Sedimentological studies of some pre-Santonian sandstones of the Asu River Group and the Eze-Aku Formation exposed in southeastern Nigeria were carried out. The study involved Intensive field work integrated with laboratory (Sedimentary petrography, X-ray diffraction (XRD), porosity and permeability determination). The study aims to determine the main controls on reservoir properties of these sandstones. The results revealed that the sandstone rocks within the study area comprised indurated sandstones that are poorly to moderately sorted, very fine–coarse grained arkosic arenites deposited in shallow to deep marine settings, associate with other non-reservoir lithologies (e.g. siltstones and shale). The sandstones depositional texture in many instances has been modified by biogenic structures that act to enhance the porosity of the sandstones. The porosity in the studied reservoir sediments ranges from 3.00 – 6.00; the permeability values range from 0.3mD – 3.5mD. X-ray diffractometry revealed that the following clay minerals constituted the major phase in the cementation of the sandstones viz kaolinite, mixed layer kaolinites (nacrite, dickite, halloysite, chrysotile, lizardite), illite, chlorite (corrensite) some silicates, carbonates and sulphate mineral groups. Compaction, cementation (carbonate, clay silica) bioturbations and dissolution of unstable framework grains are the principal diagenetic processes responsible for the modification of the reservoir quality of the sandstones within the study area.
Pebble morphometry of unbroken quartz pebbles collected from the basal section of Awi Formation exposed within the Calabar Flank; southeastern Nigeria was studied for paleoenvironmental reconstruction. The pebbles were selected from 4 locations across the Awi Formation. Morphometric studies carried out involved the measurement of the three orthogonal axes (long, intermediate and short), determination of their corresponding roundness, flatness indices and elongation indices for no less than 200 pebbles. The depositional processes responsible for shaping the pebbles and the environment that prevailed during past geological times were characterised. The results show that the pebbles are sub-rounded to sub-angular and predominantly compact-bladed. The mean values for the following morphometric parameters: Flatness index, elongation ratio, maximum projection sphericity index and oblate-prolate (OP) index are 0.57, 0.78, 0.74 and 15.65 respectively. The results were integrated with deductions from bivariate plots of roundness against elongation ratio and sphericity against OP index. Both plots indicated paleo-depositional environment of the conglomeratic sandstones in a fluvial setting with subordinate transitional marine setting (littoral influence). With the integration of other observations (e.g. unidirectional pebble imbrications, sediment stratification, fining upwards succession), a typical fluvial paleoenvironmental setting is suggested. The geology of the hinterland areas where sediments are sourced contributes largely to the materials at the depocenter. It is possible that the jointing, faulting, sheeting and/or exfoliation of the rocks of the Precambrian Oban Massif, which is believed to be the principal source of the sediments (provenance), also accounts for the abundance of vein quartz in the chosen area of this study. More importantly, besides the significance of pebble morphometry in deciphering paleoenvironments, it also gives clues for potential sites of ore bodies, concentrating them as placer deposits.
This study was conducted to evaluate the remediation of physicochemical properties of soils affected by fuel spills in Port Harcourt Environment. Four samples from four locations within Port Harcourt environment were investigated for four months. The study utilized a longitudinal experimental design (or randomized block design) where four locations were monitored over a duration of four months. this work was carried out in triplicates. The findings show an increase in SEM values of temperature (30.25±0.25oC), electrical conductivity (0.97±0.11uS/cm), sulphate (18.73±1.92mg/kg), total organic carbon (0.15±0.001%), total organic matter (0.26±0.01%), total hydrocarbon content (47.08±6.71mg/kg) and a decrease in pH (7.60±0.10) in diesel polluted soils when compared with the SEM values of control. Alternately, the concentration of phosphate and nitrate in both diesel and spent oil polluted soils reduced when compared with the control indicating a short fall in dissolved nutrients due to microbial activities. Positive remediation was seen in all the treatments used. However, a remediation mixture of 10% Sodium nitrate and 1% Potassium phosphate (10% NaNO3 + 1% K3PO4) remediated better and faster than when 10% Ammonium nitrate and 1% Potassium phosphate (10% NH4NO3 + 1% K3PO4) was used, and was more economical. Thus, establishing the fact that these chemicals can serve as a good option in any remediation process of the soil.
Mud logging is a critical geological technique that provides continuous subsurface information during drilling, thereby supporting accurate geological interpretation and informed operational decision-making. This study evaluates the NEPL Well EM-01, Alwa Ibom State, Nigeria, through the systematic application of mud logging principles, operational parameters, and field equipment to demonstrate the significance of mud logging in hydrocarbon exploration and real-time drilling evaluation. The methodology involved the integration of key mud logging tools, including shale shakers, gas detection systems, and log charts, with essential drilling parameters such as rate of penetration (ROP), weight on bit (WOB), and strokes per minute (SPM). The combined interpretation of these datasets enabled a comprehensive assessment of formation characteristics and drilling performance. Detailed examination of drill cuttings formed a central component of the study. Emphasis was placed on gas-bearing sandstone intervals where enhanced evaluation techniques were applied to reduce drilling risks. Result revealed that cuttings texture, staining, and fluorescence responses provided insights into lithological variations and hydrocarbon presence, with the identification of potential hydrocarbon-bearing zones and the differentiation of productive and non-productive intervals. The study further highlights the economic benefits of mud logging in minimizing drilling uncertainty and non-productive time, and recommends the adoption of advanced gas detection and data acquisition technologies for improved efficiency and safety.
Groundwater is the primary source of potable water for the inhabitants of Guyok and its surrounding communities in Northeastern Nigeria. Its quality is controlled by the geological formations through which it percolates and by anthropogenic activities. This study assesses the hydrochemistry of groundwater from boreholes and hand dug wells, with emphasis on major ions, physicochemical parameters, and bacteriological indicators. The analysed parameters were compared with World Health Organization (WHO,2017) standards to determine suitability for drinking and domestic use. Results show alkaline pH values ranging from 7.96 to 9.30, while electrical conductivity (234–321 µS/cm), total dissolved solids (157.1–273.0 mg/L), and total hardness (122.9–210.0 mg/L) fall within permissible limits. Major ion concentrations (Ca²⁺, Mg²⁺, Na⁺, K⁺, Fe²⁺, Mn²⁺, Cl⁻, NO₃⁻, and SO₄²⁻) also comply with WHO guideline values. In contrast, bacteriological analysis revealed elevated coliform counts in hand dug wells, reaching up to 27 cfu/mL, indicating susceptibility to microbial contamination. Overall, groundwater in the area is chemically suitable for domestic use; however, bacteriological contamination poses significant public health risks, including waterborne diseases such as diarrhoea, typhoid, and cholera. Variations between borehole and hand dug well water quality reflect differences in aquifer depth, geological protection, and land use practices. The findings provide baseline data for groundwater quality management in semi urban communities of Northeastern Nigeria and underscore the need for improved groundwater protection, routine monitoring, and community-based water treatment interventions.
