海上油田聚合物/表面活性剂二元复合驱流度优化设计

Mobility optimum design of polymer-surfactant binary composite flooding in offshore oilfield

锦州Z油田是国内首个实施聚合物/表面活性剂二元复合驱的海上油田。随着油田开发的深入,各井组间生产特征出现较大差异,原方案单一的注剂质量浓度已经不能满足油田均衡驱替的要求。为使注剂质量浓度能够更好地匹配井组生产特征,基于流动优化设计理论,在界面张力降低条件下,根据不同界面张力和含水率阶段的相对渗透率曲线变化情况,并结合驱替相段塞黏度与质量浓度关系和渗透率下降程度,建立了二元复合驱流度控制方程和流度优化设计图版。该方法应用于锦州Z油田矿场试验后发现,相比于原方案,预测提高采收率1.6百分点,节约表面活性剂和聚合物干粉用量共计536 t,实现了降本增效的目的。

Jinzhou Z Oilfield is the first offshore oilfield which carried out polymer-surfactant binary composite flooding.With the development process,the production characteristics of each well group are quite different from each other;therefore,the same injection concentration of chemical agents in the scheme is can not meet the requirements of equilibrium displacement in the oilfield.As to better match the chemical injection concentration with the production characteristics of different well groups,based on the theory of mobility optimization design,the variation of relative permeability curves under different interfacial tension and water cut stages was considered under the condition of decreasing interfacial tension.Combining with viscosity-concentration relationship and permeability decline degree of displacement phase,the mobility control equation of binary composite flooding was established,and the mobility optimum design template was formed,which can provide theoretical basis for optimizing injection concentration conveniently and quickly.This method has been applied to the field test of Jinzhou Z oilfield,which has significantly improved the development performance;compared with the original scheme,the oil recovery was predicted to increase by 1.6%,and the chemical agents of surfactant and polymer was saved by 536 tons.The goal of reducing cost and increasing benefit in oilfield development has been realized.