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We considered the constants obtained for tau (𝜏)Field in the Niger Delta basin from well-log data of three wells (A,B,C) to investigate the effect of inclusion of these constants on density-velocity relation using Hampson Russell Software to generate density curve in tau field. The curves were compared to those generated from Gardner and Lindseth c...
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... The wet and the dry seasons are the major seasons in the province; with average monthly rainfall of 0.135 m noted during the wet season, to about 0.065 m as dry season approaches Ejoh et al., 2023;Atat et al., 2020a;George et al., 2017;Atat et al., 2012;George et al., 2010). The total space occupy by the sediment is almost 5.0 x 10 5 km 3 (Atat et al., 2020b;Umoren et al., 2020;Atat et al., 2020c). The petroleum system is the Tertiary Niger Delta (Akata-Agbada). ...
... This property aids in identification of reservoir rock by lithology delineation (Atat et al., 2020b). If there is no accuracy in the estimation of fluid density, the porosity will not be appreciable (Atat et al., 2020c). Density logs provide data that can be used to estimate porosity which permeability depends on. ...
Permeability information is a necessary requirement to assess the migration and accumulation of fluids in the reservoir. Three well data (A, B, C) were available for this investigation. Microsoft Excel was used for the analysis and computation of results. Spurious values were noted and removed. Porosity was first determined and their average results for Wells A, B and C are 17.26604%, 22.83019% and 13.35095% respectively. These values of porosity indicate the reservoir classes of Wells A, B and C as good, good and fair correspondingly. This information enables the determination of average permeability of wells A, B and C corresponding to 80975.24 Darcy, 105407.1 Darcy and 65580.38 Darcy. Therefore, the reservoir of wells A and B are highly porous and permeable for the storage and migration of fluids. They should be developed for hydrocarbon exploration. This is because the porosity and permeability values of these wells are reasonable as they have met the standard. However, well C is permeable but not reasonably porous as it belongs to a fair class. The velocity information would give account of the rock elastic properties in terms of strength.
... Groundwater is tapped from the top of the stratigraphic sequence (George et al., 2017). The volume of sediment is nearly 500000km 3 (Atat et al., 2020b;Umoren et al., 2020;Atat et al., 2020c;Hospers, 1965, Akpabio andOjo, 2018). (Endoro, 2017). ...
Raw well data from oil wells A₁₁, A₂₂ and A₃₃ in the southern parts of the Niger Delta (Field) were used for porosity estimation using the Raymer Hunt Gardner (RHG) technique. Using Microsoft Excel for analysis and computation of results, gamma ray log, sonic log with respect to depth were generated. The results of these curves were used to estimate porosity. The major outcomes resulting from this porosity estimation revealed that porosity ranges from 22.0% to 41.0%, 25.0% to 37.0% and 16.0% to 38.0% for wells A₁₁, A₂₂ and A₃₃ respectively, with average values of about 33.5% for well A₁₁, 30.1% for well A₂₂ and 27.1% for well A₃₃. Therefore, the average porosity obtained gives 30.2% in the field. The result of this estimation belongs to the excellent class of porosity estimation. It shows that the available pore spaces in the oil reservoir zone are adequate for migration, that is, it can store and transmit fluid. These results show that an increase in sonic gives rise to an increase in porosity irrespective of the lithology.
... The dry and the wet seasons are experienced Ejoh et al., 2023), with mean monthly rainfall of 0.135 m as at wet season, to around 0.065 m in dry season (Atat et al., 2020a;George et al., 2017;Akpabio et al., 2023b). Appreciable sediment of nearly 5.0 x 10 5 km 3 is suspected (Atat et al., 2020b;Umoren et al., 2020;Atat et al., 2020c). It is the youngest Sedimentary basin in the Benue Trough system as stated by Atat and Umoren (2016). ...
Knowledge of net radiation is essential in any location that requires a solar energy technology application. This work evaluates net radiation in three cities of close boundaries (Uyo, Calabar, and Port Harcourt) in southern Nigeria. The atmospheric data for the period of 20 years (2000-2020) were obtained from the Nigerian Meteorological Agency (NIMET). The mean values of the surface albedo, net shortwave and longwave radiation were computed using Mathematical tools and SPSS packages. The result obtained showed that the highest value (0.694, 0.687, and 0.685 for Uyo, Calabar and Port Harcourt respectively) of the albedo was in the rainy season with its peak in August while its lowest values of 0.489, 0.577 and 0.594 for Uyo, Calabar and Port Harcourt respectively were in the dry season within the months of November to March. The net radiation Rn was observed to vary directly with the net shortwave and longwave radiation but indirectly with albedo. The highest net radiation values obtained were 6.512 MJm-2 day-1 , 4.52 MJm-2 day-1 and 4.313 MJm-2 day-1 for Uyo, Calabar and Port Harcourt correspondingly. The lowest were 2.717 MJm-2 day-1 , 2.144 MJm-2 day-1 and 2.308 MJm-2 day-1 for Uyo, Calabar and Port Harcourt respectively. Solar energy applications are encouraged in these cities since the albedo results are higher than the minimum standard of 0.3.
... The samples were collected during the rainy season from some farmlands in Ughelli LGA of Delta state. The studied area is situated in the Niger Delta region where two distinct seasons are experienced: the dry and the rainy (wet) seasons [15][16][17][18][19][20][21]. The 10 locations are listed with codes as U11 to U20 (where soil samples were taken); also, as D11 to D20 (where cassava samples were obtained). ...
Background: This research was conducted to estimate the activity concentration level of 40K, 238U and 232Th in soil and cassava and determine the transfer factor from soil to cassava in Ughelli North, Delta State, Nigeria. Materials and Methods: These were examined using gamma spectrometry and considering a lead-shielded 3 x 3inch coaxial type Sodium Iodide Thallium doped detector. Results: The mean activity concentrations of 40K, 238U and 232Th are 45.49 ± 4.28 BqKg−1, 3.15 ± 0.77 BqKg−1 and 0.56 ± 0.06 BqKg−1 respectively in soil samples and 134.08 ± 11.59 BqKg−1, 3.89 ± 0.93 BqKg−1 and 0.81 ± 0.09 BqKg−1 correspondingly in cassava samples. The mean transfer factor of 40K, 238U and 232Th from soil to cassava are 3.44 ± 0.75, 1.94 ± 0.32 and 1.34 ± 0.54 respectively. Peak values of the TF were noted as 8.52 for 40K at U18, D18, 25.58 for 238U at U12, D12 and 5.71 for 232Th at U11, D11. Conclusion: The activity concentration of 40K, 238U and 232Th in the area are lower than the world average values. Consequently, it will not pose any radiological hazard if consumed. The high value of Transfer factor is attributed to the richness of the organic matter in the soil and may indicate high ability to transfer radionuclides in the soil to food crops but from the concentration information, these radionuclides present in the soil are low as well as annual effective doses. There is no radiological risk of ingestion.
... (Effiong, et al., 2015). The study area is in the Niger Delta region experiencing two distinct seasons which are the dry and the rainy (wet) seasons (Atat and Umoren, 2016;Atat et al., 2020a;Atat et al., 2020b). The average temperature of the area is put at 25 degrees centigrade while the average humidity of the area is put at 88 percent. ...
Naturally occurring radionuclide materials are known to exist in soils and is transferred into vegetables and eventually gets into food chain. This work was aimed at determining the activity concentration of these radionuclides in soils and vegetable (fluted pumpkin) and the internal exposure due to the consumption of these materials in the vegetable in parts of South South Nigeria particularly Etim Ekpo Local Government area. The activity concentrations of twenty (20) soil samples and 20 vegetable samples from the farmlands were determined using gamma spectrometry. The activity concentration for 40K ,232Th and 238U from the soil samples ranged from 6.69±0.35 (Bqkg-1) to 168.19 ±8.82 (Bqkg-1) ,0.23 ±0.01 (Bqkg-1) to 5.91 ±0.35 (Bqkg-1) and BDL to 21.53±2.5 (Bqkg-1) respectively. The activity concentration of 40K, 232Th and 238U in the vegetable ranged from (584.23±27.71) Bqkg-1 to (958.67±48.46) Bqkg-1, from (1.84±0.11) Bqkg-1 to (9.72 ±0.56) and from (BDL) to (38.34±3.74) Bqkg-1 respectively. Transfer factors obtained ranged between 12.07±4.7 to 35.35 ±27.9 for 40K, 1.80±0.125 to 5.76 ± 4.31 for 232Th and BDL to 21.05 for 238U. Effective ingestion dose due to the consumption of vegetable from the study area obtained as 0.0021mSvy-1. This value is less than the 0.29mSvy-1 recommended dose limit for the general public; therefore, the consumption of this vegetable could not cause a radiological health effect on its consumers. However negligible or low risk could be minimised when the vegetable is washed and cooked before being consumed. Hence, the results obtained in this study indicate that the activity concentration of the farmland soils and crops represent no significant health risk on the farmers and the consumers of the vegetables.
... ……………………(3) [36,38] ℎ is the electron density number in electron cm -3 ; is the number Avogadro number; Z is the atomic number and A is the atomic mass. ...
The assessment of rock reservoir volume concentration is necessary as it accounts for the appreciable pore spaces available for hydrocarbon and other targets. Raw well data from oil wells A, B and C in some parts of the Niger Delta Basin (XA Field) were used for porosity estimates in sandstone and shale formations. Using the Microsoft Excel for analysis, gamma ray log, density log with respect to depth were generated. The results of these curves were used to estimate porosity and create models for porosity-formation factor with respect to density effect. The major findings revealed the average porosity values as about 20% for well A, 17% for well B and 19% for well C. The results show that increase in density gives rise to a decrease in porosity in both lithologies. In order to establish a relationship between porosity of this Field rock reservoir, a plot of porosity with formation factor due to density influence was necessary. These curves lead to several equations with the average for linear curves as = −400∅ + 98.08 and = (−0.2∅ + 4.9) × 10 −3 for fractional and percentage porosities respectively. These models show that both parameters are strongly related with coefficients of 0.9723 (for both plots from well A), 0.8274 (for both plots from well B) and 0.9689 (for both plots from well C) for XA Field. These results correspond to the non-linear relation, ∅ = 0.8006 −0.465 as the original values of the cementation exponent and the tortuosity factor are obtained, if the formation factor is considered as the subject.
... The study location is the Southern Niger Delta in Nigeria, which is located within latitudes 3 0 N and 6 0 N; longitudes 5 0 E and 8 0 E (Reijers et al., 1996). The region experiences wet and dry periods in a year; average rain in a month during wet season is about 1.35 x 10 2 mm and falls to 65mm during dry season (George et al., 2010;George, et al., 2017;Atat et al., 2012, Atat et al., 2020Atat et al., 2020a;2020b). Well data (A and B) were obtained for determination of an important parameter (k) in a localized model relating shear modulus with porosity information of these wells. ...
... Equation 3 is adequate for the assessment of this activity. Absorbed dose rate in air is the dose received by a person in the surrounding exposed to radioactive materials; it was calculated using Equation 4 considering the height of about 1 meter above the ground level. ...
... This was achieved using Equation 4. The result of absorbed dose rate for soil is in Tables 2 and 3. ...
The main objective of this study was to estimate the activity concentration (AC) of 238 U, 232 Th and 40 K, assess the health risk information from radionuclides presence in the soil and corn and the transfer influence from soil to corn. The key device used for the analysis was a Sodium Iodide Thallium detector. 238 U AC in soil ranges from 14.09±0.27 Bqkg-1 to 18.70±0.31 Bqkg-1 with mean value of 15.69±0.28 Bqkg-1 ; 238 U AC in corn varies from 9.36±0.22 Bqkg-1 to 14.78±0.27 Bqkg-1 with mean value of 11.53±0.24 Bqkg-1. 232 Th AC in soil is from 12.32±0.46 Bqkg-1 to 48.76±0.91 Bqkg-1 with mean value of 35.97±0.76 Bqkg-1. 232 Th AC in corn ranges from 8.26±0.37 Bqkg-1 to 35.19±0.77 Bqkg-1 with average value of 17.86±0.53 Bqkg-1. 40 K values from the soil samples varies from 313.61±6.81 Bqkg-1 to 472.63±8.36 Bqkg-1 with mean value of 384.672±7.52 Bqkg-1. 40 K varies from 374.85±7.45 Bqkg-1 to 478.55±8.41 Bqkg-1 with average value of 425.51±7.93 Bqkg-1 from corn samples. The mean transfer factor for 238 U, 232 Th and 40 K was obtained as 0.73, 0.62 and 1.13 respectively. The mean values for the Radium equivalent, absorbed dose, annual effective dose, and excess lifetime cancer risk from soil are 96.75 Bqkg-1 , 47.05 nGyh-1 , 0.06 mSvy-1 , 0.20×10-3 correspondingly [values from corn are 69.83 Bqkg-1 , 35.04 nGyh-1 , 0.04 mSvy-1 , 0.15×10-3 respectively]. These values clearly showed, the radiation doses exposed to Akwa Ibomites through the consumption of corn cultivated in these areas and inhalation of soil poses no effect to their health. Therefore, there is no radiological risk of ingestion.
... Wells J and K are situated in the South Eastern part of Niger Delta, Rivers State, Nigeria. According to [8], the latitude of the region is within 3 0 N and 6 0 N; the longitude is between 5 0 E and 8 0 E [9][10]. The location is captured in Figure (1). ...
... 9 is not adequate or suitable if values of sonic are greater than 100μsec/ft; Equation(14)is the appropriate relation after solving it completely. ...
Raw well data from oil wells J and K in some parts of the Niger Delta were used for estimating porosity in sandstone and shale units. Porosity is seen as an important parameter for estimating the appreciable volume of hydrocarbons and other fluid content that may be accessible in the reservoir. Gamma ray log and sonic log with respect to depth were generated using Microsoft Excel for analysis. The results of these suites of log were used to estimate porosity. The major outcomes resulting from the porosity estimates revealed that the average porosity values are about 35% for well J and 30% for well K. This study shows that the increase in sonic transit time gives rise to an increase in porosity irrespective of the lithology. However, sonic transit time decreases with increase in depth; depth having a strong coefficient of determination of about 0.9 with temperature, implies an increase in temperature also leads to a decrease in porosity. The Depth-Temperature relation shows T = 0.0228D + 16.671. The porosity which has been obtained in the study is appreciable as it is in the excellent class. Also, a Porosity-Transit Time Equation () has been obtained. This model satisfies and improves porosity estimates irrespective of the value of sonic in microsecond per foot for the South Eastern part of Niger Delta Basin.
... Next, to estimate vertical stress from seismic data, the inverted velocity is available at each inline and crosslines with corresponding travel time. And Eq. 8 requires density for each inline and crosslines with corresponding travel time, which is then estimated using Lindseth's approach (Atat et al. 2020): ...
Quantitative variation of pore pressure within the formations is essential for the selection of drilling mud, and to avoid catastrophic incidents such as blowouts. In this paper, we estimate to detect in-situ overpressure zone (OPZ) and to establish the adequate spatial distribution of PP from a 3D seismic data containing three wells in the foreland basin of the upper Assam shelf. We applied the fact that the porosity of Shale decreases monotonically as the effective stress increases, so we delimited the Shale volume up to 70% for PP estimation. The OPZ has been identified in the wells by comparing two methods: first, deviation of sonic transit time from normal compaction trend, and second, the separation between sonic-density porosity. The predicted PP is validated by repeat formation test and mud weight data. The 3D pore pressure model that obtained by velocity-effective stress transformation method matches with pore pressure in the wells with excellent goodness of fit. The PP gradient varies from 14.22 to 15.50 MPa/km in OPZ, and the top of OPZ ranges from 1225 to 2182 m, respectively. The spatial distribution of pore pressure is found to be mostly normal pressure for Barail, Sylhet and fracture basement except in the Kopili formation in which OPZ is spatially distributed, and higher pressure is observed in the locations toward the S-SE direction. Our results reveal the occurrence of overpressure zone in Barail and Kopili formations of Oligocene to Eocene, which can be attributed to the disequilibrium compaction phenomenon.
