hydrogels may be synthesized through free radical polymerization, such as the redox initiation system for polymerization or by the method of emulsion polymerization. In another aspect of the invention, a new and improved method combining the gel treatment and polymer flooding processes to increase the oil recovery rate from mature or abandoned reservoirs is described. According to the inventive method, the inventive process includes the steps of, in details, 1) preparing crosslinked PPGs with a predetermined size, 2) dispersing the PPGs into a brine solution to form swelled PPGs, whereas the brine concentration is preselected depending on the salinity condition of the target reservoir, 3) injecting the swelled PPGs into the target reservoir, 4) The following treatment after PPGs injection such as water flooding, polymer flooding or SP flooding etc can be performed to improve the oil recovery by reducing the excess water production, and 5) After certain amount of period, the decomposition of the injected nanocomposite PPGs eventually through the hydrolysis induced by heat or pH into linear polymer solution for the secondary polymer flooding to further enhance the oil recovery. After an extended time period, the gel degrades into a viscous polymer solution that penetrates deep into the formation matrix and increases the viscosity of a water flood, thereby improving mobility control and volumetric sweep, enabling more oil to be produced. The viscosity of the polymer solution is enhanced by the presence of nano size clay particles. On thermal degradation, the gel breaks down releasing polymer solution and nano size clays which re-associate by a physical interaction, yielding a more viscous polymer-clay solution that improves the water flood viscosity and hence sweep efficiency.

*Principal Investigator

Name: Baojun Bai, Associate Professor, Petroleum Engineering

Department:

Name: Paul Tongwa

Department:

Country/Region

USA