The Applied Research Of Microbe And Bio-surfactant On Microbial Wax Removal And Protection Technique In Ou 31 Fault Block

The crude oil in Liaohe Oilfield is a typical kind of high wax crude oil, the wax content ranges from 8% to 53%, and the high wax crude oil of which the wax content is more than 30% accounts for more than 77% of the reserves. In the process of crude oil recovery, the temperature declines in the process of crude oil moving from the near wellbore area to the well shaft, resulting in the wax precipitation in crude oil , the wax precipitation gathers in the near wellbore area, cause the well shaft blocked or the tube pillar jammed, the problem that the wax precipitat in oil well is serious, oil production declines gradually, and the cost of washing well is much. The implementation of wax-proofing and deparaffining in wax precipitation well is a improtant mean to ensure high wax well normal production.The means of paraffine prevention and removal in oil well include mechanical method, oil pipe lining and coating paraffin method,wax anti-magnetic method, chemical agents method and micro-organisms method, in which micro-organisms methods has the advantages of simple construction, low operating costs, long fuction cycle, disaffect the quality of oil, without any harm to the formation, and so on. At present, the Liaohe Oilfield usually use hot treatment and chemical method. The former has a short function cycle, the latter which inject the chemical agents may cause pollution. Comparatively speaking, micro-organisms methods become the preferred technology.The microorganism paraffine prevention and removal technology makes use of the fuction of the hydrocarbon degradation bacteria degrading long-chain alkanes such as paraffin, or uses microbial surfactants washing the crude oil sticking to well shaft, so as to deparaffin. This paper introduces the causes of paraffin deposit in oil well, the mechanism and advantages of microbial paraffine prevention and removal technology, on the basis of the characteristics of Ou 31 reservoirs (geological features, physical properties of crude oil, formation water characteristics and formation temperature and pressure), research on a hydrocarbon degradation bacteria (Rhodococcus Lj1-3)obtained from Liaohe Oilfield Drilling Institute, the result of the research is that the bacteria has good paraffine prevention and removal effect, and it can decline the freezing point; study the bacteria(Bacillus LHX3) which produce lipopeptide biosurfactant screening from Dagang Oilfield sewage in Nankai University Petroleum microbiology laboratory, it can resist high temperature, high salt, high calcium ion, pH rangs from 4 to 12, and it has the capacity of solution,desorption,viscosity break of high viscosity crude oil and dispersed emulsion of high wax crude oil;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.The two strains were applied in 20 oil wells of Ou31 field test 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 2389t. it can be seen that micro-organisms wax-proofing and deparaffining technology can not only reduce the difficult of other technologys with heavy operation and management , but also can reduce costs and increase oil production, increase output and economic efficiency dircetly.