**Abstract**

In the exploitation of oil and gas reservoirs, thermal conductivity is the property of greatest importance in the application of secondary and tertiary oil fluid recovery techniques. This is why this property has been analyzed by estimating its value using several calculation models. But each model for calculating the value of this property is burdened by the fact that in the reservoir, the rocks are not like the chosen models (being made up of geological conglomerates with various inclusions). This paper presents a technique for estimating thermal conductivity (by energy transfer between overlying strata) and determining its value by a new calculation model. The paper also determined the thermal conductivity values for several rocks constituting some Romanian reservoirs, the aim of this material being to analyze the thermal behavior of rocks in condensed gas-rich areas.

**Keywords:** thermal conductivity, numerical modeling, heat transfer, collector rocks, oil, gas, condensate
