رسائل ماجيستير
English
2023
Integrated Reservoir Characterization Of The Valanginian Carbonates In Central Saudi Arabia
Ardiansyah Ibnu Koeshidayatullah, KhalidAl-Ramadan , شريف شعبان إبراهيم حسن عالم
كلية هندسة البترول وعلوم الأرض-جامعة الملك فهد للبترول والمعادن · السعودية
The lower Cretaceous (Valanginian) carbonates are proven to be prolific reservoirs globally and specifically across the Arabian Plate. Despite the economic importance of early Cretaceous carbonate reservoirs, there is little knowledge on how the interplay between depositional and diagenetic processes impacts the petrophysical properties in Saudi Arabia. Therefore, this study aims to fill the gap by investigating the excellent exposures of the Valanginian carbonates in central Saudi Arabia by integrating sedimentological and geochemical analysis, including stable isotopes. Based on field observation and petrographic thin sections, five microfacies were identified, representinga carbonate ramp depositional setting, from the inner ramp to outer ramp. The δ18O and δ13C isotopic compositions showed differences of 2.94 and 0.64‰, and mean values of -3.58‰ and 0.45‰ respectively. The comparison of the isotopic values of the studiedsamples to the isotopic values of early cretaceous rocks indicates that the δ18O studied samples shifted towards more negative values, which reflects early-stage burial diagenesis. The elemental analysis of trace elements shows low concentrations of iron and manganese, which indicates that the study area was not exposed to meteoric diagenesis. The petrophysical measurements reflect that the sandy peloidal grainstone facies has the highest reservoir quality properties with mean porosity and permeability values of 13.3% and 1.01 mD, respectively, and it is mainly affected by diagenetic processes such as micritization, cementation, and dissolution. The lowest reservoir quality facies is the calcareous mudstone, with mean porosity and permeability values of 2.2% and 0.11 mD, respectively, which is mainly controlled by the depositional settings.