Optimization Design Of Profile Control Technique

For the oil fields developed by water flooding, injected water will occur viscous fingering towards producing wells on the horizontal direction and breakthrough towards the high permeability formations on the vertical direction because of the heterogeneity of the reservoir both on the horizontal direction and on the vertical direction, and the difference of the viscosity between the oil and water, and the unbalance of injection-production well group. Especially, during the later course of water flooding development, water cut of the oil wells will be up to 80%. Pore structure and physical parameter will change as the long time corrosion from water. It may be occurring high permeability zone and enlarging the flow pore path. As a result, the efficiency of water drive will be largely lowered. In order to enhance oil recovery of water drive, it applies profile control and water shutoff on each oil field, and the decision-making technique is born. With the large-scale field tests on each oil field, profile control technique obtains the obvious economic performance, lowers the escalating speed of water cut of the oil fields, enhances the oil production and the interim recovery percent of reserves, improves the development effectiveness and lowers the cost. According to the whole technological process of chemical profile control, considering the production status of both injected wells and the connected oil wells and on the basis of their performance data and static data, it gives a simple and viable and optimal profile control decision-making technique on the paper. Through the case history study, conclusions can be drawn as follows: with the theory of the reservoir engineering and fuzzy mathematics knowledge and on the basis of performance data and static data of injected wells and oil wells, it establishes the principle of well selection decision-making of chemical profile control; on the basis of well selection decision-making, it establishes the principle of formation selection decision-making with fuzzy composite adjudication technique; it establishes the database of the common profile control agents, and according to the formation condition, it can select the optimal profile control agent with the computer technique; it adopts various methods to calculate the dosage of the profile control, and according to the formation condition, it can select the optimal method; according to the formation condition and the function parameter of the profile control agent, it can determine the injection pressure and discharge capacity of the profile control agent; through the statistical analysis of the effectiveness of the profile control wells, it establishes the forecast model of chemical profile control effectiveness with statistics knowledge and computer technique and fitting regression method, which can performance effectiveness forecast of injected wells and the connected oil wells after profile control; on the basis of profile control forecast, it can performance chemical profile control evaluation.