Asian Journal of Geological Research <p style="text-align: justify;"><strong>Asian Journal of Geological Research</strong> aims to publish high-quality papers (<a href="/index.php/AJOGER/general-guideline-for-authors">Click here for Types of paper</a>) in all areas of Geology. The journal also encourages the submission of useful reports of negative results. This is a quality controlled, OPEN peer-reviewed, open access INTERNATIONAL journal.</p> en-US (Asian Journal of Geological Research) (Asian Journal of Geological Research) Wed, 29 Apr 2020 07:37:31 +0000 OJS 60 Petrophysical Evaluation of H-field, Onshore Niger Delta Sedimentary Basin, Nigeria <p>Petrophysical evaluations for three reservoirs, H_3, H_5 and H_7 in four wells, H-002, H-007, H-009 and H-011 were carried out to evaluate the distribution of hydrocarbon in the reservoir rocks found within H-field onshore Niger Delta.&nbsp; A suite of well logs such as gamma ray (GR), resistivity (LLD), caliper (CALI), compressional sonic (DT) and density (RHOB) logs were analyzed over H-field and shale volume, total porosity, effective porosity, water saturation and permeability were the petrophysical parameters estimated. Three reservoir sand were identified and correlated from four wells (H-002, H-007, H-009, H-011) using gamma ray and the average thickness for the three reservoirs H_3, H_5 and H_7 estimated were 106.50 ft, 23 ft and 174.25 ft respectively. The average values of volume of shale, effective porosity, total porosity, permeability, water saturation and hydrocarbon saturation of the delineated reservoir sands are 16.04 ft, 3.14 ft and 24.18 ft for shale volume, 18.5%, 18%, 18% for effective porosity, 20.25%, 20.25%, and 20% for total porosity, 1582.3515 mD, 1278.8912 mD and 1570.058 mD for permeability, 44%, 42.75% and 44% for water saturation and 56%, 57.25% and 56% for hydrocarbon saturation for reservoirs H_3, H_5 and H_7 respectively. Due to the low value of shale volume, water saturation and the good porosity and permeability nature of the reservoir which depicts the distribution of hydrocarbon in the wells within the field.&nbsp; Core data Acquisition, volumetric analysis and Interpretation within the reservoirs should be carried out to reduce uncertainties in exploration and production risk.</p> E. H. Edohor, A. O. Balogun ##submission.copyrightStatement## Wed, 29 Apr 2020 00:00:00 +0000 Structural Analysis Using Integrated Aeromagnetic Data and Landsat Imagery in a Basement Complex Terrain, Southwestern Nigeria <p>In this study, different digital format data sources including aeromagnetic and remotely sensed (Landsat ETM+) data were used for structural and tectonic interpretation of the southwestern part of Ilesha, Osun State, Nigeria. Aeromagnetic data were analyzed using advanced processing techniques (Spectral analysis, deconvolution). The aeromagnetic interpretation was carried out using the Butterworth filter, reduction to equator, derivative filters and Euler deconvolution. The results were improved by the study of enhanced Landsat ETM+ images and correlated with the extracted surface lineaments. Two main lineament sets are observed in the study area. The major lineaments strike NW-SE, NE-SW and the minor E-W. General coincidence of both landsat and aeromagnetic lineaments trends were observed in the study area, reflecting the real continuous fractures in the depth. The 3D Euler deconvolution and radial spectral analysis applied to locate and estimate the depth to anomalous bodies, shows varying depth between 48 m and 280 m. The map revealed the presence of major and minor faults, fractures as well as rock boundaries with the frequency of fracturing. This suggests that the major fractures and faults in the area are deep seated within the basement formation since that the spectral analysis enhances the anomalies associated with deep magnetic sources. The processed image displays the lineaments trending NE-SW directions.&nbsp; The new structural map derived from the combined aeromagnetic data and landsat imagery, provides an effective tool for analyzing subsurface structure in the region.</p> S. O. Ilugbo, H. O. Edunjobi, O. E. Adewoye, T. O. Alabi, A. I. Aladeboyeje, O. O. Olutomilola, D. T. Owolabi ##submission.copyrightStatement## Tue, 26 May 2020 00:00:00 +0000 Modification of Zoeppritz Equations and Its Implications for Hydrocarbon Exploration: A Case Study of an Onshore Niger Delta Sedimentary Basin <p>Zoeppritz equations are used to determine the reflection coefficient against the angle curves, which are often valid only for small seismic parameter changes across reflectors, but generally inaccurate close to the critical angle. These inaccuracies affect the quality of amplitude variations with offset (AVO) analysis, which might results in systematic errors when estimating relative seismic parameter variations at the reflectors. Thus modifying the Zoeppritz equations at the given angles allows for more accurate estimation of the usual AVO attributes, such as intercept, the gradient, and a possible third coefficient, which often leads to a better estimation of seismic-parameter contrasts at reflecting interfaces. The modification of Zoeppritz equations was analyzed using well data from oil fields in a sedimentary basin, onshore of Niger Delta area. This paper analyzed the modification of Zoeppritz equations and using them in AVO analysis to collect information on how seismic amplitudes vary with incident angles, which when combined with the P-P reflectivity (R<sub>PP</sub>) or the P-S Reflectivity (R<sub>PS</sub>) expressions, is used to obtain information on the properties of the earth layers, with the emphasis only on interface reflectivity, while thin-bed effects, attenuation and other propagation factors well known to influence AVO measurements are not considered. The modified equations are subsequently used to generate the AVO reflectivity curves, the results obtained shows that the modified Zoeppritz predicted the AVO effects correctly for the different zones of interest in the basin. The results show that the Shuey’s approximation gives better accurate results up to angle of 30<sup>0</sup> compared with others approximations, while the 3-term approximation shows that the modified Zoeppritz equations predicted AVO response accurately to about 50<sup>0</sup> of angle of incident. The result obtained can also be used to classify the different sand base types and their fluid contents, either oil, gas or brine sand base.</p> Balogun Ayomide, Adekunle Sofolabo ##submission.copyrightStatement## Mon, 22 Jun 2020 00:00:00 +0000 Engineering Geological Investigation of Pavement Failure along Emure Ekiti-Akungba Akoko Road, Southwestern Nigeria <p><strong>Aim:</strong> This engineering geological investigation work was carried to investigate the causes of persistence failure of a section of Emure Ekiti/Akungba Akoko road, Southwestern Nigeria.</p> <p><strong>Methodology:</strong> A total of 10 disturbed soil samples were collected from different locations at a common depth of 2 m. The samples were analyzed for natural moisture content, grain size analysis, Atterberg limits, standard compaction and California Bearing Ratio (CBR) test.</p> <p><strong>Results:</strong> The laboratory tests on the samples revealed that moisture content ranged from 4.10 - 6.20%, liquid limit from 29.01 - 41.13%, plastic limit from 18.05 - 22.30%, linear shrinkage from 4.8 - 8.7% and plasticity index from 10.96 - 20.03%. The grain size analysis showed that the amount of fines ranges from 15.0 - 33.0%. The specific gravity ranged from 2.67 - 2.77, maximum dry density from 1848 – 1888 kg/m<sup>3 </sup>and optimum moisture content from 17.4 - 18.4%. California Bearing Ratio (CBR) test for the investigated soil samples range from 31 - 39%. The overall results obtained revealed that the subsoil materials have good engineering qualities for engineering purposes in accordance with the Federal Ministry of Works and Housing specification for roads and bridges. Therefore, the reduction in the apparent strength of the subsoil materials that led to the observed road failure is possibly as a result of water infiltration into the structural section of the road pavement, particularly at the base layer.</p> <p><strong>Conclusion:</strong> Therefore, the pavement needs to be strengthened through adequate drainage facilities to improve its capacity, durability and performance.</p> O. A. Oluwakuse, M. M. Oluwakuse, I. A. Adeyemo ##submission.copyrightStatement## Mon, 22 Jun 2020 00:00:00 +0000