摘要
针对目前常用的CO_2泡沫压裂液存在的与CO_2配伍性差、交联不易控制、耐温耐剪切性能差、残渣含量高等问题,采用丙烯酰胺类多元共聚物BCG-8为稠化剂,通过配套添加剂优选及用量优化,形成了的基础配方为0.3%~0.6%稠化剂BCG-8+0.2%~0.45%稠化增效剂(起泡剂)B-55+0.2%~0.3%调节剂B-14+1%KCl的聚合物-CO_2泡沫压裂液体系,研究了该压裂液体系的泡沫流变性、耐温耐剪切性能、携砂性能及破胶性能。研究结果表明,该体系泡沫质量在55%~75%时表观黏度保持在较高值,在140℃、剪切速率170 s^(-1)下剪切120 min后表观黏度保持在30 mPa·s以上,黏弹性的作用使其携砂性能明显优于HPG冻胶体系的,且该体系破胶液的表面张力低于24 mN/m、残渣含量低至0.1 mg/L。该压裂液体系在延长油田页岩气井中施工顺利,措施见效快,增产效果显著,可用于页岩气等非常规油气藏的储层改造。
For the existing problems of conventional CO2 foam fracturing fluid, such as poor compatibility with CO2, uncontrollable cross-linking, poor temperature and shear resistance, and high residue content, a polymer-CO2 foam fracturing fluid system was formed using a aerylamide-based copolymer （BCG-8）as thickener, composed of 0.3%-0.6% thickener BCG-8 ＋ 0.2%-0.45% thickening synergist B-55 （foaming agent）＋0.2%--0.3% regulator B-14＋ 1% KC1, and the rheologieal property, temperature and shear resistance, proppant carrying capability and gel-breaking property of the fracturing fluid was investigated. The results showed that, the system kept higher viscosity at the foam quality of 55%-75%; The viscosity of the fracturing fluid remained more than 30 mPa·s after sheared for 120 min at the shear rate of 170 s^-1 and at the temperature of 140 ℃, which indicated that the fracturing fluid had higher viscoelastic effect, and resulted in the fracturing fluid had better proppant carrying capacity than that HPG gel had. Moreover, the broken gel fluid had lower surface tension than 24 mN/m and the residue was as low as 0.1 mg/L. With the advantages of smoothly construction, quick effect and obvious simulation effect in the shale gas wells of Yanchang oil, the system had great significance to efficient development and reservoir protection of the unconventional reservoirs.
出处
《油田化学》
CAS
CSCD
北大核心
2017年第3期438-443,共6页
Oilfield Chemistry
基金
陕西省科技统筹创新工程"陆相页岩气资源地质研究与勘探开发关键技术攻关(项目编号2012KTZB03-03)
