Evaluation of the Mechanical Behavior of Non-Consolidated Sands Under Different Stress Path

Thermal recovery processes are becoming more popular every day to extract the oil and the bitumen that are present in heavy oil reservoirs. While these techniques have had significant improvements in recent years, there is still an important gap understanding the geomechanical response of subsurface formations during these processes. Different experimental procedures are performed in order to characterize the reservoir formation and its surroundings. The results from the triaxial test are also used to find the constitutive behavior of the formations. Performing non-conventional triaxial test such as reverse triaxial compression test or undrained compression triaxial test might describe the actual behavior of the reservoir in a more accurate manner. In this work, drained triaxial compression and drained triaxial extension tests are performed using samples taken from an outcrop in Colombia to analyze the differences in the stress-strain, stress path, elastic parameter (Young and bulk modulus). The specimens show a crucial difference at the plastic region; while the compression test exhibits strain hardening, the specimens under extensional triaxial behaved perfectly plastic on extension tests leading to a simpler constitutive model.