封堵用超细碳酸钙与超细二氧化硅分散性研究

为探讨水基钻井液用超细碳酸钙粉体和超细二氧化硅粉体在水溶液中的分散状况,利用扫描电镜对超细微粒进行初始形貌分析,讨论了超声时间、pH、搅拌速度等物理分散因素对超细碳酸钙粉体和超细二氧化硅粉体分散效果及分散稳定性的影响.同时,使用阴离子表面活性剂、阳离子表面活性剂、聚合物表面活性剂等对超细微粒进行了化学分散.研究表明:放置后的超细微粒会发生团聚,其中超细碳酸钙中径达5~6μm,超细二氧化硅中径达6~7μm;物理分散方法对超细微粒的分散效果影响不大,化学试剂分散效果明显优于物理分散;相同分散剂作用下,超细碳酸钙的分散效果优于超细二氧化硅,超细碳酸钙经过化学试剂分散处理后D_(10)可以达到120 nm,Zeta电位值达-56.3 mV;优化条件下制得的分散体系中,超细碳酸钙的沉降稳定性较好,放置24 h后沉降率在5%左右.

Comparative study of drilling fluid dispersion of ultrafine SiO2 and ultrafine CaCO3

In order to investigate the dispersion of ultrafine SiO2 and ultrafine CaCO3 in aqueous drilling fluid, the micromorphology of the primary ultrafine particles were analyzed by scanning electron microscopy ( SEM), and the influences of the ultrasound time, pH, shear stirring speed and other physical factors on the dispersion and dispersion stability of ultrafine SiO2 and ultrafine CaCO3 were discussed. At the same time, the anionic surfactant, cationic surfactant and polymer surfactant were used for dispersing the superfine powders chemically. Experimental results show that the ultrafine particles were agglomerated, and the diameter of superfine CaCO3 and SiO2 is 5~6μm and 6~7μm, respectively. These physical methods have little effect on the dispersion of ultrafine powder, and the dispersion effect of chemical agents is better than that of physical dispersion. Under the same dispersion conditions, dispersion of ultrafine SiO2 is better than that of ultrafine CaCO3 . The D10 value of ultrafine CaCO3 treated by the chemical reagent can reach 120 nm, and the Zeta potential value is -56.3 mV. The stability of ultrafine CaCO3 solution is better than that of the ultrafine SiO2 system, and the settlement ratio of ultrafine CaCO3 solution after 24 hours is about 5%.