Geodetic Measurements and Numerical Models of Deformation at Coso Geothermal Field, California, USA, 2004–2016

Elena C Reinisch,Kurt L Feigl,Michael Cardiff,S Tabrez Ali,J Ole Kaven

doi:10.3390/rs12020225

Elena C Reinisch, Kurt L Feigl + Show 3 more

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https://doi.org/10.3390/rs12020225

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Journal: Remote sensing	Publication Date: Jan 9, 2020
Citations: 7	License type: CC BY 4.0

Affiliation: University of Wisconsin–Madison

Abstract

We measure transient deformation at Coso geothermal field using interferometric synthetic aperture radar (InSAR) data acquired between 2004 and 2016 and relative positions estimated from global positioning system (GPS) to quantify relationships between deformation and pumping. We parameterize the reservoir as a cuboidal sink and solve for best-fitting reservoir dimensions and locations before and after 2010 in accordance with sustainability efforts implemented in late 2009 at the site. Time-series analysis is performed on volume changes estimated from pairs of synthetic aperture radar (SAR) and daily GPS data. We identify decreasing pore-fluid pressure as the dominant mechanism driving the subsidence observed at Coso geothermal field. We also find a significant positive correlation between deformation and production rate.

Highlights

The Coso geothermal field, located near China Lake, California, is the third largest geothermal field in the United States with an installed capacity to generate ∼270 MW of electrical power
The global positioning system (GPS) range values at individual points in time are converted to pairs by first taking the difference between range estimates from COSO and COSJ to remove the far-field deformation and by time corresponding to the time intervals of the Environmental Satellite (Envisat) pairs
We find a significant difference between the volume change rates estimated before 2010, between 2010 and 2011, and after 2014 from our interferometric synthetic aperture radar (InSAR) data set

Summary

Introduction

The Coso geothermal field, located near China Lake, California, is the third largest geothermal field in the United States with an installed capacity to generate ∼270 MW of electrical power. It lies within an extensional step-over between dextral faults that hosts an actively developing metamorphic core complex [1,2]. Fluid temperatures within the reservoir reach ∼350 ◦C at the relatively shallow depths of ∼3 km tapped by more than 80 production wells (Figure 1). Following generation of electricity and condensation, the fluids are reinjected via more than 30 injection wells around the field. In late 2009, the reservoir operators of the Coso Geothermal Plant implemented the Hay Ranch Water Project, which uses a ∼15-km pipeline to recharge the existing reservoir at Coso with supplemental water, thereby increasing geothermal energy production (e.g., [6,7])

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