套管磨损与水泥环缺陷位置对套管应力的影响

The effect of casing abrasion and cement sheath's defect position on casing stress

以APDL为开发工具建立有限元模型,系统研究了非均匀地应力场中套管内壁磨损位置与水泥环缺陷位置对套管应力的影响规律。以塔里木油田迪娜2井5000m井深处为实例进行分析,结果表明,在一定磨损程度下,套管内最大等效应力总是在最大地应力方位取得最小值,在最小地应力方位取得最大值,工程中假设磨损位置在最小地应力方位是偏于安全的;水泥环缺陷明显改变了套管应力的分布规律,当套管磨损位置与水泥环缺陷位置角度相等时,套管内的应力最大,为最危险工况。

With the APDL as the development tool to establish the finite element model, the law of the effect of the casing inner wall's abrasive position in the uneven crustal stress field and cement sheath's defect position on casing stress was systematically studied in this paper. The analysis was conducted with the Dina-based Well Two in Tarim Oilfield as the example. The results show that in a certain degree of abrasion, the maximum equivalent stress always achieves the minimum value at the maximum crustal stress location and achieves the maximum value at the minimum crustal stress position. Suppose that in a project, the abrasive position is subject to safety at the minimum crustal stress position. The defect existing in cement sheath obviously changes the distribution law of casing stress. When the casing abrasive position is equivalent to the cement sheath position, the stress within the casing reaches the maximum and the most dangerous operating conditions will arise.