By John Denny
(Spring Hill, Nevis) – Nevis is a little closer to realizing its dream of cheap, renewable energy this week.
After weeks of drilling, West Indies Power has reached the geothermal reservoir and steam is coming out of the ground. The exploration drilling at the Nevis 1 site is near completion and the company plans to move to the Nevis 2 site at Near Fern Hill soon, according to CEO Kerry McDonald.
Testing is being done on the steam exiting the hole to determine its mineral and chemical composition. Those results will determine the amount of power that can be expected from each well. So far, all the drilling has been exploration. Other equipment will be brought in to drill the production wells, which are a larger diameter than the exploration well.
After testing its geothermometry, the Nevis 1 exploration well will be sealed for about two weeks. This will allow the reservoir to return to its normal temperature as it has been cooled by the fluids used in the drilling process.
Once it has reached equilibrium, more tests will be done to determine output, heat and chemistry. The drilling of production wells should begin in a few weeks, according to Mr. McDonald.
“We expect each production well to produce about 15 Megawatts,” said Mr. McDonald. “If we drill three at Nevis 1, that would be 45 Megawatts.”
Nevis only uses about 10 Megawatts/hour during peak times. Combined, Nevis and St. Kitts use about 45 Megawatts.
“Once we start producing that much, we will have to start looking for places to export to before we drill any more production wells,” he said.
The Minister for Public Utilities Hon. Carlisle Powell came to the Nevis 1 site on June 2 to witness the milestone
“I am absolutely delighted that they have been able to prove the first well as commercially viable. Of course there is still a lot of work to be done before we can turn this steam into electricity but I am confident that West Indies Power (WIP) and its subcontractors are doing the right thing,” he said.
On the day they struck steam, Mr. McDonald explained to the minister what was happening over 3,700 feet below ground.
“The drill bit is still in the pipe, so in other words, what you are seeing is steam coming around the little cracks between the drill bit and the pipe wall so this pipe is not open. All you are seeing is what’s coming around the sides, so if we opened this pipe it would be flowing about five times more than this.
“We feel all the water we use to drill with, will be out of this in roughly 30 hours and we will have nothing but the pure steam. What this says is we are in the reservoir. This is a sustainable reservoir and this is enough to build our geothermal power plant,” he said.
Mr. Bobby Tinsley, Drilling Supervisor of Therma Source, a subcontractor of WIP, explained that a series of tests would be conducted and sent to the laboratory and the relevant data collected on the reservoir.
“What you are seeing is the steam that is actually coming out of the well and the hot water. The water is getting hotter, [so] we anticipate 24-36 hours of development to get to the background fluids where we can run samples and send them off to the lab. We will do chemistry ph control right now the ph is about 6.7 which means we are very close to fresh water, non-acidic, and we plan on doing this for about three days to make sure we get the background water and get the data that we need. So it would be very exciting.
“We are basically in the reservoir now. What we have proven is the reservoir is there. The exploration rig is not designed to go through the reservoir. What it is designed to do is find the reservoir and find the top of it and test the chemistry of the water and that’s what we are doing at this point. We will probably be done with this well when the testing program is over. We will let it set so we can get thermal gradient of the formation for about 30 days and then do some more tests on it but we will probably be moving off Nevis I and headed to Nevis II,” he said.