Browsing by Author "Wang, Fei"

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    Experimental Study on the Enhanced Oil Recovery by in Situ Foam Formulation
    (Energy Science & Engineering, 2020) Hailong, Chen; Li, Zhaomin; Wang, Fei; Wanambwa, Silagi; Lu, Teng
    In situ CO2 foams (ISCF) are studied systematically by combining in situ CO2 gas reactants (carbonate anhydrous, hydrochloric acid) and bio-based surfactant. Sandpack flooding experiments at 60°C along with PVT experiments were carried out to analyze the oil displacement mechanisms. The results showed that ISCF could increase oil recovery from heterogeneous multilayer formation of permeability ratio over 6, and displacement efficiency increased with the injection volume increased before the injection of 1 PV. The incremental oil recovery by ISCF was much greater than that of conventional foam or in situ CO2 (ISC) without foam under the same injection conditions. The generated CO2 foam could reduce the interfacial tension between displacement phase and displaced phase effectively which contributed to the great increase in capillary number. The CO2 dissolution greatly reduced the viscosity of crude oil, and the highest viscosity reduction rate at 60°C could be as high as 98%. The Ca2+ concentration of produced liquids analysis revealed the ISCF could distribute intelligently the acid in heterogeneous formations.
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    Fractal Characterization of Dynamic Structure of Foam Transport in Porous Media
    (Journal of Molecular Liquids, 2017) Wang, Fei; Li, Zhaomin; Chen, Hailong; Wanambwa, Silagi; Chen, Zhuo
    The evaluation and simulation of foam fluid are still matters of significant debate despite the large number of available studies due to the excellent properties of foam and its successful applications, especially in oil and gas field development. The properties of foam fluid are substantially determined by its dynamic structure in porous media; however only a few studies that investigate and perform measurements related to such structure have been reported. In this research, a new method based on fractal theory is proposed for evaluation of aqueous foam in porous media. As a first step, the fractal characteristics of foam in porous media are confirmed by image processing and calculations. Accordingly, the foam dynamic structure is quantitatively studied by defining and calculating the foam fractal dimension. Secondly, a concise relation is established which reveals that the foam fractal dimension is nearly time-independent. Finally, a sensitivity analysis is carried out by discussing three major factors affecting foam structure in porous media. These results are expected to be helpful for further understanding the dynamic characteristics of foam fluids and their advanced applications.