Calibration of petrophysical evaluation results of clastic reservoirs using core data, in the offshore depobelt, Niger Delta, Nigeria

Oil and gas exploration relies heavily on turning drill logs into precise and accurate porosity, lithology, and permeability, as well as fluid saturation information. For example, how to minimize systematic and random mistakes associated with data collecting from multiple logging equipment or varying drilling conditions or reservoir attributes. Errors can reduce the number of logs and/or calibrate the findings to core data. If the results of a log analysis match those of core analyses, then the log analysis is valid. This paper discussed the integration of core and log data for the validation of petrophysical evaluation results and reliable facies prediction. Calibration of log-derived properties with core-derived properties showed good correlation. The intervals of observed poor matches between log and core permeability were attributed to a very thinly laminated porosity-permeability environment as the logs average a 3-foot interval and the core data is measured at a much finer increment, making a perfect match impossible. The results of permeability prediction using the empirical correlation of core permeability with the interpreted log V-cl gave a better match with the core compared with other models. After many cutoff sensitivities, the cutoff of V-cl 5% and phi 11% were observed to be the best for the evaluation of almost the entire hydrocarbon column. Four facies were recognized using the NTG_Stieber method. The results show that the facies respect the reservoir properties.