Evaluating the potential of carbonate sub-facies classification using NMR longitudinal over transverse relaxation time ratio

While the well log-based lithology classi?cation has been extensively utilized in reservoir characterization, of carbonate sub-facies remains challenging due to subtle nuances conventional well-logs. The nuclear magnetic resonance (NMR) log provides extra information pore size and geometry features, improving differentiating sub-facies. Here we explore feasibility using ratio between NMR longitudinal relaxation time transverse as a potential indicator determine We analyzed series logging data corresponding core samples Arbuckle Group containing mudstone, packstone, grainstone, incipient breccia, breccia northern Kansas for characteristics times, over ratios. results show that grainstone exhibit high, intermediate, low ratios, respectively, while have wide range Furthermore, evaluated ratios classify multivariate analysis. By adding neutron porosity, total gamma-ray, conductivity logs inputs automated facies classi?cation, prediction error decreased, especially breccia. On contrary, when photoelectric computed gamma-ray are also available, does not improve accuracy classi?cation. Our suggest is an independent indicator. However, it cannot replace other like classifying study provided valuable evidence credible elucidation importance physicochemical mechanism which essential deciphering reservoirs. Cited : Zhang, F., C. Evaluating classification ratio. Advances Geo-Energy Research, 2021, 5(1): 87-103, doi: 10.46690/ager.2021.01.09