新型酸化液体系在复杂水井中的研究与应用

Study and Application of New Acid System in Complex Well

针对长庆油田开发现状,建立了分步解堵思路,开发了一套酸化解堵液体系。结果表明,采用预处理液体系(3%盐酸+3%琥珀酸+0.5%柠檬酸+1%缓速剂HSJ+2%渗透剂STJ+5%有机分解剂YFJ)处理4 h后,胍胶和聚合物破胶液残渣的分解率分别为82.3%和96.0%,岩屑溶蚀率为11.3%;采用前置液体系(4%已二胺四乙酸+5%溶垢剂RGJ+2%渗透剂STJ)处理16 h后,硫酸钙的溶解率达86.5%,硅胶和氟硅酸钠的溶解率分别为100%和97.5%;采用主体液体系(20%复合酸+3%缓速剂HSJ+0.3%柠檬酸+5%渗透剂STJ+6%分子成膜剂CMJ)处理4 h后,岩屑的溶蚀率为38.9%。此外,预处理液和主体酸体系还具有很好的缓速性能,预处理液与CaCO3反应0.5 h时H+浓度是5%HCl体系H+浓度的9.1倍,主体酸体系与CaCO3反应0.5 h时H+浓度是土酸体系H+浓度的12.2倍。该技术已在现场成功实施15井次,改造后平均降压6.9 MPa,日增注9.6 m3,目前累计增注31060 m3,取得了较好的试验效果。

In view of the development status of Changqing oilfield,the research ideas of grading blockage removal was built and the new acidizing/blockage removal fluid system was developed.It was indicated that the decomposition rate of gel-breaking residue of guanidine gum,polymer and debris cracked after treated by the pretreating fluid system（3% hydrochloride ＋3% succinic acid ＋0.5% citric acid＋1% retardant HSJ＋2% penetrating agent STJ＋5% organic decomposition agent YFJ） for 4 h was 82.3%,96.0% and 11.3%,respectively.The corrison rate of calcium sulfate of the silica and sodium fluosilicate after treated by the prepad fluid（4% ethylene diaminetetra-acetate ＋5% scale-dissolving agont RGJ＋2% penetrating agent STJ）for 16 h achieved to 86.5%,100% and 97.5%,respectively.The decomposition rate of debris dissolved by the body fluid system（20% compound acid＋3% retardant HSJ＋0.3% citric acid＋5% penetrating agent STJ＋6% film-forming agent） for 4 h was 38.9%.In addition,the pretreating fluid and the body fluid had retarded behavior,The concentration of hydrogen ion was 9.1 times higher when the pretreating fluid system reacted with CaCO3 for 0.5 h,compared to that of the 5%HCl system,and the concentration of hydrogen ion was 12.2 times higher when the body fluid system reacted with CaCO3 for 0.5h,compared to that of the mud acid system.This technology was successfully tested in 15 wells with the average depressure of 6.9 MPa and the increasing water injection of 9.6 m3,and so far,it was accumulated by 31060 m3.The better results were achieved.