The multi-purpose research borehole at the Delftse Hout is the third of four seismic monitoring locations of the seismic monitoring network for the geothermal research project on the TU Delft campus (Geothermal Delft GTD, also known as DAPwell, https://geothermiedelft.nl/). For the geothermal research project, two deep wells (“a doublet” consisting of an injector and a producer) for geothermal energy extraction will be installed on the TU Delft campus next to the combined heat and power plant (“warmtekrachtcentrale - WKC”). The system will produce geothermal heat to supply the campus of TU Delft and part of the city of Delft. The herein presented borehole describes the installation of a multi-purpose research borehole (called DAPGEO-02), which was installed in the period February - May 2022. DAPGEO-02 is part of a seismic monitoring system for the shallow and deeper subsurface in the vicinity of the planned geothermal doublet. The locations of all four stations are given in Figure 1. The monitoring network and the related research gathers knowledge about the current status of the subsurface on the basis of periodic data measurements, and possible seasonal effects. Within the seismic monitoring network, three seismic monitoring stations have already been installed, respectively DAPGEO-01 on the proposed location of the geothermal project near the Leeghwaterstraat in Delft, DAPGEO-03 on the Kerkpolderweg in Delft, and ZH03 in on the Ackersdijkseweg in Pijnacker-Nootdorp (installed and equipped by KNMI).@en

A geothermal doublet has been installed in a sedimentary reservoir for direct-use heating on the TU Delft campus, targeted to supply around 25 MW of thermal energy at peak conditions. This contribution presents the implementation and initial data collection from the doublet, including an initial evaluation of the logging and coring campaign. Nearly half of Netherlands natural gas consumption is allocated to heating, and the on-campus CO2 emissions from heating exceed 50%. The doublet has been designed with two primary aims of research and commercial heat supply, with the wells being completed in December 2023. The project will be operated by a commercial entity, and built into a larger thermal energy system including a high temperature underground storage system, with the first energy production planned in 2025. The research questions relate to field-scale geothermal operations, e.g. how reliable is the long-term energy production?, how do materials perform in the long-term? and how can geothermal projects be best monitored? The research programme involves the installation of a wide range of instruments alongside an extensive logging and coring program and monitoring network. The doublet has been cored, with substantial continuous samples from the heterogenous reservoir, alongside a large suite of open hole well logs in the reservoir and through casing logs in overlying geological units. A fiber-optic cable will monitor distributed pressure throughout the producer reservoir section, at approximately 2300m depth, which will be installed during commissioning. A local seismic monitoring network has been installed in the surrounding area with the aim of monitoring very low-magnitude natural or induced seismicity. The project is a key national research infrastructure and is being incorporated into the European EPOS (European Plate Observing System, https://www.epos-eu.org/), such that accessibility and data availability will be as wide as possible. All observations will be included in a digital-twin framework that will allow to make better decisions in future geothermal projects.@en

A geothermal doublet has been installed in a sedimentary reservoir for direct-use heating on the TU Delft campus, targeted to supply around 25 MW of thermal energy at peak conditions. This contribution presents the implementation and initial data collection from the doublet, including an initial evaluation of the logging and coring campaign. Nearly half of Netherlands natural gas consumption is allocated to heating, and the on-campus CO2 emissions from heating exceed 50%. The doublet has been designed with two primary aims of research and commercial heat supply, with the wells being completed in December 2023. The project will be operated by a commercial entity, and built into a larger thermal energy system including a high temperature underground storage system, with the first energy production planned in 2025. The research questions relate to field-scale geothermal operations, e.g. how reliable is the long-term energy production?, how do materials perform in the long-term? and how can geothermal projects be best monitored? The research programme involves the installation of a wide range of instruments alongside an extensive logging and coring program and monitoring network. The doublet has been cored, with substantial continuous samples from the heterogenous reservoir, alongside a large suite of open hole well logs in the reservoir and through casing logs in overlying geological units. A fiber-optic cable will monitor distributed pressure throughout the producer reservoir section, at approximately 2300m depth, which will be installed during commissioning. A local seismic monitoring network has been installed in the surrounding area with the aim of monitoring very low-magnitude natural or induced seismicity. The project is a key national research infrastructure and is being incorporated into the European EPOS (European Plate Observing System, https://www.epos-eu.org/), such that accessibility and data availability will be as wide as possible. All observations will be included in a digital-twin framework that will allow to make better decisions in future geothermal projects.@en