大口径瓦斯排放井套管抗挤强度计算分析

Analysis of Large Diameter Gas Drainage Well Casing Collapsing Strength Computation

瓦斯排放井的套管具有直径大、重量大,在下入井筒过程中,经常出现套管被挤毁的现象。根据美国石油协会常规套管抗挤强度的计算公式,结合淮南矿业集团顾桥煤矿瓦斯排放井套管的实际,先进行了理论计算,然后根据大量试验获得的修正系数对理论计算结果进行修正,从而获得了套管的实际抗挤强度,并以此强度反算出套管在下入井筒时的空置深度与钻井液的填充深度,最终将套管安全的送入井底。验证了大口径套管抗挤强度计算方法的可行性。

Casings used in gas drainage wells have large diameter and heavy weight, during the lowering process, compressive collapsing is an ordinary phenomenon. Based on conventional casing collapsing strength computational formula of American Petroleum Institute, combined with gas drainage well casing practice of Guqiao coalmine, Huainan Mining Group, carried out theoretical computation first, then correction based on correction factor obtained from large numbers of test, thereby practical casing collapsing strength acquired. And to take the strength carries out inverse computation to obtain easing lowering casual vacancy depth and drilling fluid filling depth, finally lowered the casing to bottom safely. Practical examples have verified the feasibility of large diameter casing collapsing strength computation.