油井水泥与钢管胶结界面处微观结构研究(Ⅱ)

STUDY ON THE MICROSTRUCTURE AT THE CEMENTATION INTERFACE BETWEEN OIL WELL CEMENT AND CASING(Ⅱ)

摘要: 在动态养护条件下对油井水泥与钢管的胶结界面处微观结构进行了研究。结果表明,动态养护条件下油井水泥与钢管的界面处胶结强度即抗窜能力大幅度降低,与静态养护时完全不一样。在其胶结界面上,Ca(OH)2晶体和高碱性的C-S-H凝胶大量被溶蚀,耐冲蚀的钙矾石等水化产物较发育,存在一个结构疏松、强度薄弱的过渡层,该层是抵抗油气水窜的薄弱环节。

Abstract: A study on the microstructure at the cementation interface between cement and casing is conducted in the dynamic aging condition.It shows that the cementation strength, i.e., thewater channeling resistance decreases dramatically, as compared with that of in the static condition.At the cementation interface, large amounts of Ca(OH)2 crystals and C-S-H gel of high alkalinity is washout out, while such hydrate as calcium feldspar is well developed, causing a loose structured weak transition area, and lowing down the channeling resistance of the cement sheath.