The much anticipated geothermal plant in St Vincent and the Grenadines is facing severe challenges, as the three wells drilled for the project is not showing the level of stimulation as expected.
The technical team executing the project is reporting that while the wells show sufficient temperature, it is not the level of permeability required to guarantee the operation of a geothermal power plant. Prime Minister, Ralph Gonsalves told parliament last week that, “the conclusion…as provided by the technical persons is that although the results in relation to the permeability have not gone favourably due to the very tight fractures that have limited the permeability, the tested temperatures on the wells were adequate for geothermal power.”
The prime minister is adamant that the technical team will exhaust all options of well stimulation in an effort to open the fractures on the three wells and improve permeability. He said that the technical team is optimistic that following the successful stimulation results of the well SVG 03, “they are hopeful that the others will be similar and in addition, strengthen the stimulation in 03”.
Drilling of the first well SVG01 lasted from April 30, 2019 to July 27, 2019, a total of 89 days to a depth of 2,700 meters. With challenges due to the unstable formation in the well, it was necessary to correct the inclination of the well, which then though collapsed at a depth of 1,889 meters.
Total cost of drilling this well was $7.7 million and a temperature of 155 degrees Celsius was measured at a depth of 1,880 meters. The project team sees still the possibility for making the well successful with drilling a side track from 1,800 to 2,700 meters and additional stimulation.
The second well, SVG03, was drilled between August 7, 2019 and October 29, 2019, including seven days of stimulation to a depth 2,283 meters (total length 2,800 meters). The well collapsed at a depth of 1,627 meters and a sidetrack from 1,160 meters.
Total cost of the well was $7.6 million. Temperature of the well was 220 degrees Celsius at the depth of 2,800 meters with though low permeability. Well testing is outstanding but it is planned to continue stimulation to increase flow capacity.
Drilling for the third well, SVG02 began on Nov. 4, 2019 and ended Jan. 15, 2020, including 19 days’ stimulation. Depth of the well is 2,990 meters (2,869 vertical depth). Drilling cost was $5.6 million with a temperature of 230 to 250 degrees Celsius. Also this well will have to be stimulated.
Together with the Caribbean Development Bank and the board of the St Vincent Geothermal Company Ltd, efforts will be made to make the wells productive for the purpose of the project to develop a geothermal power project. Sidetracking the first well, SVG01 is next on the agenda with stimulation using a downhole packer, to seal downhole at 1,700 meters.
The same will then be tried to SVG03. It is expected that testing will be concluded around July 2020, at that time estimates can be made about the possible capacity of the wells for power generation.