早期注聚合物五点法井网密度的多目标优化

Multi Objective Optimization of Five Spot Well Spacing Density by Early Polymer Flooding Process

早期注聚合物对于海上油田和国外开发区块十分必要,鉴于油田地质情况的复杂性,原来的单一因素优化已经不再适用。以五点法井网为研究对象,综合考虑油藏和经济双重目标,以聚合物溶液浓度、注入井注入能力、生产井产液能力及生产时间为限制条件,通过理论方法和经验回归,建立了以早期注聚合物累计采出量和净现值流量为目标的多目标优化模型。结合油田区块实例,通过用适应函数算法得到井网密度的优化解。将多目标优化的合理井网密度与单一目标下合理井网密度进行比较,结果表明,多目标优化方法适用性更强,更适用于五点法井网早期注聚的研究。

Early polymer flooding plays a significant role in the exploration and development of domestic offshore oilfields and the blocks abroad. The former optimization methods with single factor are not available in view of complexity of the current oilfield geologic status. This paper establishes the multi-objective optimization model for study of cumulative production and net present value （NPV） rate by early polymer flooding process, through theoretic methods and empirical regression analysis, in which five-spot well pattern is taken as studied object, comprehensively considering reservoir and economy dual objectives, with limitations of polymer solution concentration, injection ca- pacity, productivity and production life, etc. The rational well spacing density is optimized by fitness function method and applied to the oil-field blocks. The results from comparison with the single objective optimization show that the multi-objective optimization method is better in adaptability and more suitable for five-spot well pattern study by early polymer flooding process.