Effect of non-Darcy flow on induced stresses around a wellbore in an anisotropic in-situ stress field

Abstract

After drilling a well, the stresses will be altered and the induced stresses present the new state of stress. These induced stresses result in geomechanical problems. Studies have indicated that the flow of hydrocarbon into the wellbore inuences the induced stresses. Darcy equation has been used in the past; however, the laminar flow assumption embedded in this equation cannot correctly model the flow of fluid when a non-Darcy flow dominates near a wellbore. Examples of such situations include the gas wells. In this study, analytical equations were developed based on Forchheimer flow equation to incorporate the effect of non-Darcy flow on the induced stresses around a wellbore. Then, the simplified solutions were presented by considering the second term of Forchheimer flow equation. It was found that the difference between the results of Darcy and non-Darcy flow models was proportional to the drawdown pressure. Further studies included numerical simulation of non-Darcy fluid flow in a typical reservoir. Comparison of the results with the analytical models indicated that the magnitude of stresses in non-Darcy flow was larger than that in Darcy flow. Finally, sensitivity of the reservoir properties to the induced stresses in the non-Darcy flow regime was investigated.