An Analytical Poroelastic Model to Study the LCM Performance during the Wellbore Strengthening

One of the most challenging problems during drilling operations is loss circulation, which can result in wasting productive time and operation costs. Different studies and field experiences indicate that wellbore strengthening (WBS) is a practical approach to prevent or treat this problem. Plugging the wellbore fractures with lost circulation materials (LCMs) changes the stress distribution on the wellbore wall and fracture tip, leading to decrease the fluid loss possibility. In this paper, it has been attempted to introduce a poroelastic analytical model to investigate the effective factors on wellbore stresses based on fracture mechanics. The sensitivity analysis on different factors shows that geomechanical parameters (in-situ stress anisotropy), geometry parameters (LCM plug location, fracture length), and poroelastic properties (formation pore pressure and biot coefficient) have a significant effect on WBS. Based on the modeling results, the closer the LCM bridge location to the fracture mouth, the better strengthening can be achieved, and it can be more effective in the isotropic stress conditions, low-pressure formations and for a shorter fracture, due to less stress concentration on the fracture tip.