The Applied Research Of Microbe And Bio-surfactant On Microbial Wax Removal And Protection Technique In Liaohe Oil Field

Waxy crude oil is very abundant in China, during oil recovery, when the migration of crude oil from the near wellbore area to pitshaft, the temperature gradually decreases, which made wax precipitation in crude oil. Precipitated wax accumulates in the near wellbore area, which made pitshaft choking-up and blocked by wax, it is the main reason for the oil well output reduction.At present, the general methods for wax removal in oil field are heating wax removal and chemical wax removal. The former has short action period, and the chemical compounds injected by the latter will lead to formation contamination. Comparatively, microorganism wax removal technique has many remarkable advantages, such as, simple to operate, low cost and long action period, unaffecting on the property of oil, unharmful to the formation, and so on.Microorganism wax removal technique is an important technology of wax removal, depending on the degradation of hydrocarbon degrading bacteria on long chain alkane, such as paraffin, or cleaning the crude oil of pitshaft with microbial surfactant. Besides, microorganism can grow adhering on the surface of metal or clay mineral, leading to the formation of biofilm. It has effect in wax prevent by shielding crystal nucleus and preventing the crystallization.Two strains adapted to the condition of oil well were screened from oil field, they were hydrocarbon degrading Rhodococcus sp. Ljl-3 and Lipopeptide Biosurfactants producing Bacillus sp. LHX3. The compound experiment was processed in proportion with 7:3 of the two strains, to study and verify the mechanism of hydrocarbon degrading and pour point depressing, to confirm the characteristic of the surfactant. The strains after culture and induction factor, such as surfactant, were injected into formation, with the mechanism of the strains; we can achieve the purpose of controlling the speed of wax deposit in oil well, improving the oil output, and enhancing oil recovery finally.Microorganism wax removal technique, as a new wax removal technology, obtained high comprehensive economic benefits. By field test, the two strains were applied in 20 oil wells of OU31 for controlling the speed of wax deposit in oil well, the success was 100%. The hot-washing cycle had been prolonged for more than 3 times, and the output of oil well increased by 2344t.