New insights on source rock maturation in the southern Gulf of Gabes (Tunisia) via 1-D modeling: effect of combined corrected borehole temperature and thermal conductivity on heat flow distribution

Effective quantitative modeling of petroleum generation processes requires a reasonable knowledge of various factors controlling the transformation of organic matter into oil or gas. Nevertheless, it is widely accepted that thermal conductivity and temperature have the dominant roles in controlling generation. In Tunisia, previous source rocks burial and maturity modeling were mostly carried out using corrected borehole temperature after applying formula which were set to fit domains other than Tunisian basins. The main purpose of this work is to propose a suitable method of temperature correction to fit the studied area but more importantly to emphasize the impact of thermal conductivity on heat flow distribution. For that, a total of 222 temperature values including 170 bottom hole temperatures (BHT) and 52 drill stem tests (DST) were collected from 30 onshore and offshore boreholes. The proposed equation generates corrected temperature close to true formation temperatures. As thermal conductivity depends on the relationships between a sedimentary interval component, two equations were used to determine the conductivity of each unit which are the harmonic and the geometric means. To assess the importance of applied corrections, three scenarios were tested for an Albian source rock using the 1-D Basin-Mod software. The combination of corrected BHTs and thermal conductivity provide higher source rock maturation than when uncorrected data are used. Amounts of generated hydrocarbons are estimated to become two times higher. This would guide for complementary reserves estimations to be applied in the region for better calculation accuracy. © 2021, Saudi Society for Geosciences.