On the performance analysis of AHSS with an application to SET technology - FEM simulations and experimental measurements

Solid expandable tubular (SET) is an innovative breakthrough in the petroleum industry that aims to resolve issues associated with deep wells. It consists of in-place plastic deformation of tubular diameter resulting in larger conduit size that allows drilling deeper. However, due to volume constancy, increasing the tubular diameter results in a decrease in its wall-thickness, and hence even an initially thick-walled tubular may convert into thin-walled; especially at high expansion ratios. Extending the frontier of expandable applications require larger expansion percentage and enhanced tubular integrity after expansion, which exceed the capability of current tubular material. Therefore, the current study aims to investigate new alternative materials to be used as tubular for SET technology. Selected AHSS grades including TRIP, TWIP, and DP steels are analyzed numerically using FEM. Experimental validation of the FEM model was carried out using full-scale expandable tubular testing facility available at Sultan Qaboos University (Muscat, Oman). Interesting results in terms of stress, strain, expansion force, burst and collapse pressures, length shortening and wall-thickness reduction were obtained. Bauschinger effect arises at the collapse pressure rating has been considered in the study. It was found that materials with high true uniform elongation (and therefore with large strain hardening capability) are more capable of counteracting strain intensifications caused by plastic deformation, allowing either larger expansion ratio or larger safety margin for the deformation capability of the material at a given expansion ratio.