Optimization and Performance Evaluation of Ultra-High Temperature Water-Based Completion Fluid System in Buried Hill Reservoir

基于渤中区域潜山储层特征，开展了超高温水基完井液体系优选与性能评价。通过对加重盐、抗高温缓蚀剂及防水锁剂的加量优选与完井液体系配方研究。形成了一套抗210℃超高温的水基完井液体系，该完井液体系配方为：海水 + 2%助排表活剂STIMFC-1 + 2%抗高温缓蚀剂COROHIB-1 + 25% (质量分数) NaCl。结果表明：该体系210℃热稳定性良好、表面张力为31 mN/m、界面张力为7.7 mN/m、腐蚀速率为0.012 mm/a，对储层渗透率恢复率在85%以上。构建的完井液体系能够满足潜山储层高温井完井阶段的技术需求。Based on the characteristics of the buried hill reservoir in the Bozhong area, the optimization and performance evaluation of the ultra-high temperature water-based completion fluid system were carried out. Through the study of the dosage optimization of heavy salt, high temperature corrosion inhibitor and waterproof locking agent and the formulation of the completion fluid system. A set of water-based completion fluid system with 210˚C ultra-high temperature resistance was formed. The formula of the completion fluid system is: seawater + 2% cleanup surfactant STIMFC-1 + 2% anti-high temperature corrosion inhibitor COROHIB-1 + 25% (mass fraction) NaCl. The results show that the system has good thermal stability at 210˚C, the surface tension is 31 mN/m, the interfacial tension is 7.7 mN/m, the corrosion rate is 0.012 mm/a, and the recovery rate of reservoir permeability is more than 85%. The constructed completion fluid system can meet the technical requirements of high temperature well completion stage in a buried hill reservoir.