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Microbial oil recovery (MEOR) technology has a wide application prospect in the field of enhanced oil recovery in low-permeability reservoirs, and genetic engineering plays an important role. At present, oil-production engineering bacteria constructed by genetic engineering are mainly used to obtain high metabolites and strong environmental adaptability; there are few reports on genetically engineered bacteria with different functional metabolites. However, the bacteria which could efficiently produce one metabolite have a poor ability to produce other metabolites. Therefore, in order to reduce the cost of nutrients and improve the effect of microbial oil recovery, dual-metabolite bacteria have been constructed for low-permeability reservoir. In this paper, four rhamnolipid expression plasmids are extracted from E. coli-produced biosurfactant. Then, the rhamnolipid expression plasmids are transferred into the bacteria-produced biopolymer by electrotransformation, and the metabolite performance of the constructed bacteria is evaluated. Finally, the profile control and displacement performance of the constructed bacteria are studied through low-permeability core experiments. The experimental results show that three bacteria, WS1, WS2, and WS3, are successfully constructed that have preferable ability, among which the bacteria WS2 has the best capacity for producing biopolymer and biosurfactant at the same time. After culturing 96 h, the viscosity of the bacteria WS2 fermentation broth could increase to 42.1 mPa·s, and the surface tension and interfacial tension of the fermentation broth could decrease to 24.3 mN/m and 0.035 mN/m, respectively. This time-varying biological viscosity ensures that the microbial system can enter the low-permeability reservoir at a low injection pressure, and the oil recovery of the low-permeability core could be increased by 10.18% after injecting 0.5 PV WS2 microbial system. The findings of this study can help for better understanding of gene construction and technical support for further popularization and application of MEOR in low-permeability reservoirs.

With the growth of global economic and the widespread use of aluminum profile, the consumption of the global aluminum profile increases year by year. In this paper, we proposed a novel detection algorithm of aluminum surface defects using machine vision. Firstly, the aluminum images are acquired and analyzed sequentially, then a number of image processing strategies were used to detect various surface defects. The main contribution is a new area partition method, which can automatically assign texture and no-texture regions with texture information. The proposed method is proven able to detect defects on aluminum profile surfaces, such as cracks, pits, rust or scratches, rapidly and precisely. Robustness and effectiveness in the practical aluminum casting process are improved by using the proposed system.

Aiming at the problem of clay swelling existing in the development of low permeability reservoir, a series of methods are used to evaluate the interplanar crystal spacing of the calcium montmorillonite treated by variable concentrations of 5 Clay Stabilizers in 7 kinds of stability experiments, and the factors that affect the performance of clay stabilizers are analyzed comprehensively by testing the index such as the effective components and adsorptive capacity. With this process, the optimum clay stabilizer of the best compressive performance and its reasonable concentration are determined. Finally the results are examined by the laboratory fluid flowing experiments of cores. The process above forms a complete standard system for evaluation and selection of clay stabilizers at low permeability reservoirs. As a kind of Organic Polymer Quaternary Ammonium Salt of Potassium Ion, the selected clay stabilizer ST-04 has moderate adsorptive capacity under the optimum concentration; in the cases of variable concentrations, the ST-04 has excellent performance of anti-swelling and stability, and keep its damage rate low to pores of the rock.