TY - JOUR
T1 - Competing Effects of Proppant and Surface Roughness on the Frictional Stability of Propped Fractures
AU - Luo, Jin
AU - Zhang, Qi
AU - Elsworth, Derek
AU - Zhao, Qi
N1 - Funding Information:
Q. Zhao is supported by the Hong Kong Polytechnic University (Start-up Fund No. P0034042) and the Early Career Scheme of the Research Grants Council of the Hong Kong SAR, China (No. PolyU 25220021). J. Luo acknowledges the support of the National Natural Science Foundation of China (No. 41877200). D. Elsworth gratefully acknowledges support from the G. Albert Shoemaker endowment. Test data presented in this paper is available at https://doi.org/10.6084/m9.figshare.20078678.v1 .
Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.
PY - 2023/4
Y1 - 2023/4
N2 - Proppant is often used to enhance reservoir stimulations, such as hydraulic fracturing and hydraulic shearing; however, the influence of proppant on the shear deformation of fractures and the potential consequent-induced earthquakes are rarely explored. We explore the systematics of frictional behavior, deformability and dilatancy of proppant-filled fractures to define the complex response to different fracture roughness and proppant mass loadings. Shear experiments on rough granite fractures show that proppant reduces cohesion and internal friction, reduces the shear stiffness, delays the shear displacement to a diminished peak strength, reduces the magnitude of shear dilation, and promotes ductile shear failure that is analogous to aseismic creep. A systematic transition in shear behavior occurs from fracture-roughness-dominant to proppant-dominant with increased proppant mass loading that is augmented by increased grain size. Long-wavelength fracture undulations may engage at large shear displacements, causing increased frictional resistance—identifying an intrinsic-scale effect. The presence of proppant reduces the shear dilation. Thus, the convolved interactions between proppant and fracture roughness require careful assessment in their impact on creating and sustaining permeability and modes of aseismic versus seismic ruptures.
AB - Proppant is often used to enhance reservoir stimulations, such as hydraulic fracturing and hydraulic shearing; however, the influence of proppant on the shear deformation of fractures and the potential consequent-induced earthquakes are rarely explored. We explore the systematics of frictional behavior, deformability and dilatancy of proppant-filled fractures to define the complex response to different fracture roughness and proppant mass loadings. Shear experiments on rough granite fractures show that proppant reduces cohesion and internal friction, reduces the shear stiffness, delays the shear displacement to a diminished peak strength, reduces the magnitude of shear dilation, and promotes ductile shear failure that is analogous to aseismic creep. A systematic transition in shear behavior occurs from fracture-roughness-dominant to proppant-dominant with increased proppant mass loading that is augmented by increased grain size. Long-wavelength fracture undulations may engage at large shear displacements, causing increased frictional resistance—identifying an intrinsic-scale effect. The presence of proppant reduces the shear dilation. Thus, the convolved interactions between proppant and fracture roughness require careful assessment in their impact on creating and sustaining permeability and modes of aseismic versus seismic ruptures.
KW - Frictional stability
KW - Proppant
KW - Shear behavior
KW - Surface roughness
UR - http://www.scopus.com/inward/record.url?scp=85145503209&partnerID=8YFLogxK
U2 - 10.1007/s00603-022-03215-w
DO - 10.1007/s00603-022-03215-w
M3 - Journal article
SN - 0723-2632
VL - 56
SP - 2923
EP - 2934
JO - Rock Mechanics and Rock Engineering
JF - Rock Mechanics and Rock Engineering
IS - 4
ER -