Joint Time-Lapse Acquisition and Inversion of Passive Seismic and Magnetotelluric Data for Monitoring Reservoir Processes at the Geysers Geothermal Field
A field demonstration at The Geysers will be carried out to evaluate the value added by applying this technology.
Lawrence Berkeley National Laboratory
Recipient
Berkeley, CA
Recipient Location
9th
Senate District
14th
Assembly District
$1,661,032
Amount Spent
Completed
Project Status
Project Result
This project successfully implemented an approach to jointly image time-lapse changes in water and steam concentrations and subsurface flow in a geothermal reservoir, using data from small earthquakes and magnetotelluric observations. The project advanced the technology by imaging time-lapse changes of the two data sets, based on different physical properties, for the first time. The project demonstrated this technology at The Geysers geothermal field in Northern California over an area of approximately 75 square kilometers, where seismic and magnetotelluric data were collected over several years. The project team collected seismic data from over 280,000 earthquakes and collected three magnetotelluric surveys to generate images of water and steam volumes as well as flow paths and barriers in the geothermal reservoir. Correlation of the geophysical images with known water injection and steam production volumes allowed the team to calibrate the data and to gain confidence in the results, which can now be applied throughout the reservoir, where borehole data are unavailable. The results of the joint imaging, together with reservoir data derived from observations in boreholes, allow interpretation of the images to identify water and steam saturated zones, as well as fluid pathways and barriers. This information allows the reservoir operator to improve its drilling program by minimizing drilling of unsuccessful wells, resulting in reduced costs and lower electricity rates for California ratepayers.
View Final ReportThe Issue
In operating geothermal fields, it is inherently difficult to image the movement of water and steam in a fractured geothermal reservoir in time and three-dimensional space. Tracer tests provide ground truth information about inter-well connectively, but they do not directly reveal the flow paths in the regions between the wells. Microseismicity mapped in three-dimensions can provide valuable information about fluid movement, but it is possible for water and steam to move through the fractured rock mass without triggering microseismicity, as well for microseismicity to be triggered without fluids.
Project Innovation
This project demonstrated the advantages of concurrently acquiring time-lapse magnetotelluric and passive seismic data over a producing geothermal reservoir. The data was jointly inverted for images of resistivity and seismic velocities using workflows and algorithms that enforce structural similarity constraints between the different physical properties, and subsequently correlating the spatio-temporal information in the joint-inversion geophysical images to working reservoir models. The technical advancements of this project are provided via concurrent monitoring of time-lapse changes in both resistivity and seismic velocity and the joint inversion of the multi-physics data. Ultimately, these images can be used for better estimates of rock properties and spatial distribution of steam and water at depth, for more accurate reservoir modeling and monitoring which will lead to more accurate placement of production wells. A field demonstration at The Geysers has been carried out to evaluate the value added by applying this technology.
Project Goals
Project Benefits
This Agreement will lead to technological advancement and breakthroughs to overcome barriers to the achievement of the State of California's statutory energy goals by assisting the continued growth of California's broad portfolio of renewable energy, including geothermal, as required to achieve the goals of SB 350. This project will demonstrate the advantages of concurrently acquiring time-lapse magnetotelluric and passive seismic data over a producing geothermal reservoir, jointly inverting these time-lapse data for images of resistivity and seismic velocities using workflows and algorithms that enforce structural similarity constraints between the different physical properties, and subsequently correlating the spatio-temporal information in the joint-inversion geophysical images to working reservoir models to update these models and to adjust injection and production rates.
Affordability
Determining the siting of new injection or production wells in a geothermal field holds high financial risk. This technology will improve imaging of the distribution of subsurface water and steam, for better informed decisions.
Environmental Sustainability
Differentiation of the distribution of water and steam in the subsurface will reduce the number of geothermal production and injection wells that need to be drilled.
Energy Security
California has a large geothermal resource potential. Optimal management of this source of clean energy through remote subsurface imaging technologies provides energy security for future generations.
Key Project Members
David Alumbaugh
Subrecipients
U.S. Geological Survey
EMR Solutions & Technology LLC
Jarpe Data Solutions
Match Partners
U.S. Geological Survey
