钻井膨胀管膨胀过程中不均匀变形的试验研究

模拟井眼中的钻井实体膨胀管膨胀时的力学环境 ,选用 35CrMo钢管 ,对实体膨胀管在 5种不同膨胀幅度下的管子壁厚不均度及不圆度的变化规律进行了试验研究。发现膨胀管在膨胀后其壁厚不均度及不圆度会比原来的增大 ;膨胀使管子某些管段出现了开裂 ,但在纵向上的不同管段管子出现缺陷的情况不同 ,说明钻井膨胀管膨胀过程中存在着较严重的不均匀变形现象 ,这种不均匀变形是造成膨胀后管子抗挤强度降低的一个重要因素。为此建议 :(1)对膨胀管的初始不均度及不圆度作出比API标准更严格的要求 ,使其膨胀后即使壁厚不均度及不圆度比原来的增大 ,也不至于增加太大 ;(2 )在井眼中实施膨胀管作业时 ,必须从膨胀工艺上采取措施减轻管子横向和纵向上的不均匀变形。

Experimental study of uneven deformation of solid expansion tube

Uneven deformation of solid expansion tube is studiedbased on a simulated mechanical environment of the borehole.35CrMo steel tube is selected for the simulation test. Thevariation laws of the thickness irregularity andout-of-roundness of the tube while expanding are investigated.The results show that the thickness irregularity andout-of-roundness of the tube increase after it is expanded. Theultrasonic flaw detection proves the disfigurement is differentalong the axis of the tube, therefore there exists serious unevendeformation in the course of the expansion of the tube, whichis one of the important factors causing the reduction of thecollapsing strength of the tube after expansion.