Mechanism of Microseismic Generation During Hydraulic Fracturing - With Evidence From HFTS 2 Observations

Journal Article · Mon Jul 26 00:00:00 EDT 2021 · Proceedings of the Unconventional Resources Technology Conference (URTeC)

DOI:https://doi.org/10.15530/urtec-2021-5296· OSTI ID:1855728

Tan, Yunhui ^[1]; Wang, Jiehao ^[2]; Rijken, Peggy ^[2]; Zhang, Zhishuai ^[2]; Fang, Zijun ^[2]; Wu, Ruiting ^[2]; Ning, Ivan Chen ^[2]; Liu, Xinghui ^[2]

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1. Chevron Technical Center, Richmond, CA (United States); GTI
2. Chevron Technical Center, Richmond, CA (United States)

The objective of this study is to understand how microseismic events are generated during hydraulic fracturing, as well as the role of geomechanical conditions (i.e., stress and mechanical stratigraphy) in this process. In the industry, microseismic event clouds have been generally used as an “outer-boundary” of the “stimulated reservoir volume” (SRV). However, by comparing with other surveillance data (Low frequency Distributed Acoustic Sensing, or LF-DAS strain) in the Hydraulic Fracturing Test Site (HFTS) 2 experiment, we show that this assumption is fundamentally flawed. The HFTS 2 data has three unique observations that have not been commonly observed in other datasets: 1. Due to influence of offset pad depletion, microseismic data shows that hydraulic fractures from the child well can propagate over 3000 feet into the depleted low stress zone. 2. By comparing microseismic and horizontal fiber LF-DAS strain data, we observe that microseismic event cloud does not necessarily reflect the created hydraulic fracture volume. Particularly, the extent of microseismic event clouds near heel stages are much shorter than what is shown with LF-DAS strain data. 3. Microseismic event magnitudes are larger in the depleted regions. Through geomechanical analysis, we demonstrate that the “bedding-plane-slip” model is likely the mechanism for microseismic generation during hydraulic fracturing. Furthermore, this model successfully explains the above field observations from HFTS 2 experiment. We also provide a quantitative relationship connecting the microseismic event magnitude with fracture width increment and layer mechanical property contrast.

• Research Organization: Institute of Gas Technology, Des Plaines, IL (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• Grant/Contract Number: FE0031577
• OSTI ID: 1855728
• Journal Information: Proceedings of the Unconventional Resources Technology Conference (URTeC), Journal Name: Proceedings of the Unconventional Resources Technology Conference (URTeC) Vol. 2021; ISSN 2159-6832
• Publisher: Unconventional Resources Technology Conference
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
complex reservoir
fracture width
hft 2
hydraulic fracture
hydraulic fracturing
information
reservoir characterization
strain data
upstream oil & gas
urtec 5296