In the central Mallik 5L-38 well DTS sensor cables were installed to ~940 m depth, and online
temperature monitoring during a thermal stimulation experiment was performed
(Hancock et al., 2004). In the two lateral observation wells, the sensor cables were installed to
a depth of ~1160 m in order to determine the formation temperatures.
A special feature of the experiment design is the permanent installation of the sensor cables
behind the borehole casing. After completion of the well, the sensor cables are located in the
cement annulus between casing and borehole wall. The fibre-optic cables were attached to the
outer side of the casing at every connector, within intervals of approximately 12 m, using
custom-built cable clamps (Fig. 7).