超分子聚合物清洁CO2泡沫压裂液的研究及应用

Research and application of a clean supramolecular polymeric CO2 foam fracturing fluid

关键词:  页岩气  CO₂泡沫压裂  超分子聚合物  抗高温  清洁  低残渣 

Key words:  shale gas  CO₂ foam fracturing  supramolecular polymer  high temperature resistance  clean  low residue

摘要:

采用几种聚合单体、引入特殊官能团合成了一种聚合物,与相关添加剂和CO₂配套使用,形成一种抗高温的超分子聚合物清洁CO₂泡沫压裂液(BCF压裂液)。采用泡沫压裂液性能评价方法对体系进行了室内评价:体系抗温能力可达140 ℃,具有泡沫质量高、泡沫稳定性强、耐温耐剪切性能好,携砂性能优良等特点,并且压裂液破胶彻底、表面张力低(24 mN/m以下)、残渣含量极低(小于1 mg/L)。该体系不仅解决了常规压裂液残渣含量高的问题,也克服了VES清洁压裂液与CO₂配伍性差、耐温耐剪切差等缺点,在延长油田页岩气井中成功实施并取得了良好的增产效果,对低渗、低压、易水锁、强水敏等特殊油气藏的高效开发和储层保护具有重大意义。

Abstract:

A clean supramolecular polymer CO₂ foam fracturing fluid with high temperature resistance was compounded with a polymer synthesized by several polymerization monomers and introducing specific functional groups, related additives and CO₂. The system was evaluated through the performance evaluation method of foam fracturing fluid:the temperature resistance has reached 140 ℃, with the advantages of high foam quality,long half-life, strong temperature and shear resistance,good performance of sand carrying, etc., and fracturing fluid gel would be broken completely, which has low surface tension (less than 24 mN·m-1) and very low residue (less than 1 mg·L-1). The system not only solved the high residue content problem of conventional guar gum-CO₂ foam fracturing fluid, but also overcame the shortcomings of poor compatibility with CO₂ and low resistance to high temperature and shearing of VES-CO₂ foam fracturing fluid. The system has successful implementation and good effect of increasing production in a shale gas well of Yanchang oil field, and it has great advantages in efficient development and reservoir protection of special oil and gas reservoir with low permeability, low pressure, easy water lock and strong water sensitivity.