Jökull - 01.12.1987, Page 26

) 86 05 0452" AÍ' \ 1 •
KJ-B | \ KJ-20 /

.1-14 I
\
KRAFLA- SUDURHLIDAR
PRESSURE AT 500M BELOW SEA LEVEL
KJ-16

/ f j
/ • 1 I
/ KJ-17
/
/ /
V \
Fig. 15. Pressure distribution at 500 m
below sea level in the Suðurhlíðar well
field. — Mynd 15. Þrýstingur á 500 m
dýpi undir sjávarmáli á Suðurhlíða-
svœðinu.
Deliverability curves vary widely between the upper
and lower zone wells. The upper zone wells show rapidly
declining output with increasing pressure, a feature
characteristic of water-saturated wells in general. Wells
drawing predominantly from the lower zone have rela-
tively “flat” deliverability curves. In well KJ-11, inflow
from the upper zone tended to choke the lower one
especially at low wellhead pressures. Thus, a twofold
deliverability curve was obtained, one sloping at low
pressures and the other flat at higher pressures. These
three types of curves are shown in Fig. 16.
In the Suðurhlíðar field the wells are high enthalpy
ones and tend to show small variation in flow for differ-
ent wellhead pressures.
The deliverability curve for well KJ-21 at Hvíthólar is
relatively flat, whereas the cold inflow into well KJ-22
gives rise to a more sloping curve (Fig. 17).
The discharge histories of wells drawing from boiling
reservoirs tend to differ from those drawing from single
phase ones as has been described with special reference
to the Krafla and Námafjall areas by Stefánsson &Stein-
grímsson (1980). Large variations in flow rates and en-
thalpies are observed in the beginning of the discharge
while boiling develops in the vicinity of the well. The
increase in enthalpy is accompanied by a decrease in the
total flow rate due to different mobility of steam and
water phases and non-adiabatic flashing in the vicinity of
the well. If the flow remains two-phase the flow rate will
start to increase after some weeks probably due to ther-
mal contraction of the rocks surrounding the well caused
Fig. 16. Production characteristics of
wells in the Leirbotnar and Suðurhlíðar
fields. — Einkennandi aflferlar Leir-
botna- og Suðurhlíðahola.
JHD-BJ-6607 A»G
86.05.0445 A&
PRODUCTION CHARACTERISTICS OF WELLS AT LEIRBOTNAR AND SUÐURHLIÐAR
24