Theses and Dissertations

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Open Access
Detailed Subsurface Structural and Stratigraphic Interpretation of Kunbi Marginal Oil Fleld, Niger Delta, Using Three Dimensional (3-D) Seismic Reflection Data
(2015-04-29) Obaoye, Michael Olajide
The primary objective of this study was to determine the proven, probable and possible oil reserves in the supposedly marginal Kunbi Field as a means of establishing if the oil accumulation in the field is in commercial quantity. The methodology involved the integration of seismic 3-D structural and stratigraphic time interpretation; seismic attributes like reflection intensity, root means square amplitude and complex trace attributes like instantaneous amplitude, instantaneous frequency and phase to maximize information derivation from the field. Depth mapping was integrated with detailed petrophysical analysis to build a static model with constant petrophysical parameters which were used to calculate the reserves. Post well completion nuclear logging using Haliburton's Reservoir Monitoring Tool was conducted to re-establish oil contacts by measuring carbon-oxygen ratio and other elemental yields. Stratamplitude and complex trace attributes were extracted from the interpreted seismic to infer the field's depositional environments and facies. The gamma ray log characteristic shapes were also used in conjunction with reflection geometry and high resolution biostratigraphic studies to completely detail the sequence stratigraphic setting and depositional environment of the field; classify the reservoirs according to sedimentation stacking processes. The interpreted 3-D seismic time maps were then converted to depth maps using the average velocity method while a detailed petrophysical analysis was then integrated with the depth maps to build a static model which was used to calculate the original oil in place and ultimate recoverable reserves. The result of the analysis of stratamp in Excel showed that even though the reservoirs were optimally located structurally at all the eight oil bearing levels, some of them were not optimally located stratigraphic wise and require some lateral shifts from 35 meters up to 247 meters. Integration of seismic reflection geometry, logs' shapes interpretation and Stratamplitude study confirmed that the reservoirs in this depocenter were of shallow marine, deltaic, river mouth siliciclastic sand bars, fluviatile derived, transported and deposited under moderate to high energy regime and wave dominated. The result of the static modelling and the resulting reserves calculation revealed that Kunbi Field proven, probable and possible reserves were in excess of 99.5, 162.4 and 272.2 MMBL STOIIP prior to nuclear logging with Haliburton's Nuclear Reservoir Monitoring Tool compared with the previous estimation of proven reserves of 56.9 MMBL STOIIP using the 2-D seismic data. However, post completion nuclear logging suggested that the probable (P1+P2) reserves can be as high as 256 MMBOL as compared with 162 MMBOL STOIP above. It was concluded that in addition to the proved, probable and possible oil reserves in this field, there were other drillable updip and upside oil potentials within the farmout polygon.
Open Access
Extraction and Identification of Some Antioxidant and Antimicrobial Compounds from Urena Lobata (Linn) Leaves
(2015-03-23) Adeloye, Adewale Olufunsho
This study examined the extract of Urena lobata L. leaves for its antioxidant, antibacterial and antifungal activities with a view to isolating and characterizing the biologically active components that might be present and thus provide justification for the ethnomedicinal uses of the plant in the treatment of various diseases for which it was used. Urena lobata L. leaves were collected, identified and air-dried for 3 weeks after which they were ground into coarse powder and extracted at room temperature with 50% aqueous ethanol for 72 hours with occasional agitation. The filtrate was concentrated to dryness in vacuo on a rotary evaporator to obtain the crude extracts. The crude extract was dissolved in distilled water and then partitioned successively with four different organic solvents which included n-hexane, dichloromethane, ethyl acetate and n-butanol. The solvent fractions obtained were concentrated in vacuo and then evaluated for antibacterial, antifungal activities tests. In another bench-top bioassay antioxidant screening method, all the solvent fractions were screened for antioxidant activity using the rapid thin layer chromatographic method with l,1-diphenyl-2-picrylhydrazyl (DPPH) solution in methanol as detecting reagent. A detailed bioactivity guided fractionation was carried out on the ethyl acetate extract by gradient column chromatography using combination of Accelerated Gradient Chromatographic (AGC) method and Sephadex LH-20 adsorbent. Preliminary evaluation of the crude extract for antibacterial and antifungal activity using Agar-well diffusion method with streptomycin as standard antibiotic showed that the extract had a broad spectrum of activity against both Gram positive and Gram negative bacteria isolates. The ethyl acetate and n-butanol fractions had a fast antioxidant reaction with DPPH solution, while the n-hexane and dichloromethane fractions gave no reaction with the test reagent. Three flavonoid compounds were isolated from the ethyl acetate fraction namely: 1 kaempferol, 2 quercetin, and 3 tiliroside (3-O-β-D-(6"-O-transp-coumaroyl)-α-L-glucopyranosyl-kaempferol). The structures of the flavonoid compounds were determined from spectra obtained on them using infra-red, IH and 13C NMR. The study concluded that the isolated flavonoid compounds were part of the compounds responsible for the biological activity of Urena lobata leaf extract.
Open Access
Preparation and Conductivity Measurements of some Metal 9, 10- Dihydroxyoctadecanoates
(Obafemi Awolowo University, 1986) Mbaneme, Prince Chukwulozie; Akanni, M.S.
The preparation of 9,10-dihydroxyoctadecanoic acid is carried out using oleic and elaidic acids as reported by Swern and Co-workers. Characterization of the acids is done by taking the melting points and the infrared spectra. The 9,10-dihydroxyoctadecanoic acid obtained from Oleic acid is used in preparing lead(II), Zinc(II), Mercury(II) and Cadmium(II) 9,10-dihydroxyoctadecanoates. The identity of lead(II) and Zinc(II) 9,10-dihydroxyoctadecanoates is established by the results of the melting points, elemental analysis, IR and NMR spectra. The electrical conductances of the pure soap and some binary mixtures with the corresponding metal Octadecanoates are measured. It is found that while the plots of logarithm of conductivity against inverse temperature of the lead(II) 9,10-•dihydroxyoctadecanoate (Pb(OH)2A2) show a maximum, that of Zinc(II)9,10-dihydroxyoctadecanoate(Zn(OH)2A2 and its binary mixtures Zinc(II)octadecanoate/Zinc(II)9,10-dihydroxyoctadecanoate (ZnA2/Zn(OH)2A2) are linear. However, for the binary mixtures of lead(II)octadecanoate/lead(II)9,10-dihydroxyoctadecanoate (pbA2/Pb(OH)2A2) at low mole fractions (XPb(OH)2A2 <0.02) non-linear graph characteristics of the behaviour of lead(II) carboxylate systems are observed while for high mole fractions (XPb(OH)2A2 > 0.03) the shape of the curves resemble that of pure Pb(OH)2A2,the observance of a maximum in the system is interpreted in terms of the interaction of lead ions with the hydroxyl groups. Plots of molar volume against temperature for PbA2 /Pb(OH)2A2 show curvature in support of such interactions, suggesting deviations from ideal behaviour of the liquid systems. The activation energies for conduction and dissociation (ΔHKµ +ΔH/3) for the pure lead(II) and Zinc(II)9,10-dihydroxyoctadecanoates and their mixtures are obtained. For lead(II) octadecanoate/ lead(II)9,10-dihydroxyoctadecanoate at low mole fraction the enthalpy decreases steadily up to a point with increase in mole fraction and then increases. However, for the zinc soaps and its mixtures the enthalpy terms are found to be fairly constant with increasing mole fraction even when the actual conductivity falls.
Open Access
Preparation and Characterisation of Pyrolytically-Deposited Thin Oxide Films from Metal-Organic Compounds
(Obafemi Awolowo University, 1987) Lambi, John Ngolui; Ajayi, O.B.; Akanni, M.S.
A simple and versatile pyrolytic method of preparing thin metal oxide films that is based on the Metal Organic Chemical Vapour Deposition (MOCVD) technique and that is operative at relatively low temperatures (420°C) has been utilised to prepare the thin metal oxide films of indium, zinc, aluminium and copper from the appropriate metal acetylacetonate or carboxylate. To fully understand the pyrolytic route leading to film formation, the thermal decomposition of some of the starting materials was investigated in detail at 420°C in air and N,, using separately, a Muffle furnace and a flow system. The identities of the products as determined by a combination of techniques are Cu, CO2, a carboxylic acid and an odd chain-length alkene, in the case of the copper(II) soaps; ZnO, CO2 and a ketone for the zinc soaps; and a mixture of Cu, Cu20 and CuO in the case of the copper(II) acetylacetonate. While mechanisms have been proposed to account for the degradative routes of the soaps, which of the metal acetylacetonates is still inconclusive. A combination of Ion Beam, X-ray and optical absorption studies have shown that the oxide films of indium, zinc and aluminium are, of the expected stoichiometry, while that of copper is of mixed composition (CuO/Cu2O/Cu). It is not immediately clear why carbon and alkali metal contamination was observed for the Al2O3 and CuO/Cu2O/Cu films but not for the In2O 3 film. Scanning Electron Microscopy (SEM) has shown the films to be polycrystalline. The observed optical characteristics (high transmittances, T = 75-90%; moderate reflectances, R < 21%; low absorbances, A < 8%; high refractive indices, nf > 1.5 and low extinction coefficients, k < 0.4) are as expected for these thin films. Potential uses of these thin layers based on their observed properties are also discussed.
Open Access
Kinetics and Mechanism of Aquation of Tris (3, 4, 7, 8 - Tetramethyl - 1, 10 - Phenanthroline) Iron (II) Suphate in Aqueous Sodium Lauryl Sulphate.
(Obafemi Awolowo University, 1984) Soriyan, Oladega Omopariola; Ige, Jide
In this thesis we report the kinetics and mechanism of the aquation of tris(3, 4, 7, 8-tetramethyl1,10 phenanthroline) Iron(II) sulphate in aqueous micellar solution of Sodium Lauryl sulphate(NaLS). The aquation is inhibited by NaLS in the presence of H+, OH- , SO42- , NH4+ and tetraethylammonium ion (Et4N*). The inhibition is attributed to the stable association or binding between the complex and the micelle and the decrease in the activity of water in the micellar phase. The partitioning of the substrate between the bulk water solution and the micellar phase is in favour of the latter. The kψ-[surfactant] profiles are structured due to micellar evolution. A mechanism which fits kinetic data at low surfactant concentration is proposed. From the rate law obtained and kinetic data observed, the micelle-complex binding constant K1 and micelle-acid binding constant K3 are calculated to be 2.81 x 105 and 13.80 mol -1dm3 respectively in acid medium. Using Scat chard method, K1 in neutral medium is 3.95 x 105 mol-ldm3. The decrease in K1 in acid medium is due to competition for the binding sites on the micelle by the acid proton H+ and the complex ion. The rate of reaction is a function of equilibrium distribution of all the substrates between the micellar phase and bulk water phase. The evolution of the micelle with respect to the c.m.c. is also a function of the nature of the substrate present in solution. Calculated activation parameters suggest strong steric stabilisation of the transition state with respect to enthropy. The magnitudes of activation parameters ΔH# and ΔS# are functions of the surfactant concentration. ΔH# (KJ mol-1) and ΔS# (JK-1 mol-1) for the aquation in 0.00, 1.0 x 10-4 and 2.0 x 10-4 mol dm-3 NaLS are respectively: 100.40 ± 2.04, 22.58 ± 0.16; 111.48 ± 1.15, 48.94 ± 0.09; 119.19 ± 1.15, 67.16 ± 0.09 in 1.00M H2SO4.

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