A New Method for Quality Control of Geological Cores by X-Ray Computed Tomography: Application in IODP Expedition 370

Frontiers in Earth Science

Fumio Inagaki¹  Yasuhiro Yamada²  Verena B. Heuer³  Expedition 370 Scientists⁴  Yusuke Kubo⁵  Man-Yin Tsang⁶  Stephen Bowden⁷  Satoshi Tonai⁷  Yuzuru Yamamoto⁸  Nana Kamiya⁹  Kotaro Ide^1,10  Yuki Morono^1,11  Takehiro Hirose^1,11  Kiho Yang^1,12 

[1] 0Mantle Drilling Promotion Office (MDP), Institute for Marine-Earth Exploration and Engineering (MarE3), Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan;1Graduate School of Science, Kochi University, Kochi, Japan;2MARUM - Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany;;Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan;Department of Earth Sciences, University of Toronto, Toronto, ON, Canada;Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen, United Kingdom;Department of Mathematical Science and Advanced Technology, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan;Department of Urban Management, Kyoto University, Kyoto, Japan;Faculty of Science and Technology, Kochi University, Kochi, Japan;Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Nankoku, Japan;Korea Institute of Ocean Science and Technology, Uljin, South Korea;Research and Development Center for Ocean Drilling Science (ODS), Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan;

关键词: X-ray computed tomography;    scientific drilling;    International Ocean Discovery Program;    Nankai Trough;    accretionary complex;   

DOI  :  10.3389/feart.2019.00117

来源: DOAJ

【 摘 要 】

X-ray computed tomography (XCT) can be used to identify lithologies and deformation structures within geological core, with the potential for the identification processes to be applied automatically. However, because of drilling disturbance and other artifacts, the use of large XCT-datasets in automated processes requires methods of quality control that can be applied systematically. We propose a new systematic method for quality control of XCT data that applies numerical measures to CT slices, and from this obtains data reflective of core quality. Because the measures are numerical they can be applied quickly and consistently between different sections and cores. This quality control processing protocol produces downhole radiodensity profiles from mean CT-values that can be used for geological interpretation. The application of this quality control protocols was applied to XCT data from International Ocean Discovery Program (IODP) Expedition 370 Site C0023 located at the toe of the Nankai accretionary complex. The evaluation of core quality based on this protocol was found to be a good fit to standard-evaluations based on the visual description of core, and could be used to select samples free from drilling disturbance or contamination. The quality-controlled downhole mean CT-value profile has features that can be used to identify lithologies within a formation, the presence and type of deformation structures and to distinguish formations.

【 授权许可】

Unknown