油田注水开发中水源混配防垢技术

为解决油田结垢伤害问题,国内外采用了多种除垢方法,如加防垢剂、酸洗除垢、高压射水流除垢等,并针对不同油田、结垢特点开发了不同的除垢、防垢产品。但到目前还没有一种经济实用、简单易行、高效无污染的方法。水源混配防垢技术是将地层水或油田污水与注入水混合,在地表以最佳比例混配,用Ca(OH)₂溶液调节pH值,当pH值大于835,溶液中Ca²⁺,Ba²⁺,Sr²⁺,Fe³⁺,Fe²⁺等阳离子和OH^-,CO₃^2-,HCO₃^-,SO₄^2-,S^2-等阴离子发生反应,全部生成沉淀。一方面可去除水中的成垢离子,避免地层水和注入水在油层内相遇结垢,达到保护油层的目的;另一方面,使铁进入腐蚀钝化区,防止输水管道的结垢与锈蚀。通过模型实验研究,该方法不仅可防止油层结垢伤害、输水管道的结垢与锈蚀,实现油田污水的再利用,大大降低采油成本,而且也适用于各种油田的注水开发。

Scale control through water mixing in waterflooding oilfields

Scale control through water mixing is an economically applicable, simple, highly effective and pollution free technology. Injection water is mixed with formation water or produced water in optimum proportion at surface. Ca(OH) 2 solution is used to control pH value. All the cations, such as Ba 2+, Ca 2+, Fe 3+, Fe 2+ and Sr 2+ and anions,such as OH-, CO 2- 3, HCO- 3, SO 2- 4 and S 2-will be precipitated from the solution through reaction when the pH value in the mixed water is above 8.35. On the one hand,the scale-forming ions are removed and scaling is prevented when formation water mix with injection water in oil reservoir, so as to protect the oil reservoir. On the other hand,iron would be in a passivation state of corrosion,and water pipeline would be prevented from scaling and rusting.Experimental studies show that this technology can not only control scaling and damaging of oil reservoir and scaling and rusting of water pipeline, so as to realize reutilization of produced water and to reduce production cost, but is also applicable for waterflooding in various oilfields.