Research And Application Of Microorganism Weak Gel Composite Flooding Technology In Medium-high Temperature Reservoir

At present in China, the average oilfield recovery is about30%in the oilfields that are being exploited. Many of the oilfields have come to the stage of tertiary oil recovery. The single tertiary oil recovery technology has been applied in some medium and large oilfields for more than ten years. However, the single tertiary oil recovery technology has been not able to satisfy the economic benefit.It is important to use two or three kinds of oil recovery technologies. It is very necessary to study two technology combined control and oil displacement.This paper studies core microscopic percolation in high-temperature reservoir in Jizhong area. It also makes lab experiment of the formula of microorganism weak gel composite oil displacement. At last, it preliminarily designs the weak gel industrialized experiment which the daily average injection is120m3and makes the monitoring system.(1)By doing water flooding oil recovery experiment of the sepical oil field, it concludes that building reasonable displacement pressure difference can make the recovery efficiency to69.1%.(2)Building reservoir combination model, and makes water flooding oil recovery experiment on it. The paper concludes that in the hole cracks combination, the bigger the geometric closed space is, the lower the recovery efficiency will be. When the permeability ratio is less than15-20in combination of reservoir, the oil can be fully recovered from low permeability reservoir.(3)In a heterogeneous system, these two different seepage systems have different effective driving pressure difference, their negative pressure difference can raise the recovery to10%.(4)It builds the model of three tubes in parallel and tri-porosity media, and makes injection-production simulation experiment with the model. It concludes that:During multilayer co-injection and separated layer production, it can gain high current oil recovery in high permeable reservoir, but it can hardly extract oil from low permeable reservoir. Only if part of high permeable reservoirs is sealed and reasonable differential pressure is made, oil in low permeable reservoir can be extracted.(5) By studying the formula of microbial strains compounds in lab, and selects appropriate gel ratio. So the formula of microbial strains compounds is B-1:0.1%,S-2:0.3%,S-3:0.3%,S-1:0.3%. The gel formula is:polymer concentration is0.1%, polymer-crosslinking ration is0.03%. The thesis tested the suitability between these two formulas and found they had good suitability. (6) By Analysis of site condition, adopt the way of site note weak gel, optimizing the injection equipment, reduce the effect of injection of weak gel.(7) Programming liquid monitoring plans, in order to find problems in time and adjust the injection.