Microbial Enhanced Oil Recovery (MEOR) is an effective alternative method for oil recovery in reservoirs using microorganisms or their secondary metabolites. This research aimed to evaluate the indigenous bacteria from Mae Soon reservoir by culture-dependent and culture-independent methods and to investigate the potential of biosurfactant-producing bacteria using a drop-collapsed assay. Indigenous bacteria were isolated from the oil sands of the reserved core of Mae Soon reservoir using fi ve different media (nutrient, Luria-Bertani, mineral salt, tryptic soy, and peptone yeast extract). Fifty-four facultative anaerobic bacterial isolates were obtained. Seven isolates showed their potential as biosurfactant producers in the drop-collapse assay. Based on 16S rRNA gene analysis, six of the biosurfactant-producing bacterial isolates belonged to the species Bacillus licheniformis and one belonged to the species B. subtilis. The biosurfactant producers and microbial community in the oil sands were determined using Denaturing Gradient Gel Electrophoresis (DGGE). Interestingly, DGGE bands corresponding to bacteria belonging to the genus Geobacillus sp. were detected. Overall, the results obtained from this work showed that indigenous bacteria in Mae Soon reservoir oil well were prospective for use in MEOR.

In this work, the successful preparation of the multilayer Titanium doped diamond-like carbon/Ti (Ti-DLC/Ti) films deposited on low-carbon steel (CS) using hybrid magnetron sputtering (MS) and plasma-enhanced chemical vapor deposition methods has been reported. The Ti and Ti-DLC films were alternately deposited on the CS substrate of up to 4 stacks with an average deposition rate of 16.4±1.7 nm/min and 15.1±1.5 nm/min, respectively, yielding a total thickness of up to 1703 nm. Raman spectroscopic analysis revealed a gradual increase in the I D/I G ratio with an increase in Ti layer numbers. Both XPS and NEXAFS results indicate an increase in the C-sp 2 content by increasing the number of Ti layer, which may influence on the hardness reduction. The adhesive properties were found to be improved by adding the number of Ti interlayers between the CS substrate. Moreover, the thicker multilayer films exhibit progressive homogeneity resulting in better corrosion resistance.

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Field A is an onshore oil field in Thailand. This area contains biodegraded medium-heavy crude reservoir; 19°API oil gravity and 144 cp viscosity. Therefore, the field suffers from a low recovery factor due to high crude viscosity. On one hand, bacteria have exerted an adverse effect on production, on the other hand, it means that the condition of the reservoir is suitable for implementing Microbial Enhanced Oil Recovery (MEOR). The MEOR is a technology that utilizes microorganisms (mainly bacteria), to enhance oil production, especially for medium-heavy oil. By feeding nutrients to bacteria, several metabolites were produced that would be useful for oil recovery. This technique is well known for its low investment cost, hence, high return. The technical screening confirmed that the reservoir and fluid properties are suitable for MEOR. Consequently, sixteen core samples and three water samples were collected for indigenous bacteria analysis. Although the laboratory indicated there are countless bacterial strains in the reservoir, the nitrate-reducing biosurfactant-producing bacteria group was identified. This bacteria group belongs to the Bacillus genus which produced biosurfactant and reduced crude viscosity by long-chain hydrocarbon degradation. Therefore, the treatment design aimed to promote the growth of favorable bacteria and inhibit undesirable ones. Consequently, a combination of KNO3 and KH2PO4 solutions and a specialized injection scheme was tailored for this campaign. The pilot consisted of two candidates those were well W1 (76% water cut), and well W2 (100% water cut). The campaign was categorized into three phases, namely, 1.) baseline phase, 2.) injection and soaking phase, and 3.) production phase. Firstly, the baseline production trends of candidates were established. Secondly, KNO3 and KH2PO4 solutions were injected for one month then the wells were shut-in for another month. Lastly, the pilot wells were allowed to produce for six months to evaluate the results. The dead oil viscosity of well W1 was reduced from 144 cp to 72 cp which led to a 6.44 MSTB EUR gain or 1.3% RF improvement. On the other hand, the productivity of well W2, the well with 100% water cut, was not improved. This was expected due to insufficient in-situ oil saturation for a bacteria carbon source. Considering the operational aspect, there was no corrosion issue or artificial lift gas-lock problem during the pilot.