Energy budgeting of laboratory hydraulic fracturing in granite with different viscosity injection fluids
Abstract In this study, we investigated the source parameters of microseismicity detected during laboratory hydraulic fracturing (HF) of granite conducted with high- (gear oil/1000 cP) and low- (water/1 cP) viscosity injection fluids. These HF experiments were monitored with real-time acoustic emiss...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Springer
2025-07-01
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| Series: | Geomechanics and Geophysics for Geo-Energy and Geo-Resources |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s40948-025-00948-0 |
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| Summary: | Abstract In this study, we investigated the source parameters of microseismicity detected during laboratory hydraulic fracturing (HF) of granite conducted with high- (gear oil/1000 cP) and low- (water/1 cP) viscosity injection fluids. These HF experiments were monitored with real-time acoustic emission (AE) setup which consisted of 16 calibrated sensors. The spectral parameters (corner-frequency and low-frequency spectral plateau) were determined for each AE event by fitting Omega-models with variable high-frequency fall-off exponents to the detected AE signals. Seismic parameters such as seismic moment, source radius, stress drop, and seismic energy were determined after incorporating the focal-mechanism information determined through moment-tensor inversion. Higher breakdown pressures and fracture propagation times along with greater number and strength of microseismicity were observed for experiment conducted with higher-viscosity fluid. For both experiments, an inverse relationship was observed between corner frequency and seismic moment, similar to those observed for large-scale induced-earthquakes. The corner-frequency, seismic moment, stress drop, and seismic energy were noticeably higher for the higher-viscosity injection fluid. However, the seismic source radius was slightly larger for the lower-viscosity fluid. Varied spectral and seismic parameters (16–29%) were obtained based on the adopted Omega model; however, these variations did not affect the observed relationships between seismic parameters in high- and low-viscosity experiments. The seismic efficiency was << 1% ( $${10}^{-6}-{10}^{-4}\%$$ 10 - 6 - 10 - 4 % ) for both experiments but it was much lower for experiment conducted with lower-viscosity injection fluid, implying a more pronounced aseismic response. Comparing the seismic source parameters determined in this study with those derived from large-scale induced earthquakes suggests potentially similar scaling relationships. |
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| ISSN: | 2363-8419 2363-8427 |