Permeability Evaluation in Low Permeability Reservoirs Based on Multifractal Characteristics of NMR Logs

Summary Permeability is an important parameter to evaluate the reservoir quality and estimate the resource potential. Especially in low permeability formation, there is strong heterogeneity of formation. It is particularly critical to accurately evaluate permeability for reservoir development and exploration of remaining oil. Multifractal method is a popular method to describe the self-similar characteristics of irregular geometric figures. In this paper, the multifractal analysis based on the NMR logs was applied to evaluate permeability of low permeability water layers. Firstly, a multifractal method for Nuclear magnetic resonance (NMR) T2 spectrum logging data is established. Then, after multifractal processing and analysis, fmin and Dmax have been proved to be effective multifractal parameters for evaluating permeability of water layers. Last, a method for evaluating permeability using multifractal parameters is established. In addition, the application and prospect of this method are analyzed.