지구물리와물리탐사 (Geophysics and Geophysical Exploration)

  • 제20권4호
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  • Pages.207-215
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  • 2017
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  • 1229-1064(pISSN)
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  • 2384-051X(eISSN)
한국지구물리·물리탐사학회 (Korean Society of Earth and Exploration Geophysicists)
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횡적등방성 특성을 갖는 단양 석회암의 수평응력차비 고찰

Differential Horizontal Stress Ratio for Danyang Limestone with Vertical Transversely Isotropy

  • 장성형 (한국지질자원연구원 석유해저연구본부) ;
  • 황세호 (한국지질자원연구원 지구환경연구본부) ;
  • 신제현 (한국지질자원연구원 지구환경연구본부) ;
  • 김태연 (한국지질자원연구원 석유해저연구본부)
  • Jang, Seonghyung (Korea Institute of Geoscience and Mineral Resources, Petroleum and Marine Division) ;
  • Hwang, Seho (Korea Institute of Geoscience and Mineral Resources, Geological Environment Division) ;
  • Shin, Jehyun (Korea Institute of Geoscience and Mineral Resources, Geological Environment Division) ;
  • Kim, Tae Youn (Korea Institute of Geoscience and Mineral Resources, Petroleum and Marine Division)
  • 투고 : 2017.08.31
  • 심사 : 2017.11.30
  • 발행 : 2017.11.30
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초록

비전통 에너지 자원의 하나인 셰일가스를 개발하기 위해서는 수평시추와 수압파쇄가 필요하고 이 작업들은 수평응력차비가 낮은 곳에서 실시한다. 수평응력차비는 일반적으로 최대 수평응력과 최소 수평응력을 측정하여 구하지만 동탄성계수와 이방성변수를 활용하여 구하기도 한다. 본 연구에서는 단양 석회암 암석코어 시료실험을 통해 이방성 특성을 살펴보고 수평응력차비를 구하였다. 단양 석회암체에서 퇴적 층리면에 수직, 45도, 수평방향으로 된 암석코어 시료를 성형하고 P파 속도, S파 속도, 밀도를 측정한 후 동탄성계수, 컴플라이언스계수를 구하여 수평응력차비를 계산하였다. 시료분석결과 수평응력차비는 약 0.185로 제시하였다. 단양 석회암은 층리 대칭축에 따라서 P파, S파의 속도가 변화하여 Thomsen 매개변수 값도 이와 같은 특징을 잘 반영하고 있으며 수평응력차비는 포아송 비보다 컴플라이언스 값에 영향을 많이 받고 있다. 향후 SH파 속도를 측정할 경우 좀 더 정확한 암석물리 물성을 구할 수 있을 것으로 판단된다.

To develope shale play which is one of unconventional energy resources, horizontal drilling and hydraulic fracturing are necessary and those are applied to the place where the differential horizontal stress ratio (DHSR) is low. The differential horizontal stress ratio is generally calculated by the minimum and maximum horizontal stress, but it is also calculated from dynamic elastic constants and anisotropic parameters. In this study we analyzed anisotropic properties through the core samples from Danyang limestone and calculated DHSR. The three types of core samples shaped in three directions (vertical, parallel and 45 degree to bedding) were used for laboratory test. We measured P-, S-wave velocities, and density and then calculated dynamic elastic constants, compliance and DHSR. According to the results of the core sample analysis the calculated DHSR is 0.185. Thomsen parameters of the Danyang limestone used in this study are characterized by the P- and S-wave velocities varying along the bedding symmetry axis. It is observed that the DHSR value is more affected by the change in compliance value than the Poisson's ratio. It is necessary to measure SH-wave velocity for more correct petrophysical properties.

키워드

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