改性纳米二氧化硅稳泡剂的合成与性能评价

Synthesis and performance evaluation of modified nano silica foam stabilizer

固体颗粒类稳泡剂纳米二氧化硅由于表面具有大量硅羟基而在溶剂中的分散性很差,极易团聚,使用范围被极大程度的限制。以偶联剂KH550和纳米SiO_(2)为原料,制备了接枝改性纳米二氧化硅SiO_(2)-K5。通过红外光谱(FTIR)、X射线能谱(EDS)、透射电镜(TEM)对改性纳米二氧化硅进行表征;并以泡沫体系的析液半衰期为指标,考察加量、温度和无机盐浓度对SiO_(2)-K5性能的影响。结果表明,接枝改性纳米二氧化硅SiO_(2)-K5与未改性SiO_(2)相比,其耐温、抗钠盐、抗钙盐能力均提高了30%以上。设计了以SiO_(2)-K5为稳泡剂的含粘土泡沫修井液和无固相泡沫修井液,通过实验测评,表明两种修井液老化前后点的密度变化幅度小于10%,对岩心的伤害率小于20%,恢复率大于80%。

Due to the large amount of silicon hydroxyl groups on the surface,nano silica,a solid particle foam stabilizer,has poor dispersion in the solvent,is very easy to agglomerate,and its application range is greatly limited.Using silane coupling agents KH550 and nano SiO_(2) as raw materials,grafting modification products SiO_(2)-K5 was prepared.The modified nano silica was characterized by FTIR,EDS and TEM;the effects of dosage,temperature and inorganic salt concentration on the properties of four foam stabilizers were investigated by taking the time to form 50 mL of liquid from foam system as an index.The results show that the performance of SiO_(2)-K5 is better than the other products.Compared with unmodified nano silica,its temperature resistance,sodium salt resistance and calcium salt resistance are increased by more than 30%.The clay containing foam workover fluid and solid free foam workover fluid with SiO_(2)-K5 as foam stabilizer were designed,and the results showed that the damage rate of the two workover fluids to the core is less than 20%,and the recovery rate is more than 80% after various laboratory performance tests and damage evaluation.