This work is dedicated to studying the numerical description of oil & gas field mechanical behavior. The algorithm is proposed for the stress and strain tensor distribution computation within the assumption of infinitesimal elastic strains. The proposed algorithm is verified and demonstrated to be potentially more effective than the algorithms currently used in industry for the same problem solution. The proposed algorithm is based on finite volume method with two-grid solution scheme. After algorithm verification versus COMSOL software, it is applied to geomechanical model construction for a particular oilfield located in Russia. The model is successfully constructed and the model quality check is passed.