CO2-brine-rock interactions: The effect of impurities on grain size distribution and reservoir permeability

The Bunter Sandstone formation in the UK’s southern North Sea has been identified as having the potential to store large volumes of CO2. Prior to injection, CO2 is captured with certain amounts of impurities, usually less than 5%vol. The dissolution of these impurities in formation water can cause chemical reactions between CO2, brine, and rock, which can affect the reservoir quality by altering properties such as permeability. In this study, we explored the effect of CO2 and impurities (NO2, SO2, H2S) on reservoir permeability by measuring changes in grain size distributions after a prolonged period of 9 months, simulating in situ experimental conditions. It was found that the effects of pure CO2 and CO2-H2S are relatively small, i.e., CO2 increased permeability by 5.5% and CO2-H2S decreased it by 5.5%. Also, CO2-SO2 slightly decreased permeability by 6.25%, while CO2-NO2 showed the most pronounced effect, reducing permeability by 41.6%. The decrease in permeability showed a correlation with decreasing pH of the formation water and this equally correlates with a decrease in geometric mean of the grain diameter. The findings from this study are aimed to be used in future modelling studies on reservoir performance during injection and storage, which also should account for the shifts in boundaries in the CO2 phase diagram, altering the reservoir properties and affecting the cost of storage

Anxiety and depressive disorders among infertile women attending clinic in a Nigeria teaching hospital

Children are highly valued, and childlessness is culturally not acceptable in any typical sub-Saharan African community. Involuntary infertility is associated with significant distress and psychological disturbances, and different psychiatric disorders have been reported among women undergoing fertility treatment. This study aimed to determine prevalence of anxiety and depressive disorders and factors that were predictive of these disorders among women with infertility problem that were attending clinic at a Northeastern Nigerian Teaching Hospital. The study was a cross-sectional, questionnaire-based survey of two hundred and seven adult women on treatment for infertility. Their sociodemographic variables were obtained by the use of pro formal questionnaire and clinical parameters were obtained from their case notes. Hospital anxiety and depression scale was used to determine the presence of anxiety and/or depression using cut-off point of 11. Eighty-five respondents had anxiety and/or depressive disorders which constituted 41.1% of the studied population. Fifty-seven respondents (27.5%) had anxiety disorders while fifty-three (25.6%) had depression and thirty-seven-people (17.9%) had co-morbidity for both disorders. The factors that were predictive of depression were: previous marriage, lack of support, stigmatizing behaviours, tuba-uterine factor as the cause of infertility and surgical method of treatment. Similarly, factors that were predictive of anxiety disorder were: stigmatizing behaviours and lack of supports. Others were long duration of infertility treatment and surgical treatment for infertility as against medical treatment. This study found high prevalence of depression and anxiety disorders among women on treatment for infertility and recommend that more attention be paid to their mental health.Keywords: infertility, anxiety disorder, depression, NigeriaAfr. J. Biomed. Res. Vol. 22 (May, 2019); 157- 16

Weight Loss Corrosion Study of Some Metals in Acid Medium

This research was undertaken to examine the corrosion behavior of some metals in different acid solutions using weight loss technique. The magnitude of corrosion of these metals in 0.5 – 3.0 M of solutions of HCl, H2SO4, and HNO3 was studied for an exposure period of 100 minutes (at 20 minutes interval). Rate of corrosion in metals followed this order: zinc > galvanized iron > copper >, while rate of corrosion in aqueous media followed this order: HNO3 > H2SO4 > HCl. It has been obtained that concentration increase leads to increase in rate of corrosion. Further study on the corrosion kinetics has revealed that the rate of reaction of the metals increases with increase in solution concentration, while the half life decreases with increase in solution concentration

Workflow for building and calibrating 3D pre-injection and 4D geomechanics modelling to assess caprock and fault integrity for geologic CO2 storage

Carbon capture and storage (CCS) has been established as a viable technology for the mitigation of climate change caused mainly by anthropogenic greenhouse gas emissions into the atmosphere. Ever since the publication of the special report on CCS by the Intergovernmental Panel on Climate Change in 2005, there has been an increased research and development in all areas of CCS. Some of these research involves use of numerical methods and models for optimizing storage and ensuring effective long term containment. In this paper, we propose a workflow for building and calibrating 3D preinjection and 4D geomechanics modelling to assess caprock and fault integrity for geologic carbon dioxide storage. The workflow presented here describes a seamless end -to-end process which combines a transparent flow of data with an easy-to-use graphical user interface. The workflow can conduct 3D static and 4D flow-, pressure-, and temperature-coupled calculations for rock deformations, failure and stresses. In highly heterogeneous and complex models, the workflow is capable of modelling multiple hundred faults, and multiple thousand discrete fractures. It allows the geological model, despite its high degree of complexity to be maintained throughout the geomechanical analyses process

BET Surface Area Determination of Calcium Oxide from Adamawa Chalk Mineral Using Water Adsorption Method, for Use as Catalyst.

This paper describes a test procedure for determining the total surface area of chalk mineral using the water adsorption method. The test involves saturating the thermally treated chalk sample with saturated salt solution of known relative humidity, until the water vapor forms a monomolecular layer on the treated chalk sample surface. The results of the test are expressed as Specific Surface Area (SSA), which describes the surface area/unit mass of dry treated sample with units of m2g-1. The test results presented demonstrate the BET isotherm of chalk samples after being thermally treated at 700, 900, 1100 and 1200oC. Results for a number of different treated chalk samples are presented. The proposed method uses simple and inexpensive laboratory equipment, is relatively simple to perform, and allows for rapid determination of SSA. Keywords: specific surface area, chalk mineral, water vapor, BET isother

Effects of habitat and beehive type on the yield of honey in Hong local government area of Adamawa state, Nigeria.

The study examined the effects of habitat and beehive type on the yield of honey in Hong Local Government Area of Adamawa State. Habitat potentials that could guarantee possible apicultural industry have not been examined in the study area. Data on list of plant species (trees and shrubs plants) utilized by honeybees were obtained through ocular assessment and total count method. Information on the micro-climatic factors were gathered from the Department of Meteorological Services, Adamawa State University, Mubi. Yield of honey was recorded from different bee hives for 2 years. Data on species of plants visited by honeybees were subjected to descriptive statistics (*occasionally, **frequently and *** very frequently visited), while that on woody plant species diversity was analyzed using Simpson Diversity Index. Multiple regressions were used in the assessment of effect of micro-climatic factors, woody plant species diversity on the yield of honey. A total of 19 trees belonging to 12 families and 13 shrubs belonging to 7 families were visited either occasionally, frequently and very frequently by honeybees in the study area. Results of woody and herbaceous plant species diversity indicated 0.807638712 and 0.903150826 respectively. Woody plant species diversity (11.297**) and temperature (0.527*) contributed more than other factors {P<0.05}. R.Square (65.9%) indicated high coefficient of determination between the determinant factors. Total honey yield of 94.30kg and 60.40kg were obtained for first and second years respectively. Langstroth and clay pot hives had the highest (38.39kg) and lowest (8.50kg) yields in the first year; while Israeli top-bar (25.30kg) and clay pot (4.50kg) were noted in the second year. Further research on plants visited by honeybees and their nectar status has been recommended.Keywords: Habitat, effects, beehives, honey yiel

A review of developments in carbon dioxide storage

Carbon capture and storage (CCS) has been identified as an urgent, strategic and essential approach to reduce anthropogenic CO2 emissions, and mitigate the severe consequences of climate change. CO2 storage is the last step in the CCS chain and can be implemented mainly through oceanic and underground geological sequestration, and mineral carbonation. This review paper aims to provide state-of-the-art developments in CO2 storage. The review initially discussed the potential options for CO2 storage by highlighting the present status, current challenges and uncertainties associated with further deployment of established approaches (such as storage in saline aquifers and depleted oil and gas reservoirs) and feasibility demonstration of relatively newer storage concepts (such as hydrate storage and CO2-based enhanced geothermal systems). The second part of the review outlined the critical criteria that are necessary for storage site selection, including geological, geothermal, geohazards, hydrodynamic, basin maturity, and economic, societal and environmental factors. In the third section, the focus was on identification of CO2 behaviour within the reservoir during and after injection, namely injection-induced seismicity, potential leakage pathways, and long-term containment complexities associated with CO2-brine-rock interaction. In addition, a detailed review on storage capacity estimation methods based on different geological media and trapping mechanisms was provided. Finally, an overview of major CO2 storage projects, including their overall outcomes, were outlined. This review indicates that although CO2 storage is a technically proven strategy, the discussed challenges need to be addressed in order to accelerate the deployment of the technology. In addition, beside the necessity of techno-economic aspects, public acceptance of CO2 storage plays a central role in technology deployment, and the current ethical mechanisms need to be further improved

Genetic relationships among okra (Abelmoschus esculentus (L.) Moench) cultivars in Nigeria

This study was conducted on okra (Abelmoschus esculentus (L.) Moench) cultivars at the Teaching and Research Farm, University of Maiduguri, Nigeria. The objective was to evaluate the level of genetic divergence and heritability of eight characters in 2015 and 2016 dry seasons using irrigation. The results showed highly significant (p<0.01) differences in the ten okra cultivars for days to anthesis, plant height, fresh capsule length, fresh mass per capsule and fresh capsule diameter across the two years. A high genotypic coefficient of variation, heritability, and genetic advance were detected in all the characters except for days to anthesis and fresh capsule diameter. This implied that different genetic constitution and preponderance of additive effects governed these characters, thus presenting a significant opportunity for selection. The Mahanalobis D2 analysis allotted the ten cultivars into four clusters. The highest was cluster I comprising four cultivars, followed by cluster II containing three cultivars, cluster III consisting two cultivars, and cluster IV with mono genotypic. The three most superior okra cultivars (Salkade, Y’ar gagure and Kwadag) for yield and related characters could be exploited directly or introgressed with other promising ones in future breeding programs

Prevalence of malaria parasites among blood donors in Kaduna, Nigeria

Background: Transmission of malaria parasites through blood transfusion is a well-known serious risk. Screening of blood donors for malaria as recommended by WHO is currently not included in the protocols of many Nigerian blood banks. Presence of asymptomatic Plasmodium species carriers (APCs) in some northern parts of the state has already been demonstrated using rapid diagnostic tests (RDTs) and microscopic examination of Giemsa stained blood films. This research was undertaken to determine the prevalence of malaria parasites among blood donors in Kaduna state, Nigeria.Methods: A cross sectional study was conducted among the blood donors in the three selected Hospitals of Kaduna state. A well-structured questionnaire was used to collect the data regarding demographic profile. Written informed consent was obtained and questionnaire was completed by respondents selected through simple random sampling. 360 blood donors were tested for malaria parasites through microscopic examination of Giemsa stained thick and thin blood films. The data were analysed using Statistical analysis system (SAS) and statistical software for social sciences (SPSS) version 20.Results: A total of 27 (7.5%) of the blood donors had malaria parasites in their blood. Plasmodium falciparum was the only malaria parasite species encountered. There were no mixed infections and no other blood parasites were observed. The prevalence of malaria parasites in the blood donors was significantly associated with occupation (c2=24.0845, df=6, p= 0.0005) and blood group (c2=10.589, df=4, p= O.032). The infected subjects had parasites densities of between 88-250 parasites/µl with a mean parasite density of 126 parasites/µl of blood.Conclusions: The prevalence of malaria parasites among blood donors was 7.5% Blood donors should be routinely screened for malaria parasites and the blood marked negative or positive as the case may be. Recipients of malaria parasites positive blood should be given prophylactic treatment to prevent transfusion related malaria (TRM).

Diversity of Rotavirus VP7 and VP4 Genotypes in Northwestern Nigeria

Background. Nigeria has recently been ranked third among the 10 countries with the greatest number of rotavirus disease-associated deaths per year. Estimates attribute up to 33,000 deaths annually to rotavirus disease in Nigerian children <5 years old. Although the introduction of the new oral, live attenuated rotavirus vaccines may not occur for another 4-6 years in developing countries, background data on burden of disease, cost of rotavirus disease, and characterization of circulating strains is required to hasten this introduction to children who would clearly benefit from the intervention. Methods. Between July 2002 and July 2004, fecal specimens were collected from 869 infants and young children <5 years of age presenting with diarrhea in Kaduna, Kebbi, Sokoto, and Zamfara states in northwestern Nigeria. In addition, 194 control specimens were also collected from children matched for age. Specimens were screened for the presence of rotavirus antigens. Rotavirus-positive specimens were further analyzed to determine electropherotype, subgroup specificity, and G and P genotypes. Results. Rotavirus was detected in 18% of children with diarrhea and 7.2% of the age-matched case control subjects. The highest rotavirus burden was detected in children aged <6 months. The majority of the rotaviruspositive specimens revealed viruses of long electropherotypes, subgroup II specificity, and G1P[8] genotypes. Furthermore, more than a quarter of specimens (37%) displayed mixed G and P genotypes, and almost a third could not be genotyped. Conclusions. The high numbers of mixed rotavirus infections highlight the multitude of enteric pathogens to which children in African countries are exposed. Data on circulating rotavirus strains serve to inform African government officials to the serious health threat posed by rotavirus in their respective countries and to document the diversity of strains before vaccine introductio