Experimental investigation of fracture-based wellbore strengthening using a large-scale true triaxial cell.

Fracture-based wellbore strengthening is a widely used preventive technique for lost circulation control. However, there were limited experimental studies on wellbore strengthening with an anisotropic stress state. In this paper, we describe an experimental investigation of fracture-based wellbore strengthening on cubic Berea sandstone samples (size of 12 in 3) using a large-scale true triaxial cell. The true triaxial cell allows fracture containment to simulate wellbore strengthening, which was not available using a traditional small-scale traixial cell. We used drill cuttings and Chevron loss prevention material (LPM) as wellbore strengthening materials (WSM). Three independent stresses were applied on the rock samples and bi-wing fractures were generated. The final fracture reopening pressure (FROP) exceeded the formation breakdown pressure (FBP) after plugging the WSM. Further comparison between the experimental results and modeling results from a numerical model shows a good match for the injection pressure profile. • Experimental investigation of fracture-based wellbore strengthening was conducted on a large-scale true triaxial cell. • Fracture reopening pressures were higher than formation breakdown pressures. • Results of induced and plugged fractures were shown. • Stress redistribution was observed with plugging of wellbore strengthening materials. [ABSTRACT FROM AUTHOR]