Research Of Indigenous Microbial Flooding Technology In Zhan3Block Of Shengli Oilfield

Many countries in the world haven’t so much involved in the systematic and deepstudy of indigenous microbial flooding technology, but just basic theory research. Inorder to give full play to the advantage of indigenous microbial flooding technologyand perfect its theory system, we carry out the study. By taking the indigenousmicrobe of Zhan3Block in Shengli Oilfield as the research object under thetemperature and pressure in reservoir, this paper mainly explored the activatorsformula and injection technology of different injecting quantity, injection mode andgas distribution quantity by the physical simulation method. At last, we analyzed theoil displacement mechanism. The research results of this paper lay the foundation forestablishing the study of indoor indigenous microbial flooding technique evaluationsystem, especially setting up the indigenous microbial flooding evaluation system byphysical simulation method. In addition, this paper is to study according to Zhan3Block and the research results provide certain theoretical basis and technical supportfor designing flooding scheme on site in Zhan3Block. The main research results andconclusions are as follows:1Selecting Zhan3Block as the experimental research block.The current situationof the development, reservoir and geological strata conditions and other indexes ofZhan3Block in Shengli Oilfield are in accordance with the principle of screeningblock. Moreover, it is suitable for requirement of indigenous microbial floodingtechnology under reservoir conditions. By analyzing the chemicals of the formationwater and indigenous microbe, the results show that the conditions of the ions in stratawill not limit the growth of microorganism; Microbial community structure is relativestability, and it exist all kinds of function bacterium group which are potential toflooding. Zhan3Block is potential to activate, so we choose it as the experimentalresearch block.2Ascertain activator formula by testing analysis after indoor culture.According to the composition, screening methods and thoughts of activator formula and analyzingthe total bacterial count, pH value, gas production, expanding oil circle and thesurface tension in the activating, we ascertain activator formula5which includes0.3%corn syrup dry powder,0.7%flour,0.05%xylose,0.1%sodium nitrate and0.2%diammonium phosphate as indigenous microbial flooding activatorformula.After activating, the maximum total bacterial count reached4.1×10⁹cells permilliliter; the gas production reached9.2milliliter after culturing five days; diameterof expanding oil circle reached36mm; surface tension decreased to38.2mN/m.3Explore the activators formula and injection technology of different injectingquantity, injection mode and gas distribution quantity by the physical simulationmethod.Microbial flooding physical simulation experiment is an effective means formaking a comprehensive study and evaluation on the ability of microbial floodingtechnology in improving oil recovery. By doing the experiments of indigenousmicrobial physical simulation and gas distribution of Zhan3Block we can found that,the best injection technology is injecting0.40PV activator; injecting0.20PVactivator+0.20PV formation water+0.20PV activator; gas distribution quantity15:1,at this time the activator can achieve the best effect in activating indigenous microbein oil reservoir. The total bacterial count reached4.5×10⁸cells per milliliter. Thecontent of HOB reached4.0×10⁸cells per milliliter. The content of TGB reached4.1×10⁷cells per milliliter. The content of acetic acid reached386.5mg/L. Microbialenhanced oil recovery reached8.1%.4Designing experiment to analyze indigenous microbial oil displacementmechanism.Study the change of cores whose water phase permeability before andafter culturing in incubator and pressure difference in water flooding by simulatingthe situation after injecting activators in core-plugging experiments. The resultsshowed that injecting activator could indeed block the big channel in the core andhave notable effect under600×10^-3 m²oil reservoir. Fetch the quartz sand fromdifferent places in the core and analyze cell concentration. The results showed thatcell concentration basically present decreasing tendency from inlet to the middle tooutlet. By doing the surfactant flooding experiment, we can know that indigenous microbial plugging and metabolites surfactant flooding are the main oil displacementmechanism. Between the two sides, the latter plays a leading role.