Reliability Assessment of the Hydraulic Fracturing Process in Coal Mine Based on the Analysis of Micro-Seismic Source Parameters

• Published in: Natural resources research (New York, N.Y.) N.Y.), 2021-06, Vol.30 (3), p.2317-2332
• Main Authors: Chen, Dong, Li, Nan, Wang, En-yuan
• Format: Article
• Language: English
• Subjects: Chemistry and Earth Sciences; Coal; Coal mines; Coal mining; Computer Science; Controllability; Earth and Environmental Science; Earth Sciences; Earthquakes; Evaluation; Fossil Fuels (incl. Carbon Capture); Geography; Hydraulic fracturing; Mathematical Modeling and Industrial Mathematics; Mathematical models; Mineral Resources; Original Research; Parameters; Physics; Reliability analysis; Search methods; Seismic activity; Seismic energy; Seismic response; Statistics for Engineering; Sustainable Development; Water pressure
• ISSN: 1520-7439; 1573-8981
• DOI: 10.1007/s11053-021-09840-6

In a reliability assessment of hydraulic fracturing, the efficacy of hydraulic fracturing must be evaluated, and the source properties and magnitude of micro-earthquakes induced by hydraulic fracturing in a coal mine need to be quantified. Firstly, the changing trends of the number and energy of micro-seismic events induced by hydraulic fracturing with high-pressure water were examined, and the hydraulic fracturing effect was evaluated by micro-seismic location. Then, the source parameters (seismic moment M 0 , source radius R , corner frequency f 0 , radiated seismic energy E , stress drop △ σ , and apparent stress σ a ) were calculated using the Brune model and the grid-search method, and the relationships between M 0 and other source parameters were analyzed. Finally, the source parameters between micro-earthquakes induced by hydraulic fracturing and those induced by mining were compared, and the relationship between M w (moment magnitude) and M L (local magnitude) of a micro-earthquake induced by hydraulic fracturing was ascertained. The results show that most micro-earthquakes occur in the initial stage of water pressure increase during hydraulic fracturing. In addition, the occurrence of several micro-earthquakes does not correspond strictly to the significant decrease of water pressure; the locations of micro-earthquakes can be used to evaluate the effect of hydraulic fracturing. The source parameters of micro-earthquakes induced by hydraulic fracturing in the Xieqiao coal mine can be obtained from the Brune model and the grid-search method. Corner frequency f 0 decreases with increase in seismic moment M 0 , source parameters of R and E , as well as △ σ increase with increase in seismic moment M 0 , but the apparent stress σ a fluctuates around a certain value; the relationships between the other source parameters and M 0 of micro-earthquake induced by hydraulic fracturing are consistent with that of a micro-earthquake induced by coal mining. Considering M w , M L1 can be better used to calculate the magnitude of micro-earthquakes induced by hydraulic fracturing. Through M w and M L1 , the magnitude of a micro-earthquake induced by hydraulic fracturing can be evaluated. Our results improve the evaluation of the hydraulic fracturing effect, the understanding of source properties, and evaluation of the magnitude of micro-earthquakes induced by hydraulic fracturing. It is found that these micro-earthquakes are within the safe controllable range, and t