裸眼井中膨胀管外壁胶筒的井眼适应性分析

Wellbore Adaptability Analysis of Outer Rubber of Expansion Pipe in Open Hole

为了更加合理地对裸眼井膨胀管外壁定型胶筒井眼尺寸进行选择,建立了膨胀管、胶筒、井眼和膨胀锥三维有限元模型并对其膨胀过程进行非线性有限元分析。通过对直径为194 mm的膨胀管在不同井眼下的膨胀过程进行分析后发现:随着井眼直径的减小,胶筒的压缩率、接触压力以及所需膨胀力逐渐增大,井眼直径为218 mm时胶筒前端和末端橡胶体积变化显著,造成该处的密封性能下降。因此,采用的定型胶筒应避免在直径小于218 mm的井眼中使用。在胶筒稳定膨胀阶段,226 mm和230 mm的井眼胶筒所需膨胀力相差不大,波动幅值平稳。同一井眼中,最先膨胀的胶筒压缩率、接触压力及所需膨胀力都高于后膨胀的两个胶筒,但是随井眼直径的增大,三个胶筒的压缩率、接触压力以及所需膨胀力不再受膨胀的先后顺序影响。此外,随着井眼直径的增大,胀后胶筒处的膨胀管残余应力逐渐减小。同时膨胀管内外壁残余应力的波动逐渐减弱,大小趋于相等。可见研究结果为裸眼井中膨胀管外壁胶筒的选型以及膨胀管的井眼适应性提供了理论基础。

In order to more rationally select the size of the wellbore of the outer rubber of expansion pipe In open hole,the three-dimensional finite element models were established for the expansion pipe,the rubber tube,the wellbore and expansion cone respectively and the expansion process was analyzed with the nonlinear finite element method.After analyzing the 194 mm expansion pipe relationship between the contact pressure of outer rubber of expansion pipe the expansion force and the compression ratio of outer rubber of expansion pipe under under different wells diameter during expansion process.In conclusion,with the decrease of wellbore diameter,the compression ratio,contact pressure and expansion force of the rubber increase gradually.In the wellbore which diameter is218 mm,there were signnificantly changes about the volume of rubber At the front of it,also happened at the end of rubber.As a result,reduced stealing performance of the place.Therefore,the shaped rubbers which were use in the paper should be avoided in the wellbore with a diameter of 218 mm or less.During the rubbers were stable expansion,there was not much different about expansion force requied by rubber between the diameter of wellbore226 mm and 226 mm.In the same wellbore,the contact pressure of the first expansion rubber,expansion force and compression ratio both are higher than the other expansion rubbers.But as the diameter of the wellbore increases,there were no longer affected by the order of expansion about the contact pressure,expansion force requied and compression ratio of the three rubbers.In addition,with the increase of wellbore diameter,the residual stress which in rubber of expansion pipe decreased gradually.At the same time,the fluctuation of residual stress of the inside and outside in expansion pipe gradually weakened,and their size tended to be equal.It is concluded research about selection of the outer wall of the expansion pipe in the open hole and wellbore adaptability of expansion pipe provided a theoretical basis.