WorldWide Drilling Resource

Drilling Completed for Geothermal Plant in the UK Adapted from Information by United Downs Deep Geothermal Power and Oroco Utilities Drilling to establish the first deep geo- thermal elect r ici ty plant in the Uni ted Kingdom (UK) has been successfully com- pleted at United Downs Industrial Park in Redruth, Cornwall. Geothermal Engineering Limited (GEL) was contracted to drill the deepest well on UK soil at around 16,700 feet. The well also proved to be the hottest, with temperatures of approximately 383ºF (195ºC), with initial flow tests suggesting the project is capable of producing the UK’s first geothermal electricity. To establish the United Downs power plant, two deep geothermal wells have been drilled into the hot granite rocks beneath the site. The wells are directional (j-shaped) to intercept a target geological structure (the Porthtowan Fault). The natural structure enables water to be circulated through the hot rock from the injection well to the production well in a continuous cycle. As the water moves through the rocks, it picks up heat which is extracted and converted to elec- tricity at the surface. The project was established by GEL to demonstrate the potential of the deep geothermal resource in the UK for pro- ducing carbon-free electricity and heat. The United Downs plant is expected to supply up to three megawatts of electrici- ty, which is enough energy to power 3000 homes. Dr. Ryan Law, managing director of Geothermal Engineering Ltd said, “We are delighted to have completed the drilling of these technically challenging wells. Reaching our target at the Porthtowan Fault Zone, at such a depth, was a fantastic achievement in geo- logical and engineering terms and the initial flow test are very exciting for unlocking the potential of the granite in Cornwall.” Now that drilling has finished, the third phase of the program, evaluation which is expected to run until spring of next year, will begin. The first part will be to remove a tem- porary downhole packer from UD-1 and carry out more downhole logging measure- ments. Both wells intersected the Porthtowan Fault at the predicted depth and downhole measurements confirmed plenty of natural fractures, indicating good permeability. However, a series of measurements and hydraulic tests are necessary to evaluate the fault structure to make sure the wells are in good condition and evaluate the amount of geothermal energy which can be harnessed. 50 DECEMBER 2019 WorldWide Drilling Resource ® Information: Joel Walton jwalton022@aol.com • (225) 744-4554 www.lgwa.org January 9, 2020 Paragon Casino - Marksville, LA Tower or Atrium hotel rooms call (800) 642-7777 and refer to LGWA Annual 2020 conference use code LGWA 01G Registration starts at 7 am, Seminars start at 8 am (Cocktail hour, dinner, and BINGO at 6 pm the night before the convention [the 8th].) Louisiana Ground Water Association Convention & Trade Show Visitors can get close to the wellheads UD-1 & UD-2 and standover the deepest hole in theUnitedKingdom. A 24-inch and a 17.5-inch drill bit used on the project. Photos courtesy of United Downs Deep Geothermal Power. GEO