顺南井区高温高压防气窜尾管固井技术

Anti-channeling HTHP Liner Cementing Technologies Used in Block Shunnan

顺南井区井温超高,地层压力系统复杂,气层异常活跃,防气窜固井难度大,导致固井质量不合格。为解决气体窜通和水泥石高温强度衰退的难题,开展高温高压防气窜固井优化研究。通过优化外加剂,得到了新型胶乳液硅防气窜水泥浆体系。研究结果表明,用粒径为0.18、0.125或0.09 mm的硅砂复配,能够克服178℃下水泥石高温强度衰退的难题;胶乳水泥浆体系加入液硅后,防气窜能力增大;加入纤维可以使水泥石弹性模量降低48%,抗冲击性好;水泥浆呈直角稠化,具有较好的防气窜能力。优化前置液结构,使用加重隔离液技术实现低速紊流顶替。为防止水泥浆失重导致气层不稳,替浆后反循环洗井并尽快进行环空憋压,实现以快治窜。同时,配套抗高温气密封固井工具与附件,以保证防气窜固井质量。顺南井区φ177.8 mm尾管防气窜固井质量得到良好改善,为该工区高温高压防气窜固井提供重要的技术支撑。

Ultra-high formation temperatures, complex formation pressure system, active formation gases have long resulted in difficulties in well cementing, such as gas channeling and poor cementing job quality. Studies on HTHP anti-channeling cementing optimization reveal that 0.18 mm, 0.125 mm and 0.09 mm silica sand can be used in cementing slurries to solve the decreasing of HTHP strengths of set cement at 178 ℃. Latex cement slurry, when treated with active Si O2 water suspension, has enhanced gas channeling control performance. Addition of fibers in latex cement slurry reduces the elastic modulus of the set cement by 48%, greatly improving the impact resistance of the set cement. Right-angle thickening set cement has better gas channeling control. To prevent the column of the cement slurry from losing weight, therefore destabilizing the gas zones to be cemented, reverse circulation after mud displacement should be carried out and pressurize the annulus as soon as possible, a way to effectively control gas channeling. High temperature gastight cementing tools and accessories will also help control gas channeling. Using technologies, gas-channeling control in cementing of the φ177.8 mm liner string has been successfully realized in the Block Shunnan. These technologies are of importance to gaschanneling control in HTHP well cementing in the block.