TITLE:
Delineation of Near Surface Water Flow Path of Wahawa Geothermal Field by Using 2D Inversion of Resistivity Data
AUTHORS:
S. A. Samaranayake, Nalin De Silva, U. Dahanayake, H. O. Wijewardane, N. D. Subasinghe
KEYWORDS:
Electrical Resistivity, Fracture, Direct Utilization, Surface Manifestation
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.10 No.8,
August
31,
2022
ABSTRACT: The Wahawa
geothermal field which is located in the Eastern province of Sri Lanka has an average
temperature of 60°C in its surface manifestations. Since the temperature
is considerably high, it is important to explore the feasibility of direct utilization of the energy of this geothermal
field. In the present study, electrical resistivity measurements were employed
in a 20 km2 region in order to delineate the Wahawa geothermal system
and to understand the near-surface fracture pattern. Electrical resistivity mapping
of the region has been carried out using Schlumberger array measurements with nominal
current array spacing (half spacing) of 150 m and it was observed that there was a path of low ( W) apparent resistivity. These results revealed that
the hotsprings resting on a hard rock terrain are presumably
composed of metamorphic rocks, suggesting lateral
movement of hotwater towards the hotsprings instead of a deep-influx. The area of
surface manifestations is not suitable for utilization application due to
clustering of the main feeding path. The major hotwater feeding path which is extending
in the west direction can be recommended as a
possible drilling target for direct utilization applications.