Study On Optimization Technique Of Synergic Production For Multi-oil-water Wells System

For water flooding oilfield, not only a single production well and a single injection well production should be optimized, but also, the production rate and electric quantity distribution among production wells, the injection water distribution among injection wells and injection/production voidage balancing between production wells and injection wells should be optimized, in order to get high efficiencies and benefits in the developing oilfield, subjection to capability to disposal of production liquid, power supply, and injection water supply. Therefore, the problem of synergic production optimization for production/injection wells system is proposed in this paper.For the first time a mathematical model for synergic production system optimization is established in this paper, include all the production parameters of production/injection wells in water flooding oilfield, with the optimization target of whole synergic production indexes of all the production/injection wells, such as whole wells production sum, water injection sum and dissipation of energy sum. Innovatively applying the Multi Disciplinary Optimization Method (short for MDO), the synergic production optimization problem for multi production/injection wells is divided to "production optimization of each producing well" ,"injection optimization of each injecting well" and "combination synergic production optimization of multi wells based on the results of each well production optimization".①for a single oil well’s production optimization problem, this paper provides a general optimization model and its general solving-algorithm, which is suitable for many oil wells by several different artificial-lift methods, the solving-algorithm is based on PVT model, multiphase flow model, IPR model and artificial-lifting facility work model of the oil well. For the common three kinds of artificial-lift wells that are gas lifting, rod pump and electric submersible pump oil wells, the specific solving-algorithms of the production optimization model are derived in this paper.②for a single water well’s injection optimization problem, this paper provides a calculation method for quantitative dynamic connection coefficient between production wells and injection wells, which represents the production dynamic response between the injection wells and production wells. An injection optimization algorithm is derived based on the connected oil wells production, the connection coefficient between oil and water wells, the injection/production material balance, and the wellbore flow model of the injection wells.③this paper originally provides a genetic algorithm computation model and its algorithm for synergic production optimization of production/injection wells system.Based on the theory and method study above, the software system of oil/water wells synergic production optimization is developed. By applying the software system to an offshore oilfield, the field production performances have been analyzed, potential production of oilfield has been estimated, and further, the proposals have been made by the integer and whole production optimization analyzing for all the injection and production wells, which have a practical directive meaning for the oilfield management. The practical application shows that the software system is easy to use, and the results of the analysis and optimization are contented for oilfield’s need.