速溶硅酸钾在克深区块钻水泥塞中的应用

Application of Instant Potassium Silicate for Drilling Cement Plug in Keshen Block

钻水泥塞过程中,水基钻井液容易受到水泥浆隔离液、水泥浆混浆、水泥塞的污染,严重时出现钻井液脱胶,造成恶性钻井事故。由此引入速溶硅酸钾对钻井液进行预处理,加量为0.1%~0.15%;钻水泥塞过程中根据性能与工况进行调整维护处理,加量为0.05%~0.1%。利用速溶硅酸钾在水溶液中的胶凝沉淀效应与强抗污染能力,以及硅酸根离子与钙离子反应生成硅酸钙沉淀,使钻井液保持较强的黏结性能,避免钻井事故发生。通过克深16井与克深904井钻水泥塞过程中分别使用速溶硅酸钾与纯碱处理的对比,证明速溶硅酸钾优于纯碱,同时使用速溶硅酸钾的钻井液表现出良好的流变性与热稳定性。

In the process of drilling cement plug,water base drilling fluid is vulnerable to pollution of cement paste spacer fluid,cement slurry and cement plug,drilling fluid degumming will possibly occur if such pollution is serious,which may result in vicious drilling accidents consequently.Especially,it is more prominent for organic salt drilling fluid system due to its weak calcium resistance capability.For this purpose,introduced is instant potassium silicate for drilling fluid pretreatment and maintenance treatment,with an added amount of from0.1%to 0.15%for pretreatment and from 0.05%to 0.1%for maintenance treatment according to the performance and working condition.Gel precipitation effect of instant potassium silicate in aqueous solution and its strong ability to resist pollution as well as calcium silicate precipitation effect resulting from reaction between silicate ions and calcium ions can make drilling fluid keep strong adhesive performance in order to avoid any drilling accident.Results obtained from comparative analysis on application of instant potassium silicate and sodium carbonate respectively to Keshen Well 16 and 904 in drilling cement plug show that effectiveness of instant potassium silicate is better than sodium carbonate and drilling fluid shows good rheological property and thermal stability.