A new method for acoustic wave correction in shales based on the identification for the bedding textures

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2019A new method for acoustic wave correction in shales based on the identification for the bedding texturesAuthors: Yijia WuBei YangYangQing WeiYizhen LiYang ZhouYijia WuGeological Exploration and Development Research Institute of Chuanqing Drilling Engineering Ltd., CNPCSearch for more papers by this author, Bei YangGeological Exploration and Development Research Institute of Chuanqing Drilling Engineering Ltd., CNPCSearch for more papers by this author, YangQing WeiGeological Exploration and Development Research Institute of Chuanqing Drilling Engineering Ltd., CNPCSearch for more papers by this author, Yizhen LiGeological Exploration and Development Research Institute of Chuanqing Drilling Engineering Ltd., CNPCSearch for more papers by this author, and Yang ZhouChengdu University of TechnologySearch for more papers by this authorhttps://doi.org/10.1190/segam2019-3215649.1 SectionsSupplemental MaterialAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail AbstractThe complex bedding textures of shale have been confirmed to cause acoustic attenuation during propagation so that the sonic logging tool can only receive the second wave or subsequent signals instead of the first wave, which shall result in an abnormal increase of acoustic wave value in the bedding developing area. From the point of petrophysics, the real AC value should satisfy the sum of the product of each formation component’s volume percentage and its theoretical response value. Comparing the measured AC value with the theoretical value of AC derived from cores (ACtheory), when bedding textures are developed, there will exist obvious deviation. Meanwhile, the envelope of the three porosity log curves (sonic, neutron, density) should approximately coincide in normal formation, but in bedding-developed area, sonic log will be greatly affected while neutron log won’t be because of different measuring mechanism. In addition, the neutron log is investigated to be coincident with ACtheory. Hence, considering ACtheory from cores as a bridge, the development of bedding texture can be identified by the abnormal deviation of sonic and neutron logs. On this basis, to restore the real variation trending of Acoustic Time Difference (AC) of the bedding-developing formation back to the actual position, a correction method is demonstrated according to discrete wavelet transform (DWT), which merges the low-frequency signal of the neutron curve and the high-frequency signal of the sonic curve. This study firstly proposes an identification method for the development of bedding textures in shales based on porosity logs (sonic and density logs) and rock volume model then provided a new insight to restore the real AC variation trend, which effectively avoids the limitation of core analysis in laboratory and has a great significance on the following reservoir prediction, evaluation, and transformation.Presentation Date: Tuesday, September 17, 2019Session Start Time: 1:50 PMPresentation Start Time: 4:45 PMLocation: 305Presentation Type: OralKeywords: borehole acoustics, rock physics, data reconstruction, rock core laboratory measurements, shalePermalink: https://doi.org/10.1190/segam2019-3215649.1FiguresReferencesRelatedDetails SEG Technical Program Expanded Abstracts 2019ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2019 Pages: 5407 publication data© 2019 Published in electronic format with permission by the Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 10 Aug 2019 CITATION INFORMATION Yijia Wu, Bei Yang, YangQing Wei, Yizhen Li, and Yang Zhou, (2019), "A new method for acoustic wave correction in shales based on the identification for the bedding textures," SEG Technical Program Expanded Abstracts : 3628-3632. https://doi.org/10.1190/segam2019-3215649.1 Plain-Language Summary Keywordsborehole acousticsrock physicsdata reconstructionrock core laboratory measurementsshalePDF DownloadLoading ...