套管偏磨曲率对其抗挤毁强度影响的有限元分析

FINITE ELEMENT ANALYSIS OF THE INFLUENCE OF CASING ECCENTRIC WEAR RATE ON COLLAPSING STRENGTH

随着油田开采的不断深入,应用于深井、超深井的套管经常发生偏磨现象。套管偏磨降低了其使用性能,尤其降低了其抗挤毁能力,使石油套管经常因偏磨而损坏,严重影响了原油的正常生产。文章主要运用有限元软件,研究了不同钻杆直径造成的套管偏磨对套管抗挤毁能力的影响。结果表明,随着钻杆直径增大,偏磨区域增大,但偏磨区域曲率变小。其综合影响是偏磨“月牙形”的曲率对套管的挤毁能力影响很小,而偏磨深度对套管的挤毁压力影响很大,因此实际钻井时,钻杆直径对套管抗挤强度的影响可以给以较少的考虑。

The casing eccentric wear often occurred in deep and ultra deep well exploitation. The casing eccentric wear reduces its service performance, and especially decreases its collapse resistance capacity, which causes casing failure and seriously affects the oil production. In this paper, the influence of casing eccentric wear with different diameter on casing collapse resistance capacity was researched by finite element software. The results showed that the eccentric area became bigger and the eccentric curvature became smaller while drill pipe diameter became large. The casing collapse capacity is not seriously affected by the casing curvature, but the eccentric worn depth has a greater effect on casing collapse strength. In actual drilling, the influence of drill pipe diameter on casing collapse strength can be negligibly considered.