可膨胀波纹管水力膨胀力学特性研究

Research on mechanical properties of expandable profile liners under hydraulic expansion

摘要:

可膨胀波纹管技术主要用于解决复杂深孔井下事故频发、套管层次受限等技术难题。管串水力膨胀是该技术应用的关键环节，为了研究可膨胀波纹管水力膨胀中的力学特性，提高井下事故处理的成功率，本文采用有限元数值模拟与室内试验相结合的方式共同研究波纹管的水力膨胀过程。通过多次波纹管水力膨胀室内试验，对比有限元理论分析结果，得出二者对于波纹管水力膨胀力学特性曲线基本一致。可膨胀波纹管的弹性形变压力为0～2.5 MPa，管串压力处于3～9 MPa时截面关键点位移速率较大，可膨胀波纹管的水力膨胀压力为14 MPa，膨胀后波纹管截面尺寸外径最大均值Xmax 为136.98 mm，外径最小均值Xmin为104.58 mm，达到了波纹管机械膨胀对截面尺寸的要求，为波纹管野外试验及产业化应用提供了重要的理论依据与技术支撑。

关键词:深孔钻探;复杂地层;可膨胀波纹管;水力膨胀;力学特性;有限元分析

Abstract:

Expandable profile liner （EPL）technology is mainly used to solve technical problems such as frequent accidents in complex deep boreholes and limitation of casing tiers. Hydraulic Expansion of EPL is a key link in the application. In order to study the mechanical properties of expandable profile liners under hydraulic expansion, and improve the treatment of downhole accidents, the finite element numerical simulation and indoor laboratory tests were combined to study the hydraulic expansion process of expandable profile liners (EPL). Through multiple laboratory tests on hydraulic expansion of EPL, and comparison of the results with those of the finite element theoretical analysis, it was found that both methods obtained basically consistent results. The elastic deformation pressure of EPL is 0 to 2.5 MPa, and the displacement rate of the key points on the cross-section is larger when the pressure of the liner string is 3 to 9 MPa; the hydraulic expansion pressure of EPL is 14 MPa; and the maximum and minimum diameter for the cross-section dimension of EPL after expansion Xmax are 136.98 mm and 104.58 mm; which meet the requirement of the cross-section size for mechanical expansion of EPL. It provides important theoretical basis and technical support for field experiment and industrial application of EPL.

Key words:deep-hole drilling; complex formations; expandable profile liner; hydraulic expansion; mechanical properties; finite element analysis