Dynamic microscale crack propagation in shale

Zhao，Junliang1; Zhang，Dongxiao2

2020-04-01

10.1016/j.engfracmech.2020.106906

ENGINEERING FRACTURE MECHANICS   影响因子和分区

0013-7944

1873-7315

Hydraulic fracturing and horizontal well are the two key techniques for the development of shale oil/gas. Mechanical heterogeneity and anisotropy of shale strongly influence the effects of fracturing. While numerous studies have focused on the fracture behavior of shale, the microscale fracture mechanisms of shale remain poorly understood. In this study, three representative test areas, which were dominated by a stiff mineral, a blob of organic matter and clay layers, respectively, were selected in a terrestrial shale sample from the Yanchang Formation. Micro cantilever beams were manufactured using the micro fabrication method in each test area, and in situ fracture experiments were performed to investigate crack propagation under a scanning electron microscope. The crack propagation process was characterized at micrometer scale in shale. The crack paths and the load-displacement curves revealed various fracture mechanisms. Crack deflection and crack branching owing to mechanical contrast, toughening in organic matter, and crack bridging of clay layers were observed and discussed. This study provided a novel insight into micro crack behavior in shale and presents a new framework for the investigation of the fracture characteristics of shale. The microscale shale characterization and crack mechanisms can serve as a basis or building blocks for mesoscale modeling of fracturing in shale, and the load-displacement data and fracture behaviors can provide a valuable dataset for validating modeling approaches.

Crack propagation Fracture mechanisms In situ fracture experiments Mechanical heterogeneity Micro fabrication

SCI ; EI

英语

通讯

National Major Science and Technology Projects of China[2017ZX05049-003] ; National Natural Science Foundation of China[U1663208]

Mechanics

Mechanics

WOS:000517397300011

Elsevier Ltd

20200708154560

Biogeochemistry ; Cantilever beams ; Crack propagation ; Fracture ; Horizontal wells ; Oil field development ; Organic compounds ; Scanning electron microscopy

Structural Members and Shapes:408.2 ; Geochemistry:481.2 ; Oil Fields:512.1.1 ; Petroleum Deposits : Development Operations:512.1.2 ; Organic Compounds:804.1 ; Materials Science:951

ENGINEERING

2-s2.0-85079088119

Scopus

1.BIC-ESAT,ERE and SKLTCS,College of Engineering,Peking University,Beijing,100871,China
2.School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China

Zhao，Junliang,Zhang，Dongxiao. Dynamic microscale crack propagation in shale[J]. ENGINEERING FRACTURE MECHANICS,2020,228.

Zhao，Junliang,&Zhang，Dongxiao.(2020).Dynamic microscale crack propagation in shale.ENGINEERING FRACTURE MECHANICS,228.

Zhao，Junliang,et al."Dynamic microscale crack propagation in shale".ENGINEERING FRACTURE MECHANICS 228(2020).