改性聚丙烯酰胺絮凝废弃油基钻井液中有害固相的研究

Study on modified polyacrylamide to flocculate harmful solid phase in spent oil-based drilling fluid

以丙烯酰胺和甲基丙烯酰乙基三甲基氯化铵为原料,采用反相乳液聚合法制备了应用于废弃油基钻井液的新型絮凝剂。通过红外光谱、热重分析等方法测定了絮凝剂分子的结构与热稳定性;通过特性黏度法测量了絮凝剂分子的分子质量;通过絮凝剂乳液及絮凝前后分散相的粒径变化规律,分析了该絮凝剂对废弃油基钻井液的絮凝率与絮凝效果。结果表明,该处理剂在油相中对于有用固相絮凝效果微弱,但可以高选择性地絮凝钻屑等有害固相,在絮凝剂最佳质量分数为2.5%时,固液分层效率最高(43%),絮凝效果最好(92.13%)。将该絮凝剂应用于湛江某井的废弃油基钻井液,絮凝率达到了97.92%,经固控设备处理后的废弃油基钻井滤液性能稳定,能满足现场使用要求。絮凝剂可以循环使用,有效降低了钻井液使用成本。

Acrylamide and methacryl ethyl trimethyl ammonium chloride are used as raw materials to prepare new flocculant for spent oil-based drilling fluid through inverse emulsion polymerization method.The structure and thermal stability of the flocculant are determined by means of infrared spectroscopy and thermogravimetric analysis.The molecular weight of flocculant is measured by means of intrinsic viscosity method.The flocculation rate and flocculation effect of the flocculant on spent oil-based drilling fluid are analyzed through the change rules of particle size of the dispersed phase before and after flocculating emulsion and flocculation.Results show that the flocculant has weak flocculation effect on the useful solid phase in oil phase,but can flocculate harmful solid phase such as drilling cuttings with high selectivity.The solid-liquid stratification efficiency reaches the highest(43%)and the flocculation effect is the best(92.13%)when the optimal dosage of flocculant is 2.5%.As the flocculant is applied to spent oil-based drilling fluid from a well in Zhanjiang,China,the flocculation rate reaches 97.92%.The spent oil-based drilling filtrate treated by solid control equipment has stable performance,can meet on-site use requirements,can be recycled,and reduces effectively the use cost of drilling fluid.