Geojac, This is a bit complicated, because the well is circulated with a fluid prior to cementing the casing, ie down the inside of the casing and back up the outside. This is done to ensure there is a clear pathway for the cement and critically to reduce the temperature prior to cementing. The cement recipe contains retarders to control the setting time, but this is based a maximum critical temperature, so the well must be cooled to below the critical temperature first, of the order of 60 deg C plus/minus.
The surrounding rock can be cooled relatively easily by circulation, and is a normal practice in the drilling geothermal wells. So this means the temperature of the casing is considerably below the normal granite temp (275 degC) at the time of cementing.
During the hardening of the cement the casing and surrounding cement are reaching an equilibrium temperature with the surrounding rock.
The well is designed to move at the top, and the well head will lift but only inches when it warms up.
Geothermal wells world wide are cemented in this manner. Depths of 2000-3000m are very common. Also temperatures of 275 deg is normal.
GDY have drilled 5 wells and cemented all into the granite. What GDY is doing is relatively normal. Hab-3 has a problem because something abnormal failed. It's going to be a bit of a problem to fix, but they will. It won't be next week.
RNE Price at posting:
$1.09 Sentiment: None Disclosure: Held
