A semi-empirical relation between static and dynamic elastic modulus

Researchers have long investigated the difference between static and dynamic Young's modulus in terms of values and application. In field experiences, dynamic Young's modulus can often be calculated using logging data, while core data for static experiments in the lab are scarce. On the other hand, geomechanical analyses are traditionally based on static values. Therefore, it is essential to estimate static Young's modulus based on dynamic data for petroleum reservoir case studies. A number of empirical equations have been suggested to estimate static Young's modulus based on dynamic Young's modulus. However, the validity of these relations are limited and local. In this paper, 10 suggested relations were evaluated against an experimental dataset from different geographic locations. The validity of each relation was evaluated, and the results confirmed the dependency of these equations to the original datasets. Based on the concept of effective Young's modulus, we suggested a relationship to predict the value of static Young's modulus from dynamic Young's modulus and porosity data. The approach was performed for different rock types, and the predictions were found to be very accurate. This research explored different views on this aspect and facilitated better decision making to determine the static Young's modulus of rocks in the case where only dynamic data were available.