An integrated approach of reservoir characterization of Y gas field in Central Bredasdorp Basin, South Africa

Masindi, Rotondwa; (1), None Trivedi, K. B.1, A. K. Biswas1; Opuwari, Mimonitu

doi:10.1007/s13202-022-01470-9

Cited by 5 publications

(2 citation statements)

References 40 publications

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“…Several authors have reported that the Bredasdorp Basin was formed in the Gondwana due to the movement of the South Atlantic along the Agulhas-Falkland Fracture Zone [20,26,29]. In addition, several authors have made significant contributions [25,27,[30][31][32][33][34] to study sedimentology, sequence stratigraphy, petroleum systems, and the regional tectonic settings of the Bredasdorp Basin. However, to date, few published works have been published on the impacts of mineral composition on the variations of flow zonation in the Bredasdorp Basin, offshore of South Africa.…”

Section: Overview Of Geological Settingmentioning

confidence: 99%

The Impact of Detrital Minerals on Reservoir Flow Zones in the Northeastern Bredasdorp Basin, South Africa, Using Core Data

et al. 2022

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The present study uses core data to group reservoirs of a gas field in the Bredasdorp Basin offshore South Africa into flow zones. One hundred and sixty-eight core porosity and permeability data were used to establish reservoir zones from the flow zone indicator (FZI) and Winland’s methods. Storage and flow capacities were determined from the stratigraphy-modified Lorenz plot (SMLP) method. The effects of the mineralogy on the flow zones were established from mineralogy composition analyses using quantitative X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results reveal five flow zones grouped as high, moderate, low, very low, and tight reservoir rocks. The high flow zone is the best reservoir quality rock and has porosity and permeability values ranging from 12 to 20% and 100 to 1000 mD. The high and moderate zones contribute more than 60% of each well’s flow capacities. The moderate and low flow zone extends laterally to all the wells. The tight flow zone is an impervious rock and has the lowest rock quality with porosity and permeability values less than 8% and 1 mD, respectively. This zone contributes less than 1% to flow capacity. The impact of minerals on flow zones is evident in plagioclase and muscovite content increases. An accompanied decrease in quartz content is observed, which implies that low plagioclase content ≤4% and muscovite content of ≤1% corresponds to the low, moderate, and high flow zones, while plagioclase content of ≥4% and muscovite content of ≥1% belong to the tight flow zone. Consequently, the quantity of plagioclase and muscovite can be used as a proxy to identify better quality reservoir rocks. The diagenetic process that reduces the rock quality can be attributed to quartz overgrowth and the accumulation of mica flakes in the pore spaces. In contrast, the fracture in the high flow zone is the reservoir quality enhancing process. The flow zones are generally controlled by a combination of facies and diagenetic factors.

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Section: Overview Of Geological Settingmentioning

confidence: 99%

The Impact of Detrital Minerals on Reservoir Flow Zones in the Northeastern Bredasdorp Basin, South Africa, Using Core Data

et al. 2022

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“…The published work in the Bredasdorp Basin dealing with the classification and impact of diagenesis on the reservoir properties focused on the basin's southern part [8,20]. The characterization of the younger reservoirs in the Cretaceous age, ranging from the Valangianian to Albian age in the Bredasdorp Basin, was conducted by the authors of [21].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Diagenetic Minerals on the Petrophysical Properties of Sandstone Reservoir: A Case Study of the Upper Shallow Marine Sandstones in the Central Bredasdorp Basin, Offshore South Africa

Magoba,

Opuwari,

Liu

2024

Minerals

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The upper shallow marine sandstone reservoirs of the Barremian-to-Valanginian formation are the most porous and permeable sandstone reservoirs in the Bredasdorp Basin and an important target for oil and gas exploration. There is a paucity of information on the reservoir characterization and effect of diagenetic mineral studies focusing on the upper shallow marine sandstone reservoirs in the central Bredasdorp Basin; thus, there is a need to investigate the effect of diagenetic minerals and to characterize these reservoirs due to their high porosity and permeability. Datasets, including a suite of geophysical wireline logs, routine core analysis, geological well completion reports, description reports, and core samples, were utilized. A total of 642 core porosity measures, core water saturation, and core permeability data were used for calibration with the log-derived parameters, ranging in depth from 3615 m to 4259 m. Rock samples were prepared for diagenetic mineral analyses, such as thin sections and Scanning electron microscopy, for each well to investigate the presence of diagenetic minerals in the selected reservoir units. The petrophysical analyses showed the results of porosity, volume of clay, water saturation, and permeability, ranging from 9% to 27%, 8.6% to 19.8%, 18.9% to 30.4%, and 0.096 mD to 151.8 mD, respectively, indicating a poor-to-good reservoir quality. Mineralogical analyses revealed that micrite calcite, quartz cement, quartz overgrowth, and authigenic pore-filling and grain-coating clay minerals (illite–smectite and illite) negatively affected intergranular porosity. Porosity-versus-permeability cross plot showed good correlation of 0.86 for ZN1 and 0.83 for ZN3 reservoirs, suggesting that although porosity is the main drive of permeability, there were other geological factors at play, such as diagenetic minerals and compaction.

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3D structural and petrophysical modeling of Qishn sandstone reservoir in Sharyoof field, Say'un-Masilah basin, Yemen

Saied

Alsrory²,

Fadili³

et al. 2023

Journal of Applied Geophysics

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An integrated approach of reservoir characterization of Y gas field in Central Bredasdorp Basin, South Africa

Cited by 5 publications

References 40 publications

The Impact of Detrital Minerals on Reservoir Flow Zones in the Northeastern Bredasdorp Basin, South Africa, Using Core Data

The Impact of Detrital Minerals on Reservoir Flow Zones in the Northeastern Bredasdorp Basin, South Africa, Using Core Data

The Effect of Diagenetic Minerals on the Petrophysical Properties of Sandstone Reservoir: A Case Study of the Upper Shallow Marine Sandstones in the Central Bredasdorp Basin, Offshore South Africa

3D structural and petrophysical modeling of Qishn sandstone reservoir in Sharyoof field, Say'un-Masilah basin, Yemen

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