深井盐膏及盐水地层固井隔离液体系研究

目前国内深井多钻遇盐膏和盐水地层，常用隔离液体系抗温和抗盐能力较差，温度超过100℃时，在低浓度盐作用下体系失稳沉降严重，易造成固井施工复杂，注替安全隐患极大。选用一种多糖聚合物作为高温抗盐悬浮稳定剂，辅以耐盐的降失水剂及流型调节剂，研制了一套高温抗盐隔离液体系。该体系在钠盐、钙盐和镁盐溶液中均能保持稳定的性能；使用温度可达140℃；具有较好的密度调控能力，在1.3～2.4g/cm3可调；且与常规钻井液、水泥浆具有较好的相容性。该套体系有望应用在深井超深井及盐膏地层、复合盐岩层和盐水地层固井注水泥作业中。

LABORATORY STUDY ON CEMENTING SPACER FLUID SYSTEM FOR DEEP WELL IN SALT GYPSUM BED AND BRINE WATER LAYERS

Recently salt gypsum beds and brine water layers are frequently encountered when drilling deep wells.The conventional spacer system has a relatively poor salt and temperature tolerance.When the temperature exceeds 100℃,the system loses its stability in the low concentration of saline water and can cause serious cementing accidents and has a great potential safety hazard of injection and displacement of slurry.A polysaccharide polymer is chosen as high temperature and anti salt suspension stabilizer,and supplemented by salt tolerant fluid loss additive and pattern adjusting agent,a high temperature and anti salt spacer system is developed.The system could maintain its stability in the sodium,calcium and magnesium salt solution.It can be used in a temperature of 140℃ and has a preferable regulation ability of density which can be adjusted between 1.3 and 2.4g/cm3.It also has a good compatibility with conventional drilling fluid and cement slurry.The system is expected to be used in cementing job of the deepwell,high deep well,and salt gypsum bed,composite rock salt layer,and brine water layer.