Determination of the Effects of Incrustation on the Permeability of Reservoir Rocks Using Image Analysis Methods

BariumImage analysis methods sulphate scaling is a chronicle problem in the Campos Basin, where the most usual secondary recovery technic is water flooding (which corresponds to 85% of total oil volume produced). BaS O 4 $$BaSO_{4}$$ scale deposition occurs when the injected water, rich in sulphate ions, is mixed with the formation water, rich in barium ions, resulting in solid precipitate accumulation in the wellbore, well tubings and near wellbore formation. The problem is further aggravated by the hardness and low solubility of the salt, as well as the formation damage which occurs near the production well, where the mixing between the incompatible waters is more intense. Other sulphates, such as SrS O 4 $$SrSO_{4}$$ , also cause the same problem. In this wok, new models and algorithms to simulate sulphate scaling in reconstructed reservoir rocks are presented. Three dimensional reconstructed rocks are obtained from high resolution images of thin sections of rocks found in brazilian basins (contributed by CENPES). These reconstructed rocks are numerically scaled and permeability is then calculated by the serial connection graph, allowing the determination of the injectivity index impairment as a function of the total volume precipitated. The proposed models consider the influence of the geometric and topological organization of the porous media, as well as the morphology of the scaling phase itself. Three different scaling models were designed: pore-lining, pore-filling and dendritic. An analysis of the simulation results made it possible to assess effects over permeability reduction (formation damage). A free, open source educational software for image analysis is presented. The main advantage of the proposed approach is the possibility to use small rock samples, like drill cuttings and sidewall samples, which can be obtained by a small fraction of the of a full core. Another benefit is that destructive laboratorial experiments are replaced by fully reproducible computer simulations