Investigation and Determination of the Appropriate Model for Relative Permeability in Iranian Carbonate Reservoirs

The determination of relative permeability model used in reservoir simulation software is the corner stone of reservoir studies. Nowadays, in order to estimate relative permeability, several models are presented, having their own features. Corey model is one of the most well-known models, because it has simple calculation. However, it behaves inappropriately in facing heterogenic carbonate rock. Also, insufficient studies on comparing different models on carbonate rock are undeniable. Therefore, the assessment of different models and determining the appropriate model to result in a better estimation in carbonate rock is the aim of this study. In this work, after conducting unsteady-state relative permeability experiment under reservoir conditions from three reservoirs, namely A, B, and C, the relative permeability was calculated by using JBN method. Then, all the models could be compared. According to the results, it can be concluded that the LET model in heterogenic carbonate rock (various rock type) leads to a better result compared with the other models and it causes a significant decrease in standard error value for the relative permeability of oil and water to 0.00488 and 0.00119. Furthermore, it is found that this model can predict the S-shape behavior of relative permeability, seeing in Iranian carbonate reservoirs, perfectly.