A Numerical Study on the Application of Stress Cage Technology

Abstract

Lost circulation is considered a time-consuming, costly problem during the construction of oil and gas wells. There are several preventive techniques to mitigate this problem. Stress cage technology is a mechanical lost circulation method, in which the formation at the wellbore wall is strengthened to stop the creation of induced fractures as one of the main causes of lost circulation. In this research, a two-dimensional numerical model, considering the elastic, poro-elastic, and thermo-poro-elastic behavior of the rock, is built to investigate the effectiveness of the stress cage method. Results show that better performance of the technology is achieved if the fractures are bridged close to their apertures. Additionally, it was found that the difference between the elastic, poro-elastic, and thermo-poro-elastic models is slightly visible. The conclusion states that the application of the stress cage methods leads to an increase in hoop stress and subsequent formation fracture gradient.

Keywords

• lost circulation
• wellbore strengthening
• kirsch equation
• stresses around the borehole