Once the 9 5/8” casing is cemented in place, we will reconfigure the wellhead and BOP and continue drilling, this time at a diameter of 8 ½”. Drilling will continue for another 1,000m approximately, but this will depend on exactly where we intersect the target fault structure. As soon as we are sure we have drilled through it, we will stop, run further geophysical logs and then conduct a short production test. That will complete the activity on UD-1, so then we will move the rig 8m along the site and start drilling UD-2. The slower than expected drilling speeds means that we are behind our original schedule and we now expect to finish UD-2 at the end of June.
A word about depth…
We always talk about the wells being 2,500m and 4,500m deep but actually that’s a kind of shorthand. They are the target ‘true vertical depths’ (TVD) at which we plan to intersect the eastern edge of the Porthtowan Fault Zone. The wells will continue through the fault zone and therefore finish up being quite a bit deeper.
There is also a difference between TVD and ‘measured depth’ (MD) which is the drilled length of the wells. They are not the same thing because the wells aren’t vertical. All our progress reporting is based on MD. As we get deeper, and the wells get further away from being vertical, there will be an increasing difference between MD and TVD. The TVD will always be less than MD.
The exact final depth of UD-1 will depend on where we hit the fault and how thick it turns out to be but we expect the well to end up with a measured depth of about 5,500m and a true vertical depth of about 5,300m.
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From the Global Geothermal News archives:
- Thursday, January 17, 2019 - United Kingdom: First Well at United Downs Deep Geothermal Power Project to be Production Well
- Tuesday, January 8, 2019 - United Kingdom: Video Overview of United Downs Deep Geothermal Project
- Tuesday, November 6, 2018 - United Kingdom: Drilling Starts This Week at United Downs Geothermal Power Plant
