一种泡沫酸配方及其分流酸化性能评价

泡沫酸因其诸多优于常规酸的性能而被广泛应用于油田增产措施中.室内确定了一种泡沫酸体系配方,以12%HCl和3%HF土酸为酸基液,泡沫体系由0.8%复合型起泡剂EL-23与0.3%高聚物稳泡剂D组成.泡沫体系与酸液配伍性好,泡沫半衰期20 min.分流实验表明,泡沫酸显著降低高渗岩心而增加低渗岩心的注入量,泡沫流体在不同渗透率地层的注入量比例得到合理调整.酸化前后渗透率变化率表明,泡沫酸对低渗层的改善程度高于高渗层.泡沫对水层具有选择性封堵能力,防止酸对水层过度酸化,使酸液更充分改善油层的渗流能力.泡沫酸对渗透率和油水层均具有分流选择性酸化的特点.

A foamed acid system and its diversion acidizing performance

Foamed acid is widely applied in reservoir stimulation measures due to its many properties superior to conventional acid.A foamed acid system was developed in laboratory.Acid base liquid is composed of 12% HCl and 3%HF,and foam system is made up of compound foaming agent EL-23 of 0.8% and high polymer foam stabilizer D of 0.3%.the foam system has good compatibility with acid base liquid.The half-life of foam is up to 20 min.Diverted acidizing experiments show that the foamed acid system can increase injection volume in low-permeability core but decrease that in high-permeability core.The injection volume in different permeability porous media is reasonably adjusted.The experimental results also show that the acidizing effect of the foamed acid system on low permeability reservoir is superior to that on high permeability reservoir,that is,it has a feature of selective acidizing.It has also a behavior of selective plugging to water layers,can protect the water layers from excessive acidification,and improves flow condition of oil layers.The foamed acid has selective diversion aciding effect not only to oil and water layers but also different permeablity reservoirs.