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Influence of the Cleavage Anisotropy of Pocheon Granite on Hydraulic Fracturing Behaviour

포천 화강암의 결 이방성이 수압파쇄거동에 미치는 영향

  • 정성규 (과학기술연합대학원대학교(UST) 지반신공간공학과) ;
  • 장리 (한국건설기술연구원 지반연구소) ;
  • 염선 (한국건설기술연구원 지반연구소) ;
  • 김광염 ;
  • 민기복 (서울대학교 에너지시스템공학부)
  • Received : 2016.08.17
  • Accepted : 2016.08.29
  • Published : 2016.08.31

Abstract

In this study, laboratory hydraulic fracturing tests are carried out to evaluate the effects of the cleavage anisotropy of Pocheon granite. Breakdown pressure is smaller when cracks are generated to the direction of rift plane in constant pressurization rate condition because of higher microcracks density. Besides not only injection rate changes but also the amount of injection pressure for fracture initiation and crack expansion is detected while testing due to internal deformation. Pressurization rate is higher while hydraulic fracture testing with constant injection rate condition in case of the specimen which has rift plane perpendicular to borehole because there are much flow paths to penetrate compared to the specimen which has hardway plane perpendicular to borehole. Observation by X-ray CT scanning shows that almost all of cracks due to hydraulic fracturing are generated to the direction of plane which has higher microcrack density that is rift plane or grain plane.

Keywords

Hydraulic fracturing;Pocheon granite;Breakdown pressure;Microcracks;X-ray CT

Acknowledgement

Supported by : 한국에너지기술평가원

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