WG 12- Deep Roots of Volcanic Geothermal Systems

Operating Agent: Orkustofnun (The National Energy Authority of Iceland)

Working Group Leader: Guðni Axelsson, Iceland GeoSurvey (ISOR), Iceland. Email: gax@isor.is

Status: Initiated in April 2014

Participants: Iceland, New Zealand, Norway, Switzerland

Description

Interest in the future use of geothermal resources includes the deeper “roots” of systems. Production from greater depth provides several advantages including: 1) greater output from wells because of higher temperature and pressure if sufficient permeability can be found/enhanced, especially true if the fluid is supercritical or the well produces super-heated steam; 2) extending the resource vertically rather than laterally; 3) fewer expected environmental effects because of greater production depth and smaller horizontal extent. There is the potential to apply reinjection-production doublets or EGS technology if permeability is limited, however there are still numerous technical problems to be overcome.

The goal of Working Group 12 is to improve understanding of the deep roots of volcanic geothermal systems with possible future utilization in mind. This includes advancing knowledge on the nature and characteristics of heat sources and heat transfer processes in the roots of volcanic geothermal systems through dissemination of information and research methods, and improving methods for exploration and modelling of the roots by facilitating cooperation and information sharing between scientists involved in such research. The work of Working Group 12 is conducted in three tasks:

Task A- Compilation of Conceptual Models of the Roots of Volcanic Geothermal Systems and Associated Research Methods

Participants compile open-source information (reports, peer-reviewed journal-articles and conference-papers) on conceptual models of the deep roots of volcanic geothermal systems, both in their home-countries and worldwide. These can be models based on the mapping of extinct, eroded systems as well as on exploration of active systems. This compilation will be stored and accessible through the IEA-GIA web-page. It will provide material that can be used as the background of deep root research in the participating countries, as well as world-wide. Information on mapping, exploration and modelling methods and tools should also be compiled.

Task B- Advancement of Methods for Deep Geothermal Exploration

Participants disseminate information on advances in methods applicable for the exploration of the deep roots of volcanic geothermal systems, as well as facilitating cooperation between research groups involved in such work in participating countries. This applies in particular to enhancing the depth resolution of available methods (e.g. resistivity and analysis of micro-seismic activity) and using the power of joint interpretation of varying data-sets. This will be achieved through participation in meetings and workshops associated with relevant research projects of participating countries, and through linking of Working Group 12 meetings with such events, as well as through other types of cooperation. Relevant research projects active at present are for example the GEORG Deep Roots Project in Iceland, The EU-supported IMAGE project as well as work associated with the IPGT cooperation.

Task C- Methods for Modelling Conditions and Processes in Deep Geothermal Resources

The goal of this task is to aid in the advancement of methods that can be applied to modelling the physical processes occurring in the roots of volcanic geothermal systems. The purpose of this is to illuminate the overall process controlling the upwards transfer of heat from its source. It is also to improve and advance the methods that are applied in conventional geothermal reservoir modelling, which will be useful for geothermal resource management.

Heat transfer from the roots of volcanic geothermal systems up to shallower levels is a complicated process involving flow of magma, flow of fluids (two-phase and/or supercritical water), heat transfer, thermo-elastic rock mechanics and chemical processes. The aim of Working Group 12 is to enhance synergy between different research groups and avoid duplication of effort, to encourage sharing of open-source software, and to share testing/validating of software in development. This will be achieved, for example, through participation in meetings and workshops associated with relevant research projects of participating countries, and through linking of Working Group 12 meetings with such events, as well as through other types of cooperation. Relevant projects involved in modelling methods active at the moment are for example the GEORG Deep Roots Project, the Geothermal Supermodels project and work associated with the IPGT cooperation.

2016 Working Group 12 Report