固井水泥浆体积收缩对环空气窜的影响研究

发布时间：2018-06-09 00:28

  本文选题：固井 + 水泥浆　； 参考：《西南石油大学》2016年硕士论文

【摘要】：固井后环空带压问题一直是固井界的一个技术难题,大部分天然气井在固井后都会面临这一问题。导致环空带压的一个主要原因就是环空气窜,而引起环空气窜的原因很多,其中水泥浆防窜性能对环空气窜会产生重要的影响,水泥浆在凝结过程中的体积收缩是水泥浆防气窜性能的重要指标之一。因此探究水泥浆体积收缩对气窜的影响机理,对于水泥浆防窜性能的设计有着重要的指导意义。本文在现有研究的基础上从体积收缩过程及影响因素出发,开展了不同阶段体积收缩对气窜影响的研究。从水化反应及水化过程出发结合体积收缩曲线、水化热曲线和TGA曲线对体积收缩的成因及收缩的过程进行了分析,发现在水泥水化过程中自由水向束缚水和化学结合水转化的越多,体积收缩率就越大。通过OWC-1102型高温高压水泥浆体积收缩仪和比长仪测试分析了不同水泥浆体系的体积收缩率,并对体积收缩的影响因素及影响机理进行了研究,发现90℃下水灰比从0.3增加到0.6,初凝时刻对应的体积收缩率增加了0.24%,终凝时刻对应的体积收缩率增加了1.2%；90℃下加入35%的硅粉较未加硅粉的基础配方初凝时刻对应的体积收缩率降低了0.38%,终凝时刻对应的体积收缩率降低了0.69%；加入15%的矿渣和未加矿渣的基础配方相比初凝时刻对应的体积收缩率降低了0.17%,终凝时刻对应的体积收缩率降低了0.46%。选用了合理的实验手段和方法测试了不同阶段的体积收缩、水泥浆凝结过程中孔隙压力的变化、水泥浆凝结硬化后界面胶结强度的变化,结合气窜成因重点分析了初凝前体积收缩和凝结硬化后体积收缩这两个阶段的收缩对气窜的影响,实验数据分析表明：初凝前的体积收缩率从0.81%降到0.39%时,初凝时刻的孔隙压力降低值从0.9MPa降低到0.3MPa,一、二界面的胶结强度随着体积收缩率的增加而逐渐降低；同时有钻井液滤饼存在时,体积收缩对界面胶结强度的影响更大；通过计算胶结强度增长速率分析对比了有无钻井液滤饼存在条件下外观体积收缩对胶结强度的影响规律；从水泥浆配方优化方面提出了改善水泥浆体积收缩的措施,室内实验结果表明优化后的水泥浆体系的常规工程性能良好,体积收缩性能得到了一定的缓解。由于实验条件的限制本文关于水泥浆初凝到终凝之间的体积收缩率对气窜的影响未做深入研究,建议后续对此部分内容进行深入研究。
[Abstract]:The post-cementing annular zone pressure problem is always a technical problem in cementing field, and most natural gas wells will face this problem after cementing. One of the main causes of annular zone pressure is annulus air channeling, and there are many reasons for ring air channeling, among which the anti-channeling performance of cement slurry has an important effect on annular air channeling. Volume shrinkage of cement slurry during solidification is one of the important indexes to prevent gas channeling of cement slurry. Therefore, it is of great significance to study the influence mechanism of cement slurry volume shrinkage on gas channeling for the design of cement slurry anti-channeling performance. In this paper, based on the existing studies, the effects of volume shrinkage on gas channeling in different stages are studied from the point of view of volume shrinkage process and influencing factors. Based on hydration reaction and hydration process combined with volume shrinkage curve, hydration heat curve and TGA curve, the causes and process of volume shrinkage were analyzed. It is found that the more free water transforms into bound water and chemically bound water in the hydration of cement, the larger the volume shrinkage rate is. The volume shrinkage rate of different cement slurry systems was analyzed by OWC-1102 high temperature and high pressure cement slurry volume shrinkage meter and specific length meter, and the influencing factors and influencing mechanism of volume shrinkage were studied. It is found that the volume shrinkage at the initial setting time increases by 0.24, and the volume shrinkage at the final setting time increases by 35% at 90 鈩，

本文编号：1997935