Geothermal Power Development

Phases:

  1. Exploration and reconnaissance
  2. Pre-feasibility
  3. Feasibility
  4. Design and construction
  5. Operations and maintenance

Exploration and reconnaissance phase:
The fundamental purpose of the exploration and reconnaissance phase is to determine if there exists a commercially exploitable geothermal resource. The first assignment is to perform a desk study, which entails collection and analysis of all available existing data regarding the geothermal field and the environment in order to define the resource and scope of the following exploration activities. The desk study is followed up by field work, which usually includes:

Geological mapping of important geological features in order to get acquainted to the geological structure of the geothermal system
Geochemical analysis of fluids from surface manifestations or shallow wells if available to get indications on the reservoir temperatures
Geophysical explorations, like resistivity measurements, gravity and seismic profiling where needed, to get better understanding of the subsurface features of the geothermal resource
Drilling of shallow exploration wells (usually 50-300 m) to measure temperature gradients in order to locate the up-flow zone of hot fluids in the geothermal reservoir

Pre-feasibility phase:
If the results from the exploration phase are positive, the development moves to the pre-feasibility phase where the exploration becomes more focused on the most favorable location. Activities in the pre-feasibility phase may include:

  • More focused geophysical exploration
  • Drilling of slim wells (+300 m)
  • Environmental impacts assessment
  • Drilling of deep exploration well
  • Fluid chemical analysis
  • Production potential assessment
  • Pre-feasibility data analyzed and reported

Feasibility phase:
In the feasibility phase, the commercial level of the geothermal resource is generally demonstrated by the following activities:

  • Environmental impact assessment
  • Drilling of production/injection wells
  • Fluid sampling and chemical analysis
  • Well testing and well logging
  • Conceptual modeling
  • Production potential assessment (reservoir modeling)
  • Preliminary design of power plant and surface equipment
  • Feasibility data analyzed and reported

Design and construction:
If the geothermal project is feasible, power purchase agreements have been reached and financing is secured, the project moves to the detailed design and construction phase. Detailed design and constructions begins with the following activities:

  • Production/injection wells and drilling platform design
  • Drilling of production/injection wells
  • Infrastructure facilities design and civil works
  • Detailed design of power plant and steam gathering system
  • Detailed design of power transmission lines and point of access determined
  • Service providers contracted for detailed design, engineering, procurement, construction and project management
  • Construction of the power plant and facilities
  • Training of operators and commissioning