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Papers by chigozie israel-cookey

Energy and Power Engineering

SSRN Electronic Journal, 2019

Aimed at determining a more reliable method of estimating permeability from well log data, in the... more Aimed at determining a more reliable method of estimating permeability from well log data, in the absence of core data, 4 predictive empirical models for estimating permeabilities (RGPZ model, Van Baaren’s model, Timur’s model and Berg’s model) were applied to two different reservoirs in a single well from an oil field in the Niger Delta. With the models employed at different cementation factors (m=1.5, 1.65, 1.80, 1.95, 2.10, 2.25, 2.40, 2.55, 2.70, 2.85, 3.00), using well log data from the reservoirs of interest, as a function of depth, measures of normalized root mean square error (NRMSE), relative to permeabilities measured from core analysis at the same reservoir interval, were used to determine which predictive model was more reliable. Obtained results showed the most reliable predictive model at m=1.65. At this cementation factor, the NRMSE for RGPZ model, Van Baaren’s model, Timur’s model and Berg’s model were 4.95, 30.38, 1.85, and 1.20 respectively in the first reservoir and 4.28, 24.69, 1.56 and 1.09 respectively in the second reservoir. Hence, Van Baaren’s model provided a more reliable measure of in-situ permeabilities in the reservoirs of the Niger delta as it had a lower measure of NRMSE in the reservoirs of interest.

American Journal of Scientific and Industrial Research, 2010

This paper investigates the combined effects of radiative heat transfer and a transverse magnetic... more This paper investigates the combined effects of radiative heat transfer and a transverse magnetic field on steady flow of an electrically conducting optically thin fluid through a horizontal channel filled with porous medium and non-uniform temperatures at the walls. Closed-form analytical solutions are constructed for the problem. The results are discussed quantitatively with the aid of the dimensionless parameters entering the problem.

International Journal of Applied Earth Observation and Geoinformation, 2004

International Journal of Heat and Mass Transfer, 2003

Global Journal of Pure and Applied Sciences, 2007

Journal of Applied Sciences and Environmental Management, 2010

The generation of tsunamis with the help of a simple dislocation model of an earthquake and their... more The generation of tsunamis with the help of a simple dislocation model of an earthquake and their propagation in the basin are discussed. In this study, we examined the formation of a tsunami wave from an initial sea surface displacement similar to those obtained from earthquakes that have generated tsunami waves and its propagation through the sea to the shore. Linear shallow water wave equations were employed to explain the propagation of the waves in the open sea while nonlinear wave equations were introduced to explain the behaviour of the wave near the shore. The influence of the Coriolis force on the propagation of tsunami was shown to become very important when the tsunami travel distance is significant in relations to the earth's complete rotation time. The group velocity of tsunami waves which is the velocity of wave energy propagation and its independence on the wave number was demonstrated. @ JASEM

This paper investigates the problem of double-diffusive convection in a horizontal layer filled w... more This paper investigates the problem of double-diffusive convection in a horizontal layer filled with a reacting fluid with temperature-dependent internal heat source within the Darcy limit. The linear stability theory is applied for the onset of both stationary (monotonic) and oscillatory convection. The critical Rayleigh numbers for the onset of convection are determined in terms of the governing parameters. The results show that positive increments in the internal heat source parameter hasten the onset on both stationary and oscillatory convection.

Abstract: This study investigates the influence of radiation and mass concentration on Magnetohyd... more Abstract: This study investigates the influence of radiation and mass concentration on Magnetohydrodynamic (MHD) flow over a moving plate with time dependent suction in an optically thin environment. By introducing fairly realistic assumptions and for a small time dependent perturbation, the concentration temperature and velocity profiles are obtained. The effects of magnetic parameter M, radiation parameter F, porosity parameter X and G r on the flow variables are discussed qualitatively.

Journal of the Nigerian Association of Mathematical Physics, 2010

This paper investigates the condition leading to the onset of stationary convection in a low Pran... more This paper investigates the condition leading to the onset of stationary convection in a low Prandtl number horizontal fluid layer in a porous medium heated from below with internal heat source. The internal heat source is taken as directly proportional to the temperature leading to a sinusoidal temperature gradient in the fluid layer. The effects of heat generation, porosity parameter and different Prandtl numbers, Pr are presented. The results show that the onset of stationary instability is hastened by increasing values of the internal heat generation as well as increments in the Prandtl number. Further, increases in the porosity parameter delayed the onset of stationary instability.

The onset of stationary and oscillatory magnetoconvection in a rotating infinitely horizontal por... more The onset of stationary and oscillatory magnetoconvection in a rotating infinitely horizontal porous layer filled with electrically conducting Newtonian fluid heated from below with temperature – dependent heat source within the Darcy limit using linear stability analysis is investigated for free – free boundaries. The effects of heat source, magnetic field and rotation parameters on the onset of convection are presented graphically and analyzed in detail. It is found that increases in magnetic and rotation parameters delayed the onset of stationary and oscillatory convection, thereby stabilizing the system. The heat source parameter increment accelerates the onset of convection and the system is more unstable; while Prandtl number slowed the onset of oscillatory convection.

International Journal of Research, 2018

A study was conducted on the effects of relative humidity on the solar radiation intensity in Por... more A study was conducted on the effects of relative humidity on the solar radiation intensity in Port Harcourt, Nigeria. The data for this research work was obtained from the Nigerian Environmental Climatic Observatory Project Station (NECOP) situated at Rivers State University, Port Harcourt, Nigeria. The average solar radiation and relative humidity data from January to March 2018 were collated on daily, weekly and monthly intervals. The results obtained showed that average relative humidity is 61.20% for January, 71.89% for February and 74.18% for March 2018. While the average solar radiation intensity is 77.339 W/m 2 for January, 77.000 W/m 2 for February, and 71.297 W/m 2 for March 2018. The maximum average relative humidity occurred in the month of March, signifying a steady increase in the rainy season period. The increase in average relative humidity gives rise to a decrease in solar radiation and vice versa. This depicts an inverse relationship between humidity and solar radia...

Asian Research Journal of Mathematics

An investigation of an oscillatory blood flow in an indented artery with heat source in the prese... more An investigation of an oscillatory blood flow in an indented artery with heat source in the presence of magnetic field was carried out. The formulated governing models are solved using Frobenius method where the solutions are transformed into Bessel functions 0 () I r β and 0 () K r β of order zero of the first and second kind. The computational results are presented graphically for the velocity profile (,) w r t , the temperature profile () r θ. The study reveals that the blood flow is appreciably influenced by the presence of a magnetic field and also by the value of the Grashof Gr number. It is observed that the presence of the magnetic field M retards the velocity profile as well as the flow rate; the Grasof number Gr causes an increment in the velocity profile which is consistent with the existing laws of physics. Furthermore, the radiation parameter Rd does affect the velocity profile which means, it

Asian Research Journal of Mathematics

In this article we studied blood flow through an indented artery and assumed blood to be Jeffrey ... more In this article we studied blood flow through an indented artery and assumed blood to be Jeffrey fluid. The study investigates the influence of heat transfer on the flow profile of Jeffrey fluid in an indented artery. Also, the formulated governing equations are transformed into coupled Bessel differential equation and solved analytically. The effects of various physical parameters such as Prandtl number of blood, 21 Pr  ,Grashof number, Gr ,Darcy number, Da ,Hartmann number M, Reynold number, Re ,as well as the Jeffrey parameter, 1  and a constant parameter,  on the velocity profile and temperature profile. The results are discussed in detail with the graphs obtained using Mathematica version 10.3.

Journal of Environment and Earth Science

In this study, pore pressure has been predicted using seismic data and derived compressional wave... more In this study, pore pressure has been predicted using seismic data and derived compressional wave velocity (Vp)-Vertical Effective Stress (VES) coefficients. Post Stack Time Migration (PSTM), angle stack gathers, seismic horizons, checkshot, wireline logs, drilling and pressure data from six wells in the Onshore West Niger Delta, Nigeria were analysed and interpreted. Using generated velocity and density crossplots, the active overpressure generating mechanisms for the studied area were deduced. The Vp-VES coefficients were modelled using the direct pressure data and the overburden profile computed from density log. Post stack seismic inversion was performed to improve the seismic resolution as well as derive acoustic impedance using well velocities and stacking velocities from velocity analysis of the 3-D seismic data. The derived Vp-VES coefficients were used to transform the seismic acoustic impedance velocity into seismic pore pressure volume. Pore pressure profiles were accordingly extracted along well paths so as to test the accuracy of the model. Interpreted density-velocity crossplots revealed a decrease in velocity at constant density of 2.4 g/cc, an indication that unloading mechanisms contribute to overpressure in the field. The Bowers' Vp-VES coefficients of 7.43 and 0.77 were determined for A and B parameters respectively. Based on the results obtained, the top of overpressure occurred at a depth of 3750 ft and 3800 ft in UMO-001 and UMO-002 wells respectively with a corresponding average pore pressure gradient of 0.47 psi/ft for both wells, indicating that the wells are mildly overpressured. Onsets of unloading were observed in UMO-001 and UMO-002 wells at depths of 6250 ft and 6800 ft with pore pressure gradients of 0.51 psi/ft and 0.60 psi/ft respectively. The Derived Seismic Pore Pressure (DSPP) matched the measured pressure value (kick) of 5300 psi at a depth of 7450 ft and this validated and further increased confidence on the values of the Vp-VES coefficients derived. These results show that the derived seismic acoustic impedance volume, vertical effective stress and overburden model produce high resolution seismic pore pressure cube in both time and space. The derived models when applied especially, with seismic acoustic impedance volume can be used to plan and drill future wells with great successes in the studied area.

Asian Research Journal of Mathematics

In this research article, the effect of Vadasz number on magnetoconvection in a Darcy Porous Laye... more In this research article, the effect of Vadasz number on magnetoconvection in a Darcy Porous Layer with concentration based internal heating is studied. The flow is governed by the Oberbeck-Boussineq model for Newtonian fluid. The stability analysis method based on the perturbation of infinitesimal amplitude is carried out using the normal mode analysis. The onset criterion for both the stationary and oscillatory convection on the stability of system is obtained. The analysis examines the effects of pertinent parameters on the stability of the system: magnetic field parameter, solutal Rayleigh number, Lewis number and Vadasz number. The result show that, internal heat parameter, and Lewis number, , hastens the onset of instability in the system, whereas magnetic field, , Vadasz number, and solutal Rayleigh number, delay the onset of instability.

Journal of the Nigerian Association of Mathematical Physics, 2009

Global Journal of Pure and Applied Sciences, 2007

Global Journal of Mathematical Sciences, 2006

Energy and Power Engineering

SSRN Electronic Journal, 2019

Aimed at determining a more reliable method of estimating permeability from well log data, in the... more Aimed at determining a more reliable method of estimating permeability from well log data, in the absence of core data, 4 predictive empirical models for estimating permeabilities (RGPZ model, Van Baaren’s model, Timur’s model and Berg’s model) were applied to two different reservoirs in a single well from an oil field in the Niger Delta. With the models employed at different cementation factors (m=1.5, 1.65, 1.80, 1.95, 2.10, 2.25, 2.40, 2.55, 2.70, 2.85, 3.00), using well log data from the reservoirs of interest, as a function of depth, measures of normalized root mean square error (NRMSE), relative to permeabilities measured from core analysis at the same reservoir interval, were used to determine which predictive model was more reliable. Obtained results showed the most reliable predictive model at m=1.65. At this cementation factor, the NRMSE for RGPZ model, Van Baaren’s model, Timur’s model and Berg’s model were 4.95, 30.38, 1.85, and 1.20 respectively in the first reservoir and 4.28, 24.69, 1.56 and 1.09 respectively in the second reservoir. Hence, Van Baaren’s model provided a more reliable measure of in-situ permeabilities in the reservoirs of the Niger delta as it had a lower measure of NRMSE in the reservoirs of interest.

American Journal of Scientific and Industrial Research, 2010

This paper investigates the combined effects of radiative heat transfer and a transverse magnetic... more This paper investigates the combined effects of radiative heat transfer and a transverse magnetic field on steady flow of an electrically conducting optically thin fluid through a horizontal channel filled with porous medium and non-uniform temperatures at the walls. Closed-form analytical solutions are constructed for the problem. The results are discussed quantitatively with the aid of the dimensionless parameters entering the problem.

International Journal of Applied Earth Observation and Geoinformation, 2004

International Journal of Heat and Mass Transfer, 2003

Global Journal of Pure and Applied Sciences, 2007

Journal of Applied Sciences and Environmental Management, 2010

The generation of tsunamis with the help of a simple dislocation model of an earthquake and their... more The generation of tsunamis with the help of a simple dislocation model of an earthquake and their propagation in the basin are discussed. In this study, we examined the formation of a tsunami wave from an initial sea surface displacement similar to those obtained from earthquakes that have generated tsunami waves and its propagation through the sea to the shore. Linear shallow water wave equations were employed to explain the propagation of the waves in the open sea while nonlinear wave equations were introduced to explain the behaviour of the wave near the shore. The influence of the Coriolis force on the propagation of tsunami was shown to become very important when the tsunami travel distance is significant in relations to the earth's complete rotation time. The group velocity of tsunami waves which is the velocity of wave energy propagation and its independence on the wave number was demonstrated. @ JASEM

This paper investigates the problem of double-diffusive convection in a horizontal layer filled w... more This paper investigates the problem of double-diffusive convection in a horizontal layer filled with a reacting fluid with temperature-dependent internal heat source within the Darcy limit. The linear stability theory is applied for the onset of both stationary (monotonic) and oscillatory convection. The critical Rayleigh numbers for the onset of convection are determined in terms of the governing parameters. The results show that positive increments in the internal heat source parameter hasten the onset on both stationary and oscillatory convection.

Abstract: This study investigates the influence of radiation and mass concentration on Magnetohyd... more Abstract: This study investigates the influence of radiation and mass concentration on Magnetohydrodynamic (MHD) flow over a moving plate with time dependent suction in an optically thin environment. By introducing fairly realistic assumptions and for a small time dependent perturbation, the concentration temperature and velocity profiles are obtained. The effects of magnetic parameter M, radiation parameter F, porosity parameter X and G r on the flow variables are discussed qualitatively.

Journal of the Nigerian Association of Mathematical Physics, 2010

This paper investigates the condition leading to the onset of stationary convection in a low Pran... more This paper investigates the condition leading to the onset of stationary convection in a low Prandtl number horizontal fluid layer in a porous medium heated from below with internal heat source. The internal heat source is taken as directly proportional to the temperature leading to a sinusoidal temperature gradient in the fluid layer. The effects of heat generation, porosity parameter and different Prandtl numbers, Pr are presented. The results show that the onset of stationary instability is hastened by increasing values of the internal heat generation as well as increments in the Prandtl number. Further, increases in the porosity parameter delayed the onset of stationary instability.

The onset of stationary and oscillatory magnetoconvection in a rotating infinitely horizontal por... more The onset of stationary and oscillatory magnetoconvection in a rotating infinitely horizontal porous layer filled with electrically conducting Newtonian fluid heated from below with temperature – dependent heat source within the Darcy limit using linear stability analysis is investigated for free – free boundaries. The effects of heat source, magnetic field and rotation parameters on the onset of convection are presented graphically and analyzed in detail. It is found that increases in magnetic and rotation parameters delayed the onset of stationary and oscillatory convection, thereby stabilizing the system. The heat source parameter increment accelerates the onset of convection and the system is more unstable; while Prandtl number slowed the onset of oscillatory convection.

International Journal of Research, 2018

A study was conducted on the effects of relative humidity on the solar radiation intensity in Por... more A study was conducted on the effects of relative humidity on the solar radiation intensity in Port Harcourt, Nigeria. The data for this research work was obtained from the Nigerian Environmental Climatic Observatory Project Station (NECOP) situated at Rivers State University, Port Harcourt, Nigeria. The average solar radiation and relative humidity data from January to March 2018 were collated on daily, weekly and monthly intervals. The results obtained showed that average relative humidity is 61.20% for January, 71.89% for February and 74.18% for March 2018. While the average solar radiation intensity is 77.339 W/m 2 for January, 77.000 W/m 2 for February, and 71.297 W/m 2 for March 2018. The maximum average relative humidity occurred in the month of March, signifying a steady increase in the rainy season period. The increase in average relative humidity gives rise to a decrease in solar radiation and vice versa. This depicts an inverse relationship between humidity and solar radia...

Asian Research Journal of Mathematics

An investigation of an oscillatory blood flow in an indented artery with heat source in the prese... more An investigation of an oscillatory blood flow in an indented artery with heat source in the presence of magnetic field was carried out. The formulated governing models are solved using Frobenius method where the solutions are transformed into Bessel functions 0 () I r β and 0 () K r β of order zero of the first and second kind. The computational results are presented graphically for the velocity profile (,) w r t , the temperature profile () r θ. The study reveals that the blood flow is appreciably influenced by the presence of a magnetic field and also by the value of the Grashof Gr number. It is observed that the presence of the magnetic field M retards the velocity profile as well as the flow rate; the Grasof number Gr causes an increment in the velocity profile which is consistent with the existing laws of physics. Furthermore, the radiation parameter Rd does affect the velocity profile which means, it

Asian Research Journal of Mathematics

In this article we studied blood flow through an indented artery and assumed blood to be Jeffrey ... more In this article we studied blood flow through an indented artery and assumed blood to be Jeffrey fluid. The study investigates the influence of heat transfer on the flow profile of Jeffrey fluid in an indented artery. Also, the formulated governing equations are transformed into coupled Bessel differential equation and solved analytically. The effects of various physical parameters such as Prandtl number of blood, 21 Pr  ,Grashof number, Gr ,Darcy number, Da ,Hartmann number M, Reynold number, Re ,as well as the Jeffrey parameter, 1  and a constant parameter,  on the velocity profile and temperature profile. The results are discussed in detail with the graphs obtained using Mathematica version 10.3.

Journal of Environment and Earth Science

In this study, pore pressure has been predicted using seismic data and derived compressional wave... more In this study, pore pressure has been predicted using seismic data and derived compressional wave velocity (Vp)-Vertical Effective Stress (VES) coefficients. Post Stack Time Migration (PSTM), angle stack gathers, seismic horizons, checkshot, wireline logs, drilling and pressure data from six wells in the Onshore West Niger Delta, Nigeria were analysed and interpreted. Using generated velocity and density crossplots, the active overpressure generating mechanisms for the studied area were deduced. The Vp-VES coefficients were modelled using the direct pressure data and the overburden profile computed from density log. Post stack seismic inversion was performed to improve the seismic resolution as well as derive acoustic impedance using well velocities and stacking velocities from velocity analysis of the 3-D seismic data. The derived Vp-VES coefficients were used to transform the seismic acoustic impedance velocity into seismic pore pressure volume. Pore pressure profiles were accordingly extracted along well paths so as to test the accuracy of the model. Interpreted density-velocity crossplots revealed a decrease in velocity at constant density of 2.4 g/cc, an indication that unloading mechanisms contribute to overpressure in the field. The Bowers' Vp-VES coefficients of 7.43 and 0.77 were determined for A and B parameters respectively. Based on the results obtained, the top of overpressure occurred at a depth of 3750 ft and 3800 ft in UMO-001 and UMO-002 wells respectively with a corresponding average pore pressure gradient of 0.47 psi/ft for both wells, indicating that the wells are mildly overpressured. Onsets of unloading were observed in UMO-001 and UMO-002 wells at depths of 6250 ft and 6800 ft with pore pressure gradients of 0.51 psi/ft and 0.60 psi/ft respectively. The Derived Seismic Pore Pressure (DSPP) matched the measured pressure value (kick) of 5300 psi at a depth of 7450 ft and this validated and further increased confidence on the values of the Vp-VES coefficients derived. These results show that the derived seismic acoustic impedance volume, vertical effective stress and overburden model produce high resolution seismic pore pressure cube in both time and space. The derived models when applied especially, with seismic acoustic impedance volume can be used to plan and drill future wells with great successes in the studied area.

Asian Research Journal of Mathematics

In this research article, the effect of Vadasz number on magnetoconvection in a Darcy Porous Laye... more In this research article, the effect of Vadasz number on magnetoconvection in a Darcy Porous Layer with concentration based internal heating is studied. The flow is governed by the Oberbeck-Boussineq model for Newtonian fluid. The stability analysis method based on the perturbation of infinitesimal amplitude is carried out using the normal mode analysis. The onset criterion for both the stationary and oscillatory convection on the stability of system is obtained. The analysis examines the effects of pertinent parameters on the stability of the system: magnetic field parameter, solutal Rayleigh number, Lewis number and Vadasz number. The result show that, internal heat parameter, and Lewis number, , hastens the onset of instability in the system, whereas magnetic field, , Vadasz number, and solutal Rayleigh number, delay the onset of instability.

Journal of the Nigerian Association of Mathematical Physics, 2009

Global Journal of Pure and Applied Sciences, 2007

Global Journal of Mathematical Sciences, 2006