New Analytical Approach for Reservoir Stress Approximation Based on Acid Fracturing Data

In this research attempts were made to estimate the in-situ stresses acting on a hydrocarbon reservoir based on routine activities of acid injection in oil reservoir. it was found that the relation between the re-opening pressure of fracture and principal in-situ stresses can be estimated using rock mechanics equations for the circular underground cavities. an appropriate relation between the maximum and minimum horizontal principal in-situ stresses and reservoir parameters such as permeability, reservoir pressure, young’s modulus, acid viscosity, injection flow rate and etc., was developed by using the well-known darcy equations for fluid flow in porous media. accordingly, knowing the flow rate of acid injection during well operations and some other reservoir parameters, in-situ stresses may be estimated. the method was then successfully applied to a large carbonate reservoir as a case study in south-west of iran. maximum and minimum effective horizontal stresses were calculated by employing the presented method.