Downhole logging

Now that we have drilled down to the depths that we need before setting casing and drilling a very deep hole all the way to the basement we have decided to stop and measure downhole geophysical logs. This is a method in which sensors are deployed down the borehole to record different aspects of the physical properties of rocks. This can give us information over parts of the section where we don’t have any core and is a standard method in the oil industry.

In this photograph you see our logging engineer, Kerry Swain, working with the rig crew to deploy the first set of geophysical instruments into the borehole in order to measure porosity, resistivity, and natural gamma radiation. This is called the “triple combo”. Success with this is dependent on the stability of the hole and not having too much material cave-in and block the passage of the instrument which is simply lowered on a strong metal cable and can get caught if we are not careful.  So far the hole has been behaving itself so we can only hope that this lasts for the duration of the logging operations which go on for about a day and a half.