document: It is difficult in directly predicting permeability from porosity in tight sandstones due to the poor relationship between core derived porosity and permeability that caused by the extreme heterogeneity. The classical SDR (Schlumberger Doll Research) and Timur-Coates models are all unusable because not enough core samples were drilled for lab NMR experimental measurements to calibrate the involved model parameters. Based on the classification scale method (CSM), after the target tight sandstones are classified into two types, the relationship between core porosity and permeability is established for every type of formations, and the corresponding permeability estimation models are established. Field examples show that the classification scale method is effective in estimating tight sandstone permeability.
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