Effect of discontinuity stress shadows on hydraulic fracture re-orientation

Qingyuan He, Fidelis T. Suorineni, Tianhui Ma, Joung Oh

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Hydraulic fracturing has been applied to the cave mining industry as a pre-conditioning method to improve rock mass caveability and fragmentation sizes. In theory, the hydraulic fracture orientation is dictated by and is perpendicular to the minimum in-situ stress orientation. Such orientations will not always result in the creation of a blocky rock mass to aid caveability. The understanding of hydraulic fracture re-orientation induced by the stress shadow effect is important for either avoiding the undesirable interaction between multiple transverse hydraulic fractures or taking advantage of this phenomenon to create prescribed hydraulic fractures that result in the creation of blocky rock masses. In this paper, the existing knowledge of the stress shadow effect around a pre-existing discontinuity is reviewed. A 3D numerical modelling code, Rock Failure Process Analysis (RFPA) is used to investigate factors influencing hydraulic fracture re-orientation. It is established that hydraulic fractures can be forced to propagate in desired directions if advantage is taken of the stress shadow effect in combination with knowledge of rock mass homogeneity and site far field stress conditions. Both the differential stresses between σ2 and σ3 and between σ1 and σ3 affect the hydraulic fracture re-orientation geometry. The minimum far field stress magnitude has no direct impact on hydraulic fracture re-orientation. Rock mass homogeneity significantly influences how far a hydraulic fracture propagates along its predefined orientation from its initiation point before re-orientation.

Original languageEnglish
Pages (from-to)179-194
Number of pages16
JournalInternational Journal of Rock Mechanics and Mining Sciences
Volume91
DOIs
Publication statusPublished - Jan 1 2017
Externally publishedYes

    Fingerprint

Keywords

  • Differential stress
  • Hydraulic fracture re-orientation
  • Rock mass homogeneity, Numerical modelling
  • Stress shadow effect

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology

Cite this