等井径膨胀套管螺纹接头的应力分析

The Stress of the Thread Connection of Mono-diameter Expandable Tubular

等井径膨胀套管技术可实现无内径损失钻井,是钻井完井领域的革命性技术。作为其核心技术之一的膨胀套管螺纹接头在膨胀成形时易发生断裂或漏失,这是制约该技术发展的主要难点。鉴于此,根据塑性变形的基本理论,选取新型孪生诱发塑性钢TWIP作为螺纹接头材料,采用ABAQUS有限元分析软件建立模型,模拟膨胀套管螺纹接头的成形过程,并分析螺纹接头成形过程中应力-应变的变化规律以及膨胀后螺纹接头的残余应力分布情况。分析结果表明,螺纹接头成形过程中根部和螺纹顶部为薄弱环节,成形后轴向及周向存在较大残余应力。研究结果可为等井径膨胀套管螺纹接头承载性能的后续研究提供参考。

The mono-diameter expandable tubular is a revolutionary technology in the field of drilling and completion which allows for drilling without compromising hole diameter. The expandable tubular thread connection, one of the core technologies, is prone to breakage or leakage during expanding, and is the main challenge restric- ting the development of the technology. To address the issue, based on the basic theory of plastic deformation, the new twinning induced plasticity TWIP steel as the thread connection material, using ABAQUS finite element analy- sis software to establish model, the forming process of the expandable tubular thread connection is simulated. Then, the stress-strain variation law during expanding and the distribution of residual stress of the thread connection after the expansion are analyzed. The results show that the top and root of the thread are the weak point during expan- ding. Great residual stress in axial and circumferential direction will be formed after expanding. Study results could provide references for follow-up studies on bearing capacity of mono-diameter expandable tubular thread connection.