强水敏低渗油藏酸化防膨研究及现场应用

针对石西油田低渗油藏强水敏性伤害储层,油井转注水初期,普遍存在注入压力高、注不进的实际问题,基于黏土矿物的防膨原理和现场防膨经验,为了提高XH-F3防膨剂的防膨效果,采用乙醇与注入水混配,其防膨率得到显著提高,满足了油田指标要求。静态实验结果表明,采用该防膨技术,岩心破碎率低、腐蚀率低,配伍性好。现场实验表明,注入该防膨型醇水配制的酸液,酸化后注入压力大大下降,注水量增加3~5倍,达到了防止黏土矿物膨胀、实现近井地带酸化解堵的目的。

Study and application of acidification anti-swelling for low permeability reservoir with strong water sensitivity

For the strong water sensitivity damaging the stratum, the concentration of 3 wt% XH-F3 anti-swelling agent is selected by single factor in the low permeability reservoir. However, its anti-swelling rate is not up to the requirements of oil field. The mixture of ethanol and water injection improved the anti-swelling effect (anti-swelling rate of 92.34%) which meet the requirements of oilfield. The static experiment results show that the core breaking rate is low, the corrosion rate is also low and the compatibility is good using the anti-swelling technology. Field experiments show that the injection pressure decreased greatly, and the injection volume increased by 3-5 times after injection of the acid liquid containing anti-swelling alcohol water, so as to prevent the swelling of clay minerals and achieve the goal of removing block near the well area.