支撑式跨隔测试管柱力学分析及其应用

与传统的单封隔器管柱相比,支撑式跨隔测试管柱受力状况更加复杂,测试风险加大,常常失利。为了解支撑式跨隔测试失败的原因,为管柱组合及施工参数选择提供依据,根据支撑式跨隔测试的特点和传统管柱力学研究的不足,用微元体分析法和能量法对有限长跨隔段、支撑段管柱的屈曲行为重新进行分析,求得了有限长管柱的屈曲临界载荷和屈曲构型。分析表明,有限长管柱有3种屈曲构型:1个半波弯曲、2个半波弯曲和螺旋弯曲。据此,可以计算有限长管柱的附加弯矩及附加弯曲应力,校核其强度安全性;可以合理组合管柱、合理确定测试压差。当井径一定时,可以作出跨距-测试压差安全施工界限图。该研究指导了塔中和轮南地区若干口井的跨隔测试,测试成功且没有发生管柱、工具损坏事故。

Mechanical analysis of support anchor straddle packer test tubular string and its application

Compared with single parker test,support anchor straddle packer test tubular string is more complicated.And,the test tubular string works under more serious conditions and loads.So,support anchor straddle packer test tubular string and down hole tools were often damaged,resulting unsuccessful testing,even disasters.To solve the problem mentioned above and develop regulations to direct support anchor straddle packer testing,considering the disadvantages of present achievements of tubular string mechanics which could only calculate unrestrained tubular strings,separated mini-element analysis method and energy method are used to analyze the buckling behavior of the tubular strings between two parkers and supporting tubing.It is found that the tubular strings with limitable length and restrained by parkers and borehole may buckle into one semi-sinusoidal curve,two semi-sinusoidal curve and helix.Also deduced are the three criterion buckling loads.From buckling analyses of this paper,loads,stresses,strength safety of support anchor straddle packer test tubular string could be analyzed.If the combination of tubular strings is designed,the permissible testing pressure differential could also be calculated.Based on regulations and calculations resulted from this paper,several wells were successfully tested with support anchor straddle packer.