DESIGN AND CONSTRUCTION OF A METALLIC BIO-DIGESTER FOR THE PRODUCTION OF BIOGAS FROM COW DUNG

Biogas production has contributed greatly as an alternative source of fuel power to solving various developing nations’ problems including high dependency on petroleum products. This gives a clear objective why its production is seriously needed, as it plays a significant role in destroying and converting municipal and agricultural wastes into a useful fuel which can be used in homes and on farms for lighting, heating and moving equipment by supplying the fuel power needed This work focused on design and construction of a metallic bio digester for the production of biogas. Cow dung was mixed with water in ratio 1:2 of particulate mass. The experiment was carried out in a metallic digester under mesophilic temperature. The average retention time for the experiment was 30days. The average internal temperature of the biogas digester was 32.3oC. The total volume of biogas produced was 5.208 m3. The concentrations of methane and carbon dioxide in the biogas produced were found to be 59% and 40% respectively. The developed metallic bio-digester has been found to be appropriate for the production of biogas from cow dung at mesophilic temperature

THE IMPACT OF PERFORATION GEOMETRY ON OIL WELL PRODUCTIVITY

The increase in demand for oil and gas today requires oil operators to maximize productivity. In order to produce more fluid from the reservoir into the wellbore, perforations must penetrate considerably beyond invaded zone with impaired permeability. The production engineers must take advantage of the perforation controllable parameters to maximize the well productivity. In this study, a simple analytical model incorporating perforation length, radius, and shot density was used to analyze oil well productivity. The results shows that the production rate can be increased by the perforation length, radius, and shot density. The drawdown pressure was reduced with increase in the perforation length and shot density. Higher fluid velocity was controlled with increase in the shot density, length and radius of perforation. The length of perforation and shot density are better in optimizing well productivity. Optimum perforation parameters are required as further increase result in increase in cost relative to the productivity

Rock Compaction Fault Displacement Evidence from Analysis of Sub-Parallel Subsurface Strata

Sedimentary units often show compaction variation across fault blocks resulting from jarring vertical shortening; a common occurrence in growth fault system innate to the Niger Delta. Rock displacement traceable on slip surface with varied dip was mapped on 3D seismic data. Interpretation done on available well logs reveal existing zones of sand formation that fairly correlates with compaction patterns seen on seismic lines across fault blocks with reference to vertical deviations in horizons across fault planes. These anomalies were stochastically analyzed for its topology effects using Density logs from the field in an attempt to ascertain the influence of rock strata on fault displacement and how this translates to compaction patterns. It was discovered that the effect of differential compaction propelled by wobbly underlying rocks primarily drives the local complexities imaged on the seismic data as varied turgid deformation zones also prolific from computed seismic attributes

EXPERIMENTAL STUDY OF SWELLING CAPACITY OF EWEKORO SHALE, SOUTH WESTERN NIGERIA: CASE STUDY-USING OIL-IN-WATER EMULSION MUD.

The formulation of drilling mud plays a very important role in providing optimum drilling operations in reducing or preventing the occurrence of challenges in the wellbore. One of the most challenging formations faced by the drilling operators is the shale; it is been discovered that approximately 90 % of formation drilled in the oil and gas industry is shale, and about 70 % of the challenges during drilling are shale related. This study is focused on investigating the swelling capacity of shale from Dahomey basin in Nigeria in emulsion mud formulated with diesel oil and non-edible plant oils (Hura crepitans and Calophyllum inophyllum). The shale sample was studied under the influence of water-based mud and emulsion mud. The physicochemical properties of plant oil samples were analyzed, the mud was formulated and rheological and filtration properties were measured. The swelling rate and water absorbed of the shale samples were determined. It was discovered that the plant oil performed better than the diesel oil, with oil from Hura crepitans been efficient in reducing the shale/fluid interaction and by so doing, reducing the swelling rate and water absorbed by the shale. The volume of fluid loss was discovered to be less than that observed from diesel and Calophyllum inophyllum oil

Rock Compaction Fault Displacement Evidence from Analysis of Sub-Parallel Subsurface Strata

Sedimentary units often show compaction variation across fault blocks resulting from jarring vertical shortening; a common occurrence in growth fault system innate to the Niger Delta. Rock displacement traceable on slip surface with varied dip was mapped on 3D seismic data. Interpretation done on available well logs reveal existing zones of sand formation that fairly correlates with compaction patterns seen on seismic lines across fault blocks with reference to vertical deviations in horizons across fault planes. These anomalies were stochastically analyzed for its topology effects using Density logs from the field in an attempt to ascertain the influence of rock strata on fault displacement and how this translates to compaction patterns. It was discovered that the effect of differential compaction propelled by wobbly underlying rocks primarily drives the local complexities imaged on the seismic data as varied turgid deformation zones also prolific from computed seismic attributes

Comparative Characterization of Petrophysical and Mechanical Properties of Siliciclastic Reservoir Rocks within a compressional structure of the Teapot Dome Oilfield, Wyoming, USA

Working with subsurface engineering problems in Hydrocarbon exploration as regard rock elastic and petrophysical properties necessitate accurate determination of in-situ physical properties. Several techniques have been adopted in correlating log-derived parameters with petrophysical and mechanical behavior of the rocks. However, limited field applications show there are no particular parameters and correlations that are generally acceptable due to the regional variation in geologic features (i.e., degree of mineralogy, texture, etc.). This study presents a method that assesses the disparity in petrophysical properties of oil and gas reservoir rocks in relation to their elastic/mechanical properties from 10 well-logs and 3D migrated seismic data. Two distinct facies were identified from seismic data after computing attributes. Reflection strength attribute of 2.5 and above depicts Bright spots within the central section of the field as clearly revealed by Variance and Chaos attributes. Formation properties calculated from logs were conformally gridded in consonance with the reflection patterns from the seismic data. The average Brittleness index (BI) of 0.52 corresponds to Young's modulus (E) values of between 8 and 16 for the dense portion. This portion is the laminated, reasonably parallel, and undeformed part, flanked by the unlaminated and chaotic zones. From cross plots, the distinguished lower portion on the plot is the segment with higher sand of more than 50 %. This segment corresponds to the reservoir in this study as confirmed from the genetic algorithm neural network Acoustic impedance inversion process result. Similarly, the plot of Compressional velocity (Vp) and Poisson’s ratio (ν), reveals the laminated sand value of not less than 0.32 of ν, and Vp of about 4.2 km/s. The average porosity is about 16 %, average water saturation is about 16 %, and average permeability is approximately 25 md. Rock properties trends in a unique pattern and showing fluctuation that confirms the compressive nature of the structure with corresponding petrophysical properties. This trend is sustained in permeability computed and suggests a significant gravity-assisted compaction trend and fluid movement. It gives a reasonable idea of the fluid movement interplay and mechanical property variation within the sequence and across the dome. This part probably has been subjected to fair compressional deformational forces initiated from outside the survey

Sequential Prediction of Drilling Fluid Loss Using Support Vector Machine and Decision Tree Methods

Machine learning methods have been applied to predict depths of fluid loss in hydrocarbon exploration.During drilling, lost circulation can be described as the unpleasant loss of all or part of drilling mud or fluid into the immediate formations or affected formation by excessive hydrostatic pressure, sufficient to fracture the formation or expand existing fractures encountered during the drilling process. In this study, we deployed Python codes of Support Vector Machine (SVM) and Decision Tree (DT) methodsto categorical data obtained from drilling operations in a producing field to predict lost circulation occurrence. The modelsleveraged the capability of both SVM and DT to achieve binary classification by adopting flow-out percentage of less than 70 percent as the points of lost circulation. That is, 70% represented asNo Loss. Prediction models were applied to 10 input variables preprocessed with principal component analysis (PCA) to reduce dimensionality and focus on essential variables. The preprocessed SVM model gave an improved result while preprocessing does not affect DT models. Overall, DT models predicted accurate fluid losszones and can be scaled up to field operations with options ofcontinuous sampled variables

Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from −90% to +30%, were reported in many countries following early COVID-19 pandemic response measures (‘lockdowns’). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95–0.98, P value <0.0001), second (0.96, 0.92–0.99, 0.03) and third (0.97, 0.94–1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96–1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88–1.14, 0.98), third (0.99, 0.88–1.12, 0.89) and fourth (1.01, 0.87–1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02–1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03–1.15, 0.002), third (1.10, 1.03–1.17, 0.003) and fourth (1.12, 1.05–1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways

Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries.

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from -90% to +30%, were reported in many countries following early COVID-19 pandemic response measures ('lockdowns'). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95-0.98, P value <0.0001), second (0.96, 0.92-0.99, 0.03) and third (0.97, 0.94-1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96-1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88-1.14, 0.98), third (0.99, 0.88-1.12, 0.89) and fourth (1.01, 0.87-1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02-1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03-1.15, 0.002), third (1.10, 1.03-1.17, 0.003) and fourth (1.12, 1.05-1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways

Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries.

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from -90% to +30%, were reported in many countries following early COVID-19 pandemic response measures ('lockdowns'). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95-0.98, P value <0.0001), second (0.96, 0.92-0.99, 0.03) and third (0.97, 0.94-1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96-1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88-1.14, 0.98), third (0.99, 0.88-1.12, 0.89) and fourth (1.01, 0.87-1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02-1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03-1.15, 0.002), third (1.10, 1.03-1.17, 0.003) and fourth (1.12, 1.05-1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways