JOURNAL OF ROCK MECHANICS

JOURNAL OF ROCK MECHANICS

The application of acoustic emission methods in the analysis and evaluation of hydraulic fracturing processes.

Document Type : Original Article

Authors
1 Rock Mechanics Group, Mining Faculty, Tarbiat Modares Uni. Tehran, Iran
2 Rock Mechanics, Mining Department, Faculty of Engineering, Tarbiat Modares University
Abstract
Due to the increasing use and high cost of hydraulic fracturing operations, the design of this process requires the identification and proper understanding of the extent and manner of influence of various parameters in the implementation. Various factors such as the effective stress regime, rock mechanical properties of the formation, the presence of joints and natural fractures, as well as operating parameters such as: fluid rheology (the reaction or change in the form of the fluid against the stresses applied to it), flow rate and the method of fluid injection have an impact on the pressure and geometry of the hydraulic fracture. In order to study the effects of the aforementioned parameters, the use of advanced evaluation methods in the laboratory is used. In this study, by reviewing the most important evaluation and analysis methods of hydraulic fracturing experiments, by describing the acoustic propagation method, a complete classification of acoustic data analysis methods is presented. Various aspects of design, sensor placement, determination of wave characteristic limits and implementation tips for the appropriate acquisition of acoustic data in various rock engineering experiments can be used according to the ISRM international recommendation. In the following, by reviewing the most important studies, the specific results obtained from the acoustic propagation method in the analysis of the formation and mechanism and fracture pressure, the propagation of the cracks created, the location of the events and the precise determination of the geometry of the fracture network, as well as the parametric analyses of various effective factors, have been classified and examined. Many parameters affect the type of mechanism of AE events. The results of the experiments showed that in the hydraulic fracturing process, the dominant mode of fracture is shear. However, by conducting a more detailed location and mechanism analysis, it was determined that in the initial stage of tensile fracture and in the stage of fracture propagation, shear will be observed in the events recorded.
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  1. ابراهیم قربانی، پارامترهای موثر بر نتیجه عملیات شکست هیدرولیکی,” اکتشاف و تولید نفت وگاز،  شماره 1394 (123-1)
  2. Ishida et al., “ISRM Suggested Method for Laboratory Acoustic Emission Monitoring,” Rock Mech Rock Eng, vol. 50, no. 3, 2017, doi: 10.1007/s00603-016-1165-z.
  3. D. Byerlee, “Acoustic emission during fluid injection into rock,” in Proceedings of the 1st Conference on Acoustic Emission/Microseismic Activity in Geologic Structures and Materials, 1977, pp. 87–98.
  4. Lockner and J. D. Byerlee, “Hydrofracture in Weber sandstone at high confining pressure and differential stress,” J Geophys Res, vol. 82, no. 14, pp. 2018–2026, 1977.
  5. Weeks, D. Lockner, and J. Byerlee, “Change in b-values during movement on cut surfaces in granite,” Bulletin of the Seismological Society of America, vol. 68, no. 2, pp. 333–341, 1978.
  6. P. Frash, “Laboratory-scale study of hydraulic fracturing in heterogeneous media for enhanced geothermal systems and general well stimulation,” ProQuest Dissertations and Theses, p. 155, 2014.
  7. P. Frash, “Laboratory simulation of an enhanced geothermal reservoir.” Colorado School of Mines. Arthur Lakes Library, 2012.
  8. Ning, Z. Shicheng, Z. Yushi, M. Xinfang, W. Shan, and Z. Yinuo, “Experimental Analysis of Hydraulic Fracture Growth and Acoustic Emission Response in a Layered Formation,” Rock Mech Rock Eng, vol. 51, no. 4, pp. 1047–1062, 2018.
  9. Li et al., “Acoustic Emission Response of Laboratory Hydraulic Fracturing in Layered Shale,” Rock Mech Rock Eng, vol. 51, no. 11, pp. 3395–3406, 2018.
  10.