A 3D model of the thermal field within the Polish Carpathians and the Carpathian Foredeep (S Poland)

Abstract

Numerical 3D parametric models of temperature and thermal gradient distribution within the Polish Carpathians and the Carpathian Foredeep are constructed for the interval between ground level and the 160°C isotherm. The model construction was preceded by detailed analysis of over 500 thermal logs from the area investigated and its closest vicinity. This analysis showed that the vertical changes in temperature and thermal gradient have a non-linear character with no regular pattern in the distribution of the parameters modelled, so a 3D modeling approach was chosen as the most appropriate method for their quantitative description. Furthermore, standardization of the thermal logs was recognized as mandatory so the influence of drilling process would be eliminated. Among a broad array of methods and their preconditions discussed, the Kukkonen-Szewczyk method was selected for the data collected in the study area. Modeling results show a close relationship between thermal gradient, lithology and petrophysical rock properties as well as a correlation between the distribution of positive thermal anomalies and yield of hydrocarbon accumulations within the Carpathian Foredeep. The accuracy of the model has been assessed as ~10%. The model was then used for discussion of hydrocarbon generation and prediction of formation temperature.