Tamunonengiyeofori Dagogo | University of Port Harcourt (original) (raw)
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Papers by Tamunonengiyeofori Dagogo
Imperial journal of interdisciplinary research, 2016
: The geotechnical properties of foundation soils in an area of the Niger Delta have been assesse... more : The geotechnical properties of foundation soils in an area of the Niger Delta have been assessed in this study. Motivated by the need to provide adequate information regarding the bearing competencies of the soils in the region, so as to inform and encourage adherence to appropriate building regulations and forestall the increasing incidence of building collapse and its attendant consequences. The average shear wave velocity of the first 30 m of the surface soil (V s30 ) parameter, which is a conventionally accepted soil bearing capacity index was estimated over the area spanning 25 km 2 . Shear wave velocities were estimated by analysing the dispersion properties of surface waves using the multichannel analysis of surface waves technique. The obtained values of shear velocities ranged from 263 – 465 m/s for varying thicknesses of layers at different depths. The 1 dimensional shear velocity profiles show the occurrence of velocity reversals at several of the 25 survey points. Using these shear velocity profiles for the first 30 m of the near surface soils, the V s30 parameters were computed. The obtained V s30 values ranged between 209 – 235 m/s. Based on these values the soils in the area were classified as class D soils according to the NEHRP code. Thus proper foundation reinforcement is recommended for structures to be sited in the area
Journal of Petroleum Exploration and Production Technology, 2021
Eocene Sokor-1 reservoir is intrinsically heterogeneous and characterized by low-contrast low-res... more Eocene Sokor-1 reservoir is intrinsically heterogeneous and characterized by low-contrast low-resistivity log responses in parts of the Termit subbasin. Discriminating lithology and fluid properties using petrophysics alone is complicated and undermines reservoir characterization. Petrophysics and rock physics were integrated through rock physics diagnostics (RPDs) modeling for detailed description of the reservoir microstructure and quality in the subbasin. Petrophysical evaluation shows that Sokor-1 sand_5 interval has good petrophysical properties across wells and prolific in hydrocarbons. RPD analysis revealed that this sand interval could be best described by the constant cement sand model in wells_2, _3, _5 and _9 and friable sand model in well_4. The matrix structure varied mostly from clean and well-sorted unconsolidated sands as well as consolidated and cemented sandstones to deteriorating and poorly sorted shaly sands and shales/mudstones. The rock physics template built b...
International Journal of Geosciences, 2021
The Eocene Sokor1 Formation is proven oil reservoir rocks in the Termit sub-basin. These sandston... more The Eocene Sokor1 Formation is proven oil reservoir rocks in the Termit sub-basin. These sandstone intervals are deeply buried, highly heterogeneous in character and characterized by Low Contrast Low Resistivity (LCLR) log responses. Petrophysical and quantitative well-based rock physics interpretations were integrated for property estimations, fluid and lithology typing in reservoir characterization. Six (6) reservoir sandstone intervals were identified, delineated and correlated across five (5) wells. The estimated petrophysical properties showed that the Eocene Sokor1 sandstones have averagely good reservoir properties with sand_5 interval exhibiting exceptional reservoir properties. V p /V s vs. AI and μρ vs. λρ elastic cross-plots color coded with reservoir properties (V sh and ϕ), show distinct and well separated data clusters signifying hydrocarbon bearing sandstones, brine sandstones and shales/mudstones in the 3D crossplot planes with varying seismic elastic property values in each well thereby, enhancing reservoir characterization and providing information's about the burial history, reservoir quality and property distribution in the sub-basin. The analysis suggests that, although the reservoir interval has averagely good petrophysical properties in all wells, the seismic elastic crossplots show that these properties are much better distributed in wells 2 and 3 than in wells 4, 5 and 9. Therefore, sand_5 reservoir interval in wells 2 and 3 is likely to be more hydrocarbon bearing and productive than wells 4, 5 and 9 in the sub-basin.
Journal of Petroleum Exploration and Production Technology, 2020
Reservoir characterization plays a significant role in the exploration, development, and producti... more Reservoir characterization plays a significant role in the exploration, development, and production of hydrocarbon reservoirs. The use of integrated approach in characterization improves on the accuracy, certainty, and robust interpretation of reflectivity data. The study aimed to integrate reflectivity and spectral attributes to adequately characterize hydrocarbon reservoirs in MUN onshore Niger delta field. Well log and rock physics analyses identified and delineated reservoirs, discriminated lithology, characterized fluid, and established relations between elastic and reservoir properties for field-wide interpretation of the reflectivity data. The wells were tied to the reflectivity data, and H4 seismic horizon was mapped. Subsequently, sweetness, reflectivity and spectral attributes were extracted along H4 horizon after inversion and spectral decomposition of the reflectivity data and independently interpreted. Channel-like structure with high-amplitudes, low-to-moderate acousti...
Journal of Petroleum Exploration and Production Technology, 2020
Integrating seismic amplitudes and spectral attribute analysis has successfully mapped, validated... more Integrating seismic amplitudes and spectral attribute analysis has successfully mapped, validated and characterised hydrocarbon-saturated channel sands by high-amplitude low-frequency anomaly. The aim of the study was targeted at using these novel geophysical tools to improve characterisation of tertiary clastic reservoir in the field. These attributes were extracted along H4 seismic horizon and analysed independently for structure, lithology and hydrocarbon saturation. The result of the analysis shows that both attributes complimented each other in mapping the hydrocarbon-saturated reservoir channel sands. However, the spectral attributes in combination with spectral-based Red, Blue and Green (RGB) colour blending attribute map reveal finer and subtle details of the channel structure and stratigraphy which hitherto were not apparent in the seismic amplitude maps. The channel sands trend NE–SW, broadening towards the southwest and bounded by major growth faults to the northeast and ...
International Journal of Geosciences, 2019
Rock Physics Modelling and Seismic Inversion were carried out in an Onshore Niger Delta Field for... more Rock Physics Modelling and Seismic Inversion were carried out in an Onshore Niger Delta Field for the purpose of characterizing a hydrocarbon reservoir. The aim of the study was to integrate rock physics models and seismic inversion to improve the characterization of a selected reservoir using well-log and 3D seismic data sets. Seven reservoir sands were delineated using suite of logs from three wells. In this study, the sand 4 reservoir was selected for analysis. The result of petrophysical evaluation shows that the sand 4 reservoir is relatively thick (62 ft) with low water saturation (0.33), shale volume (0.11) and high porosity (0.32). These results indicate reservoir of good quality and producibility. Cross-plot of property pairs (acoustic impedance (I p) vs. lambda-rho (λρ) and mu-rho (µρ) vs. lambda-rho (λρ) color-coded with reservoir properties reveals three distinct probable zones: hydrocarbon sand, brine sand and shale. Results show that low I p , λρ and µρ associated with hydrocarbon charged sands correspond to low S w and V sh and high ϕ. The integration of rock physics models and inverted rock attributes effectively delineated and improved understanding of already producing reservoirs, as well as other hydrocarbon charged sands of low S w , V sh , and high ϕ to the east of existing well locations, which indicate possible bypassed hydrocarbon pays. The results of this work can assist in forecasting hydrocarbon prospectivity and lessen chances of drilling dry holes in MUN onshore Niger delta field.
American Journal of Geoscience, 2016
Production-induced subsidence due to compressibility and fluid property changes in a Niger delta ... more Production-induced subsidence due to compressibility and fluid property changes in a Niger delta field has been investigated using well log and 4D seismic data sets. The objective of the study is to evaluate changes in time lapse seismic attributes due to hydrocarbon production and infer to probable ground subsidence. Petrophysical modeling and analysis of well data revealed that Density (ρ), Lambda rho (λρ) and Acoustic impedance (Ip) are highly responsive to changes in reservoir properties. These properties and water saturation attribute were subsequently, extracted from time-lapse seismic volumes in the immediate vicinity of well locations. Result show that monitor horizon slices exhibit appreciable increases in ρ, λρ, Ip and water saturation values compared to the base data, especially around the well locations. These increases in relative values of rock/attribute properties between the time-lapse surveys for a constant overburden stress are obvious indications of pore pressure and fluid depletion in the reservoir. Depletion in these properties increases the effective stress (pressure) and the grain-to-grain contact of the reservoir matrix, with a corresponding decrease in compressibility. Consequently, pore and matrix volume decreases, the reservoir compacts and the ground subsides. However, this is suspected to be small and at the reservoir scale due to low initial reservoir porosity and the relatively large lateral dimension compared to the thickness of the reservoir.
International Journal of Geosciences, 2016
We carried out time-lapse analysis in a producing Niger Delta X-field, by first investigating the... more We carried out time-lapse analysis in a producing Niger Delta X-field, by first investigating the response and sensitivity of rock properties/attributes to lithology and pore fill in 3-D cross plot domain and by Gassmann's fluid substitution modeling. Furthermore, 4-D seismic data were inverted into acoustic impedance volumes through model based inversion scheme. This served as input into a multi-attribute neural network algorithm for the extraction of rock attribute volumes based on the results of the petrophysical log analysis. Subsequently, horizon slices of rock properties/ attributes were extracted from the inverted seismic data and analyzed. In this way, we mapped hydrocarbon depleted wells in the field, and identified probable bypassed hydrocarbon zones. Thus, the integration of well and time lapse seismic (4-D) data in reservoir studies has remarkably improved information on the reservoir economic potential, and enhanced hydrocarbon recovery factor.
Archives of Applied Science Research, 2016
Seismic attenuation analysis is important for several reasons, including aiding seismic risk eval... more Seismic attenuation analysis is important for several reasons, including aiding seismic risk evaluation. Quality factors and attenuation coefficients have been estimated for an X-field in the Niger Delta, whose near surface sediments has remained largely uncharacterized. Using surface waves extracted from seismic data acquired by conventional reflection methodology and employing the quality factor versus offset (QVO) technique of attenuation analysis, reliable attenuation coefficient and quality factor distributions for the field covering about 25 km2 has been generated. The value of quality factors obtained indicate that the near surface sediments are low in attenuation to surface waves, being largely unconsolidated. The value of quality factors ranges from 20 to 80, corresponding to attenuation coefficients of between 0.0006 to 0.002 m-1. The estimated attenuation factors in this study tend to have some form of dependence on the thickness of unconsolidated sediments. In most parts...
Imperial journal of interdisciplinary research, 2016
: The geotechnical properties of foundation soils in an area of the Niger Delta have been assesse... more : The geotechnical properties of foundation soils in an area of the Niger Delta have been assessed in this study. Motivated by the need to provide adequate information regarding the bearing competencies of the soils in the region, so as to inform and encourage adherence to appropriate building regulations and forestall the increasing incidence of building collapse and its attendant consequences. The average shear wave velocity of the first 30 m of the surface soil (V s30 ) parameter, which is a conventionally accepted soil bearing capacity index was estimated over the area spanning 25 km 2 . Shear wave velocities were estimated by analysing the dispersion properties of surface waves using the multichannel analysis of surface waves technique. The obtained values of shear velocities ranged from 263 – 465 m/s for varying thicknesses of layers at different depths. The 1 dimensional shear velocity profiles show the occurrence of velocity reversals at several of the 25 survey points. Using these shear velocity profiles for the first 30 m of the near surface soils, the V s30 parameters were computed. The obtained V s30 values ranged between 209 – 235 m/s. Based on these values the soils in the area were classified as class D soils according to the NEHRP code. Thus proper foundation reinforcement is recommended for structures to be sited in the area
Journal of Petroleum Exploration and Production Technology, 2021
Eocene Sokor-1 reservoir is intrinsically heterogeneous and characterized by low-contrast low-res... more Eocene Sokor-1 reservoir is intrinsically heterogeneous and characterized by low-contrast low-resistivity log responses in parts of the Termit subbasin. Discriminating lithology and fluid properties using petrophysics alone is complicated and undermines reservoir characterization. Petrophysics and rock physics were integrated through rock physics diagnostics (RPDs) modeling for detailed description of the reservoir microstructure and quality in the subbasin. Petrophysical evaluation shows that Sokor-1 sand_5 interval has good petrophysical properties across wells and prolific in hydrocarbons. RPD analysis revealed that this sand interval could be best described by the constant cement sand model in wells_2, _3, _5 and _9 and friable sand model in well_4. The matrix structure varied mostly from clean and well-sorted unconsolidated sands as well as consolidated and cemented sandstones to deteriorating and poorly sorted shaly sands and shales/mudstones. The rock physics template built b...
International Journal of Geosciences, 2021
The Eocene Sokor1 Formation is proven oil reservoir rocks in the Termit sub-basin. These sandston... more The Eocene Sokor1 Formation is proven oil reservoir rocks in the Termit sub-basin. These sandstone intervals are deeply buried, highly heterogeneous in character and characterized by Low Contrast Low Resistivity (LCLR) log responses. Petrophysical and quantitative well-based rock physics interpretations were integrated for property estimations, fluid and lithology typing in reservoir characterization. Six (6) reservoir sandstone intervals were identified, delineated and correlated across five (5) wells. The estimated petrophysical properties showed that the Eocene Sokor1 sandstones have averagely good reservoir properties with sand_5 interval exhibiting exceptional reservoir properties. V p /V s vs. AI and μρ vs. λρ elastic cross-plots color coded with reservoir properties (V sh and ϕ), show distinct and well separated data clusters signifying hydrocarbon bearing sandstones, brine sandstones and shales/mudstones in the 3D crossplot planes with varying seismic elastic property values in each well thereby, enhancing reservoir characterization and providing information's about the burial history, reservoir quality and property distribution in the sub-basin. The analysis suggests that, although the reservoir interval has averagely good petrophysical properties in all wells, the seismic elastic crossplots show that these properties are much better distributed in wells 2 and 3 than in wells 4, 5 and 9. Therefore, sand_5 reservoir interval in wells 2 and 3 is likely to be more hydrocarbon bearing and productive than wells 4, 5 and 9 in the sub-basin.
Journal of Petroleum Exploration and Production Technology, 2020
Reservoir characterization plays a significant role in the exploration, development, and producti... more Reservoir characterization plays a significant role in the exploration, development, and production of hydrocarbon reservoirs. The use of integrated approach in characterization improves on the accuracy, certainty, and robust interpretation of reflectivity data. The study aimed to integrate reflectivity and spectral attributes to adequately characterize hydrocarbon reservoirs in MUN onshore Niger delta field. Well log and rock physics analyses identified and delineated reservoirs, discriminated lithology, characterized fluid, and established relations between elastic and reservoir properties for field-wide interpretation of the reflectivity data. The wells were tied to the reflectivity data, and H4 seismic horizon was mapped. Subsequently, sweetness, reflectivity and spectral attributes were extracted along H4 horizon after inversion and spectral decomposition of the reflectivity data and independently interpreted. Channel-like structure with high-amplitudes, low-to-moderate acousti...
Journal of Petroleum Exploration and Production Technology, 2020
Integrating seismic amplitudes and spectral attribute analysis has successfully mapped, validated... more Integrating seismic amplitudes and spectral attribute analysis has successfully mapped, validated and characterised hydrocarbon-saturated channel sands by high-amplitude low-frequency anomaly. The aim of the study was targeted at using these novel geophysical tools to improve characterisation of tertiary clastic reservoir in the field. These attributes were extracted along H4 seismic horizon and analysed independently for structure, lithology and hydrocarbon saturation. The result of the analysis shows that both attributes complimented each other in mapping the hydrocarbon-saturated reservoir channel sands. However, the spectral attributes in combination with spectral-based Red, Blue and Green (RGB) colour blending attribute map reveal finer and subtle details of the channel structure and stratigraphy which hitherto were not apparent in the seismic amplitude maps. The channel sands trend NE–SW, broadening towards the southwest and bounded by major growth faults to the northeast and ...
International Journal of Geosciences, 2019
Rock Physics Modelling and Seismic Inversion were carried out in an Onshore Niger Delta Field for... more Rock Physics Modelling and Seismic Inversion were carried out in an Onshore Niger Delta Field for the purpose of characterizing a hydrocarbon reservoir. The aim of the study was to integrate rock physics models and seismic inversion to improve the characterization of a selected reservoir using well-log and 3D seismic data sets. Seven reservoir sands were delineated using suite of logs from three wells. In this study, the sand 4 reservoir was selected for analysis. The result of petrophysical evaluation shows that the sand 4 reservoir is relatively thick (62 ft) with low water saturation (0.33), shale volume (0.11) and high porosity (0.32). These results indicate reservoir of good quality and producibility. Cross-plot of property pairs (acoustic impedance (I p) vs. lambda-rho (λρ) and mu-rho (µρ) vs. lambda-rho (λρ) color-coded with reservoir properties reveals three distinct probable zones: hydrocarbon sand, brine sand and shale. Results show that low I p , λρ and µρ associated with hydrocarbon charged sands correspond to low S w and V sh and high ϕ. The integration of rock physics models and inverted rock attributes effectively delineated and improved understanding of already producing reservoirs, as well as other hydrocarbon charged sands of low S w , V sh , and high ϕ to the east of existing well locations, which indicate possible bypassed hydrocarbon pays. The results of this work can assist in forecasting hydrocarbon prospectivity and lessen chances of drilling dry holes in MUN onshore Niger delta field.
American Journal of Geoscience, 2016
Production-induced subsidence due to compressibility and fluid property changes in a Niger delta ... more Production-induced subsidence due to compressibility and fluid property changes in a Niger delta field has been investigated using well log and 4D seismic data sets. The objective of the study is to evaluate changes in time lapse seismic attributes due to hydrocarbon production and infer to probable ground subsidence. Petrophysical modeling and analysis of well data revealed that Density (ρ), Lambda rho (λρ) and Acoustic impedance (Ip) are highly responsive to changes in reservoir properties. These properties and water saturation attribute were subsequently, extracted from time-lapse seismic volumes in the immediate vicinity of well locations. Result show that monitor horizon slices exhibit appreciable increases in ρ, λρ, Ip and water saturation values compared to the base data, especially around the well locations. These increases in relative values of rock/attribute properties between the time-lapse surveys for a constant overburden stress are obvious indications of pore pressure and fluid depletion in the reservoir. Depletion in these properties increases the effective stress (pressure) and the grain-to-grain contact of the reservoir matrix, with a corresponding decrease in compressibility. Consequently, pore and matrix volume decreases, the reservoir compacts and the ground subsides. However, this is suspected to be small and at the reservoir scale due to low initial reservoir porosity and the relatively large lateral dimension compared to the thickness of the reservoir.
International Journal of Geosciences, 2016
We carried out time-lapse analysis in a producing Niger Delta X-field, by first investigating the... more We carried out time-lapse analysis in a producing Niger Delta X-field, by first investigating the response and sensitivity of rock properties/attributes to lithology and pore fill in 3-D cross plot domain and by Gassmann's fluid substitution modeling. Furthermore, 4-D seismic data were inverted into acoustic impedance volumes through model based inversion scheme. This served as input into a multi-attribute neural network algorithm for the extraction of rock attribute volumes based on the results of the petrophysical log analysis. Subsequently, horizon slices of rock properties/ attributes were extracted from the inverted seismic data and analyzed. In this way, we mapped hydrocarbon depleted wells in the field, and identified probable bypassed hydrocarbon zones. Thus, the integration of well and time lapse seismic (4-D) data in reservoir studies has remarkably improved information on the reservoir economic potential, and enhanced hydrocarbon recovery factor.
Archives of Applied Science Research, 2016
Seismic attenuation analysis is important for several reasons, including aiding seismic risk eval... more Seismic attenuation analysis is important for several reasons, including aiding seismic risk evaluation. Quality factors and attenuation coefficients have been estimated for an X-field in the Niger Delta, whose near surface sediments has remained largely uncharacterized. Using surface waves extracted from seismic data acquired by conventional reflection methodology and employing the quality factor versus offset (QVO) technique of attenuation analysis, reliable attenuation coefficient and quality factor distributions for the field covering about 25 km2 has been generated. The value of quality factors obtained indicate that the near surface sediments are low in attenuation to surface waves, being largely unconsolidated. The value of quality factors ranges from 20 to 80, corresponding to attenuation coefficients of between 0.0006 to 0.002 m-1. The estimated attenuation factors in this study tend to have some form of dependence on the thickness of unconsolidated sediments. In most parts...