深水巨厚盐膏层固井水泥浆体系研究
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摘要
墨西哥湾某井深水存在盐膏层,由于深水表层温度低、盐层蠕变致使井径缩小、冲蚀和溶解盐层导致水泥浆含盐量越来越高、盐膏层的夹层孔隙压力高/压力窗口窄等难点,给固井质量带来挑战。在分析墨西哥湾某井盐膏层特点和固井难点的基础上,表层采用单级首尾浆封固技术。首浆用具有一定抗盐能力的5%KCl全液体减轻剂低密度体系,尾浆用抗盐的10%NaCl+5%KCl聚合物常规密度水泥体系。室内研究表明,该套水泥浆体系适用于LASS系统,抗盐性好,具有良好的流动性、失水可控、稠化时间可调且过渡时间短、防窜等优点,保证了深水盐膏层固井质量。
The deep water of Mexico basin has huge salt-paste layer.It challenges cementing quality,such as low temperature, creep of gypsum, erosion and dissolving salt layers, narrow pressure window. Based on the analysis of the characteristics and the difficulty of cementing,the single-stage lead and tail slurry sealing technology is adopted. The lead slurry adopts low density system of all liquid slurry which water is 5 % KCl with certain salt resistance.And the tail slurry adopts normal density cement system with 10 % Na Cl+5 %KCl. Laboratory research shows that the cement slurry system suitable for LASS systems, good salt resistance.It also has some advantages,such as good liquidity,fluid loss control,adjustable thickening time and short transition time, combating gas migration.The cementing quality of deep salt layer is guaranteed.
The deep water of Mexico basin has huge salt-paste layer.It challenges cementing quality,such as low temperature, creep of gypsum, erosion and dissolving salt layers, narrow pressure window. Based on the analysis of the characteristics and the difficulty of cementing,the single-stage lead and tail slurry sealing technology is adopted. The lead slurry adopts low density system of all liquid slurry which water is 5 % KCl with certain salt resistance.And the tail slurry adopts normal density cement system with 10 % Na Cl+5 %KCl. Laboratory research shows that the cement slurry system suitable for LASS systems, good salt resistance.It also has some advantages,such as good liquidity,fluid loss control,adjustable thickening time and short transition time, combating gas migration.The cementing quality of deep salt layer is guaranteed.
引文
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[2]李振鹏,孟彦如,龚建明,等.墨西哥湾深水储层特征[J].海洋地质动态,2009,25(6):6-9.
[3]许前富,罗宇维,冯克满,等.一种高密度盐膏层固井水泥浆的研究及应用[J].钻井液与完井液,2014,31(1):68-71.