Náttúrufræðingurinn - 1981, Síða 84

S U M M A R Y
Geochemistry and Geothermal
Investigations
by
Slefán A rnórsson,
Science Institute University vf lceland
The role of geochemistry in geothermal
exploration and development is described.
Individual geochemical tasks are linked to
the four major investigational phases, (1)
surface exploration, (2) exploratory drilling,
(3) appraisal drilling and testing and (4)
production drilling and production. During
the surface exploration phase geochemistry
is particularly useful in estimating under-
ground temperatures, in delineating
regional groundwater movement, mapping
the areal extent of aquifers and water
movement within geothermal systems, and
in defining environmentai influence of the
intended utilization. During the exploratory
and appraisal drilling phases geochemistry
yields information on underground temper-
ature conditions, the nature and location of
aquifers, direction of underground water
flow, mixing processes, and boiling in the
aquifer. Geochemistry also furnishes data
for engineering design and defines and aids
solution of eventual scaling and corrosion
problems as well as fluid disposal. Monitor-
ing of the chemistry of well discharges dur-
ing production can be particularly useful in
following changes in reservoir characteristics
caused by boiling in the aquifer and in-
vasion of cold water into the geothermal
reservoir.
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