Development of a geothermal reservoir is shown using a 3D seismic slice along with a 3D temperature model and selected temperature logs of nearby wells. Microseismic events are also shown from the stimulation of one well. Data courtesy USDOE Geothermal Data Repository.
Geothermal energy is a sustainable and renewable thermal energy source extracted from the depth of the Earth. This relatively low-cost energy source can have a huge capital risk attached to its exploration and development. This is where geothermal reservoir characterization comes into play. The various subsurface parameters directly or indirectly dictate the economic potential of an exploration project. Understanding the unique analysis of each of these subsurface variables is critical to the efficient economic development of a potential asset.
3D visualization is an effective tool for the integration and modeling of subsurface data to derive a meaningful reservoir analysis. Geoscientists and engineers can use a 3D model as a tool to analyze reservoir behaviors and make informed economic decisions.
Parameters for Geothermal Reservoir Characterization
Geothermal development projects rely heavily on very disparate types of reservoir data that elaborates on subsurface geological environments. This data influences the understanding of the economic potential of the project.
Geothermal reservoirs are unique in the wide range of rock types in which they are found. The geothermal exploration process captures this varying data through standard subsurface and petrologic analysis, surface geology and geophysical surveys (gravity, magnetic and seismic), and heat flow data to obtain a similarly varied analysis. The analysis expands upon the parameters such as rock permeability, porosity, resistivity, conductivity, seismicity, fluid volume, and heat flow within the reservoir. The details assist the geothermal project to:
- Locate the geothermal reservoir and faults and fractures.
- Determine the optimal drilling location and wellbore design.
- Specify a drilling plan for geothermal well with detailed analysis on the rate of penetration (ROP), borehole diameter and depth, fluid transmission, casing requirement, and selection of rig.
- Identify hazards in drilling and barriers for further project development.
Efficient visualization of reservoir characteristics provides an accurate analysis of the geothermal subsurface on which operators can make informed decisions regarding project development while also minimizing their investment risk.
Visualizing the Economic Potential of a Project
Integration and visualization of the varied geothermal data allow engineers and geoscientists to guide the project in an economic direction. A comprehensive 3D model of geothermal data facilitates an effective correlation between diverse geospatial data. This enhances collaboration between the different disciplines in determining the optimal geothermal pay zone and potential performance of the reservoir.
Each step within a project has an associated cost—including costs incurred during exploration, drilling production and injection wells, well maintenance, redrilling, and operating expenses such as replacement well drilling. Efficient visualization of reservoir characteristics enhances the prospect identification and asset development opportunities that facilitate cost and time savings for a project.
CoViz 4D & EarthVision: Identification, Integration, Analysis
CoViz 4D and Earth Vision—software products from Dynamic Graphics, Inc.—are well suited to the analysis of highly diverse data types in a robust visualization 3D environment. EarthVision facilitates the development of petrophysical and structural geological models of the area to determine the best location to start developing. With CoViz 4D, different models can be integrated to form an enhanced comprehensive model of the reservoir. The software also utilizes temporal data for time-phased analysis of reservoir characteristics. With easy-to-analyze three-dimensional visualization, stakeholders can save time and capital spent in exploration and asset development.