Research on stress sensitivity of fractured carbonate reservoirs based on CT technology

Yongfei Yang, Zhihui Liu, Zhixue Sun, Senyou An, Wenjie Zhang, Pengfei Liu, Jun Yao, Jingsheng Ma

Research output: Contribution to journalArticle

21 Citations (Scopus)
48 Downloads (Pure)

Abstract

Fracture aperture change under stress has long been considered as one of primary causes of stress sensitivity of fractured gas reservoirs. However, little is known about the evolution of the morphology of fracture apertures on flow property in loading and unloading cycles. This paper reports a stress sensitivity experiment on carbonate core plugs in which Computed Tomography (CT) technology is applied to visualize and quantitatively evaluate morphological changes to the fracture aperture with respect to confining pressure. Fracture models were obtained at selected confining pressures on which pore-scale flow simulations were performed to estimate the equivalent absolute permeability. The results showed that with the increase of confining pressure from 0 to 0.6 MPa, the fracture aperture and equivalent permeability decreased at a greater gradient than their counterparts after 0.6 MPa. This meant that the rock sample is more stress-sensitive at low effective stress than at high effective stress. On the loading path, an exponential fitting was found to fit well between the effective confining pressure and the calculated permeability. On the unloading path, the relationship is found partially reversible, which can evidently be attributed to plastic deformation of the fracture as observed in CT images.

Original languageEnglish
Article number1833
JournalEnergies
Volume10
Issue number11
Early online date10 Nov 2017
DOIs
Publication statusPublished - Nov 2017

Keywords

  • CT
  • Digital core
  • Fracture opening
  • Pore-scale simulations
  • Stress sensitivity

ASJC Scopus subject areas

  • Computer Science(all)
  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Energy (miscellaneous)

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