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Surfactant flooding process is one of the chemical methods widely used for enhanced oil recovery (EOR) from petroleum reservoirs that utilizes chemically synthesized surfatants. Such surfactants are not bio-degradable and hence pose environmental concerns. Because of stringent environmental restrictions, it is a high time for petroleum exploration and production industry to move towards biosurfactants. Since biosurfactants are generally more expensive than chemical surfactants, one of the ways to reduce its cost is to use fermentation extracts which contain significant amount of biosurfactants know as surfactin. Surfactin is a cyclic lipopeptide produced by various strains of Bacillus subtilis. In this work, a lyophilized surfactin extract produced by Bacillus subtilis organism was evaluated for its potential in EOR application as an alternative to chemical surfactants. The surfactin mixture was produced by fermentation and characterized by liquid chromatography-mass spectroscopy (LC–MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques. Interfacial tensions (IFT) between two light crude oils and aqueous phases were measured. Wettability alteration potential was evaluated by contact angle measurements. EOR performance was evaluated by oil/water displacement experiments at room conditions using a glass micromodel and sandstone rock samples. The analysis showed presence of surfactin containing nearly 80% of surfactin C. IFT measurements showed a significant reduction in IFT in the presence of surfactin. Contact angle measurements showed alteration of wettability of glass surface from near neutral-wet to water-wet condition. Coreflooding experiments on Berea sandstones showed about 1.7–5% incremental oil recovery by surfactin flooding. Glass micromodel experiment also showed reduction in residual oil and oil-in-water emulsions after surfactin injection.

Naturally-occurring gas hydrate, either in deepwater continental margins or in permafrost regions, is a promising unconventional energy resource which has attracted a lot attention from governments and researchers. In this paper, we studied the phase behavior for methane hydrate and mixed-gas hydrate. Four permafrost hydrates and three marine hydrate deposits were selected for analysis. They were Messoyakha (Russia), Mount Elbert (Alaska), Mackezie (Canada), Qilian Mountain (China) in permafrost regions and Blake Ridge (West Coast of US), Shenhu (South China Sea), and Nankai Trough (Japan Sea) in deepwater continental margins. The thickness of the gas hydrate stability zone (GHSZ) was calculated and compared. Our results show that the thickness of the GHSZ in permafrost regions is 1.3 to 4.5 times thicker than that in marine regions due to three factors: lower mudline temperature, smaller geothermal gradients and higher percentage of non-methane gases. The ramifications are that both the gas initially-in-place and the gas production rate will likely be higher in the permafrost environment. In addition, like other unconventional reservoirs, sustained gas production from a gas hydrate reservoir will likely require constantly drilling new wells to replace declining production from existing wells. All these suggest that development of gas hydrate in deep marine environment may be cost prohibitive. On the other hand, the well cost and drilling challenges will be significantly lower in the onshore permafrost environment where the resource density is also higher. Consequently, we see more potential for commercial development of permafrost hydrates than marine hydrates.