다공질 사암의 층리에 따른 국부적 공극특성 변화와 수리 이방성 특성
A Study of Locally Changing Pore Characteristics and Hydraulic Anisotropy due to Bedding of Porous Sandstone
1
조회
0
다운로드
3
인용
0
참고문헌
키워드
초록
퇴적암에서 나타나는 이방성은 층리에 의한 영향이 크며, 암석의 수리적 특성에도 영향을 주게 된다. 본 연구에서는 층리가 발달한 다공질 사암을 대상으로, 층리구조에 의해 발생한 공극구조 이방성이 사암의 수리이방성에 미치는 영향을 분석하였다. 사암의 공극구조 이방성 파악을 위해 X-ray CT(computed tomography)를이용하여 내부 공극률의 변화양상을 분석하였다. 층리방향에 따른 수리이방성은 층리면과 수평면이 이루는 각도를 0°에서 90°까지 15°간격으로 코어링한 샘플을 제작하여 투수실험을 통해 파악하였다. 투수실험 결과 층리면과 투수방향이 수직인 경우 투수율이 가장 작은 값을 나타낸 반면, 층리면과 투수방향이 평행일 때 가장 높은투수율을 나타내었으며, 평균 수리이등방비(K90∘/K0∘)가 1.8로 층리에 따른 수리 이방성이 확연하게 나타났다. 또한, 이러한 사암의 수리이방특성은 층리에 의해 공극특성이 서로 다른 층상구조가 형성되기 때문임을 확인하였다.
Abstract
Anisotropy observed in sedimentary rock such as sandstone is mainly caused by existence of bedding consequently influencing on its hydraulic characteristics. The aim of this study is to investigate the influence of locally changing pore structure due to bedding on the hydraulic anisotropy of sandstone, in terms of localized porosity. X-ray CT scan is applied to observe the internal pore structures which is hard to be seen by other experimental methods. Permeability test is also conducted for samples cored at every 15° from 0° to 90° with respect to bedding plane. As a result, the permeability anisotropy is manifest having 1.8 of anisotropy ratio (K90∘/K0∘)and corresponds with the anisotropy of porosity due to bedding.
참고문헌 (29)
- Al-Harthi A. A., "Effect of planar structures on the anisotropy of Ranyah sandstone, Saudi Arabia", Engineering Geology, 50, pp.49~57 (1998)
- Amadei, B., "Importance of Anisotropy when Estimation and Measuring In Situ Stress in Rock", International Journal of Rock Mechanics and Mining Science and Geomechanics Abstracts, 33(3), pp.293~325 (1996)
- Baud, P., "Effects of bedding and foliation on mechanical anisotropy, damage evolution and failure mode", Geological Society Abstracts, 245, pp.223~249 (2005)
- Bear, J., "Dynamics of fluids in porous media" (1972), American elsevier publishing, Dover publications
- Benson, P. M., "Pore fabric shape anisotropy in porous sandstones and its relation to elastic wave velocity and permeability anisotropy under hydrostatic pressure", International Journal of Rock Mechanics & Mining Sciences, 42, pp.890~899 (2005)
- Chenevert, M.E., "Mechanical Anisotropies of Laminated Sedimentary Rocks", Society of petroleum engineers journal, pp.67~77 (1965)
- Choi, A-S., "A study on the fracture mechanism and the test for strength properties of the granite-gneiss", Journal of Korean Society for Rock Mechanics, Tunnel & Underground, 10, pp.165~172 (2000)
- 최미진, "횡등방성 암반 내 터널의 이방성 해석", 터널과 지하공간, 15(6), pp.391~399 (2005), 한국암반공학회
- Cho, J-W., "Deformation and strength anisotropy of Asan Gneiss, Boryeong Shale, and Yeoncheon Schist", Internal Journal of Rock Mechanics & Minining Sciences, 50, pp.158~169 (2012)
- 추민경, "암석 내 공극구조의 평가를 위한 전기임피던스의 적용", 지질공학, 21(4), pp.323~336 (2011), 대한지질공학회
- Clavaud, J-B., "Permeability anisotropy and its relations with porous medium structure", Journal Of Geophysical Research, 113 (2008)
- David, C., "Pore structures and transport properties of sandstone", Transport in porous media, 11, pp.161~177 (1993)
- Dehler, W., "Stress path testing of an Anisotropic sandstone", J.Geotech. Geoenviron. Eng, 133, pp.116~119 (2007)
- Gatelier, N., "Mechanical damage of an anisotropic porous rock in cyclic triaxial tests", International Journal of Rock Mechanics & Mining Sciences, 39, pp.335~354 (2002)
- Grattoni, C. A., "Anisotropy in pore structure of porous media", Powder Technology, 85, pp.143~151 (1995)
- Harrison, J. P., "Engineering Rock Mechanics Part 2: Illustrative worked examples" (2001), Elsevier
- Kim, H-Y., "Determination of elastic constants of transversely isotropic rocks by simple uni-axial test", Journal of Korean Society for Rock Mechanics, Tunnel & Underground Space, 5, pp.318~322 (1995)
- Kim, H., "Anisotropy of elastic moduli, P-wave velocities, and thermal conductivities of Asan Gneiss, Boryeong Shale, and Yeoncheon Schist in Korea", Engineering Geology, 147-148, pp.68~77 (2012)
- Kim, Y-S., "Engineering characteristics of shales due to the angle of bedding plane", The Journal of Korea Geotechnical society, 17(1), pp.5~13 (2001)
- 이연규, "횡등방성 암석의 강도해석을 위한 이방성 Mohr-Coulomb 파괴조건식", 터널과 지하공간, 21(3), pp.174~180 (2011), 한국암반공학회
- Louis, L., "Comparison of the anisotropic behaviour of undeformed sandstones under dry and saturated conditions", Tectonophysics, 370, pp.193~212 (2003)
- Louis, L., "Microstructural control on the anisotropy of elastic and transport properties in undeformed sandstones", International Journal of Rock Mechanics & Mining Sciences, 42, pp.911~923 (2005)
- Louis, L., "Microstructural Inhomogeneity and Mechanical Anisotropy Asso ciated with Bedding in Rothbach Sandstone", Pure appl. geophys, 166, pp.1063~1087 (2009)
- Matsukura, Y., "Effect of microstructure and weathering on the strength anisotropy of porous rhyolite", Engineering Geology, 63, pp.39~47 (2002)
- Anisotropy of Sandstone Permeability, "Meyer, R", CREWES, 14~, pp.Research Report, 14 (2002)
- Rasolofosaon P. N. J., "Comparison between permeability anisotropy and elasticity anisotropy of reservoir rocks", Geophysics, 67(1), pp.230~240 (2002)
- Stewart, M. L., "A study of pore geometry effects on anisotropy in hydraulic permeability using the lattice-Boltzmann method", Advances in Water Resources, 29, pp.1328~1340 (2006)
- Walls, J. D., "Effects on pore pressure, confining pressure and partial saturation on permeability of sandstone, A dissertation submitted to the department of geophysics and the committee on graduate studies of In partial fulfillment of the requirements for the degree of doctor of philosophy", 박사, pp.1982
- Zhang X-M., "Experimental study on anisotropic strength properties of sandstone", EJGE, 15, pp.1325~1335 (2010)