DErisking Exploration for geothermal Plays in magmatic ENvironments

Høy risiko kyttet til geotermiske ressurser og høye letekostnader utgjør vesentlige barrierer i oppskalering av geotermisk energi som en del av det grønne skiftet. DEEPEN prosjektets målsetting er å øke sannsynligheten for boring av vellykkede brønner nær-magmatiske systemer. Muligheten for å hente ut høytemperatur geotermiske ressurs fra slike systemer vil gi økt effetivitet og reduserte kostnader for produksjon av elektrisk kraft. Planen er å overføre Play-Fairway metodikken utviklet av olje og gass industrien til anvendelse for geotermiske system. Prosjektet er et samarbeid mellom partnere fra Island, Norge, USA, Tyskland, Frankrike og Sveits.

The overall DEEPEN project outcome provides a scientific basis and an approach for for applying the Play Fairway Analysis (PFA) methogology in "superhot" magmatic plays. In the DEEPEN project, geological elements of magmatic plays and indicators for multiple plays in magmatic systems have been defined for two DEEPEN use cases, the Hengill volcanic system on Iceland, and the Newberry volcano in Oregon, USA, representing hydrothermal/hybrid and EGS-type magmatic plays, respectively. These geologic elements were used as a basis for developing a generalized fairway analysis of multiple plays in a single magmatic system. They were further used to identify indicators for the presence of natural supercritical fluids in magmatic settings, as well as applicable exploration methods. The DEEPEN project has developed exploration methods to be used for subsurface imaging of deep and hot bodies, covering different methodologies comprising geochemical tools for targeting superhot fluids, assessment of supercritical fluid composition and utilization, tools for fracture analysis based on seismic and EM anisotropy, MT network design for deep targets, benchmarking of seismic velocity models using well logs, and multi-geophysical inversion. A high quality seismic dataset was used to detect and image deep and hot bodies and fault zones around the IDDP-3 target region at high resolution using microseismic event analysis, tomographic methods, DAS acquisitions, 2D/3D modelling, and inversion of magnetic data. Methodologices were developed for seismic event detection, seismic imaging, and source parameter estimations to assess the suitability of mapping superhot and supercritical target regions. Methods for resource assessment and technical economical analysis for superhot and supercritical systems were adapted from conventional geothermal system analysis. For the Hengill case, the volumetric resource method of USGS was demonstrated in a Monte Carlo simulation framework. For the Newberry case study, resource assessment and TEA was performed using the Geophires and GETEM tools developed by NRE.

Most high-temperature geothermal resources are found in magmatic plays. In this project we will develop methodology for de-risking of magmatic geothermal systems, including super-critical plays. First, we will develop a toolbox of geophysical, geochemical and geological tools, for mapping and characterization of magmatic systems and faults in non-sedimentary rocks, from regional scale to prospect scale. This includes methods traditionally used in geothermal exploration and methods adapted from the oil and gas industry. Cross-disciplinary integration will be performed by means of Play Fairway Analysis, with focus on the three risk elements (1) heat source, (2) recharge and (3) producibility. The methodology will be demonstrated on exploration cases in Iceland and the U.S.