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Author Feng, Congjun ♦ Yang, Hua ♦ Pu, Renhai ♦ Wang, Yaning ♦ Wang, Daxing ♦ Liang, Xiaowei ♦ Zhang, Mengbo ♦ Huang, Yougen ♦ Fei, Shixiang
Source SpringerLink
Content type Text
Publisher The Geological Society of Korea
File Format PDF
Copyright Year ©2017
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Earth sciences
Subject Keyword tight oil ♦ tight sandstone ♦ well logging evaluation ♦ sandy debris flows ♦ Earth Sciences
Abstract Using core, well logging, geological analysis, production, and test data, this study characterizes a method of well logging for identifying lithology, oil or water layers, and thickness of oil layers of tight sandstone reservoir in the Chang 7 member of the Upper Triassic Yanchang Formation, southwestern Ordos Basin, China. This reservoir consists of two rock types: fine sandstone and siltstone. The fine sandstone has distinct oil traces and flecks, which strongly indicate the presence of oil, and this rock is therefore the superior reservoir. The siltstone exhibits essentially no oil shows and thus is an unproductive layer. A method of density and neutron curve normalization and overlay was used to identify the tight fine sandstone, tight siltstone, mudstone, and shale. The criteria for identifying the tight fine sandstone are a natural gamma value of less than 93 API (American Petroleum Institute units) and a difference between the normalized curves exceeding 0.05. A resistivity-porosity plot was used to identify oil or water layers relatively effectively. The criteria for identifying the tight oil layers are (1) a resistivity exceeding 28 Ω·m and a porosity exceeding 9.5% or (2) a resistivity between 20 and 28 Ω·m, a porosity exceeding 9.5%, and an oil saturation exceeding 65%. Based on the lithologic identification via normalization and overlay of the density and neutron curves and the criteria for distinguishing the tight oil layers, the thickness of the tight fine sandstone oil reservoir was accurately determined by overlaying the normalized difference curve on the resistivity curve.
ISSN 12264806
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2017-03-11
Publisher Place Seoul
e-ISSN 15987477
Journal Geosciences Journal
Volume Number 21
Issue Number 2
Page Count 11
Starting Page 201
Ending Page 211


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Source: SpringerLink