一种耐高温低伤害纳米复合清洁压裂液性能评价

Performance evaluation of a high temperature-resistant &low damage nano-VES fluids

针对清洁压裂液的耐温性较差、滤失量过大等问题,研制了一种新型的耐高温低伤害纳米复合清洁压裂液。实验结果发现,一定浓度的MWNT,能够与蠕虫状胶束形成更为紧密的拟交联三维网状结构且能明显增黏;采用流变性实验优化MWNT质量分数为0.3%,得出纳米复合清洁压裂液配方为3%(w)BET-12两性表面活性剂+0.3%(w)MWNT。性能评价结果表明,在170s-1、150℃下,该压裂液黏度仍能保持在20mPa·s以上;70℃时滤失量相比传统清洁压裂液大大降低;剪切恢复性能良好,体系悬砂性能好,遇地层水或原油中烃类物质能自动破胶,高效且彻底,符合施工要求;对储层伤害较小,裂缝导流能力伤害率仅有8.9%。研究表明,该纳米复合清洁压裂液适合在中高温油气田推广应用。

Aiming at the problems of clean fracture fluids with low temperature-resistant and high fluid loss, a novel high temperature-resistant and low damage nano-VES fluids was developed. The results show that the tighter three-dimensional network which formed by MWNT and zwitterionic surfactant BET-12 can enhance viscosity when the concentration of MWNT is appropriate. The added MWNT concentration for 3% BET-12 was optimized to be 0.3% by rheological measurements. The results of performance evaluation of the nano-VES fluids indicate its viscosity is more than 20 mPa·s at 170 s^-1 and 150℃. The volume of fluid-loss of nano-VES fluids is obviously lower than base fluids at 70℃, the system with excellent shear restoration and proppant suspension capability. When the nano-VES fluids contact with formation water or hydrocarbon substance, the gel can be quickly broken down. The damage rate of fracture flowed conductivity of the fluid is 8.9%, showing a less formation damage compared with polymer fluids. Research result shows that the nano-VES fluids can he applied to middle and high temperature reservoir development.