Haagse Aardwarmte Leyweg (HAL) is a geothermal operation where two old wells were tested and chemically treated, however were not taken into production. For this project we supported the project manager of Aardyn with all decisions regarding dependencies of the wells and reservoir. In 2017 a detailed test plan was set up using wireline tools and laboratory analyses. Based on the results we designed stimulation programme that we safely executed. HAL is currently the first and only project in The Netherlands that provides heat to an urban district.