This study was designed to proposed a multivariate model of monthly mean daily Photo synthetically active radiation (PAR) from the constant ratio of the global solar radiation for six selected tropical ecological zones between 4.40°N and... more
This study was designed to proposed a multivariate model of monthly mean daily Photo synthetically active radiation (PAR) from the constant ratio of the global solar radiation for six selected tropical ecological zones between 4.40°N and 1 3.03°N of Nigeria (Port Harcourt, Enugu, Abeokuta, Ilorin, Bauchi and Sokoto). The measured global solar radiation data was obtained from the Archives of the Nigerian Meteorological Agency, Oshodi, Lagos, over a period of thirteen years (2000-2012). The estimation was based on a correlation between clearance index, PAR and extraterrestrial computed using generalized 45% and 40% of monthly mean daily data set of global solar radiation and extraterrestrial solar radiation respectively on horizontal surfaces. The performance of the models developed were tested for validation using mean bias error (MBE), root mean square error (RMSE), mean percentage error (MPE), Nash-Sutcliff equation (NSE), chisquares (χ 2) and index of agreement (d). The polynomial regression model developed to estimate PAR judging from the model performance and validation test indicates that the proposed model could be used to estimate PAR in six tropical ecological zones in Nigeria and other stations with similar climatological conditions across the globe. The paper also revealed that there is an apparent increase in the magnitude of PAR and clearness index along tropical belts as a result of the movement of the Hadley cell circulatory system along the equatorial line from the Sahel Savannah to the Mangrove Swamp belt.
_________________________________________________________________________________ ABSTRACT— Well log data from eight wells located in the X fields of the Niger Delta Basin were used in the determination of some Petrophysical... more
_________________________________________________________________________________ ABSTRACT— Well log data from eight wells located in the X fields of the Niger Delta Basin were used in the determination of some Petrophysical characteristics of the reservoir sands. Well log data were obtained from sonic, gamma-ray, matrix density and resistivity logs. The Petrophysical characteristics investigated were porosity, water saturation, tortuosity and permeability. The results of the analysis revealed the presence of different sand and shale units. The thickness of each sand unit was highly variable, ranging between 6.1 and 21.5 m. Average porosities vary between 25.0 and 72.0 percent and generally decreasing with depth. A modeled water saturation showed a better value for water saturation (calculation) for non-Archie media. The correlation between the modeled water saturation method (using a different value of cementation factor m and tortuosity a as given by some literature) gives a weake...
We here present a method for improved lithology and gas sand detection in the sandy Formations of the Niger Delta, Nigeria. The absence of Full-waveform sonic log data necessitated a theoretically generated S-wave log using the... more
We here present a method for improved lithology and gas sand detection in the sandy Formations of the Niger Delta, Nigeria. The absence of Full-waveform sonic log data necessitated a theoretically generated S-wave log using the Greenberg-Castagna equation) / (2844 77. 0 s ft V V P S − × =. The theoretically generated S-wave with sonic log generated P-wave are utilized in the estimation of the D-scale factor () 2 2 2 2 S P S P V V V V D − × + =. Which when normalized by density (ρ) from the density log data yield the Poisson's Dampening-Factor (PDF) log, PDF= D/ρ. Here, PDF is demonstrated to have higher values in gas saturated sands (0.3-0.98ms/m*cc/g) than in brine sand and shaly (0.02-0.10 ms/m*cc/g) regions of each of the two wells where available data permit such estimate and estimate of other useful Petrophysical parameters. Lack of useful data at certain prospective regions of these wells limit the success chance of the method at detecting more gas reservoirs. One out of t...
The electrical conductivity (EC) Resistively (calculated) and salinity of some selected soil samples collected from three landforms, namely Beach Ridge Sand (BRS), coastal plain sand (CPS), sandstone/shale Hill ridges (SHR) from Akwa Ibom... more
The electrical conductivity (EC) Resistively (calculated) and salinity of some selected soil samples collected from three landforms, namely Beach Ridge Sand (BRS), coastal plain sand (CPS), sandstone/shale Hill ridges (SHR) from Akwa Ibom State of the Federal Republic of Nigeria were measured the obtained data were subjected to spearman rank order statistics and result shows that there were positive correlation of 0.20 between soil EC and salinity. The electrical conductivity of the area under study falls within the range of 0.031 ds/m for SHR 3A t0 0.200ds/m for SHR 2A while the salinities are between 0.6mg/l for BRS 3B and 0.9mg/l for SHA 2A soil samples. Soil sample SHR 3A has the highest resistivity measurement of 32.Ωm, while SHR 2A soil sample has the lowest of 6. Ωm. from the EC data the signal strength of EC measurements decreases with soil depth and most of the EC values falls within the range of 20 – 80 (μs/cm) which is the optimum level for most plants, usually indicates ...
In this study, we have estimated overpressures using well logs from three wells in onshore Niger Delta Field. Key logs required for the prediction were conditioned and quality controlled to meet the standard required for reliable results.... more
In this study, we have estimated overpressures using well logs from three wells in onshore Niger Delta Field. Key logs required for the prediction were conditioned and quality controlled to meet the standard required for reliable results. The overburden stress (or true vertical stress), normal compaction trends (NCT) and shale velocity trends were generated from the volume of shale, density, gamma, resistivity and sonic logs. Prediction points were picked at depths with thick shale and where there are no washouts (identified from caliper log). Pore pressures in the wells were then predicted using Eaton's exponent of 5 and compared with measured pressures (RFT data). Overpressures were estimated by observing the deviations of the predicted fluid pressures from the hydrostatic pressure line. The results obtained from the analysis reveal that two of the three wells are mildly overpressured at all depths while one well (G-005) experiences hard overpressure at a depth of about 15400 ...
The electrical conductivity (EC) and salinity of some selected soil samples collected from three landforms, namely Beach Ridge Sand (BRS), coastal plane sand (CPS), sandstone/shale Hill ridges (SHR) from Akwa Ibom State of the Federal... more
The electrical conductivity (EC) and salinity of some selected soil samples collected from three landforms, namely Beach Ridge Sand (BRS), coastal plane sand (CPS), sandstone/shale Hill ridges (SHR) from Akwa Ibom State of the Federal Republic of Nigeria were measured, the obtained data were subjected to spearman rank order statistics and result shows that there were positive correlation of 3.98 between EC and salinity. The electrical conductivity of the area under study falls within the range of 0.033 ds/m and 0.123 ds/m while the salinities are between 0.70 mg/l and 0.85mg/l. From the EC data the signal strength of EC measurements decreases with decrease in salinity, the EC range of the three landforms is the optimum level for most plants, usually indicates well fertilized soils, and salt sensitive plants may be injured.
Well log data from wells located in the X fields of the Niger Delta Basin were used in the determination of some Petrophysical characteristics of the reservoir sands. Well log data were obtained from sonic, gamma-ray, matrix density and... more
Well log data from wells located in the X fields of the Niger Delta Basin were used in the determination of some Petrophysical characteristics of the reservoir sands. Well log data were obtained from sonic, gamma-ray, matrix density and resistivity logs. The Petrophysical characteristics investigated were porosity, water saturation, tortuosity and permeability. The results of the analysis revealed the presence of different sand and shale units. The thickness of each sand unit was highly variable, ranging between 6.1 and 21.5 m. Average porosities vary between 25.0 and 72.0 percent and generally decreasing with depth. A modeled water saturation showed a better value for water saturation (calculation) for non-Archie media.The correlation between the modeled water saturation method (using a different value of cementation factor m and tortuosity a as given by some literature) gives a weaker correlation for the non-Archie media while the Archie media gives a stronger correlation when com...
The cross plotting of rock properties for fluid and lithology discrimination was carried out in a Niger Delta oil field using well data X-26 from a given oil field in the coastal swamp depobelt. The data used for the analysis consisted of... more
The cross plotting of rock properties for fluid and lithology discrimination was carried out in a Niger Delta oil field using well data X-26 from a given oil field in the coastal swamp depobelt. The data used for the analysis consisted of suites of logs, including gamma ray, resistivity, sonic and density logs only. The reservoir of interest Horizon 1, was identified using the available suite of logs on the interval where we have low gamma ray, high resistivity and low acoustic impedance specifically at depths 10,424ft (3177.24m) to 10 724ft (3268m). We first obtained other rock attributes from the available logs before cross plotting. The inverse of the interval transit times of the sonic logs were used to generate the compressional velocities and the S-wave data was generated from Castagna´s relation. Employing rock physics algorithm on Hampson Russell software (HRS), rock attributes including Vp/Vs ratio, Lambda-Rho and Mu-Rho were also extracted from the well data. Cross plottin...
Considering the heterogeneity of the reservoir sands in the Niger Delta basin which are primary causes of low hydrocarbon recovery efficiency, poor sweep, early breakthrough and pockets of bypassed oil there arises a need for in-depth... more
Considering the heterogeneity of the reservoir sands in the Niger Delta basin which are primary causes of low hydrocarbon recovery efficiency, poor sweep, early breakthrough and pockets of bypassed oil there arises a need for in-depth quantitative interpretation and more analysis to be done on seismic data to achieve a reliable reservoir characterization to improve recovery, plan future development wells within field and achieve deeper prospecting for depths not penetrated by the wells and areas far away from well locations. An effective tool towards de-risking prospects is seismic inversion which transforms a seismic reflection data to a quantitative rock-property description of a reservoir. The choice of model-based inversion in this study was due to well control, again considering the heterogeneity of the sands in the field. X-26, X-30, and X-32 were used to generate an initial impedance log which is used to update the estimated reflectivity from which we would obtain our inverte...
Thermo physical properties of Alates (Swarmers) termite wing has been investigated. The result of our investigation shows the values of thermo physical parameters of the sample materials as 0.0403Wm-1K-1 being the mean thermal... more
Thermo physical properties of Alates (Swarmers) termite wing has been investigated. The result of our investigation shows the values of thermo physical parameters of the sample materials as 0.0403Wm-1K-1 being the mean thermal conductivity value, bulk density of 188. 8kgm-3 and thermal diffusively value being 8.2485 x 10-8m2s-1. The values are within the values for commonly used insulating materials. Comparing the rate of cooling as well as heat absorption into the material as lagging material with the performance of fiberglass and cork, Alate's wing is adjudged to be a potential insulating raw material.
In this research work, a modified water displacement method (MWDM) was designed and used in addition to geometry method (GM) to measure the bulk volume and then determine the bulk density values of asbestos ceiling board, cardboard paper,... more
In this research work, a modified water displacement method (MWDM) was designed and used in addition to geometry method (GM) to measure the bulk volume and then determine the bulk density values of asbestos ceiling board, cardboard paper, chalk, clay (compacted) and gypsum board that have been sun-dried to constant weight. The mean bulk densities determined by both methods were compared with the reference bulk density values of the same porous materials obtained in this work using standard test procedure in accordance with ASTM D6683-14. It was observed that, for all the tested porous materials, the percentage error in the mean bulk density values ranged from 2.3% to 49.6% when using GM and 0.9% to 5.7% by using the MWDM. Also, at 0.05 level of significance with a degree of freedom of 3, correlation coefficients of 0.7430 and 0.9955 were obtained in the cases of GM and the MWDM respectively. Again, all other analyses performed similarly revealed that the mean bulk densities obtained...
Electrical resistivity survey using Schlumberger Vertical Electrical Sounding (VES) field technique was carried out at Ekpri Ikang in Bakassi local government area of Cross River State. The survey is aimed at determining the water bearing... more
Electrical resistivity survey using Schlumberger Vertical Electrical Sounding (VES) field technique was carried out at Ekpri Ikang in Bakassi local government area of Cross River State. The survey is aimed at determining the water bearing formation of the area. Data acquired were interpreted using WinRes Program into a curve showing true resistivity and thickness of the subsurface layers. Result indicates that there are four distinct layers in the study area. Analyses of the data and interpretation of the sounding curve reveals that the water bearing layer exist in the layer two (2) and three (3) with resistivity values of 347.6Ω and 375.5Ω, also with thickness of 14.5m and 21.3m, depth of 39.6m and 61.0m. It is therefore recommended that boreholes for good drinking water be drilled to the layer two (2) and three (3) of the investigated area.
This paper presents the results of ambient radioactive radiation, radiation health hazard indices and excess lifetime cancer risk estimation within University of Uyo campus, Use Offot, Uyo, Niger Delta region of Nigeria. Mean annual... more
This paper presents the results of ambient radioactive radiation, radiation health hazard indices and excess lifetime cancer risk estimation within University of Uyo campus, Use Offot, Uyo, Niger Delta region of Nigeria. Mean annual outdoor and indoor equivalent doses of 0.284mSv/yr. and 0.854mSv/yr. respectively were recorded, being less than 1mSv/yr. maximum recommended limit for general public. Mean annual outdoor and indoor effective doses of 0.174mSv/yr. and 0.645mSv/yr. respectively with a total of 0.819mSv/yr. were computed. The mean outdoor and indoor ELCR values of 0.61x10-3 and 2.26 x 10-3 respectively, with a mean total of 2.87 x 10-3 were also computed. The results though higher than the world’s average, are comparable with those of some other locations within the Niger Delta region.
