Large deflection plastic studying on preforming of multilateral tool

Abstract

Non‐linear analyses of the preforming process of a multilateral junction assembly are reported in this paper and plasticity and geometric non‐linearity including large deformation have been accounted for. A circular arch with both longitudinal sections being built‐in and compressed laterally by a rigid elliptic hold‐down plate is studied first. A rigid–perfectly plastic model is adopted and a collapse mode is proposed. By analysing the relationships between loading and deformation under each collapse mode, the incipient collapse load and force–deflection curve for the circular arch are presented. The relation between compressing force and deformation during preforming process of multilateral junction assembly is then obtained by integrating along the multilateral leg longitudinally. The research will provide guidance for structural design of multilateral tools and for application of multilateral well technology.

Keywords:

• Multilateral junction assembly
• Built‐in circular arch
• Rigid elliptic hold‐down plate
• Large deformation
• Collapse mode
• Load–deflection curve

This work is supported by the Key Laboratory of Oil and Gas Equipment from Ministry of Education (no. 2006STS04) and Science Foundation of Southwest Petroleum University.