Comparison of in-situ and ex-situ microbial enhanced oil recovery by strain Pseudomonas aeruginosa WJ-1 in laboratory sand-pack columns |
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Authors: | Q F Cui Y J Luo L Yu Z Z Zhang |
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Affiliation: | 1. State Key Laboratory of Heavy Oil Processing, Faculty of Chemical Engineering, China University of Petroleum, Beijing, China;2. Institute of Porous Flow &3. Fluid Mechanics, Research Institute of Petroleum Exploitation and Development, China National Petroleum Corporation, Langfang, Hebei, China;4. Institute of Porous Flow &5. Fluid Mechanics, CNPC Key Laboratory of Enhanced Oil Recovery, Langfang, Hebei, China |
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Abstract: | Microbial enhanced oil recovery (MEOR) applies biotechnology to improve residual crude oil production from substratum reservoir. MEOR includes in-situ MEOR and ex-situ MEOR. The former utilizes microbial growth and metabolism in the reservoir, and the latter directly injects desired active products produced by microbes on the surface. Taking biosurfactant-producing strain Pseudomonas aeruginosa WJ-1 for research objects, in-situ enhanced oil recovery and ex-situ enhanced oil recovery by biosurfactant-producing strain WJ-1 were comparatively investigated in sand-pack columns.The results showed that P.aeruginosa WJ-1 really proliferated in sand-pack columns, produced 2.66 g/L of biosurfactant, altered wettability, reduced oil-water interfacial tension (IFT) and emulsified crude oil under simulated in-situ process. Results also showed that higher biosurfactant concentration, lower IFT, smaller average diameters of emulsified crude oil were obtained in in-situ enhanced oil recovery experiment than those in ex-situ enhance oil recovery experiment. Similar wettability alteration was observed in both in-situ and ex-situ enhanced oil recovery experiment. The flooding experiments in sand-pack columns revealed that the recovery of in-situ was 7.46%/7.32% OOIP (original oil in place), and the recovery of the ex-situ was 4.64%/4.49% OOIP. Therefore, in-situ approach showed greater potential in enhancing oil recovery in contrast with ex-situ approach. It is recommended that the stimulation of indigenous microorganisms rather than injection of microbial produced active products should be applied when MEOR technologies were employed. |
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Keywords: | flooding experiment in-situ ex-situ microbial enhanced oil recovery (MEOR) Pseudomonas aeruginosa sand-pack columns |
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