一种新型广谱水基固井前置液体系的研究

以流变学原理为基础，提出了控制接触污染的前置液紊流顶替理念。研究出了一种具备强抗钙能力和优良化学兼容性、流变参数可灵活调整、密度调节范围宽、能选择性固化的新型广谱水基前置液体系。冲洗液中含有磷酸盐类的稀释剂和络合剂、丹宁类稀释剂及纤维素类增粘剂，这3种双效主剂以一定比例复配，具有良好协同效能。隔离液采用重质碳酸钙、重晶石为加重剂，通过调节悬浮稳定剂和降滤失剂等外加剂的比例和加量来调控性能，并加有配伍性好的阴离子型抗钙表面活性剂，以抑制水泥中阳离子对隔离液体系的侵污。在隔离液基础上，将加重材料替换为一种具有潜在水化活性的材料，通过激活剂的优选和采用膨润土预水化配制法，研制了可固化隔离液。提出优质前置液体系设计的关键在于体系化学处理剂的合理选择，它能使不同理化性能的流体相互之间具有良好的相容性，克服了采用传统顶替机理难以解决的流体污染后工程性能恶化引起的不良后果，为提高顶替效率提供了有利条件。该前置液体系对保证固井作业安全和提高层间封隔效果有广阔的应用前景。

Study on a Widely Acceptable New-Type Cementing Front Spacer

Based on the mechanism of rheology, a conception of turbulent flow replacement of mud by front spacer and a widely acceptable new cementing front spacer was put forward. This spacer is characterized by flexibly adjustable rheological properties, wide range of applied density, suitable to varied cement slurries, good resistance to Ca2+ contamination and broad chemical compatibility. It does not evidently affect strength of the set cement. By application of this new-type cementing front spacer, the replacement effectiveness of mud is raised up by elimination of channeling occur and the setting ability of the spacer itself can assist the front segment of the set cement to have satisfied strength so that the cementing quality is evidently guaranteed.