The Development of a Multi-purpose Geothermal Site in an Urban Area

In May 2007, students of Deft University, Department of Applied Earth Sciences, made for their 23rd lustrum an appraisal study regarding a combination of geothermal energy combined with CO2-injection. According to the pre-study, nine exploration wells in the Delft area show an anticline below the University grounds, which holds various sand bearing members at a depth of about 2 to 2.5 km. One member consists of highly permeable sands, which may produce about 120 m3/hr of water. The expected geothermal temperature of about 75C can be used for new and renovated buildings. In order to drill an injection and production well for geothermal use on a small foot print, a new light weight composite tubing is proposed. It is possible to drill almost weightless with an innovative mobile telescopic rig. The tubing of the injection and production wells also contain a thermoplastic inner wall, which is expected to be less corrosive and less expensive when compared to regular steel tubing. Hence, the option of CO2-injection into the returning water is considered. The two innovative aspects in this feasibility study, i.e. composite drilling and CO2-injection, got the attention of the industry, university and other (non-) governmental organizations.