Kenya:

Menengai Fieldwork - Fancy Technology!

GRC Student member Helen Robinson blogs about her geothermal fieldwork at the Menengai crater in Kenya.

Helen is a PhD researcher in geothermics, University of Glasgow, MGeol graduate, Plymouth University.

Cluff Rig, Great Rift Drilling 1

So today was a case of finishing off in the caldera. It is always advisable when doing fieldwork, to allow a day or two of finishing off. It gives you time to revisit locations that may have confused you in some way, or add to the data pool. Anything that you feel the need to readdress. Once you have left you can’t go back!

Firstly, we went to visit Great Rift Drilling’s Rig 1, owned by Cluff Geothermal, now that it is fully constructed. It’s a much smaller set up than the rig we visited on Day 2. Hydraulics are used to control the drill string in this case. It is much more compact, takes 4 days to take down, move and reconstruct; compared to the 21 days for the larger rigs owned by GDC. They also cost a tenth of the cost to move compared with the GDC rigs.

The amount of water used is vastly reduced with these rigs as more often than not, air is used to lubricate and to raise drill cuttings to the surface. The only time water is used to excess is when the lithology is very loose or unconsolidated. This is when cave ins, or sluffs, occur within the drilled hole. Mud contributes to keeping the lithology where it is, stopping debris filling the bottom of the hole. In this instance, when the water and mud returns to the surface, it is sieved so it can all be reused.

These rigs can drill to 3000m, in comparison to 7000m for the larger rigs. However at Menengai, the maximum depth is 3200m, which was a one off. The rig can also case to 2000m. It is packed with wireless technology, meaning it takes less manpower to work and control and it is overall more accurate. All in all it is a much more cost effective piece of equipment and brilliant with it! There are currently four in the world, so the viability of the rig in this location is being tested. It is an amazing bit of kit, incredibly impressive!

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