Combining Saturation Height Functions and Resistivity Modelling in Complex Formations
Uncertainty in petrophysical interpretations is usually reduced by verifying results using multiple methods. For example, we commonly compute porosity using multiple logs and equations before comparing these porosity results with those measured on core samples.
When calculating fluid saturations, it is normal practice to compare log results with those from saturation height functions based on core sample measurements or other techniques. However, evaluations of complex formations are complicated by the effects of heterogeneity on both resistivity and capillary pressure measurements.
Resistivity, electrical properties, permeability, and saturation height functions all use measurements which vary, depending on the nature of the formation and the direction in which the measurements were taken.
This presentation will investigate some of the solutions available to aid the petrophysicist in understanding how formation complexities affect the measurements and how the solutions can be combined to verify the different techniques. The comparison of different model types can also be used to provide valuable information about the nature of the formation and its flow properties.
Illustrations will be used from previous studies where these solutions have proved successful.
Rick Aldred is a petrophysicist with 40 years of experience, including 15 years with operating oil companies, 10 years with logging companies providing petrophysical consulting services, 10 years in petrophysical software R&D, and 5 years as an independent consultant.
In 1980 Rick graduated from Keele University in England with a Joint (Hons) degree in Geology and Physical Geography. He has subsequently worked in Europe, North Africa, the Middle East, the Indian Subcontinent, East and Southeast Asia, and Australia.
He currently works as a consultant petrophysicist based in Brisbane, Australia. He specializes in building software solutions to solve complex petrophysical problems, training in advanced petrophysical applications, and performing general petrophysical interpretation work.