Simulating porosity and permeability of NMR log in carbonate reservoirs of Campos Basin - Southeast Brazil - using conventional logs and artificial intelligence techniques

摘要

In this study, we examined the ability of Artificial Intelligence (AI) techniques in deriving parameters of NMR log starting from conventional logs. To perform this, it was applied Fuzzy Logic (FL) and Artificial Neural Networks (ANN) techniques separately, forming independent schemes. On the other hand, Genetic Algorithms (GA) and Simple Mean (SM) approaches were used to assign weighting factors to FL and ANN estimates, with the objective to optimize the individual contributions of each one. This methodology made use of, as input data, gamma rays (GR), resistivity laterolog (RLA1), density (RHOB), neutron (NPOR) and sonic (DTCO) logs from two wells drilled through a carbonate reservoirs in Campos Basin - Brazil. The output responses were compared with free fluid porosity (CMFF) and SDR lateral permeability (KSDR - Schlum-berger Doll Research), both derived from NMR log of the same wells. The results indicate that ANN performed better when compared with FL, but this last was essential in the success of SM and GA estimates. However, each approach showed a good fit with the parameter curves of NMR log, confirming the utility of the present methodology in the case when there are only conventional logs in the studied well.