This study presents a numerical modeling of wellbore instability (shear failure) using fracture mechanics approach. A typical well bore consists of various layers of rock formations having inherent cracks and distinct mechanical properties. Using the concept of linear elastic fracture mechanics (LEFM), the wall of a distinct layer of the wellbore containing cracks of various sizes (ranging from 0.5” to 2.5”) inclined at a particular angle and subjected to a range of bottom hole pressure (3000 – 7000 psi) was numerically modeled using the ABAQUS software package. The insights from these models were used to guide the prediction of the onset of shear failure wellbore instability and consequently the determination of the lower bound mud weight window for safe drilling operations in conventional wells.
Originally Published by AUST Research.