SMP为苯酚、甲醛与亚硫酸盐的缩聚物，具有良好的降滤失性能，Ⅱ型可抗盐、抗钙镁离子等，适应于高矿化度地层，是配制深井超深井钻井液的优良降滤失剂，一般加量为2%-5%，抗温可达220℃。
       SMP is a polycondensate with phenol, formaldehyde and sulfite. SMP-II can resist high concentration of salt and calcium or magnesium ions, adapted to high salinity formation. It has good fluid loss control performance, and is an excellent fluid loss agent for ultra-deep drilling. The dosage is generally 2% -5%. The temperature resistance of SMP-II can be up to 220 ℃.