特厚壁套管抗挤强度计算及现场应用

COLLAPSING STRENGTH CALCULATION AND ON-SITE APPLICATION OF EXTRA-HEAVY WALL CASING

对于套管挤毁问题较为严重的油气水井 ,采用非API标准的特厚壁套管来提高其抗挤强度 ,是今后预防套管挤毁的重要发展方向。目前 ,特厚壁套管的抗挤强度计算和尺寸系列尚未形成工业标准 ,文章提出特厚壁套管的抗挤强度计算方法和尺寸系列 ,供设计者和厂家参考。API/ISO套管挤毁工作组曾对本文公式进行了测评 ,结果显示具有较高的计算精度。大量计算表明 ,特厚壁套管的抗挤强度大大提高 ,约为加厚前原套管抗挤强度的 1.5～ 4倍 ,甚至 6倍。最后还介绍了特厚壁套管在中原油田的现场应用情况。

In regard to the oil/gas/water well with seriously collapsed casing, it is an importantly developing trend for preventing casing from being collapsed to apply non-API extra-heavy wall casing to raising collapsing strength. The industrial standard of the collapsing strength calculation and size series of extra-heavy wall casing hasn't yet formed at present. In the paper, the collapsing strength calculation method and size series of the extra-heavy wall casing are put forward, thus giving a reference to designers and production units. The formulas proposed in the paper were evaluated by API/ISO casing collapsing work team and the results indicate that these formulas are of relatively high accuracy. Through a lot of calculation it is shown that the collapsing strength of the extra-heavy casing is greatly increased, being larger than that of the original casing (before thickening) by 1.5-4 times, even by 6 times. Finally, the on-site application of the extra-heavy wall casing in Zhongyuan Oil Field is also preliminarily introduced in the paper.