Browsing by Author "Majorine, Namaganda"

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    Geochemical evaluation and correlation of source rocks, crude oils and oil seepage. A case: Albertine Graben, Uganda
    (The University of Dodoma, 2021) Majorine, Namaganda
    Geochemical evaluation and correlation of source rock samples, crude oils and oil seepage samples was carried out in the Albertine Graben, Uganda to establish the existence of a genetic relationship between the Graben’s source rocks and the crude and seepage oils. Evaluation of samples was carried out using data from pyrolysis analysis of samples, while the correlation of samples was based upon the recognition of unique patterns from biomarker analysis. The study involved one (1) seepage, two (2) source rock samples, and five (5) crude oils from Mputa, Kingfisher, Gunya, Ngiri, and Job-Rii wells. The TOC values of the source rock samples ranged from 1.25 to 7.2%, implying that the source rocks had a high potential to generate hydrocarbons. Furthermore, source rock samples with TOC ≥ 0.5% were also evaluated for petroleum potential using petroleum indices of Tmax, S1, S2 and HI. The source rock samples Tmax values ranged between 432 and 447°C, implying that the source rock maturities were within the oil window. The S1 and S2 parameters ranged from 0.02 to 1.78 mg/g rock and 0.87 to 37.71 mg/g rock, respectively, implying that the genetic potential of the source rock samples varied from poor to excellent. Additionally, the HI values ranged between 65 and 523 mgHC/gTOC, implying that the source rock samples were composed of kerogen types II, II/III, and III. Biomarker (terpanes (m/z 191) and steranes (m/z 217)) analysis, pristane/phytane ratios and n-alkane distribution were also performed on source rock samples, seepage, and crude oil samples. The results show that the source rock samples, seepage and crude oils were derived from mixed organic matter dominated by algal deposited in a sub-oxic depositional environment. Oil-oil and oil-source correlation using cross plots and ternary diagrams of steranes and terpanes, indicated that there was a correlation between the crude oils and the oil seepage based on sterane analysis. However, no correlation was observed between source rock samples, and crude oils and oil seepage. Based on terpanes analysis of the study samples, a correlation was exhibited between only one source rock sample (SRE 2) and the crude oils samples. However, there was no correlation shown by all the three study samples: source rock extracts, crude oil, and seepages. The findings of this study will aid in further research and development programs as well as guide the Uganda’s petroleum regulatory authorities and exploration companies on the hydrocarbon potential of the Albertine Graben.