scholarly journals High injection rates counteract formation of far-reaching fluid migration pathways at The Geysers geothermal field

2020 ◽  
Author(s):  
Stanislaw Lasocki ◽  
Beata Orlecka-Sikora
Keyword(s):  
Geothermal Field ◽  
Fluid Migration ◽  
High Injection ◽  
The Geysers ◽  
Migration Pathways ◽  
Injection Rates

High injection rates decrease the probability of creating undesired, far-reaching fluid migration pathways at Cooper Basin geothermal field

2021 ◽  
Author(s):  
Elvira Battimelli ◽  
Stanisław Lasocki ◽  
Paolo Capuano
Keyword(s):  
Geothermal Field ◽  
Injection Rate ◽  
Seismic Events ◽  
Fluid Migration ◽  
Wellhead Pressure ◽  
High Injection ◽  
The Geysers ◽  
Migration Pathways ◽  
Cooper Basin ◽  
Injection Rates

<p>Enhanced Geothermal Systems apply the pressurized fluid injection to fracture impermeable rocks to form pathways in which water circulates. The cold water under high pressure is pumped into the hot subsoil, where it heats up and returns to the surface. However, the induced fractures may coalesce into unwanted paths that allow the fluids to reach pre-existing faults, triggering major seismic events.</p><p>This work investigates the relationship between injection and a degree of disordering of sources, ZZ, at Cooper Basin geothermal field in Australia, following the methodology developed and applied to study The Geysers geothermal field case (Lasocki & Orlecka-Sikora, 2020). The parameter ZZ quantifies the potential of seismicity to build pathways for fluid migration. It is the average distance between the seismic events in the eight-dimensional parameter space consisting of three hypocentral coordinates, T- and P-axis plunges, T-axis trend, and polar and azimuthal angles in the spherical system of coordinates beginning at the open hole of an injection well. A decrease of ZZ indicates an increasing hazard of forming far-reaching migration pathways. In The Geysers case, ZZ turned out to be highly correlated with the injection rate.</p><p>Here we focus on the case of Habanero 4 well stimulation from 17 - November 30, 2012 (data access, see: IS EPOS, 2020). We processed 489 seismic events with known focal mechanisms. The events moment magnitude varies between 0.8 and 3.1.  </p><p>Our analysis shows that ZZ is significantly correlated with both the injection rate and the wellhead pressure. The higher the injection rate / the wellhead pressure was, the less probable was the creation of undesired fluid migration pathways. The Cooper Basin’s and The Geyser’s reservoir rocks are vastly different, the former – granite, the latter – greywacke sandstone, likewise the stimulation techniques applied in these two reservoirs. However, in both cases, ZZ was positively correlated with injection rate; thus, the potential to build unwanted paths for fluids was negatively correlated. These results suggest that such correlation may be a global feature of rock fracturing caused by pressurized fluid injections.</p><p><em>This work has been supported by S4CE (Science for Clean Energy) project, funded from the European Union’s Horizon 2020 - Framework Programme, under grant agreement No 764810 and by PRIN-MATISSE (20177EPPN2) project funded by Italian Ministry of Education and Research.</em></p><p> </p><p><strong>References:</strong></p><p>IS EPOS (2020), Episode: COOPER BASIN, https://tcs.ah-epos.eu/#episode:COOPER_BASIN, doi:10.25171/InstGeoph_PAS_ISEPOS-2020-001</p><p>Lasocki, S., & Orlecka-Sikora, B. (2020). High injection rates counteract formation of far-reaching fluid migration pathways at The Geysers geothermal field. Geophysical Research Letters, 47, e2019GL086212. https://doi.org/10.1029/2019GL086212</p>

scholarly journals Spatial and temporal multiplet analysis for identification of dominant fluid migration path at The Geysers geothermal field, California

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Staszek ◽  
Ł. Rudziński ◽  
G. Kwiatek
Keyword(s):  
Temporal Analysis ◽  
Geothermal Field ◽  
Fluid Injection ◽  
Fluid Migration ◽  
Multiple Events ◽  
Spatial And Temporal Analysis ◽  
Hydraulic Conditions ◽  
The Geysers ◽  
Multiplet Analysis

AbstractMultiplet analysis is based on the identification of seismic events with very similar waveforms which are used then to enhance seismological analysis e.g. by precise relocation of sources. In underground fluid injection conditions, it is a tool frequently used for imaging of subsurface fracture system. We identify over 150 repeatedly activated seismic sources within seismicity cluster induced by fluid injection in NW part of The Geysers geothermal field (California). Majority of multiple events (ME) occur along N–S oriented planar structure which we interpret as a fault plane. Remaining ME are distributed along structures interpreted as fractures, forming together a system of interconnected cracks enabling fluid migration. Temporal analysis reveals that during periods of relatively low fluid injection the proportion of ME to non-multiple events is higher than during periods of high injection. Moreover, ME which occur within the fault differ in activity rate and source properties from ME designating the fractures and non-multiple events. In this study we utilize observed differences between ME occurring within various structures and non-multiple events to describe hydraulic conditions within the reservoir. We show that spatial and temporal analysis of multiplets can be used for identification and characterization of dominant fluid migration paths.

Fracture detection using P-wave and S-wave vertical seismic profiling at The Geysers

Geophysics ◽  
1988 ◽  
Vol 53 (1) ◽  
pp. 76-84 ◽  
Author(s):  
E. L. Majer ◽  
T. V. McEvilly ◽  
F. S. Eastwood ◽  
L. R. Myer
Keyword(s):  
Fractured Rock ◽  
Geothermal Field ◽  
P Wave ◽  
Velocity Variation ◽  
Fracture Detection ◽  
S Wave ◽  
Fracture Geometry ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
The Geysers

In a pilot vertical seismic profiling study, P-wave and cross‐polarized S-wave vibrators were used to investigate the potential utility of shear‐wave anisotropy measurements in characterizing a fractured rock mass. The caprock at The Geysers geothermal field was found to exhibit about an 11 percent velocity variation between SH-waves and SV-waves generated by rotating the S-wave vibrator orientation to two orthogonal polarizations for each survey level in the well. The effect is generally consistent with the equivalent anisotropy expected from the known fracture geometry.

scholarly journals Tracking the development of seismic fracture network from The Geysers geothermal field

2018 ◽  
Vol 67 (1) ◽  
pp. 341-350 ◽  
Author(s):  
Beata Orlecka-Sikora ◽  
Szymon Cielesta ◽  
Stanisław Lasocki
Keyword(s):  
Fracture Network ◽  
Geothermal Field ◽  
The Geysers
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