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Knowledge of reservoir fluid properties is very important in reservoir engineering calculations such as reserves estimates, material balance equation, and numerical reservoir stimulation etc. Laboratory measurements are the most dependable methods for pressure-volume-temperature (PVT) analysis of reservoir fluid properties. During reservoir performance evaluation, the measurements of PVT data are not readily available, hence engineers resort to the use of existing empirical correlations to obtain PVT data. Often time, the data obtained from correlations do not agree with the experimental data, thereby yielding a considerable amount of error. To correct that error in this study, Kartoatmodjo and Schmidt correlation for estimating the oil formation volume factor was optimized using the particle swarm optimization (PSO) algorithm to minimize the error in estimating the oil formation volume factor from Kartoatmodjo and Schmidt correlation at various depletion pressure. The optimized correlation is a function of bubble point pressure, API gravity, gas gravity and reservoir temperature. Therefore, to validate the optimized correlation, PVT data from differential liberation test in the laboratory was used as case a study and the result obtained with the optimized correlation matches closely with the experimentally values at various depletion
pressure. Also, the Kartoatmodjo and Schmidt optimized correlation was validated with Standing, Kartoatmodjo and Schmidt, Glaso and Petrosky-Fashad correlations. The optimized Kartoatmodjo and Schmidt gave the least average relative error of ±0.00065 and the highest correlation coefficient of 0.99996 after 154th successive iterations with the PSO algorithm.

Principles of sequence stratigraphy have been applied in the study of the Emi Field, Offshore Depobelt, Eastern Niger Delta. Using 3D seismic data, wireline logs of six wells, check shots, and biostratigraphic data sets, two sequence boundaries and three maximum flooding surfaces were identified as the key surfaces of three depositional sequences. Marker shales, characterized by index fossils Haplophramoides-24 and Bolivina-48 were used to date the maximum flooding surfaces, separated by the 5.6 Ma and 4.1Ma sequence boundaries. Based on log motifs and biostratigraphic data, the stratigraphic interval penetrated by the six wells was inferred to be
deposited in a neritic paleoenvironment. Two major faults named F1 and F3 run across the study area and closures considered as good hydrocarbon prospects were identified and delineated. Analysis of horizons within the sequences and individual systems tracts reveals that hydrocarbon is hosted both in reservoirs within the transgressive systems tracts and highstand systems tracts. The existence of reservoirs, and the presence of well-developed fault systems in the sands associated with the systems tracts, indicates that the Emi field has great potential for hydrocarbon productivity.

Pressure transient testing provides an indirect determination of reservoir and well parameters, it is one of the most essential techniques used to provide details about the reservoir characteristics and well conditions. There are several tests available to properly characterize well and reservoir parameters, in this study, drawdown test is considered with an objective to obtain permeability and skin of a reservoir within the drainage area, from a pressure survey data. Several methods have been developed to obtain skin and permeability from drawdown
test, the conventional method uses the graphical technique where the pressure and time data are analyzed with a semi-log plot. The results obtained do not equate the actual parameters of the reservoir, therefore, there is a need to optimize this error. This study is focused on minimizing the error in the mathematical model with particle swarm optimization algorithm. The manual analytical method and the particle swamp algorithm were done in Microsoft Excel. Data was obtained from a well in the Niger Delta region of Nigeria. The results from the algorithm showed a higher level of accuracy, compared to the results obtained from the manual analytical method. The statistical analysis indicates a better result with the particle swamp optimization algorithm, with a relative error of 0.0510 against the 3.9743 from the conventional method. Also, correlation coefficient, R-value of 0.9999 against 0.4733 from the conventional method.

Drilling mud are complex heterogeneous fluids consisting of several additives. Cellulose from waste paper are viscosity builder in polymers, its use as viscosifier additive will reduce overall well cost, improve waste anagement while reducing environmental pollution. This study experimentally examined the effectiveness of waste paper cellulose as a viscosifier. Rheological properties such as density, pH and rheology (plastic viscosity, yield point) tests were performed and compared to a control mud. The mud samples were beneficiated to meet API specification for drilling fluids. At temperatures 28, 45 and 60 ˚C, the sample and control muds had the same density of 8.7 lb/gal; the pH values were 7.5 and 7.7, respectively. They have the same average plastic viscosity of 4.3 (±0.3) cp; while the average yield point values were 17.0(±0.3) and 12.0(±0.4) lb/100sqft, respectively. After the mud samples were beneficiated, results showed that, the sample mud with density of 8.8 lb/gal, pH of 9.0±0.4, average plastic viscosity of 12 cp and yield point of 37 lb/100sqft compared with control mud density of 8.7 lb/gal, pH of 9.3±0.3, average plastic viscosity of 11 cp and yield point of 40 lb/100sqft. Results showed that cellulose extracted from waste paper can replace standard viscosifiers.

Gasoline station workers (GSWs) are occupationally exposed to gasoline daily. Our previous study on the toxicological and biochemical profile of GSWs in Onitsha, Anambra state revealed that GSWs are at risk of benzene and Lead-mediated toxicity. This was because the GSWs had increased methaemoglobin (used as a biomarker to measure benzene) and blood lead levels. The aim of this paper was to assess the effects of gasoline on the haematological parameters of GSWs in Onitsha, Anambra State, Nigeria. The blood samples of 160 subjects (80 GSWs and 80 controls) were tested for the full blood count (FBC) which includes the total white blood cell count, red blood cell count, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, platelet count, haemoglobin concentration and packed cells volume. Questionnaires were distributed to the GSWs in order to ascertain their duration of exposure to gasoline. The GSWs were divided into three: group A (those exposed for 1 to 6 months) (n=34); group B (those exposed for 6 months to 2 years) (n=22); group C (those exposed for over 2 years) (n=24). Blood sample of 2 mls volume was collected by venepuncture and used for the FBC. The FBC was performed within 24 hours of sample collection. Ethical approval was obtained from the ethics committee of the Nnamdi Azikiwe University, Nnewi, Anambra state while the informed consent of the participants was duly sought and obtained. The FBC was analysed by flow cytometry using the Sysmex Autoanalyzer. The RBC count, MCH, MCHC, PCV and platelet count were significantly reduced in the GSWs when compared with the controls (p<0.05). The RBC count, WBC count, haemoglobin concentration, MCH, MCHC and PCV were highest among group A participants and lowest among group C participants (p<0.05). RBC count, MCH, MCHC, PCV and platelet count were significantly reduced in the test subjects compared to the controls and this could imply ongoing anaemia among the GSWs. The Red Blood Cell and White Blood Cell counts, Haemoglobin, MCH, MCHC and Packed Cells Volume were highest among group A workers and lowest among group C. These findings, just like in the previous one, also suggests that GSWs are highly exposed to toxic gasoline vapour, and reduced haematological parameters among the workers exposed for longer durations suggest the presence of iron deficiency anaemia and
leukocytopenia among these subjects which could consequently affect red blood cell production and functions, and also immunity.

Liquefied Petroleum Gas (LPG), as a product of natural gas processing that is a mixture of hydrocarbon gases mainly propane, butane, butylene and impurities such as Sulphur compound. LPG production and distribution in Nigeria appeared to have had limited growth over the last three decades before 2016. In this study, a stochastic model is applied to secondary historical data from 1994 to 2020, on the production, consumption and streamline distribution pattern for the country. Certain assumptions were made including changes in the various stages in the production value chains (production, storage, distribution, pipeline infrastructure, and supply chains) in-country.
Linear regression and correlation approaches were adopted, using the models which agreed with the plots from the Department of Petroleum Resources. It indicated that LPG consumption increased rapidly from 2016 upward following increases in infrastructural surplus, investment and awareness enlightenment initiatives. The results obtained have a strong correlation between demand-supply bond driven by market forces in the urban and suburban cities in-country. These indicators can be considered reliable parameters for sustainable strategic
planning, policy development and implementation for rapid economic recovery.