How did the Geoenergy Test Bed (GTB) develop in 2015?
October 2015: Near Surface Soil-Gas Survey
A near surface soil-gas survey was completed in October 2015 by members of the British Geological Survey’s Gas Monitoring Facility. The facility has the capability to measure concentrations of a range of gases in both the soil and atmosphere as well as determining the flux of gases across the soil/air boundary. Measuring the natural background gas variations of near surface gases at the GTB helps to establish baseline conditions. (The pictures below are for the purpose of illustrating technique only. They were not taken on the GTB site.)
August 2015: Electrical Resistivity Tomography survey
The Electrical Resistivity Tomography Survey (ERT) was completed in August 2015 by the Geophysical Tomography team from the British Geological Survey. ERT is a geophysical technique which measures the resistivity of the earth. It is a non-invasive technique meaning the ground is not disturbed or affected in any way. An array of electrodes are laid out in a series of single lines with a cable joining the electrodes together. A small DC electrical current is injected into the ground between one pair of electrodes and the voltage is measured between another set of electrodes. An instrument called a terrameter sends energy to the electrodes and measures the resulting voltage. The ERT survey produces a cross-section of data which indicates the stratigraphy and sub surface features.
July 2015: Drilling the first borehole
The first characterisation borehole was drilled in July 2015 to a depth of 169m. This was drilled by our GTB partner the Corps of Royal Engineers to prove stratigraphic boundaries.