Papers by CHUKWUEBUKA NNAMDI ONWUBUARIRI
Acta Montanistica Slovaca
In order to identify the boundaries and intersections of linear geological features within the st... more In order to identify the boundaries and intersections of linear geological features within the study region, the aeromagnetic data obtained from the Obudu area in southeast Nigeria was enhanced using precise methodologies, such as the Horizontal derivative (HD), first vertical derivative (FVD), and second vertical derivative (SVD). The process of separating the regional and residual aeromagnetic data information involved applying the polynomial fitting algorithm prior to filtering. The depth to magnetic sources was estimated using the usual Euler deconvolution approach. The studied area is characterized by fluctuations in aeromagnetic signals, indicating alterations in the magnetic susceptibilities of the underlying sedimentary and basement rocks based on the available information derived from the interpreted data. The filtered aeromagnetic maps may exhibit lineaments that exhibit movement along the NE-SW and NW-SE directions. The depths at which anomalies arise from structural complexities were assessed by Euler configurations within the vertical range of 0 to 2100 meters. The presence of a low sedimentation thickness and a high density of lineaments within the studied area suggests a potential correlation between the identified geological formations and hydrothermal mineralization.
Journal of the Indian Society of Remote Sensing, 2025
e high costs associated with exploration and development has hindered the extensive exploitation ... more e high costs associated with exploration and development has hindered the extensive exploitation of geothermal energy, a
renewable resource, compared to solar, wind, and biomass energy. Therefore, we conducted a thorough analysis and evaluation of the Lower Benue Trough's geothermal potential using high-resolution radiometric data and remote sensing techniques
to assess absorbed terrestrial radiation and other critical parameters. For the study area, a forty-year remote sensing dataset
(1980–2019) from MERRA-2 and aero-radiometric data provided by Fugro were used. Data interpretation employed software tools such as Oasis Montaj, ArcGIS, Surfer, Microsoft Excel, IIwis, and Matlab. The highest observed heat catchment
magnitude was 334.198 W/m2. Results indicated that the Lower Benue Trough has an average Curie depth of 13.96742 km,
a geothermal gradient of 159.4072 mW/m2, and a heat flow of 42.639 °C/km. The study also produced gamma spectrometric
images showing radioactive elements like uranium, thorium, and potassium, as well as ternary maps and other analyses that
were specific to the Lower Benue Trough
International Journal of Innovative Science and Research Technology, 2024
Sand production in the Niger Delta oil region is one of the most difficult challenges encountered... more Sand production in the Niger Delta oil region is one of the most difficult challenges encountered during the many stages of field development planning, resulting in expensive drilling, production costs, and damage to oil installations. This geomechanical problem is expected because the Niger Delta Province is dominantly a loosed sandstone terrain, and the sand grains are highly friable. The study centres on employing empirical relationships of rock mechanical parameters from wireline logs to predict
the vulnerability of lithologic formations to sand production in a reservoir in the Niger Delta. The reservoir five sandstone units were first recognized by using wireline logs (Gamma ray and self-potential logs), and the fluids were differentiated using resistivity, porosity, and density logs. The identified hydrocarbon prospecting sands were correlated throughout the five (5) wells. Gamma ray, resistivity and porosity logs were used for the correlation. Shear and compressive wave from the sonic log were then used to derive the rock mechanical parameters (Poisson ratio (ν), Young modulus (E), shear/rigidity modulus (G), bulk and matrix/grain moduli
(Kb and Km), bulk and grain compressibility (Cb and Cr), Unconfined compression strength (UCS) and Critical flow rate pressure (CFRP). Four Prediction of Sand Production indicators (Formation sanding indicator
method, Schlumberger formation sanding indicator, Bulk Elastic Modulus Ratio and Composite Modulus Estimation) derived from the rock mechanical parameters were used to adequately analyse sanding. The
analysed reservoir exhibits sandstone units with lower value of Poisson ratio, Bulk modulus, Young’s modulus, Shear modulus and Unconfined compression strength of 2.3GPa, 0.26, 11.2GPa, 7.93GPa, and 16.73MPa,
respectively. The formation shale exhibited higher values of Poisson ratio, indicative of its ductile nature that is resulting mostly from its clay content; the Bulk modulus, Young’s modulus, Shear modulus, and Unconfined compression strength exhibited high values (8.23 MPa,0.37,17.08 MPa, 25.02 MPa, 66.22 MPa respectively) while porosity and compressibility showed decreased values (0.07, 0.08 Mpa-1 respectively), leading to enhanced stiffness due to elevated moduli, hence less prone to deformation than the loosed sandstone units. The results of the four (4) Prediction of Sand Production models indicate a high risk of sanding during production of the investigated reservoir. A Critical flow rate pressure (CFRP) of 18.30 MPa is predicted to mitigate against sanding in the wells if the critical flow rate during production stays below 18.30 MPa. Thus, this research application of empirical relationships derived from rock mechanical parameters and wireline logs in predicting sand production can effectively aid informed investment decisions, risk assessment and performance optimization in Niger Delta reservoirs.
Archives of advanced engineering science, May 29, 2024
This study investigated the suitability of drinking water in Orlu, Nigeria, facing challenges due... more This study investigated the suitability of drinking water in Orlu, Nigeria, facing challenges due to limited surface water availability and environmental deterioration. To solve the problem of the availability of potable water, electrical resistivity surveys using Schlumberger array were conducted to identify potential groundwater resources. Twelve locations were assessed, revealing resistivity values indicative of potential aquifers. Following the geophysical survey, the physicochemical properties of water samples collected from various locations were analyzed. Parameters including pH, dissolved oxygen (DO), total dissolved solids (TDS), and minerals were evaluated against WHO and Nigerian drinking water standards. The analysis indicated generally good water quality across the sampling sites. pH levels were within the recommended range, and DO concentrations met the minimum requirements. Similarly, TDS and biochemical oxygen demand values suggested low levels of organic matter and dissolved solids. Mineral content also remained below WHO-permissible limits. A Water Quality Index further confirmed that the water quality within the study area can be graded from good to excellent in quality. These findings suggest that the groundwater resources identified in the study hold promise for providing safe drinking water in Orlu and its environs.
Spatial analysis is a field of study that utilizes geographic or spatial information to understan... more Spatial analysis is a field of study that utilizes geographic or spatial information to understand and analyze patterns, relationships, and trends in data. It is characterized by the use of geographic information, which allows for the analysis of data in the context of its location and surroundings. It is different from aspatial techniques which do not consider the geographic context and may not provide as complete of an understanding of the data. Spatial analysis is applied in a variety of fields which includes urban and regional planning, crime rate investigation, public health studies and epidemiology, environmental science, geosciences, marketing, and to gain insights and make decisions about complex spatial problems. The aim of this review paper is to explain the concept of spatial analysis as a Geographic Information System (GIS) tool, differentiate it from aspatial techniques, discuss different spatial analysis techniques including buffer, interpolation, and kernel density analysis, and highlight its importance. The paper followed a methodology that involved multiple definitions of spatial analysis from various sources. Comparative analysis of spatial and aspatial datasets and techniques was conducted, followed by application of spatial analysis in various fields including land cover classification, public health management, solid waste disposal management, and identification of the impact of urban sprawl. Applications of spatial analysis techniques were also reviewed. The importance of this paper lies in its contribution to the understanding and utilization of spatial analysis as a GIS tool. By explaining the concept, differentiating it from non-spatial techniques, and providing examples of its applications, the paper highlights the significance and potential of spatial analysis in various fields.
This study addresses the critical role of downhole refraction as a method for assessing subsurfac... more This study addresses the critical role of downhole refraction as a method for assessing subsurface characteristics, particularly in areas facing challenges such as ground roll issues and weak reflection signals during seismic data acquisition. Focused on the Agudama, Kenfa, and Yenegwe settlements in the Niger Delta region, where frequent engineering structure collapses occur, the research aims to understand the depth and velocity of unconsolidated zones through downhole refraction. The study emphasizes the limitations of relying solely on uphole refraction and highlights the necessity of downhole methods for accurate velocity determination. The research employs various techniques, including borehole drilling, velocity measurements, and seismic pulse generation. The study's primary objectives include investigating the causes of engineering structure failures, proposing geophysical solutions, and contributing valuable insights into the geological context of the Niger Delta region. The fieldwork involved a comprehensive approach, combining reconnaissance surveys, downhole refraction studies, and the use of specialized equipment such as a Geometrics Stratavisor NZXP seismograph and explosives for seismic sources. The results of the downhole refraction survey reveal a double-layer velocity model in the research areas, indicating variations in weathered or unconsolidated layer thickness and velocities. The study establishes a relationship between elevation, weathered layer thickness, and velocities in both weathered and consolidated layers, offering valuable information for engineering considerations. The research concludes that the downhole refraction method is crucial for evaluating weathered strata properties and provides cost-effective subsurface information. The study recommends drilling below the weathered zone for seismic energy source placement, excavation depths for stable structures, and future investigations focusing on closely spaced data points and additional soil properties. These recommendations aim to enhance the safety and durability of structures in the study area, contributing to the understanding and mitigation of engineering structure failures in the Niger Delta region.
This study investigated the suitability of drinking water in Orlu, Nigeria, facing challenges due... more This study investigated the suitability of drinking water in Orlu, Nigeria, facing challenges due to limited surface water availability and environmental deterioration. To solve the problem of the availability of portable water, electrical resistivity surveys using a Schlumberger array were conducted to identify potential groundwater resources. Twelve locations were assessed, revealing resistivity values indicative of potential aquifers. Following the geophysical survey, the physicochemical properties of water samples collected from various locations were analyzed. Parameters including pH, dissolved oxygen (DO), total dissolved solids (TDS), and minerals were evaluated against WHO and Nigerian drinking water standards. The analysis indicated generally good water quality across the sampling sites. pH levels were within the recommended range, and DO concentrations met the minimum requirements. Similarly, TDS and BOD values suggested low levels of organic matter and dissolved solids. Mineral content also remained below WHO-permissible limits. A Water Quality Index further confirmed that the water quality within the study area can be graded from good to excellent in quality. These findings suggest that the groundwater resources identified in the study hold promise for providing safe drinking water in Orlu and its environs.
Petroleum and Coal , 2024
This study investigates the weathered layer parameters of the Gbaran (OML 28) field in the Niger ... more This study investigates the weathered layer parameters of the Gbaran (OML 28) field in the Niger Delta using uphole refraction. 57 boreholes were bored and logged to study stratum components and characteristics. Weathered layer thickness ranges from 15.1m to 4.3m, with an average unconsolidated layer thickness of 6.9105m. Most of the unconsolidated stratum is silt or clay. This stratum has seismic wave velocities from 299 to 997m/s, averaging 697.14m/s. Consolidated stratum velocities average 1742.58m/s, ranging from 1551 to 1925. Subsurface refraction surveys were conducted at numerous locations, drilling and logging 57 boreholes. The acquisition plan included flushing drilling, cut lithology sampling, and logging from 0 to 60 metres. The velocities and thicknesses measured for each uphole site distinguish worn and cemented layers. Weathered layer thickness shows geological formation-influenced variations. Weathered layer velocity is 299-997m/s lower than consolidated layer velocity. Consolidated layer velocity is 1551-1925 m/s. Weathered layer thickness, velocity, and consolidated layer velocity are examined, focusing on thickness-velocity relationships. The recommendations include foundation design, construction methods, water management, geotechnical research, seismic design, monitoring, and geotechnical specialist coordination. Seismic refraction surveys can characterize underlying material variations and aid engineering design and risk assessment in the Niger Delta's dynamic geology.
Journal of Basic Physical Research, 2023
The seismic reflection method has played a crucial role in geological exploration, spanning from ... more The seismic reflection method has played a crucial role in geological exploration, spanning from petroleum to engineering investigations. This study aims to enhance seismic acquisition in the demanding Niger Delta terrain, particularly in the OML 28 block, considering environmental and urban complexities. A comprehensive 3D reshoot seismic survey was conducted, involving systematic partitioning of the field into 7 swaths, while ensuring quality control measures. Shot points that fell on non-seismic objects were strategically relocated to ensure full-fold coverage and adequate subsurface sampling without having any negative environmental implications, utilizing techniques like point shift, smooth curve and laminar flow. Fold coverage analysis delineated distinct ranges across various offsets, including near, mid, far, and full offsets. Notably, the nominal full-fold coverage for OML 28 was 312, with observable improvements in midoffset ranges compared to near-offset and far-offset. Merging offset ranges facilitated achieving the required fold through swath overlap, ensuring thorough subsurface sampling. Additional analyses encompassed bin statistics, offset/azimuth rose diagrams, and surface topography examination, shedding light on trace distribution and elevation variations. Drilling operations were essential, revealing disparities between drilled and loaded depths, indicating potential signal attenuation concerns. Arrival time analysis emphasized drilling past weathered layers to mitigate signal attenuation. This study enhances seismic acquisition optimization, providing insights into fold coverage variations across offsets and emphasizing comprehensive drilling practices for signal enhancement. These findings are crucial for refining subsurface imaging and geological comprehension, particularly in challenging terrains like the Niger Delta.
Engineering and Applied Sciences, 2024
This study addresses the critical role of downhole refraction as a method for assessing subsurfac... more This study addresses the critical role of downhole refraction as a method for assessing subsurface characteristics, particularly in areas facing challenges such as ground roll issues and weak reflection signals during seismic data acquisition. Focused on the Agudama, Kenfa, and Yenegwe settlements in the Niger Delta region, where frequent engineering structure collapses occur, the research aims to understand the depth and velocity of unconsolidated zones through downhole refraction. The study emphasizes the limitations of relying solely on uphole refraction and highlights the necessity of downhole methods for accurate velocity determination. The research employs various techniques, including borehole drilling, velocity measurements, and seismic pulse generation. The study's primary objectives include investigating the causes of engineering structure failures, proposing geophysical solutions, and contributing valuable insights into the geological context of the Niger Delta region. The fieldwork involved a comprehensive approach, combining reconnaissance surveys, downhole refraction studies, and the use of specialized equipment such as a Geometrics Stratavisor NZXP seismograph and explosives for seismic sources. The results of the downhole refraction survey reveal a double-layer velocity model in the research areas, indicating variations in weathered or unconsolidated layer thickness and velocities. The study establishes a relationship between elevation, weathered layer thickness, and velocities in both weathered and consolidated layers, offering valuable information for engineering considerations. The research concludes that the downhole refraction method is crucial for evaluating weathered strata properties and provides cost-effective subsurface information. The study recommends drilling below the weathered zone for seismic energy source placement, excavation depths for stable structures, and future investigations focusing on closely spaced data points and additional soil properties. These recommendations aim to enhance the safety and durability of structures in the study area, contributing to the understanding and mitigation of engineering structure failures in the Niger Delta region.
International Journal of Engineering Applied Sciences and Technology, 2022
Seismic survey which primarily involves using artificially generated seismic energy to examine th... more Seismic survey which primarily involves using artificially generated seismic energy to examine the subsurface is a common exploration practice in Nigeria. The manner which seismic exploration is carried out affects not only the expected outcome but also the environment, the flora and fauna. In this study, implications of employing the following drilling techniques, the single deep hole technique and the pattern drilling technique were x-rayed as it affects the expected sampling of the subsurface and the human environment in line with the united nations sustainable development goals on sustainable environment and
Modeling Earth Systems and Environment, 2023
A critical analysis, assessment and evaluation of geothermal resource potentials of Lower Benue T... more A critical analysis, assessment and evaluation of geothermal resource potentials of Lower Benue Trough was carried out using high-resolution aeromagnetic and radiometric data collected by Fugro airborne surveys, having flight line spacing of 200 m, tie line spacing of 2 km, flight line trend of 035°, and tie line trend of 125°. The data collected within the study area were interpreted and analyzed to determine the geothermal viability of the area for possible harnessing to curb energy crisis ravaging the area and as well generate a clean energy that is environmentally friendly. The interpretation of the acquired data was carried out with the aid of the following software-Oasis Montaj, ArcGIS, Surfer, Microsoft Excel and IIwis. It was observed from this study that the average curie depth, average geothermal gradient and the average heat flow of the Lower Benue Trough are 13.96742 km, 159.4072 mW/m 2 and 42.639 °C/km respectively. The following for Lower Benue Trough were also generated and they include-total magnetic intensity map (TMI), TMI map reduced to the equator (RTE), first vertical derivative (FVD), upward continuation maps (UC), gamma spectrometric images of radioactive elements (potassium, thorium, and uranium), ternary map, and others. This research in summary exposed the geothermal viability of the study area and its possible potential for petroleum exploration.
American Journal of Engineering and Technology Management, 2024
Spatial analysis is a field of study that utilizes geographic or spatial information to understan... more Spatial analysis is a field of study that utilizes geographic or spatial information to understand and analyze patterns, relationships, and trends in data. It is characterized by the use of geographic information, which allows for the analysis of data in the context of its location and surroundings. It is different from aspatial techniques which do not consider the geographic context and may not provide as complete of an understanding of the data. Spatial analysis is applied in a variety of fields which includes urban and regional planning, crime rate investigation, public health studies and epidemiology, environmental science, geosciences, marketing, and to gain insights and make decisions about complex spatial problems. The aim of this review paper is to explain the concept of spatial analysis as a Geographic Information System (GIS) tool, differentiate it from aspatial techniques, discuss different spatial analysis techniques including buffer, interpolation, and kernel density analysis, and highlight its importance. The paper followed a methodology that involved multiple definitions of spatial analysis from various sources. Comparative analysis of spatial and aspatial datasets and techniques was conducted, followed by application of spatial analysis in various fields including land cover classification, public health management, solid waste disposal management, and identification of the impact of urban sprawl. Applications of spatial analysis techniques were also reviewed. The importance of this paper lies in its contribution to the understanding and utilization of spatial analysis as a GIS tool. By explaining the concept, differentiating it from non-spatial techniques, and providing examples of its applications, the paper highlights the significance and potential of spatial analysis in various fields.
Petroluem and Coal, 2023
In order to interpret the airborne magnetic data and to evaluate the approximate location, depth,... more In order to interpret the airborne magnetic data and to evaluate the approximate location, depth, and geometry of the magnetic sources within Obudu area using standard Euler deconvolution method, high resolution aeromagnetic data over the area was processed digitally and analyzed using Oasis Montaj 8.5 software. Data analysis and enhancement techniques including reduction to equator, horizontal derivative, first and second vertical derivatives, upward continuation and regional-residual separation were carried out. Standard Euler deconvolution for structural indices of 0, 1, 2, and 3 were obtained. Results show that the total magnetic intensity ranges from-122.9nT to 147.0nT, regional intensity varies between-106.9nT to 137.0nT, while residual intensity ranges between-51.5nT to 44.9nT indicating the masking effect of deep-seated structures over surface and shallow subsurface materials. Results also show that the positive residual anomalies have a NE-SW orientation which coincides with the trend of major geologic structures in the area. Euler deconvolution for all the structural indices has depth to magnetic sources ranging from <0m to >2000m. Interpretation of the various structural indices revealed the locations and depths of the source bodies and the existence of geologic models including sills, dykes, pipes, and spherical structures. This area is characterized by shallow basement materials and represents a good prospect for solid mineral exploration.
Implications of Fold Monitoring in Seismic Data Acquisition: Case Study of Niger Delta, 2023
Fold calculation and monitoring are an integral and important aspect of seismic data acquisition.... more Fold calculation and monitoring are an integral and important aspect of seismic data acquisition. Before an acquisition is carried out, so many factors must be put into consideration. These factors include grid orientation, source point (SP) and receiver point (RP) spacing, source line (SL) and receiver line (RL) spacing, source points (SP) number in each Salvo, receiver lines (RL) number in each swath, end taper, number of swaths, receiver line overlap between swaths and acquisition polygon limits. In this work, the study area was divided into 7 swaths of 12 receiver lines each, with the fold of each swath calculated in three phases which include near offset fold coverage (0-3650m), mid offset fold coverage (3650-7300m) and far offset fold coverage (7300-10950m). These phases of fold calculations were later merged to ascertain the full fold coverage of each swath and in turn the full fold coverage of the entire study area. The maximum fold coverage for each of the swaths within the study area ranges from 358-446, with average maximum fold coverage of 393.3 which is more than twice the minimum fold coverage expectancy (180) for the study area. Fold calculations were carried out, while the lateral extent where full fold coverage is experienced within each swath was noted. It was also observed that where the full fold coverage of one swath ends, the full fold of another swath begins. This implies that when all the swaths are merged, no fold drop will be experienced, unless at the tapering ends of the entire study area.
Geophysical Investigation of Environmental and Engineering Features Using Aeromagnetic Data of Ogoja and Environs Southeastern Nigeria, 2023
This study investigates the environmental and engineering implications of linear geologic feature... more This study investigates the environmental and engineering implications of linear geologic features in Ogoja and its surroundings using interpreted aeromagnetic data. The regional and residual fields of the aeromagnetic data for the research region were separated using polynomials fitting techniques for first to fourth order. To trace and find the contact linear geologic structures within the study area, high resolution filters such as horizontal derivative (HD), first vertical derivative (FVD), and second vertical derivative (SVD) were used in Edge enhancement filtering for best fit residual anomaly. The depth to anomalous magnetic sources was estimated using the conventional Euler deconvolution approach. According to the findings, the research area is distinguished by near-surface lineaments that occur at maximum depths of 2000 m. Major trends could be seen in the NE-SW direction of the extracted lineaments from FVD and SVD, whereas minor trends aligned in the NW-SE direction. It is impossible to overstate the likelihood that some of the engineering and environmental issues in the research region, such as road failures, house cracks, and gully erosions, may be related to these near-surface geological phenomena.
Earth and Planetary Science
The scarcity of food afflicting third-world countries, particularly Nigeria, case study Orlu zone... more The scarcity of food afflicting third-world countries, particularly Nigeria, case study Orlu zone, Imo State, Nigeria, is intolerable, given the high rate of environmental degradation in the form of erosions, nation’s poor economic state, insecurity, and extremely low per capita income of citizens, motivated this research. This research is tailored to a possible approach to combating the threat of food insecurity via geophysical investigation of agricultural potential areas and as well help in managing food insecurity ravaging the area, particularly in this post-COVID lockdown era. In this research, a geophysical approach—Landsat imagery and interpretation—was used to identify areas with high agricultural yielding potentials and how to exploit them for bumper agricultural harvests to sustain livelihood and alleviate the food crisis and food inflation ravaging the zone. Within the study area, the following data were collected: Normalized Difference Vegetation Index (NDVI) map, lineam...
Geophysical Evaluation of Agricultural Potential of Orlu and Environs Using Landsat Imagery, 2023
The scarcity of food afflicting third-world countries, particularly Nigeria, case study Orlu zone... more The scarcity of food afflicting third-world countries, particularly Nigeria, case study Orlu zone, Imo State, Nigeria, is intolerable, given the high rate of environmental degradation in the form of erosions, nation’s poor economic state, insecurity, and extremely low per capita income of citizens, motivated this research. This research is tailored to a possible approach to combating the threat of food insecurity via geophysical investigation of agricultural potential areas and as well help in managing food insecurity ravaging the area, particularly in this post-COVID lockdown era. In this research, a geophysical approach—Landsat imagery and interpretation was used to identify areas with high agricultural yielding potentials and how to exploit them for bumper agricultural harvests to sustain livelihood and alleviate the food crisis and food inflation ravaging the zone. Within the study area, the following data were collected: Normalized Difference Vegetation Index (NDVI) map, lineament map and drainage pattern map. They were interpreted, and areas with high agricultural yield potentials were mapped. Band ratios (3/4, 4/2, 3/1, 5/4) were generated to reduce the effects of shadowing and as well improve the features present. The NDVI values that indicate soil viability, generated within the study area range from –0.22 to 0.51
Failures associated with civil engineering structures in the study area with specific reference t... more Failures associated with civil engineering structures in the study area with specific reference to roads and buildings have been attributed to lack of proper understanding of the weathered layer characteristics. This study was therefore carried out using downhole seismic refraction data from twenty borehole locations within parts of PortHarcourt, Niger Delta, Nigeria to determine the weathered layer characteristics of the area. The survey was carried out with the Geometrics Stratavisor NZ11 instrument using a set of hydrophones arranged in a definite manner in each of the boreholes. The data was processed using Udysys software and analyzed graphically using the seismic refraction interpretation technique. Several contour and analytical maps were generated for the weathered and consolidated layers. Similarly, four interpretative cross sections namely NW-SE, NE-SW, N-S and E-W were used for the purpose of correlation. Results of the study revealed that the velocity of the weathered la...
The interpretation of 12 Schlumberger vertical electrical sounding (VES) data was carried out to ... more The interpretation of 12 Schlumberger vertical electrical sounding (VES) data was carried out to investigate the electrical properties of soil and how it can contribute to gully formation. Terrameter Signal Averaging System (SAS) model 300 was used in the absence of any signal enhancer as the expected targeted depth to be investigated is within the range of penetration of the instrument. During this data acquisition, readings were taken using maximum electrode separation of 400m, with layer resistivity values at 65.168Ωm and 44800Ωm for both minimum and maximum values respectively. The depth and thickness values of layers under investigation were also taken and have the values of 0.9m and 177m for minimum and maximum values respectively. These acquired values were computed together and as well were interpreted. The results of the interpreted VES data showed that the saturated groundwater layer (aquifer) is non-saline, and there is no trace of any clayey or muddy material within the ...
Uploads
Papers by CHUKWUEBUKA NNAMDI ONWUBUARIRI
renewable resource, compared to solar, wind, and biomass energy. Therefore, we conducted a thorough analysis and evaluation of the Lower Benue Trough's geothermal potential using high-resolution radiometric data and remote sensing techniques
to assess absorbed terrestrial radiation and other critical parameters. For the study area, a forty-year remote sensing dataset
(1980–2019) from MERRA-2 and aero-radiometric data provided by Fugro were used. Data interpretation employed software tools such as Oasis Montaj, ArcGIS, Surfer, Microsoft Excel, IIwis, and Matlab. The highest observed heat catchment
magnitude was 334.198 W/m2. Results indicated that the Lower Benue Trough has an average Curie depth of 13.96742 km,
a geothermal gradient of 159.4072 mW/m2, and a heat flow of 42.639 °C/km. The study also produced gamma spectrometric
images showing radioactive elements like uranium, thorium, and potassium, as well as ternary maps and other analyses that
were specific to the Lower Benue Trough
the vulnerability of lithologic formations to sand production in a reservoir in the Niger Delta. The reservoir five sandstone units were first recognized by using wireline logs (Gamma ray and self-potential logs), and the fluids were differentiated using resistivity, porosity, and density logs. The identified hydrocarbon prospecting sands were correlated throughout the five (5) wells. Gamma ray, resistivity and porosity logs were used for the correlation. Shear and compressive wave from the sonic log were then used to derive the rock mechanical parameters (Poisson ratio (ν), Young modulus (E), shear/rigidity modulus (G), bulk and matrix/grain moduli
(Kb and Km), bulk and grain compressibility (Cb and Cr), Unconfined compression strength (UCS) and Critical flow rate pressure (CFRP). Four Prediction of Sand Production indicators (Formation sanding indicator
method, Schlumberger formation sanding indicator, Bulk Elastic Modulus Ratio and Composite Modulus Estimation) derived from the rock mechanical parameters were used to adequately analyse sanding. The
analysed reservoir exhibits sandstone units with lower value of Poisson ratio, Bulk modulus, Young’s modulus, Shear modulus and Unconfined compression strength of 2.3GPa, 0.26, 11.2GPa, 7.93GPa, and 16.73MPa,
respectively. The formation shale exhibited higher values of Poisson ratio, indicative of its ductile nature that is resulting mostly from its clay content; the Bulk modulus, Young’s modulus, Shear modulus, and Unconfined compression strength exhibited high values (8.23 MPa,0.37,17.08 MPa, 25.02 MPa, 66.22 MPa respectively) while porosity and compressibility showed decreased values (0.07, 0.08 Mpa-1 respectively), leading to enhanced stiffness due to elevated moduli, hence less prone to deformation than the loosed sandstone units. The results of the four (4) Prediction of Sand Production models indicate a high risk of sanding during production of the investigated reservoir. A Critical flow rate pressure (CFRP) of 18.30 MPa is predicted to mitigate against sanding in the wells if the critical flow rate during production stays below 18.30 MPa. Thus, this research application of empirical relationships derived from rock mechanical parameters and wireline logs in predicting sand production can effectively aid informed investment decisions, risk assessment and performance optimization in Niger Delta reservoirs.
renewable resource, compared to solar, wind, and biomass energy. Therefore, we conducted a thorough analysis and evaluation of the Lower Benue Trough's geothermal potential using high-resolution radiometric data and remote sensing techniques
to assess absorbed terrestrial radiation and other critical parameters. For the study area, a forty-year remote sensing dataset
(1980–2019) from MERRA-2 and aero-radiometric data provided by Fugro were used. Data interpretation employed software tools such as Oasis Montaj, ArcGIS, Surfer, Microsoft Excel, IIwis, and Matlab. The highest observed heat catchment
magnitude was 334.198 W/m2. Results indicated that the Lower Benue Trough has an average Curie depth of 13.96742 km,
a geothermal gradient of 159.4072 mW/m2, and a heat flow of 42.639 °C/km. The study also produced gamma spectrometric
images showing radioactive elements like uranium, thorium, and potassium, as well as ternary maps and other analyses that
were specific to the Lower Benue Trough
the vulnerability of lithologic formations to sand production in a reservoir in the Niger Delta. The reservoir five sandstone units were first recognized by using wireline logs (Gamma ray and self-potential logs), and the fluids were differentiated using resistivity, porosity, and density logs. The identified hydrocarbon prospecting sands were correlated throughout the five (5) wells. Gamma ray, resistivity and porosity logs were used for the correlation. Shear and compressive wave from the sonic log were then used to derive the rock mechanical parameters (Poisson ratio (ν), Young modulus (E), shear/rigidity modulus (G), bulk and matrix/grain moduli
(Kb and Km), bulk and grain compressibility (Cb and Cr), Unconfined compression strength (UCS) and Critical flow rate pressure (CFRP). Four Prediction of Sand Production indicators (Formation sanding indicator
method, Schlumberger formation sanding indicator, Bulk Elastic Modulus Ratio and Composite Modulus Estimation) derived from the rock mechanical parameters were used to adequately analyse sanding. The
analysed reservoir exhibits sandstone units with lower value of Poisson ratio, Bulk modulus, Young’s modulus, Shear modulus and Unconfined compression strength of 2.3GPa, 0.26, 11.2GPa, 7.93GPa, and 16.73MPa,
respectively. The formation shale exhibited higher values of Poisson ratio, indicative of its ductile nature that is resulting mostly from its clay content; the Bulk modulus, Young’s modulus, Shear modulus, and Unconfined compression strength exhibited high values (8.23 MPa,0.37,17.08 MPa, 25.02 MPa, 66.22 MPa respectively) while porosity and compressibility showed decreased values (0.07, 0.08 Mpa-1 respectively), leading to enhanced stiffness due to elevated moduli, hence less prone to deformation than the loosed sandstone units. The results of the four (4) Prediction of Sand Production models indicate a high risk of sanding during production of the investigated reservoir. A Critical flow rate pressure (CFRP) of 18.30 MPa is predicted to mitigate against sanding in the wells if the critical flow rate during production stays below 18.30 MPa. Thus, this research application of empirical relationships derived from rock mechanical parameters and wireline logs in predicting sand production can effectively aid informed investment decisions, risk assessment and performance optimization in Niger Delta reservoirs.