Challenges of the Thermal Modelling in Solotvyno Depression (Transcarpathian) for the Tasks of Oil-and-Gas and Geothermal Studies

This study is dedicated to the potential of applying thermal modelling for the area of Solotvyno depression (Transcarpathian, Ukraine) based on the open-source and archival geological data. Thermal parameters, such as thermal conductivity and diffusivity, heat flow, and formation temperature distribution are important for understanding the thermal history of the basin for various tasks of hydrocarbon and geothermal exploration.

The collected dataset includes past heat flow measurements, temperature point records, thermal logs and results of laboratory core studies. The provided analysis shows high uncertainty of thermal logging data and point temperatures because of the measurement conditions, causing average difference from the formation temperatures up to 10-20°C and making most of them an unreliable data for the model calibration. Such tendency repeats in most of the studied wells on different exploration areas within the Solotvyno depression.

Main lithotypes – sandstones, siltstones, shale and tuffs – have overlapping ranges of thermal parameters (thermal conductivity and diffusivity) which is caused by the prevailing mixed composition of these rocks. The most of core measurements were done for tight clastic and volcanic rocks. Some important lithotypes, like Mesozoic marls and carbonates, don’t have a representative sampling.

Provided research shows a high necessity of modern thermal studies of different scale, technical and methodological improvement for further drilling, logging operations and laboratory measurements.