Geological Characterization of the Miocene–Pliocene Succession in the Semliki Basin, Uganda: Implications for Hydrocarbon Exploration and Drilling in the East African Rift System

Mutebi, Stephen; Sen, Souvik; Sserubiri, Tonny; Rudra, Arka; Ganguli, Shib Sankar; Radwan, Ahmed E.

doi:10.1007/s11053-021-09951-0

Cited by 15 publications

(3 citation statements)

References 54 publications

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“…From facies interpretation, it was realized that sediment deposition in Kaiso Tonya area was highly intercalated (interbeds of different lithofacies i.e., there were thin lithofacies with different interbedded lithologies (clay, silt, fine and coarse sands) or in some cases stacked i.e., deposited at shorter intervals. This attribute influences the reservoir characteristics [22,23]. Hence, stratigraphically, the study area had different lithologies that were deposited at very short intervals or stacked deposits, and was interpreted to have been caused by the short changes in climatic conditions (wet and dry) that happened over time during sedimentation processes.…”

Section: Discussionmentioning

confidence: 99%

Depositional Structures, Tectonic and Stratigraphic Units and Their Effect on The Reservoir Rock Units of South Lake Albert Basin, Albertine Rift, Uganda.

2024

J Res Edu

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The study focused on interpretation of three-dimension (3D) seismic and suites of wireline log datasets, to construct and interpret models and facies analysis to assess the depositional structures, tectonic and stratigraphic unit’ settings. Challenges and uncertainties of low to moderate reservoir quality parameters attributed to limited understanding of depositional structures, tectonic and stratigraphic units had been identified in previous studies within the study area. From the study undertaken, the study area is structurally complex with compartments and flower structures. The stratigraphic interpretation, realized that sediments were highly intercalated (clay, silt, fine and coarse sands) majorly attributed to the short changes in climatic (wet and dry) conditions. It was further deduced that compartmentalization and intercalations of sediments had a very high effect on the reservoir rock properties which might affect the recovery of the available fluids.

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Section: Discussionmentioning

confidence: 99%

Depositional Structures, Tectonic and Stratigraphic Units and Their Effect on The Reservoir Rock Units of South Lake Albert Basin, Albertine Rift, Uganda.

2024

J Res Edu

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“…Quartz cementation was observed in the studied samples, characterized by minor quartz overgrowths. Overgrowth generally occurs in deep burial diagenetic conditions and favoured by higher temperature (Lai et al 2017;Worden et al 2018;Mutebi et al 2021). Mechanical compaction was inferred based on the concavo-convex detrital grain contacts (Figs.…”

Section: Diagenetic Processes Affecting Rahmi Sandstonesmentioning

confidence: 99%

Reservoir characterization of the middle Miocene Kareem sandstones, Southern Gulf of Suez Basin, Egypt

Farouk

Sen²,

Pigott

et al. 2022

Geomech. Geophys. Geo-energ. Geo-resour.

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In this study, we have assessed the petrographical and petrophysical characteristics of the progradational, syn-rift Middle Miocene Rahmi sandstone gas reservoir (Lower Kareem Formation) from the East Matr and Amal hydrocarbon fields, southern Gulf of Suez by integrating sidewall cores and wireline logs. We interpreted a reservoir gas gradient of around 0.09 psi/ft from the downhole pressure measurements. Based on well log-based petrophysical analyses, we interpreted that the Rahmi reservoir in the East Matr field has a 0.10–0.18 v/v total porosity, 0.08–0.14 v/v effective porosity, 0.08–0.17 v/v shale volume along with water saturation ranging between 0.09 and 0.32 v/v. The correlated reservoir in the Amal field is observed to have higher porosities (0.17–0.22 v/v total porosity and 0.15–0.19 v/v effective porosity), although it exhibits higher water saturation (0.38–0.54 v/v). The reservoir consists of very fine to coarse grained, poorly to moderately sorted, subangular to subrounded, poorly cemented and moderately compacted sublithic, subarkosic and arkosic arenites with moderate to good intergranular porosity. Abundant lithic fragments and poor textural maturity of the Rahimi sandstones imply a high energy shoreface depositional environment in close proximity to the hinterland. Porosity reduction is attributed to dolomite cementation, kaolinite, formation of pseudomatrix by mechanical compaction of argillaceous lithics, and quartz overgrowth. Long and concavo-convex intergranular contacts indicate that silica needed for quartz cementation was derived by moderate degree of chemical compaction of the quartz grains. Partial to near-complete dissolution of the labile grains (feldspar and lithics) and dolomite attributed to the reservoir quality improvement. Scattered dolomite cements prevented more severe mechanical and chemical compaction.

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“…Estimation of total organic carbon (TOC) content is an important step in geo-chemical assessment and rock Evalpyrolysis to measure source rock potential [6]. Measuring the TOC content of rock samples directly is expensive and timeconsuming.…”

Section: Introductionmentioning

confidence: 99%

Estimating Total Organic Carbon (TOC) Content and Porosity of the Ranikot Formation in the Central Indus Basin, Pakistan, Using Seismic Inversion and Well Log Analysis

Ehsan,

Zaheer,

Abbasi

2024

Journal of GeoEnergy

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An approach is proposed to improve modeling for shale gas reservoirs, integrating key parameters such as total organic carbon (TOC) and porosity. Seismic inversion uses seismic reflection data and well-log information to improve geological and geophysical interpretation and estimate rock properties with high-resolution subsurface acoustic impedance, including low and high frequencies. The Ranikot Formation in the Central Indus Basin, Pakistan, is a Paleocene-age formation with the potential to act as reservoir, seal, and source rock. The porosity of the Lower Ranikot reservoir in the Mehar Block was calculated using seismic inversion analysis with the Mehar-02 well. The petrophysical analysis yielded an effective porosity of 5.8%. Similarly, when calculated using seismic inversion, the porosity fell within the 5.5%–6.0% range. Determining the TOC content is crucial in evaluating unconventional shale resources. Petrophysical approaches, such as the ΔlogR method, offer a fast, convenient, and cost-effective means of estimating TOC from well logs. This method is commonly used in conventional source rock evaluation and applied to unconventional resource play evaluation. On the other hand, seismic inversion techniques were used to conduct TOC analysis in the absence of core data in order to estimate the source potential of the Upper Ranikot Formation. To estimate the TOC log for the Upper Ranikot shales in the Mehar Block, the Passey equation was used on the well logs of the Mehar-02 well. The estimated TOC for the Upper Ranikot shales is around 2.0%, which falls within the fair TOC range.

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Geological Characterization of the Miocene–Pliocene Succession in the Semliki Basin, Uganda: Implications for Hydrocarbon Exploration and Drilling in the East African Rift System

Cited by 15 publications

References 54 publications

Depositional Structures, Tectonic and Stratigraphic Units and Their Effect on The Reservoir Rock Units of South Lake Albert Basin, Albertine Rift, Uganda.

Depositional Structures, Tectonic and Stratigraphic Units and Their Effect on The Reservoir Rock Units of South Lake Albert Basin, Albertine Rift, Uganda.

Reservoir characterization of the middle Miocene Kareem sandstones, Southern Gulf of Suez Basin, Egypt

Estimating Total Organic Carbon (TOC) Content and Porosity of the Ranikot Formation in the Central Indus Basin, Pakistan, Using Seismic Inversion and Well Log Analysis

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