南翼山油田注水井酸化酸液体系优化

Optimization of acid system for acidizing of water injection wells in Nanyishan Oilfield

南翼山油田Ⅲ+Ⅳ油藏岩性复杂,非均质性强,层间差异大,且注水井措施较少,吸水剖面不均匀、单层突进现象突出,常规的酸化配方无法有效解决储层污染问题。利用室内岩心实验方法,对主体酸液体系及酸液添加剂进行研究,确定了适合该油藏的酸液体系,优化酸化工艺参数,规范注水井酸化选井选层方法,探索出工艺可行、成本低廉的酸化解堵技术。现场实施5口井,酸化解堵有效率100%,平均单井日增注17.9 m^3、降压3.2 MPa,平均视吸水指数提高0.0123 m^3/(d·MPa·m),取得了良好的降压增注效果。注水井酸化酸液体系优化研究,建立了完善的效果评价体系,对同类油藏的开发具有很好的指导意义。

The lithology ofⅢ+Ⅳreservoir in Nanyishan Oilfield is complex,heterogeneity is strong,and interlayer differences are large.Furthermore,there are few stimulations for water injection wells,the water absorption profile is uneven,and single-layer intrusion is obvious.Conventional acidizing formulations cannot effectively solve the problem of reservoir pollution.By means of laboratory core experiment,the main acid system and acid additive are studied,the acid system suitable for this reservoir is determined,the acidizing process parameters are optimized,the acidizing and selecting method of injection wells is standardized,and the feasible acidizing plugging removal technology with low cost is explored.The acidizing system was implemented in five wells on site,and the effective rate of acidizing plugging removal was 100%.The average daily injection rate of a single well was increased by 17.9 m^3,the pressure decreased by 3.2 MPa,and the average apparent water absorption index increased by 0.0123 m^3/(d·MPa·m),achieving a good effect of reducing pressure reduction and increasing injection.The research on the optimization of acid system for acidizing of water injection wells and the establishment of a complete effect evaluation system have a good guiding significance for the development of similar oil reservoirs.