Geothermal Plays – Introduction

First in a series of 7 Posts about Geothermal Plays. Better understanding of a location’s geology can lead to appreciation of the potential for accessing Geothermal Energy. Technologies and tools have advanced rapidly to open up the technical and economic potential for Geothermal Energy across many more locations.

Exploring for Geothermal Energy resources, a location’s geology must first be characterised, applicable geological data obtained, and then the resource would be able to be assessed for technically reasonable, economic drilling and production.

The concept of Geothermal Plays has been well described by Professor Inga Moeck in a series of papers.  She noted that “successful reservoir production from geothermal systems depends mainly on the appropriate selection of exploration methods.”  Certainly, de-risking a Geothermal system needs data and proper assessment to be successful.

Ref. •Inga S. Moeck, “Catalog of geothermal play types based on geologic controls”, Renewable and Sustainable Energy Reviews 37 (2014) 867-882 •Inga S. Moeck, Graeme Beardsmore, Colin C. Harvey “Cataloging Worldwide Developed Geothermal Systems by Geothermal Play Type”, Proceedings World Geothermal Congress 2015, Melbourne, Australia •Illustration: https://www.dnr.wa.gov/programs-and-services/geology/geologic-maps/3d-geology#.2 

Different types of Geothermal Plays are able to be identified as follows:

1. Convection-dominated – upflow of fluids transporting heat from depth to shallower reservoirs (or the surface):

  • Magmatic plays (extrusive-associated with volcanism or intrusive-no volcanism)
  • Plutonic plays (extrusive-associated with volcanism or intrusive-no volcanism) c
  • Extensional domain, fault controlled or fault-leakage controlled (non-magmatic)

2Conduction-dominated – no asthenospheric anomalies, deep aquifers (hydrothermal) or hot dry rock (petrothermal) heated by locally elevated near normal heat flow:

  • Intracratonic basin plays
  • Orogenic belt with foreland basin plays
  • Basement (crystalline rock) plays

Each type of Geothermal Play would have various Exploration technologies applicable to best gather the data needed for proper evaluation. Exploration would be conducted at the surface, in the overburden, and at depth as per the previous Geothermal Exploration flyers posted here. 

Technologies and tools have advanced rapidly to open up the potential for Geothermal Energy across many more locations

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