Optimization of Exogenous Microbial and Experimental Study on Injection-Production Parameters Optimization of Microbial Huff and Puff Technology

CO2 huff and puff technology in horizontal well has become the main measure to enhance recovery factor in shallow heavy oil reservoir which drived by edge and bottom water of Jidong oilfield. With the increase of cycle stimulation, the water cut went up quickly and the development effects of oil field were seriously affected. In order to improve horizontal well productivity and reduce the water cut, the technical idea of microbial huff and puff was put forward. Through the experiments of viscosity reduction, interfacial tension between oil and water and emulsifying property evaluation, the suitable exogenous microorganism W-4 was selected. A three-dimensional physical model was designed and made by using rock cuttings. The size of the model was 30 cm × 30 cm × 12 cm, the permeability was 1160 μm2, the porosity was 31%; the model was used to carry out the experiment of injection-production parameters optimization. The experimental results showed that the effect of increasing oil production was obvious, Degree of reserve recovery risen 3.86%～14.04% more than the development way of depletion. In order to achieve the best effect of increasing oil production injection-production parameters were optimized. The results were that the rate of injection was 0.2 PV～0.3 PV, the time of well shut was 20 days～30 days, the velocity of injection was 3 ml/min～5ml/min, liquid withdrawal rate was 350 ml/hr～400 ml/hr and the ratio of functional bacteria and nutrient medium was 1:2~1:3.