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非渗透添加剂在建筑、隧道、水电工程等水泥施工作业中已有广泛的应用。它可改善水泥石的微观结构,降低水泥石的渗透性,提高水泥石的抗渗性能。高压油气井注水泥作业,应用非渗透添加剂,可防止注水泥后的环空窜流,提高层间封隔能力;同时,可降低水泥浆滤失,减少对油气层的污染。目前,石油工业中应用比较成熟的非渗透剂主要有三类: 胶乳类油井水泥中用得最普遍的胶乳有聚乙酸烯脂、聚乙烯醇及丁二烯苯乙烯聚合物。水泥中掺入胶乳,主要是利用胶乳的成膜特性,首先在渗透性地层表面形成一层低渗塑性膜,降低水泥浆滤失;其次在水泥浆水化胶凝期间,因孔隙水与水泥不断反应而消耗,使胶乳浓度不断增大,胶乳粒子聚结形成一种能充填孔
Non-permeable additives in the construction, tunnels, hydropower projects such as cement construction operations have been widely used. It can improve the microstructure of cement stone, reduce the permeability of cement stone and improve the impermeability of cement stone. High-pressure oil and gas well cementing operations, the application of non-permeable additives to prevent annulus after injection of cement cross-flow, improve the ability to seal between the layers; the same time, reduce the loss of cement slurry and reduce pollution to the oil and gas layers. At present, there are mainly three types of non-penetrating agents that are relatively mature in petroleum industry. Latexes The most commonly used latex in well cement is polyacetal, polyvinyl alcohol and butadiene styrene polymers. The cement is mixed with latex mainly by utilizing the film-forming characteristics of the latex. First, a low-permeability plastic film is formed on the surface of the permeable layer to reduce the loss of the cement slurry. Secondly, during the hydration and gelation of the cement slurry, Constant response and consumption, the latex concentration increases, latex particles coalesce to form a filling hole