Geothermal Resource Decision Workshop: Exploration of Fault-Hosted Deep Circulation Geothermal Systems

About this Training

This 3-day hands-on interactive training workshop provides a foundation for the principals of geothermal resource decision-making using a conceptual model approach. During the exploration and development of geothermal reservoirs, a multidisciplinary resource team must provide predictions and assess subsurface uncertainty to support high-value decisions. This workshop is designed to simulate this real-life geothermal decision-making process, from determining if a geothermal reservoir exists through to committing to a power plant.

This training workshop consists primarily of a progressive series of hands-on realistic exercises for a synthetic case study of a fault-hosted deep circulation geothermal system. Each exercise is preceded by short lecture(s) to provide context for the exercise. The lectures cover fundamental concepts on types of geothermal systems, exploration methods, planning exploration campaigns, geology, geochemistry, geophysics, thermodynamics of water flow in rock, conceptual modelling, geothermal well types, well targeting, well temperature log and production test interpretation, probabilistic resource capacity assessment, project economics, decision risk assessment and financial modelling for decision making.

Small teams (typically 3 to 5 participants) collaboratively engage in hands-on exercises with guidance and mentoring from geothermal expert(s). Each exercise builds upon the previous ones as the team progresses through project development phases. In the exercises, participants use realistic data to design geology and geophysical surveys, build geothermal conceptual models, from which they will target a different types of wells (temperature gradient holes, slim holes and production wells), and generate probabilistic predictions for the geothermal resource`s electrical power generation capacity. Participants use an interactive simplified financial model to evaluate how exploration decisions impact project economics. The conceptual models serve as the basis for making informed drilling decisions based on those predictions and the economic context, with subsequent comparison of decisions with actual outcomes for validation. The outcomes provide participants with immediate feedback on the reliability of their predictions and decisions. Accordingly, as new data is “acquired” in each exercise, conceptual models and power capacity estimates are iteratively updated. Teams have the opportunity to present the results of the exercises to the group and receive constructive feedback from the expert course trainer. The workshop concludes with the “big reveal” of the actual results of the synthetic case study.

Over the last 25 years, the global geothermal community has highly regarded this Geothermal Resource Decision Workshop since its inception in 2000. This workshop has received outstanding reviews from geoscientists and reservoir engineers in the geothermal and petroleum industries. The workshop demonstrates the application of geothermal resource assessment technology and offers participants the opportunity to interact with geothermal industry peers and experts.

Training Objectives/Key Learning Outcomes

Upon completion of the course, participants will be able to:

  • Design conceptually effective and financially efficient exploration surveys.
  • Understand elements of conceptual models for different geothermal resource types and how resource type affects exploration strategy.
  • Rank exploration prospects based on key indicators.
  • Understand the integration of the most decisive types of surface geoscience data to build geothermal fault-hosted deep circulation conceptual models.
  • Use geothermal conceptual models to support predictions and understand uncertainty in well target decisions and resource capacity estimates.
  • Understand iterative updating of conceptual models using immediate feedback on well target success, geothermal well logs and well performance tests.
  • Appreciate realistic impacts of uncertainty and economic constraints on geothermal exploration programs, well design and resource capacity decisions.
  • Weigh resource issues that affect decisions to build a power plant or terminate investment to minimize loss.

Target Audience

Both geothermal and non-geothermal industry professionals who wish to better appreciate what geothermal resources are and how surface geoscience data, subsurface well data, and production test data are integrated to support geothermal resource exploration decisions in the context of realistic conceptual models and economic constraints, including:

  • Geothermal geoscientists (geologists, geochemists, geophysicists)
  • Geothermal engineers
  • Geothermal managers
  • Oil, gas, or mining professionals interested in joining the geothermal workforce

Course Level

  • Basic
  • Intermediate

Training Methods

The 18-hour workshop is available in both in-person and virtual formats. The in-person workshop will be delivered over 3 full day sessions (6 hours per day). The virtual workshop will be delivered over 6 half-day sessions (3 hours per day).

Participants will receive detailed course materials including pdfs of all presentations, exercise handouts and materials including a resource capacity assessment tool in Excel and a simplified financial model tool in Excel, and references to relevant publications mentioned during the training.

For the online training workshop format, the following computer specifications are required:

  • Computer: Individual computer with webcam, internet access and a web browser.
  • Software: Lectures are delivered in the Gathertown virtual workspace for remote teams software and hands-on exercises are conducted simultaneously in the Miro infinite whitespace workspace.
  • Internet speed: A minimum of >3 Mb/s is recommended, although >5 Mb/s download and upload are ideal.

Trainer (Nick Hinz)

Your expert course trainer conducts structural and geological mapping, wellsite geology, integrated geothermal conceptual model development, and well target and resource assessment services to geothermal field developers, research consortia and educational institutions. He has nearly 25 years of experience in both magmatically heated, and deep-circulation heated systems hosted in volcanic and sedimentary settings in Northern and Central America, the Caribbean, Eastern and Southern Africa, Turkey, Western Europe, Indonesia, Philippines, Taiwan, and Japan. Services include detailed integration of surface structural geology, geophysics and geochemistry and subsurface geology and thermodynamics to build resource conceptual models used to target wells and assess resource capacity. Support for drilling programs includes wellsite geology, wellsite geoscience training and real time resource conceptual model updates for drilling decisions. Structural geology and stress calculation research and applications have been directed at both local geothermal prospects and regional assessments. Worldwide training services include extensive field instruction in structural geology mapping, wellsite geologist training and conceptual model workshops for industry and universities. He has published more than 100 papers on geothermal projects worldwide as first or coauthor.

Course Agenda

Note: The Course Agenda outline is only indicative and may be customized on an as-needed basis to meet the needs, speed, and capabilities of the group. The Course Agenda may be adjusted accordingly on the fly as the training progresses by changing the order of lectures, combining exercises, etc.

1.1. Introduction to Workshop

  • Welcome and Introductory Remarks.
  • Lecture: General Introduction: Workshop agenda, schedule, meet your trainer(s), and workshop motivation, geothermal exploration decision making, types of geothermal systems, geothermal exploration best practices, and exploration methods covered in the workshop.
  • Demo/Discussion (virtual online format only): Software Intro: Useful tips, settings and tools for working in Gathertown environment and the Miro infinite whiteboard.

1.2. Geoscience Exploration Methods

  • Lecture: Geothermal Exploration Thermodynamics: Thermodynamics of fluid flow in rocks and the descriptive power of isotherms.
  • Exercise: Isotherms: Understanding buoyant fluid flow and heat transfer processes in fractured rock, draw isotherms for a simplified deep circulation conceptual model
  • Discussion: Isotherm Exercise reveal
  • Lecture: Introduction to Geologic Settings and Anatomy of Deep Circulation Systems: Basin and Range case histories of deep circulation exploration and development.
  • Lecture: Geothermal Exploration Geology: Introduction to geothermal geology and structure, hydrothermal alteration, and the synthetic case study named the “Frankenflow Prospect.”
  • Exercise: Geology Map QA/QC: Identify realistic/unrealistic geology.
  • Lecture: Geothermal Exploration Geochemistry and Alteration: Introduction to geochemistry, fluid types, mixing and boiling processes, geothermometry, alteration and inferring the origins and properties of reservoir water.
  • Lecture: Geothermal Exploration Geophysics: Introduction to geophysics, matching geophysical techniques with targets, magnetotelluric (MT) resistivity, clay cap, role of MT in conceptual models, CSMAT, gravity, HTEM.

1.3. Project Economics

  • Lecture: Introduction to Economics of Drilling and Power Plant Commitments: financial model spreadsheet, exploration budgets, field size assumptions, geothermal well types (thermal gradient holes TGH, slim hole wells, and production/injection wells), and the economic model exercise spreadsheet.
  • Exercise: Economics Tool: Teams explore the financial model spreadsheet provided by proposing an exploration strategy for the base case project assumption, get bids and then check the strategy against the likely project economics and potential value of information.
  • Lecture: Inform participants of economic project constraints and budget for Frankenflow Prospect.
  • Exercise: Economics and Initial Geology Plan: Frankenflow introduction, review initial geology map using checklist, given a budget, plan an exploration program for Frankenflow Prospect.
  • Discussion: Group presentations of exercise and discussion. Compare and contrast initial geology map with updated geology map after LiDAR interpretation and fieldwork.

1.4. Designing Geophysical Surveys and Building Conceptual Models

  • Lecture: Exploration Geophysics Survey Planning: Geophysics considerations for resistivity imaging, density modelling, seismic imaging, survey design guidelines and constraints.
  • Exercise: Design Geophysics Surveys: Design CSMAT and gravity surveys.
  • Discussion: Group presentations of exercise and discussion.
  • Lecture: Building Geothermal Conceptual Models: Step-by-step process of conceptual model construction.
  • Exercise: Build an Conceptual Model for Frankenflow Prospect Based on the Surface Geoscience Data: Use geophysics to build a conceptual model (1st iteration) using CSMAT resistivity profiles and conductance map.
  • Discussion: Group presentations of exercise and discussion.

1.5. Geothermal Well Targeting, Well Data Interpretation, Power Capacity Assessment, and Well Testing

  • Lecture: Geothermal Well Targeting: Using the conceptual model to target wells, well targeting strategies, pitfalls, and decision tables.
  • Exercise: Targeting Temperature Gradient Holes (TGH): Use your conceptual model to target TGH wells.
  • Lecture: Interpreting Borehole Temperature Logs and Revising Isotherms: Interpretation of synthetic and real well temperature data from different zones in a conceptual model
  • Exercise: Targeting Additional TGH and/or Slim Holes: Evaluate the results from TGH drilling and target either more TGH or 1 slim hole well.
  • Discussion: Group presentations of exercises and discussion.
  • Lecture: Geothermal Capacity Assessment: Pre-drilling probabilistic geothermal capacity assessment methodologies, volumetric heat-in-place method, power density method, estimating probabilistic resource areas, how to draw P10-P50-P90 areas in map view derived from probabilistic isotherms in conceptual model cross-sections, power density analogues, introduction to power density tools, testing P-areas with well targeting
  • Exercise: Revise Conceptual Model: Use results of TGH and/or slim hole drilling to update your conceptual model (2nd iteration).
  • Discussion: Group presentations of exercise and discussion.
  • Exercise: Estimate Power Capacity, Revise Economics, Target Wells: Draw P-areas on cross-sections and map, estimate power capacity using the Power Density tools. Revise economic model. If the resource is large enough, target 4 production wells.
  • Discussion: Group presentations of exercise and discussion.
  • Lecture: Well Testing: Completion testing, well heating, flow testing; self-flowing vs pumped wells
  • Exercise: Revise Conceptual Model, Power Capacity Estimate, Target Development Wells: Review production well drilling results, and revise your conceptual model (3rd iteration), P-areas, capacity estimate, and economic model. If your project is economically viable, target development production and injection wells.
  • Discussion: Group presentations of exercise and discussion.

1.6. Geothermal Power Plant Decision and Final Reveal

  • Exercise: Power Plant Commitment Decision: Based on your economic analysis and power capacity estimate, decide if you will or will not develop the Frankenflow prospect.
  • Discussion: Group presentations of exercise and discussion.
  • Lecture: The Final Reveal: Reveal of the actual Frankenflow prospect synthetic data comprising conceptual model, 3D geological model, numerical reservoir simulation, resource capacity estimation and full distribution of well results.
  • Discussion: Review of team results relative to actual conceptual model and power capacity of the Frankenflow prospect.
  • Closing Remarks.

Additional Supplemental Custom Lectures and Discussion Topics Available Upon Request:

  • Current Status of the Exploration and Development of EGS
  • Geothermal Well Testing: Conventional and EGS
  • Reservoir Management: Geochemistry and Geophysics
  • Geothermal Reservoir Engineering: Numerical Modelling and Simulation
  • Designing Geothermal Exploration Programs: Workflow, Timeline, and Approximate Budgets