Investigation of The Effect of Depth and Elasticity Modulus Difference between Reservoir Rock and the Surrounding Rock on Stress Arching

In this paper, the compression drive mechanism, which can be considered as the most related oil drive mechanism with the geomechanical properties of the reservoir, has been investigated. The constant total vertical stress on the reservoir and uniaxial reservoir compaction with zero lateral strain are two main assumptions in the conventional reservoir compaction modeling. These assumptions are not considering the stress arching which leads to a reduction in the total vertical stress. In this paper, due to the high capability of Abaqus software in numerical modeling of porous media, this software has been used to model the compaction of oil reservoirs with different elastic properties and located at different depths. Based on the obtained results, the difference in the elastic modulus of the reservoir with the surrounding rock and the ratio of depth to the dimensions of the reservoir are the most important parameters controlling the stress arching. Also, the study of the effect of stress arching on the compaction drive mechanism showed that the stress arching can reduce the compaction of reservoir pores by up to 50% and halve the oil production compared to its initial estimate by the compaction drive mechanism without considering the stress arching. Therefore, it is necessary to consider the effect of stress arching in estimating oil recovery due to compaction drive mechanism, especially in fields with a high depth to lateral expansion ratio and reservoir rocks with a lower modulus of elasticity than the surrounding rocks.