REVIEW OF METHODS FOR QUICK ROCK’S THERMAL MATURITY CALCULATION – SYNTHESIS OF RESULTS GIVEN AT INOVA 2011, 2017 AND 2019

Thermal properties of rocks are valuable geological information and can include several variables. Thermal maturity is one of them and, until now, there are three innovations (refs. 1, 2, 3; Inova, 2019, 2017, 2011) where those problems are directly or indirectly solved. The maturity can be calculated relatively simply applying numerical indices corresponding to paleodepth and geological time spent at some depth. It is numerical problem, task 1. However precise calibration asks for knowing neutral layer temperature what needs to be measured (engineering problem, task 2). Maturity has been calculated in the southern Croatia (ref. 1; Inova 2019), using standard graphical, location depend, time-temperature diagram (task 1). However, here was solved the problem of precise “neutral layer” temperature measurement using Raspberry Pi upgraded device (task 2). Similar maturity model has been constructed in the northern Croatia (ref. 2; Inova 2017), where neutral layer has not been measured (but assumed), but time-temperature diagram was calculated with own programmed software (task 1). As time-temperature indices as spatial point depending function, the Universal Kriging is proposed as the most appropriate mapping method, where applicable (ref. 2; Inova 2017). Eventually, favourable rocks for thermal maturity calculation can be regionally outlined using hybrid indicator mapping, based on the Ordinary Kriging applied on indicator values (ref. 3; Inova, 2011). Looking together, those three innovations offered complete algorithm for rock thermal maturity calculation, using own programs for both task 1 and 2 as well as adapted RasPi device for task 2.