前置液体系在龙17井固井中的应用

龙17井是中国石油天然气集团公司川庆钻探工程公司和中国石油西南油气田公司在九龙山构造的一口重要预探井，设计井深为5 850 m。为解决Φ177.8 mm套管悬挂固井前钻井液漏失严重的难题，经固井专家对固井方案和工艺设计的研究，决定采用西南石油大学研制的具有高效抗污染和提高界面胶结质量的前置液体系。应用结果表明，前置液在改善界面胶结质量和保证有效层间封隔的效果明显，不仅能保证固井施工安全，而且还避免了因顶替效率低、界面胶结质量差导致的测井质量差和潜伏的环空油气水窜问题。

APPLICATION OF PREFLUSH TO CEMENTING IN THE WELL LONG 17

The well Long 17 is an important pre exploratory well in Jiulongshan structure, jointly drilled by CNPC Sichuan changqing Drilling &; Exploration Corporation and PetroChina Southwest Oil &; Gasfield Company, with a designed well depth of 5850 m. To solve the severe lost circulation problem occurred before cementing with Φ177.8 mm casing, the cementing program and procedures are deeply studied, it is determined to use the preflush system developed by Southwest Petroleum University which is highly effective in preventing contamination and improving cement bond quality. The application results have showed that this preflush is effective in improving bond quality and ensuring good isolation between layers of formations. It is helpful not only for successful cementing operation, but also for avoiding poor logging quality resulted from poor displacement and poor bond quality and thus avoiding potential oil/gas/water channeling.