Clay mineral signatures of fault-related fluid flows in a sandstone reservoir: A case study from the Teloua Formation, Tim Mersoї Basin, Niger

Elmola, Ahmed Abd; Asaad, Ali; Patrier, Patricia; Beaufort, Daniel; Ballini, Marine; Descostes, Michaël

doi:10.1016/j.jafrearsci.2020.103840

Cited by 8 publications

(4 citation statements)

References 75 publications

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“…This is confirmed by the XRD results, which point to very low quantities of mica and the absence of K-feldspars. The growth of illite in deeply buried sedimentary rocks is strongly controlled by the K + /H + activity ratio in the pore waters (Berger et al, 1997;Abd Elmola et al, 2020). Therefore, the presence of smectite and the absence of illite in the samples analysed was probably a consequence of the low K + /H + activity ratio of the hydrothermal fluids which circulated through the formations.…”

Section: Mineralogical and Chemical Variations Between The Bahloul And Fahdene Formationsmentioning

confidence: 96%

“…Clay minerals are an abundant component of sedimentary rocks and can be used to study the thermal evolution of sedimentary successions during lowgrade metamorphism (Velde et al, 1986;Velde and Vasseur, 1992;Hillier et al, 1995;Abd Elmola et al, 2017). For example, the transformation of smectite to illite is strongly dependent on temperature and is therefore in general depth-dependent (Hower et al, 1976).…”

Section: Introductionmentioning

confidence: 99%

“…For example, the transformation of smectite to illite is strongly dependent on temperature and is therefore in general depth-dependent (Hower et al, 1976). Moreover, the chemical composition and crystal structure of clay minerals are sensitive to fluid flows associated with burial diagenesis and hydrothermal activity (Lacroix et al, 2012;Abd Elmola et al, 2020). Therefore, a combination of clay mineral analyses and organic matter characterization studies may help to understand the burial and thermal history of a clay-rich source rock (Rahman et al, 2017;Ola et al, 2018;Deconinck et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Maturity of Potential Cretaceous Source Rocks at the Isis Field, Offshore Eastern Tunisia: Influence of Hydrothermal Fluids

Kort

Elmola

Ouazaa

et al. 2021

Journal of Petroleum Geology

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An increase in source rock thermal maturity is in general linked to burial‐related heating according to the regional geothermal gradient, but maturities may also locally be influenced by high‐temperature hydrothermal fluids or igneous intrusions. In the present study of the Isis field located in the Gulf of Gabes (offshore Tunisia), we combine an analysis of organic matter maturity indicators and clay mineral signatures to constrain possible fluid/rock interactions and to define controls on the maturity of potential source rocks. Cuttings samples were collected from source rock intervals in the Cretaceous Bahloul (Cenomanian – Turonian) and underlying Fahdene (Albian – Cenomanian) Formations at the PM borehole, and detailed organic geochemical and clay mineralogical analyses of source rock samples and extracts were carried out. Samples from the Bahloul Formation (2381 m to 2400 m) consist of black to dark grey claystones and globigerinid limestones. Those from the Fahdene Formation (2400 m to 2700 m) comprise alternating claystones and chalky limestones containing globigerinids including Ticinella primula. Both source rock intervals have similar mineralogical compositions consisting of calcite, quartz, albite, anorthite, minor anatase, pyroxene and pyrite. The clay mineralogy of the formations is composed of abundant smectite (two generations), subordinate kaolinite and minor illite and/or mica. The Fahdene source rock contains organic matter consisting of mixed kerogen Types II/III; Type II OM is present in the Bahloul Formation.At the borehole location, the source rock intervals in the Fahdene and Bahloul Formations have been affected by hydrothermal fluids which are derived from an unconformably overlying basalt succession which is >300 m thick. Based on bulk mineral assemblages, the Bahloul Formation has been modified by the hydrothermal fluids more significantly than the underlying Fahdene Formation. Analyses of the clay minerals compositions indicate that interactions between the hydrothermal fluids and the host rocks were very rapid and were localized within fractures and micropores. The Bahloul Formation source rocks have reached an advanced stage of thermal maturity (overmature or end‐ oil window) compared to the thermally immature source rocks in the Fahdene Formation.The results show that the main control on source rock maturation at the studied well was maximum palaeotemperature and this may locally have been influenced by short‐term hydrothermal and magmatic heating as well as by the regional geotherm. Clay minerals were less affected by hydrothermal heating compared to organic matter indices; this may be because mineral components are slower to react to short‐term higher temperature conditions than organic matter.Thus magmatic activity and hydrothermal fluids may locally accelerate the thermal maturation of source rocks even at shallow depths. The study also shows that a combination of clay mineral characterization and organic matter indicators can be useful for the assessment of thermal maturity in potential source rocks.

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Section: Mineralogical and Chemical Variations Between The Bahloul And Fahdene Formationsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Maturity of Potential Cretaceous Source Rocks at the Isis Field, Offshore Eastern Tunisia: Influence of Hydrothermal Fluids

Kort

Elmola

Ouazaa

et al. 2021

Journal of Petroleum Geology

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“…As a result, little is known about the groundwater system of the basin, and the impacts of the mining have been insufficiently studied and documented. Indeed, most of the studies that have been done in the area have focused mainly on mining geology, sedimentology, tectonics, and the determination of mineralization processes (Abd Elmola et al, 2020;Billon & Patrier, 2019;Bohari et al, 2018;Cavellec, 2006;Gerbeaud, 2006;Konaté et al, 2007;Mamane Mamadou et al, 2020Sani et al, 2021;Wagani et al, 2011). Regarding groundwater, whether for geochemical and/or hydrodynamic characterisation of aquifers, the studies have mainly focused on local scales of the mining areas (Anthony et al, 2019;Boko et al, 2017aBoko et al, , 2017bDodo & Zuppi, 1999;Illias et al, 2019Illias et al, , 2021.…”

Section: Introductionmentioning

confidence: 99%

Building a regional hydrogeological model in a data-scarce area and implications for local scale studies: Case of the Tim Mersoï Basin (Northwestern Niger)

Dobi,

Boubacar,

Kouakou

et al. 2023

Preprint

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This study investigates the feasibility of implementing a 3D hydrogeological model in a vast data-scarce area in northwestern Niger where groundwater resources are strongly impacted by climate changes and anthropogenic activities (uranium mining) in northwestern Niger, West Africa. A large scale fully integrated hydrological model was built and calibrated using HydroGeoSphere. The model conceptualization and parametrization were done using various sources of datasets. The model was calibrated using a stepwise approach by increasing the temporal resolution of the model inputs: steady state, dynamic equilibrium, and transient state. The calibration results showed that the model could reproduce the measured groundwater heads with a correlation coefficient of up to 0.79. The model was then validated by comparing total water storage computed from GRACE data over the TMB and the outputs of the model. The results showed the model reproduced quite well the amplitudes and direction of the variations measured by GRACE. Therefore, GRACE data were useful in the qualitative validation of the model. The outputs of the model allowed a quantitative analysis of the groundwater resources of the Tim Mersoï Basin (TMB). The global recharge was estimated at 15.74 mm/year, i.e., an interannual average of 13.58% of the rainfall. Most importantly, this model can be used in a hierarchical model set up to provide initial and boundary conditions for local scales (mining areas for example) studies.

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The Fourier transform infrared spectroscopy (FTIR) analysis for the clay mineralogy studies in a clastic reservoir

Jozanikohan

Abarghooei

2022

J Petrol Explor Prod Technol

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The complete characteristics knowledge of clay minerals is necessary in the evaluation studies of hydrocarbon reservoirs. Ten samples taken from two wells in a heterogeneous clastic gas reservoir formation in NE Iran were selected to conduct the transmission Fourier transform infrared spectroscopy (FTIR) tests for the clay mineralogy studies. The FTIR analysis showed that there were clear signs of clay minerals in all samples. The wavenumber region of the clay minerals in FTIR tests was detected to be 3621, 3432, 1034, and 515 cm−1 for illite, 3567, 3432, 1613, 1088, 990, 687, 651, and 515 cm−1 for magnesium-rich chlorite, 3700, 3621, 3432, 1034, 687, and 463 cm−1 for kaolinite, and 3567, 1088, 990, and 463 cm−1 for glauconite. After screening of samples by the FTIR method, the samples were then analyzed by powder X-ray diffraction (PXRD), wavelength dispersive X-ray fluorescence (WDXRF), and scanning electron microscopy (SEM). The PXRD and SEM result showed illite was by far the most common clay present. Kaolinite, magnesium-rich chlorite, and traces of smectite and the mixed-layer clays of both the illite–smectite and chlorite-smectite types were also recognized. The combination of PXRD and WDXRF results could quantify the clay abundances in the each well too. It was concluded that the FTIR analysis successfully could show the absorption bonds of all constituent clays. However, the infrared absorption spectra of mixed-layer clays overlapped those of the respective constituents of each mixed-layer minerals. This can be considered as the evidence of the usefulness of FTIR technique in the screening of the samples for the clay mineralogy studies.

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Clay mineral signatures of fault-related fluid flows in a sandstone reservoir: A case study from the Teloua Formation, Tim Mersoї Basin, Niger

Cited by 8 publications

References 75 publications

Maturity of Potential Cretaceous Source Rocks at the Isis Field, Offshore Eastern Tunisia: Influence of Hydrothermal Fluids

Maturity of Potential Cretaceous Source Rocks at the Isis Field, Offshore Eastern Tunisia: Influence of Hydrothermal Fluids

Building a regional hydrogeological model in a data-scarce area and implications for local scale studies: Case of the Tim Mersoï Basin (Northwestern Niger)

The Fourier transform infrared spectroscopy (FTIR) analysis for the clay mineralogy studies in a clastic reservoir

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