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)

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。

The significance and necessity of study on microstructure are described, and the microstructure at cementation interface between cement and casing is investigated in the condition of static aging. It shows that there are large amounts of Ca(OH) 2 crystals that may be easily washed out, and C S H gel of high alkalinity at the interface, and it is a loose structured weak transition area, thus the channeling resistance of cement sheath is inevitably lowed down.