油基钻井液因其良好的性能被广泛应用于深井、复杂结构井钻井中,但伴随其广泛应用,油基钻井液与水泥浆因接触污染引起井下复杂情况案例越来越多.为此,首先分析了水泥浆中掺混钻井液和钻井液外加剂对其性能影响,在此基础上,借助于扫描电镜、X射线衍射仪及傅里叶变换红外光谱仪等现代分析手段,探究掺混前后水泥浆物相和微观形貌的变化.研究结果表明:油基钻井液中降滤失剂、氯化钙在水泥水化不同阶段增加了的氢氧化钙的溶解度,加快了C3S水化速度,使得水泥浆凝聚、变稠,导致水泥浆流动性急剧变差;而主乳化剂、辅乳化剂及黏土增加了油基钻井液界面膜的强度与厚度,难以与水泥浆形成"油包水"或"水包油"乳化结构而造成污染.该系统性研究更加深入地认清了油基钻井液与水泥浆接触污染的本质,为防范两者接触污染提供技术参考.%Oil-base drilling fluid is widely used for the drilling of deep wells and complex-structure wells owing to its better proper-ties. With its wide application, however, the complicated conditions occur more and more frequently in the hole because of the contact contamination between the oil-base drilling fluid and the cement slurry. In this paper, the effects of the drilling fluid and its additive on the properties of cement slurry were firstly analyzed. Then, the phase and microscopic morphology of cement slurry before and after it was blended with drilling fluid and its additive were investigated by means of modern analysis technologies, e.g. SEM, XRD and FTIR. It is shown that the cement slurry is condensed and thickened for the content of calcium hydroxide is consumed and increased in the different stages of cement hydration by the filtrate reducer and the calcium chloride in the oil-base drilling fluid, respectively, and consequently the mobility of the cement slurry gets worse seriously. The primary emulsion, auxiliary emulsion and clay increase the strength and thickness of the film at the interface of oil-base drilling fluid, so the emulsified structures of oil in water/water in oil cannot be formed easily. As a result, the contamination is induced. The systematic study plays a significant role in understanding the essence of contact contamination between oil-base drilling fluid and cement slurry, providing the technical reference for the prevention of contact contamination between them.
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