Slotted liner is a widely used sand control technology for completion of thermal wells. During installation, liners are subjected to tensile and compressive loads generated by string weight and wellbore drag and to bending when run through curved wellbores. Additionally, torque is often applied to "break" friction, reducing axial drag and extending reach. These conditions lead to combined loading of liners with simultaneous axial, bending, and torsional loads.
Combined loading that exceeds the elastic capacity of the liner during installation can alter the structural capacity of the liner and reduce its ability to withstand subsequent operational loads. In particular, permanent deformation of liner struts during installation can create weak zones that trigger localization of deformations and liner failure under thermal service loading conditions (i.e. constrained thermal expansion). Further, the presence of ‘residual’ torque from installation can trigger and exacerbate the tendency of the liner struts to buckle.
This paper describes an evaluation of the impact of installation loading on subsequent thermal service structural performance. Specifically, the relationships between both plastic twist and residual torque from installation loads and the critical strain capacity of the slotted liner under constrained thermal expansion are examined. Results demonstrate that a slotted liner can tolerate some plastic twist during installation without a significant impact on slot width or subsequent thermal service performance. However, large plastic twist or residual torque from installation can bias the liner to fail in torsional buckling during thermal service. The results further show that both the plastic twist applied during installation and the residual torque remaining after installation that can be tolerated varies between slotted liner configurations.
Prior published work considered slotted liner installation limits and thermal operating limits separately. This paper advances industry understanding of slotted liner by examining the impact of installation loads on subsequent thermal service performance. Further, the methods demonstrated in this paper can support installation procedures by providing a basis for determining the maximum torque that can be applied to liner.