TITLE:
Evaluation of Factors of Soil Resistivity in the Niger Delta
AUTHORS:
Tamunoene K. S. Abam, Ferdinand Dumbari Giadom, Robert E. O. Iduma, Ifeyinwa L. Nwankwo
KEYWORDS:
Factors, Resistivity, Aggressivity, VES, Environment of Deposition
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.5,
May
31,
2023
ABSTRACT: Soil conductivity is responsible for its aggressive behavior to metallic
objects either in contact or buried in the
ground. Rapid deterioration and eventual rupture of pipelines leading ultimately
to crude oil spillages have been of economic as well as environmental
concern. Although many factors contribute to soil resistivity, these
relationships have hardly been quantitatively expressed. This paper explores
the factors affecting soil resistivity firstly by matching the spatial regional
distribution with each of the identified factors of influence, including ground
elevation soil type, depth to water table and undrained strength. 183 Vertical
Electrical Sounding VES with the ABEM SAS 1000, using Schlumberger electrode
configuration were carried out along a pipeline route to generate resistivity
distribution across a linear alignment that traverses three geomorphic
sub-environments in the Niger Delta Region. The apparent resistivity values averaged
over depths of 3 m and 10 m were plotted against the co-ordinates using Surfer-16 and overlaid on
Google earth Pro to produce a spatial distribution with enhanced location
visibility. The results show that apparent resistivity is influenced by depth
to water table with lower values in areas of shallow water table occurrence.
Furthermore, it is shown that changes in resistivity below the water table are
more due to variation in soil type. Within a soil type above the water table,
soil resistivity increases monotonically with depth until the depth of probe
extends to a different soil horizon. Results of this study provide guidance as
to what ground resistivity to expect in different part of the delta as well as
provide valuable information to assess the
risks to assets either as a means of prioritizing maintenance or of
improving design for new installations in the Niger Delta Region.