Jökull - 01.12.1961, Page 48

c/> loí e c i & 500 1000 1500 aooo Tempe 10 50 60 70 8D 90 1C rature 0 1 °c 0
• • • « I • •
i • • •
■ » • • «
REYKIR THERMAL AREA B0REH0LE G-l

FIGURE IV.
at a relatively great depth, that is, at about 1.000
meters. It was hoped that the new borehole
would reveal the structural importance of the
fault and possibly produce water at a higher
temperature than the previous boreholes.
The borehole was completed at a depth of
1.380 meters. Only insignificant production was
obtained from the depth of 670 meters.
An accurate temperature survey was carried
out with a thermistor when the borehole had
reached temperature equilibrium. The results
are given in FIGURE IV.
The results give a temperature of 98 °C
at the small fissure cut at 670 meters. Imme-
diately below the fissure the temperature drops
to 90 °C, and is fairly constant in the lower
part of the borehole.
The temperature data are indicative of a
horizontal permeable layer at the depth of 670
meters. Moreover, no upflow of thermal water
through the fault is indicated. Thus the results
appear negative as to the importance of the
Tertiary fault line. The Reykir thermal area
appears to be controlled by a horizontal layer
rather than the fault. None of the older bore-
holes had been drilled deep enough, in order
to cut the horizontal layer.
(c) The Hengill thermal area.
This area is one of the great natural-steam
areas of Iceland. The southern part of the
thermal area, the region around the small com-
munity of Flveragerdi, is favourably located as
to exploitation. A natural-steam power plant is
now planned to be erected in this part of the
area.
Large scale drilling was initiated in 1958.
A total of 8 boreholes has been completed. The
clepth v'aries from 300 to 1.200 meters, ancl the
e £ E Temp ^ 160 180 200 2 erature°C 20 240
- 0 £ Q. <D Q 200 400 600 800 1000
\
\ 2

HENGILL THERMAL AREA \J . TEMPERATURE IN B0REH0LES T.
1 Borehole G -1 2 Borehole G -7 T \
f r

FIGURE V.
46