膨胀管技术中膨胀芯头锥角设计

膨胀套管技术是20世纪90年代才兴起的一门节约井眼直径的钻井技术,在我国还处于理论探索阶段。用ADINA软件中的弹塑性有限元接触问题建立了可膨胀管膨胀过程的力学模型,通过对膨胀芯头锥角α的不同取值,在相同工况下对N-80钢级材料的244.5 mm(95/8″)套管膨胀至298.4 mm(113/4″)的膨胀过程进行详细的计算机模拟分析,并且在定性和定量地比较套管膨胀后的等效应力、接触压力、残余应力、膨胀芯头所需的推动力以及套管轴向收缩量的基础上,得出了膨胀芯头的锥角α取值为12.3°时更有利于膨胀套管的膨胀,为膨胀芯头的结构设计提出了依据。

ANGLE DESIGN OF EXPANSION CONE IN EXPANDABLE CASING TECHNOLOGY

In 1990’s, The expandable casing technology was a new drilling technology to save the hole diameter, in the world, but it is now at the stage of theoretic research in our country. The mechanics model of the expand process of the expandable casing with the elastic-plastic finite-element contact question of the ADINA software was established. Through choosing different value of the angle of the expansion cone, the detailed computer simulation analysis of the expand process that expanded the diameter of the N-80 steel tubular from 244.5mm to 298.4mm was done under the same work condition, and under the foundation of qualitative and quantificational comparison of the equivalent stress, the contact pressure, the residual stress, the expansion cone and the axial shrinkage of the tubular, the optimal angle of the cone 12.30 degree was obtained. It provided the supports for the structural design of the expansion cone.