Investigation of fracture toughness of oil well cement sheath using HCCD test and NBD test

This work present Hollow center cracked disc (HCCD) test and Notched Brazilian Disc (NBD) test of oil well cement sheath using experimental test and Particle Flow Code in two-dimensions (PFC۲D) to determine mode I fracture toughness of cement sheath. Cement sheath model was calibrated by outputs of experimental test. Secondly, numerical HCCD model and NBD model with diameter of ۰.۱ mm were prepared. Notch lengths were ۲۰ mm, ۳۰ mm and ۴۰ mm. Tests were performed by loading rate of ۰.۰۱۸ mm/sec. The results show that by using FJ bond, it is possible to determine failure mechanism of cement slurry according to experimental one. Mode I fracture toughness was constant by increasing the notch length. Mode I fracture toughness and tensile strength of cement slurry can be related to each other by the equation, σt =۵.۸ KIC. HCCD test and NBD test yields the similar fracture toughness due to similar tensile stress distribution on failure surface.

کلیدواژه ها:

HCCD ، NBD ، Mode I fracture toughness ، cement slurry ، discrete element method