Title | A new method for predicting sweet spots of shale oil using conventional well
logs |
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Author | Li, J; Wang, M; Lu, S; Chen, G; Tian, W; Jiang, C ; Li, Z |
Source | Marine and Petroleum Geology vol. 113, 104097, 2019 p. 1-15, https://doi.org/10.1016/j.marpetgeo.2019.104097 |
Year | 2019 |
Alt Series | Natural Resources Canada, Contribution Series 20190216 |
Publisher | Elsevier |
Document | serial |
Lang. | English |
Media | paper; on-line; digital |
File format | pdf (Adobe® Reader®); html; xml |
Area | China |
Lat/Long WENS | 116.0000 120.5000 38.2500 36.7500 |
Subjects | fossil fuels; geochemistry; mineralogy; geophysics; Science and Technology; Paleogene; Eocene; petroleum resources; hydrocarbons; oil shales; geophysical interpretations; well log analyses; resistivity
logging; modelling; models; bedrock geology; lithology; sedimentary rocks; shales; lacustrine deposits; geochemical analyses; pyrolysis; hydrocarbon recovery; hydraulic fracturing; mineralogical analyses; x-ray diffraction analyses; Shahejie
Formation; Zhanhua Sag; Bonan Sag; Bohai Bay Basin; Luo 69 Well; Luo 67 Well; Xinyishen 9 Well; Methodology; Phanerozoic; Cenozoic; Tertiary |
Illustrations | flow diagrams; location maps; geoscientific sketch maps; tables; graphs; plots; well logs; profiles; lithologic sections |
Program | Geoscience for New Energy Supply (GNES) Canadian Energy Geoscience Innovation Cluster (CEGIC) |
Released | 2019 10 21 |
Abstract | In this paper, a new method called sweet spot index (SSI) is proposed by the combination of shale oil mobility and shale reservoir fracability to predict the vertical distribution of shale oil sweet
spots using conventional logs. In the SSI method, logging evaluation models for TOC, S1 (volatile petroleum), and mineral content are initially established. Mobile oil content is obtained by subtracting the amount of adsorbed oil from the total oil
content, which is the S1 value after the recovery of light and heavy hydrocarbons. The adsorbed oil content is calculated based on the oil adsorption model established by a stepwise pyrolysis experiment. The formation fracability is estimated by a
combination of estimates of brittle mineral content and Young's modulus. Formations with higher brittleness and lower Young's modulus are considered better simulation candidates. The SSI value is the product of the normalized mobility and the
fracability index, which minimizes the section of just an organic matter sweet spot (i.e., high oil content) or an inorganic sweet spot (i.e., easily fractured) and has the advantage of accurately predicting its vertical distribution. In the case
study, the new method is successfully implemented to predict sweet spots of the Es3L (lower sub member of the third member of the Eocene Shahejie Formation) in the Bonan Sag, Bohai Bay Basin, China. The lower limit value of SSI is set to 0.1 based on
its relationship with shale oil production. The effectiveness, reliability and adaptability of the SSI method have been verified by three wells in the Bonan Sag. |
GEOSCAN ID | 321198 |
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