One of the objectives of the REFLECT project is to make possible the collection of samples at depth from hot geothermal wells (>200ºC). A more ambitious aim within the project is to allow for sample collection at even higher temperatures, up to 300-400ºC at superheated/supercritical pressures. The sampler is designed to tolerate harsh environments at high pressures and elevated temperatures, capable to sample from individual feed-zones at specific depths giving information that is otherwise lost once the fluid flashes and/or mixes with shallower feed-zones while flowing up the well.

Concerning this, the REFLECT project has achieved a new milestone for the development of a downhole sampler and fluid transfer system for high-temperature geothermal wells. The project partner ÍSOR – Iceland GeoSurvey has worked on the principles of the sampler and prepared preliminary technical drawings, and project partner Hydroisotop has worked on the fluid transfer system. The potential sampling scenarios in wells ranging from typical high- to ultra-high-temperature wells have also been studied. The methodology of well sampling for high-temperature geothermal wells is the same as for conventional well logging using slick-line equipment and a lubricator pipe. A prototype of the sampler is planned to be built in the year 2022 with subsequent testing and in-situ sampling for validation.

Figure  – The methodology of well sampling of high-temperature geothermal wells using well logging slick-line equipment and lubricator pipe (Picture provided by ÍSOR)

With this work, the REFLECT project has achieved a new milestone that will contribute to better operation of geothermal systems for sustainable use.