Technical Session - 2

Title:            Development of the stress model around boreholes
Authors:       Do Quang Khanh, Le Nguyen Hai Nam, Nguyen Xuan Huy, Hoang Trong Quang, Tran Nguyen Thien Tam, Bui Tu An
Abstract:     Knowledge of the stresses around boreholes is essential for wellbore problems. The stress model around boreholes, which is associated with the in-situ stresses, rock properties as well as the wellbore pressure and configuration, is developed. The new approach uses transformation formula of a full stress tensor including its orientations and magnitudes. The general solution for three-dimensional (3D) space is derived to the arbitrarily inclined wells. A calculating program for the stress analysis of wellbores (SAoWB), which is written in Matlab language, has described and calculated all components of the stress tensor at the wellbore wall as well as around boreholes. In this paper, case studies are presented using the program SAoWB based on the new approach. The first one is to cross-check Barton’s study on the compressive failure and breakout width analysis in KTB wellbore, Germany. The field case studies are applied for boreholes at different interest depths of the studied wellbore at Cuu Long basin, offshore Vietnam. The obtaining results from our program SAoWB are in good agreement with the failure observations from high solution image logs of the studied wellbore. The developed stress model around boreholes has presented fully, quickly and precisely all components of the stress tensor around boreholes. It helps to understand better the stress state around boreholes as well as to solve wellbore problems such as wellbore stability analysis, optimization of well trajectory or drilling mud.

Keywords:  Stress Model, Boreholes, Failure Observations, Wellbore Problems, Stability Analysis.
Pages:        115-122

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