Characterization of the aquifer systems in the coastal areas of Niger Delta using gamma ray and electric logs
| dc.contributor.author | Okoro, Felibens Edeheri | |
| dc.date.accessioned | 2025-11-10T11:45:11Z | |
| dc.date.available | 2025-11-10T11:45:11Z | |
| dc.date.issued | 2023-07 | |
| dc.description | Doctoral thesis in geophysics. It contains maps. pictures and tables. | |
| dc.description.abstract | Gamma ray and electric logs obtained within the coastal areas of Niger Delta were utilized to characterize the aquifer systems in the area with the view to, among other things, isolate fresh water and contaminated aquifers as well as providing pragmatic results and a new lens for individuals and agencies to view the ever-increasing pursuit of groundwater development initiatives in the area. Sixty-two (62) wells and their accompanying logs as well as strata samples from these wells were studied across the five geomorphological zones of the area. The Geophysical logging operations were done using Mount Sopris Instrument, MGX II Logger. WellCAD software was used in the interpretation of the well log data. The gamma logs neatly delineated the different aquifers. The area generally is underlain by alternating sequences of sands and clay. This sequence is capped by laterized soil around the coastal plain sand areas. The area consists of a multiple aquifer system with three categories of aquifers delineated as Deep (410-600m), Medium (135-409m) and Shallow (5-134m) aquifers. Based on the amount of gamma Count Per Second (CPS), the aquifer system in the area can be classified into Very Low Gamma Count (Highly Sandy Aquifers), Low Gamma Count (Sandy Aquifers) and Medium Gamma Count (Slightly Clayey Aquifers).The very low gamma count aquifers indicating high sandy aquifer have counts ranging from 9.9 to 12.9 CPS. Considering the porosity of the aquifer media, aquifer systems of the area are classified as high (>65%), medium (36-65%), low (21-36%) and very low (<21%) porosities. Based on the distribution of aquifer resistivity values at different depths where aquifers were mapped, the entire study area was adjudged to have the following aquifer systems viz: Very Low Resistivity Aquifers with values ranging from 0 to 20 Ohm-m (Saline Water), Low Resistivity Aquifers ranging from 20 and 100 Ohm-m (High Ferrous Contamination), Medium Resistivity Aquifers with values ranging from 100 to 500 Ohm-m (Low Ferrous Contamination) and High Resistivity Aquifers with values above 600 Ohm-m (Fresh Water with no Saline or Ferrous Contamination). The saline-fresh water boundary varies from location to location within the study area. The boundary was observed to be shallow within Tunu flow station of Bayelsa State; NLNG Amadi Creek and Amadi Creek 2 of Rivers State; Erunailaje, Akpata Ijaw, Ayetoro and Adoloseimo areas of Ondo State. Deep saline–fresh water boundary occurs around Bonny water, Finima water Board, Bille, Idama, Kula and Asaramatoru areas of Rivers State; Jinrinwo and Abealala Ilaje area of Ondo State as Well as Ogidigben area of Delta State. The study showed that there are aquifers deeper than 80 metres within the Onne, nAmadi Creek, Kidney Island and Amadi flats areas that can produce potable water free from saline water and ferrous contamination provided there is no over pumping and the hydrostatic balance is maintained. Aquifer resistivities of over 600 Ohm-m were established to be fresh water. The study also showed that salt water can be isolated in most of the areas particularly in the salt water swamps and coastal beaches areas by drilling very deep boreholes. Some of the aquifers in the coastal plain sand environments can be considered to be free from any contamination in depths exceeding 120m.The resistivity logs indicated different saline water aquifer depths for the boreholes in the area where the vertical distribution of saline water ranges from 0-80m around Onne, Amadi Creek and Kidney Island and 0-145m around Bonny, 0-218m around Finima Bonny and 0-260m in Bille. The implication is that, wells drilled from surface and terminated within these depth ranges at these locations will encounter saline water and wells drilled below these depths will not encounter saline water. It is recommended that because of the nature of the aquifers of the coastal area of Niger Delta, there is an urgent need to protect the aquifers from further contamination by enacting appropriate laws to protect the groundwater of the area and to curtail indiscriminate drilling of boreholes and over extraction of water from the few fresh water aquifers of the Niger Delta It is hoped that the results will be useful to researchers, stakeholders and government agencies involved in developing local and regional water plans. | |
| dc.description.sponsorship | Department of Geophysics, FUTO. | |
| dc.identifier.citation | Okoro, F. E. (2023). Characterization of the aquifer systems in the coastal areas of Niger Delta using gamma ray and electric logs. {Unpublished Doctoral Thesis}, Federal University of Technology, Owerri. | |
| dc.identifier.uri | https://repository.futo.edu.ng/handle/20.500.14562/2283 | |
| dc.language.iso | en | |
| dc.publisher | Federal University of Technology, Owerri | |
| dc.rights | Attribution-NonCommercial-ShareAlike 4.0 International | en |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-sa/4.0/ | |
| dc.subject | Aquifer | |
| dc.subject | contamination | |
| dc.subject | ferrous aquifer | |
| dc.subject | mount sopris | |
| dc.subject | saline water | |
| dc.subject | WellCAD | |
| dc.subject | department of geology | |
| dc.title | Characterization of the aquifer systems in the coastal areas of Niger Delta using gamma ray and electric logs | |
| dc.type | Doctoral Thesis |