埕岛油田隐形酸完井液体系研究及其应用

Development of Latent Acid Completion Fluid for Chengdao Oilfield

埕岛油田砂岩储层高渗疏松,水敏性中等,临界矿化度2～4g/L。针对该油藏开发的储层保护型隐形酸完井液,含有可释放H+的隐形酸载体及多种功能性添加剂,以海水为基液,反应后变为中性液体。60℃下储层岩心粉在0.3%～0.5%该隐形酸载体海水溶液中12小时溶蚀率为2.42%～3.03%。对各个组分及其用量进行了实验筛选,得到了完井液配方:0.3%隐形酸载体+2%聚胺类黏土稳定剂HCS+1%缓蚀剂HCW-CA+1%聚丙烯酸酯类减阻剂JZS+过滤海水。0.3%隐形酸载体海水溶液与原油混合后出现增稠现象,加入JZS可使混合液黏度和油水界面张力降低。埕岛油田4口新井射孔完井中使用该隐形酸完井液为射孔液,投产后产油量大大高于使用防水伤害完井液射孔完井的4口对比井。

The sandstone oil reservoir in Chengdao,Shengli,was characterized by high permeability,loose consolidation,mediate water sensibility,and critical salinity in range 2—4 g/L. The latent acid completion fluid developed for this reservoir was sea water based and reservoir formation protective,contained an H^＋ releasing latent acid compound（LAC） and lots of functional additives and became neutral fluid eventually. 2.42%—3.03% of mass of powdered reservoir cores were dissolved out in 0.3%—0.5% LAC sea water solution at 60℃ in 12 hrs. As a result of ingredient and dosage sieving experiments,a formulation of latent acid completion fluid was established：0.3% LAC＋2% polyamine clay stabilizer HCS＋1% corrosion inhibitor HCW-CA＋1% polyacrylate drag reducer JZS＋filtrated sea water. The 0.3% LAC sea water solution and the crude oil created viscous thickening mixture and introducing JCS might reduce the water/oil interfacial tension and hence the viscosity of the thickened mixture. Four newly drilled wells were completed with perforation in this latent acid completion fluid and their oil productivity was much higher than other four wells perforated in a standard fluid without water induced demage.