Phases of geothermal power development:

Exploration and reconnaissance

Pre-feasibility

Feasibility

Detailed design and construction

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

 

Detailed 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

 

Operations and Maintenance:

After commissioning, the geothermal power plant starts to render normal service of providing sustainable energy to the clients. With normal maintenance and responsible reservoir management and utilization, a geothermal power plant can provide renewable energy to the clients for decades.