高温裂缝性油藏凝胶封堵剂的性能评价

Performance evaluation of gel plugging agent for high-temperature fractured reservoirs

关键词:  裂缝性油藏  凝胶封堵剂  直角稠化  性能评价  高温 

Key words:  fractured oil reservoirs  gel plugging agent  right-angle thickening  performance evaluation  high temperature

摘要:

目的 针对高温裂缝性油藏钻井过程井漏失严重的问题,利用有机碱式铬交联凝胶封堵剂进行封堵油藏漏失。方法 采用黏度测试、高温老化、稠度测试以及模拟堵漏实验等方法,评价了凝胶封堵剂的流变性能、热稳定性、稠化性、岩心封堵后突破压力梯度及封堵性。结果 以AM/AANa二元共聚物为凝胶封堵剂基液,有机碱式铬OACrC-1作为交联剂,乳酸为缓凝剂的凝胶封堵剂成胶前的表观黏度较低,稠度小于110 mPa·s,且稠化过渡期较短,表现出直角稠化性,且在120 ℃下具有良好的热稳定性；凝胶封堵剂注入效果在实验范围内随缝宽的增加变好,岩心突破压力梯度及封堵性表明凝胶封堵剂对缝宽不同的岩心均具有较好的封堵性能,封堵率可达85.9%及以上。结论 该凝胶封堵剂在高温裂缝性油藏具有良好的封堵性,耐温能力达到120 ℃,在钻井过程中封堵漏失层具有重要的应用价值和指导意义。 

Abstract:

Objective In view of the serious problem of well leakage during drilling in high-temperature fractured oil reservoirs, the organic basic chromium cross-linked gel plugging agent was studied to plug the drilling leakage. Methods The rheological property, thermal stability, thickening property, breakthrough pressure gradient and plugging property of the gel plugging agent after core plugging were evaluated by viscosity test, high temperature aging test, thickening test and simulated plugging test. Results The experimental results showed that the apparent viscosity of the gel plugging agent was very low by using AM/AANa binary copolymer as base fluid, organic basic chromium OACrC-1 as cross-linking agent, and lactic acid as retarder before gelling. The thickness was less than 110 mPa·s. The thickening transition period was short, the agent showed right angle thickening property, and had good thermal stability at 120 ℃. The injection effect of gel plugging agent became better with the increase of fracture width within the experimental range. The core breakthrough pressure gradient and plugging performance showed that the gel plugging agent had good plugging performance for cores with different fracture width, and the plugging rate was more than 85.9%. Conclusion sThe gel plugging agent has good plugging performance in high-temperature fractured reservoirs, and its temperature resistance reaches 120 ℃. It has important application value and guiding significance in plugging lost circulation layer during drilling.