Integrated analysis of source rock evaluation and basin modelling in the Abu Gharadig Basin, Western Desert, Egypt: Insights from pyrolysis data, burial history, and trap characteristics

Abstract

Source rock evaluation and basin modelling play crucial roles in understanding hydrocarbon potential. In this study, pyrolysis data from 92 shale ditch samples were employed to assess the source rocks in the Abu Gharadig Basin (Western Desert, Egypt). The organic richness ranged from 0.53% to 4.1% by weight, indicating varying hydrocarbon‐generating capabilities. Specifically, kerogen types II and III exhibited the potential to generate hydrocarbons, ranging from fair to good oil sources. The burial history analysis provided insights into the sedimentation and subsidence rates during different geological periods. The Late Jurassic‐Early Cretaceous period witnessed modest rates of sedimentation and subsidence. In contrast, the Oligocene and Late Miocene periods experienced medium burial rates, while the Late Cretaceous‐Early Tertiary period exhibited high burial rates. Specific formations were examined in detail, with the Apollonia Formation standing out as a significant hydrocarbon reservoir. It entered the early oil window at approximately 17.87 Ma and the wet gas window at about 17.41 Ma in the ASSIL‐1X well. However, it didn't reach the GPAA‐4 well. The Abu Roash ‘D’ member also showed promise, entering the early oil window at 38.20 and 47.38 Ma, and the wet gas window at 37.40 and 43.64 Ma. Similarly, the Abu Roash ‘F’ member exhibited favourable hydrocarbon generation, entering the early oil window at 39.90 and 54.86 Ma, and the wet gas window at 39.70 and 51.62 Ma in both the ASSIL‐1X and GPAA‐4 wells. Based on the analysis, the Apollonia, Abu Roash ‘D’ and ‘F’ members were identified as source rocks, while the Kharita, ‘C’, ‘E’ and ‘G’ members were recognized as reservoir rocks. The Abu Roash Shale acted as an effective seal rock. The geological structure of the region revealed the presence of NW‐SE normal faults, forming a three‐way dip closure trap. This research substantially enhances our comprehension of the hydrocarbon system within this basin. It achieves this by thoroughly investigating source rock evaluation, basin modelling and delivering invaluable insights into the mechanisms that govern hydrocarbon generation, expulsion and trap age.