We are restarting geothermal well testing operations this morning. This follows a review of our injection testing programme after the seismicity that was felt and heard last Wednesday.
We know that some people want to better understand what caused the felt seismicity last Wednesday. Microseismicity is linked to well testing during the early stages of any deep geothermal development. This is because even low injection volumes and flow rates cause tiny movements along the natural fractures in the rock very deep underground. Normally, the events generated are far too small to be felt, or heard, at the surface. But occasionally an event is felt or heard. This doesn’t mean that felt events like the one last Wednesday are dangerous. Relatively small seismic events can be felt or heard, but they would need to be much bigger to cause cosmetic damage to buildings, or to be dangerous.
We started injection testing in late January, and over the past few weeks we have taken a cautious approach, with gradual step increases in flow rates and volumes. In this period, our microseismic monitoring system has recorded over 300 microseismic events, nearly all of which have been far too small to be felt or heard – but which help us to build a picture of where water is flowing in relation to the well. Following the felt event last Wednesday, we haven’t carried out any further injections, to give us the time to review our plans.
We’re now restarting pumping at lower flow rates and volumes in order to complete this part of our programme, which should be finished by the end of this month. Further phases of logging and testing are due to be carried out during April and May, and we’ll issue more information before each phase.
There’s lots more information on well testing and seismicity on our website at https://www.edengeothermal.com/the-project/drilling-and-operations/well-testing/ But please do also contact us direct if you have any queries or questions about the geothermal programme. You can email us at firstname.lastname@example.org, send us a direct message from Facebook or call our well-testing phone line on 01202 898150. (You’ll speak to a receptionist, who will take a message for us and we’ll call you back.) We have a public viewing area at our site and we’re always happy to meet people and answer questions face to face, too.