Ultra Deep Geothermal energy in The Netherlands

Abstract

Goals to reduce greenhouse gas emissions and energy transition poses new opportunities and challenges for the exploration in geothermal energy. An Ultra Deep Geothermal Energy play in Dinantian limestone, the Kolenkalk, has recently come into focus in the Netherlands. The Dinantian limestone was encountered by multiple wells, but its presence and distribution throughout the Dutch subsurface is largely undiscovered yet. Several projects in northern Belgium and the area of Venlo proved good reservoir quality in the Dinantian carbonates. In the northern part of the Netherlands, large build-up structures from Dinantian age were interpreted on seismic data. Limited well data suggests no reservoir properties in these structures. However, links were made with the similar appearing Tengiz Platform in the Caspian Sea area where giant reservoirs were found inside these platforms. Fracture and karst based permeability may be one of the most important features that could develop good reservoir properties in the overall dense Kolenkalk. These zones are mainly expected along large faults and isolated platform margins and may be predictable from seismics. The Dinantian UDG play was defined and a risk matrix was developed. This resulted in a classified potential map, featuring a combination of all acquired and interpreted data. It was concluded that (1) the overall risk in the Dinantian UDG play is high, (2) data is limited on the Dinantian limestone and (3) reservoir properties are heterogeneous, but could be (very) good locally.