Depth to magnetic basement in the Anambra Basin, Benue Trough of Nigeria from aeromagnetic data: A prelude for hydrocarbon exploration

2021 ◽  
pp. 1-57
Author(s):  
Olatunbosun O. Olagundoye ◽  
Chiedu S. Okereke ◽  
Aniekan E. Edet ◽  
Dominic Obi ◽  
Aniediobong Ukpong
Keyword(s):  
Depth Estimation ◽  
Data Transformation ◽  
Hydrocarbon Exploration ◽  
Hydrocarbon Generation ◽  
Depth Range ◽  
Aeromagnetic Data ◽  
Benue Trough ◽  
Anambra Basin ◽  
Magnetic Basement ◽  
Fault Structures

Data transformation, regional-residual separation, trend analysis, and Analytic Signal (AS) depth estimation were applied to aeromagnetic data covering the Anambra Basin, which is a major depocentre in the Benue Trough, southeast Nigeria with the primary objectives of accentuating attributes of magnetic sources and determining if sufficient sediment thickness exists for hydrocarbon generation, maturation, and expulsion. The application of data transformation techniques (such as map projection, merging, and reduction-to-pole) and regional-residual ensured the computation of a crustal magnetic field that would be suitable for magnetic analyses. Results indicate that the magnetic basement in the basin forms an undulating surface overlain by sediments with average thickness ranging between 4 km and 7.5 km, while maximum thickness reaches 8 km in some areas. This depth range suggests promising prospect for source-facies maturation and expulsion. We expect that areas in the study area with these appreciable sediment thicknesses, good preservation of graben-fill, and suitable areal closures or fault structures would be favorable for hydrocarbon prospectivity.

scholarly journals Interpretation of aeromagnetic data over Abeokuta and its environs, Southwest Nigeria, using spectral analysis (Fourier transform technique)

2016 ◽  
Vol 63 (4) ◽  
pp. 199-212 ◽  
Author(s):  
Oluwaseun T. Olurin ◽  
Saheed A. Ganiyu ◽  
Olaide S. Hammed ◽  
Taiwo J. Aluko
Keyword(s):  
Spectral Analysis ◽  
Fourier Transform ◽  
Ground Level ◽  
Magnetic Data ◽  
Depth Range ◽  
Aeromagnetic Data ◽  
Southwestern Nigeria ◽  
Southwest Nigeria ◽  
Below Ground ◽  
Magnetic Basement

AbstractThis study presents the results of spectral analysis of magnetic data over Abeokuta area, Southwestern Nigeria, using fast Fourier transform (FFT) in Microsoft Excel. The study deals with the quantitative interpretation of airborne magnetic data (Sheet No. 260), which was conducted by the Nigerian Geological Survey Agency in 2009. In order to minimise aliasing error, the aeromagnetic data was gridded at spacing of 1 km. Spectral analysis technique was used to estimate the magnetic basement depth distributed at two levels. The result of the interpretation shows that the magnetic sources are mainly distributed at two levels. The shallow sources (minimum depth) range in depth from 0.103 to 0.278 km below ground level and are inferred to be due to intrusions within the region. The deeper sources (maximum depth) range in depth from 2.739 to 3.325 km below ground and are attributed to the underlying basement.

scholarly journals Estimation of The Structural Pattern and Sedimentary Thickness Over Part Of Anambra Basin, Nigeria Using Aeromagnetic Data

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Priscilla E. Ikioda ◽  
Charles O. Ofoegbu ◽  
Etim D. Uko ◽  
Olatunji S. Ayanninuola
Keyword(s):  
Spectral Analysis ◽  
Analytical Techniques ◽  
Average Depth ◽  
Intensity Data ◽  
Aeromagnetic Data ◽  
Structural Pattern ◽  
Near Surface ◽  
Anambra Basin ◽  
Potential Depth ◽  
Magnetic Basement

AbstractAeromagnetic data acquired over part of the Anambra Basin is analyzed to determine the structural pattern and sedimentary thickness of the basin. The study area is covered by high resolution aeromagnetic data on sheets 301 (Udi), 302 (Nkalagu), 312 (Okigwe) and 313 (Afikpo), and lies between latitudes 5o30’0’‘-6o30’0’‘ and longitudes 7o0’0”-8o0’0”. The whole area was divided into 25 overlapping blocks of 37.2km2 each and a 2D energy spectral analysis was carried out. Total magnetic intensity data was subjected to filtering and analytical techniques to determine the structural pattern, mineralization potential, depth to the basement, variation in the sedimentary thickness. The structural map generated using the vertical derivatives shows that the major structural orientation of the area is in the ENE-WSW trend and the minor trend is the NW to SE direction widespread all over the area. These structures are as a result of the various near-surface magnetic intrusion within the study area. The spectral analysis result shows two depth layers, the deep and the shallow depth, the depth to magnetic basement for the deep anomalous source ranges from 3.3km to 4.8 4km with an average depth of 3.99km, while the depth to shallow magnetic sources ranges between 0.46km to 0.67km and an average of 0.56km within the area. The mineralization pattern in this area follows the ENE-WSW direction.

scholarly journals Interpretation of Aeromagnetic Data over the Nigerian Sector of the Mamfe Basin

2020 ◽  
pp. 1-6
Author(s):  
Okeke Sunday Okechukwu ◽  
◽  
Onwuegbuche Anthony Azunna ◽  
Chinwuko Augustine Ifeanyi ◽  
Okonkwo Churchill Chukwunonso ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Magnetic Field Intensity ◽  
Signal Amplitude ◽  
Hydrocarbon Generation ◽  
Aeromagnetic Data ◽  
Study Region ◽  
Benue Trough ◽  
Qualitative Interpretation ◽  
Geological Modelling ◽  
Anomaly Map

Four Aeromagnetic data over a part of the Nigerian Sector of the Mamfa Basin have been analyzed using qualitative approach and spectral analysis. The aeromagnetic maps, its analytic signal amplitude and geological modelling sketch helped in identifying the nature and depth of the magnetic sources in the study region. The qualitative interpretation reveals that the study area is characterized by magnetic lineament trend in NE-SW direction and subordinate E-W direction. The results obtained are in line with the trend of the Benue Trough. The aeromagnetic maps reveal that the sedimentary thickness increases towards the northern parts of the study area. The results also reveal that the total magnetic field intensity range from 7800 to 8290 nanotesla (nT) in the study area. The residual anomaly map reveals that the maximum anomaly value is 160nT which is found around Bansara and Ugep environs while the minimum magnetic value is -140nT towards the Abakiliki and Ikom areas. Results from spectral analysis indicated two magnetic source depths, which account for deeper and shallower sources. The deeper magnetic sources vary from 2.76 km near Abakiliki to 5.37 km near Bansara, whereas the shallow magnetic sources vary from 0.58 km near Ikom to 1.76 km near Ugep. The depth to basement map reveals that the sediment thickness increases towards the northern parts of the study area. The depths to basement are deeper in the northern and central parts trending northwest-southeast direction and shallower in the eastern and southern parts of the study area. The result also shows a linear depression with sedimentary accumulation trending northwest-southeast. The temperatures at depth for each anomaly block were estimated to range between 48.46 and 225.69°C with an average of 117.04°C. Based on the computed sedimentary thickness (2.76-5.37km) and temperature at depth (62-220°C), the possibility of hydrocarbon generation in the northern and central parts of the study area is realistic

scholarly journals Estimation of Depth to Bouguer Anomaly Sources Using Euler Deconvolution Techniques

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gideon Oluyinka Layade ◽  
Hazeez Edunjobi ◽  
Victor Makinde ◽  
Babatunde Bada
Keyword(s):  
Bouguer Anomaly ◽  
Depth Estimation ◽  
Hydrocarbon Exploration ◽  
Survey Method ◽  
Depth Range ◽  
Euler Deconvolution ◽  
Structural Index ◽  
Geological Information ◽  
Geophysical Measurement ◽  
Deconvolution Techniques

Abstract The geophysical measurement of variations in gravitational field of the Earth for a particular location is carried out through a gravity survey method. These variations termed anomalies can help investigate the subsurface of interest. An investigation was carried out using the airborne satellite-based (EGM08) gravity dataset to reveal the geological information inherent in a location. Qualitative analysis of the gravity dataset by filtering techniques of two-dimensional fast Fourier transform (FFT2D) shows that the area is made up of basement and sedimentary Formations. Further enhancements on the residual anomaly after separation show the sedimentary intrusion into the study area and zones of possible rock minerals of high and low density contrasts. Quantitative interpretations of the study area by 3-D Euler deconvolution depth estimation technique described the depth and locations of gravity bodies that yielded the gravity field. The result of the depth to basement approach was found to be in the depth range of 930 m to 2,686 m (for Structural Index, SI = 0). The research location is a probable area for economic mineral deposits and hydrocarbon exploration.

scholarly journals Analysis of gravity and aeromagnetic data to determine structural trend and basement depth beneath the Ajdabiya Trough in northeastern Libya

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Abdelhakim S. Eshanibli ◽  
Abel Uyimwen Osagie ◽  
Nur Azwin Ismail ◽  
Hussin B. Ghanush
Keyword(s):  
Gravity Data ◽  
Depth Estimation ◽  
Magnetic Data ◽  
Aeromagnetic Data ◽  
Pass Filter ◽  
Magnetic Basement ◽  
Basement Depth ◽  
Well Data ◽  
High Pass ◽  
Modelling Process

AbstractIn this study, we analyse both ground gravity and aeromagnetic data in order to delineate structural trends, fault systems and deduce sedimentary thicknesses within the Ajdabiya Trough in Libya’s northeast. A high-pass filter and a reduced-to-the-pole (RTP) transformation are applied to the gravity and aeromagnetic data respectively. Different filters are used to enhance the structural signatures and fault trends within the study area. The Werner deconvolution and source parameter imaging (SPI) techniques are applied to the RTP magnetic data for source depth estimation. Four well-data within the area are used as constraints in the two-dimensional forward modelling process. The results show that the Ajdabiya Trough is characterised by gravity anomaly highs and magnetic anomaly lows. The analysis of gravity data shows predominant Northeast–Southwest structural trends, whereas the analysis of magnetic data shows predominant North–South magnetic lineaments within the Ajdabiya Trough. The Euler deconvolution depth estimates of faults depths range between 1500 and 9500 m. The SPI estimates of the magnetic basement range between 2500 and 11,500 m beneath the study area (deepest beneath the Ajdabiya Trough). Constrained by the well-data, six major layers characterize the four profiles that are taken within the area. One of the profiles shows a high-density intrusion (about 4 km from the surface) within the sedimentary sequence. The intrusion may be the result of the rifting Sirt Basin which caused a weakening of the crust to allow for mantle intrusion.

Characteristics of Fault Structures in the South Coastal Zone of Taizhou Based on Aeromagnetic Data

2021 ◽  
Author(s):  
Ming Wang ◽  
Shengjun Liang ◽  
Jiaojiao Li ◽  
Xiaoxing Lin ◽  
Yongjun Zhang
Keyword(s):  
Coastal Zone ◽  
Aeromagnetic Data ◽  
The South ◽  
Fault Structures
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