DOI: 10.1306/10091313059
Scopus记录号: 2-s2.0-84903643050
论文题名: Effects of smectite on the oil-expulsion efficiency of the Kreyenhagen Shale, San Joaquin Basin, California, based on hydrous-pyrolysis experiments
作者: Lewan M.D. ; Dolan M.P. ; Curtis J.B.
刊名: AAPG Bulletin
ISSN: 0149-1537
EISSN: 1558-9267
出版年: 2014
发表日期: 2014
卷: 98, 期: 6 起始页码: 1091
结束页码: 1109
语种: 英语
Scopus关键词: Clay minerals
; Cracking (chemical)
; Efficiency
; Experiments
; Geochronology
; Impregnation
; Kerogen
; Oil shale
; Rocks
; Shale
; Hydrous pyrolysis
; Paleozoic source rocks
; Precipitation reaction
; Representative sample
; Rock properties
; Thermal cracking
; Total Organic Carbon
; Woodford shales
; Shale oil
; clay mineral
; cracking
; crude oil
; Eocene
; illitization
; maturation
; Paleozoic
; pyrolysis
; rock
; shale
; smectite
; source rock
; total organic carbon
; California
; San Joaquin Basin
; United States
Scopus学科分类: Energy
; Earth and Planetary Sciences
英文摘要: The amount of oil that maturing source rocks expel is expressed as their expulsion efficiency, which is usually stated in milligrams of expelled oil per gram of original total organic carbon (TOC0). Oil-expulsion efficiency can be determined by heating thermally immature source rocks in the presence of liquid water (i.e., hydrous pyrolysis) at temperatures between 350°C and 365°C for 72 hr. This pyrolysis method generates oil that is composition-ally similar to natural crude oil and expels it by processes operative in the subsurface. Consequently, hydrous pyrolysis provides a means to determine oil-expulsion efficiencies and the rock properties that influence them. Smectite in source rocks has previously been considered to promote oil generation and expulsion and is the focus of this hydrous-pyrolysis study involving a representative sample of smectite-rich source rock from the Eocene Kreyenhagen Shale in the San Joaquin Basin of California. Smectite is the major clay mineral (31 wt. %) in this thermally immature sample, which contains 9.4 wt. % total organic carbon (TOC) comprised of type II kerogen. Compared to other immature source rocks that lack smectite as their major clay mineral, the expulsion efficiency of the Kreyenhagen Shale was significantly lower. The expulsion efficiency of the Kreyenhagen whole rock was reduced 88% compared to that of its isolated kerogen. This significant reduction is attributed to bitumen impregnating the smectite interlayers in addition to the rock matrix. Within the interlayers, much of the bitumen is converted to pyrobitumen through crosslinking instead of oil through thermal cracking. As a result, smectite does not promote oil generation but inhibits it. Bitumen impregnation of the rock matrix and smectite interlayers results in the rock pore system changing from water wet to bitumen wet. This change prevents potassium ion (K+) transfer and dissolution and precipitation reactions needed for the conversion of smectite to illite. As a result, illitization only reaches 35% to 40% at 310°C for 72 hr and remains unchanged to 365°C for 72 hr. Bitumen generation before or during early illitization in these experiments emphasizes the importance of knowing when and to what degree illitization occurs in natural maturation of a smectite-rich source rock to determine its expulsion efficiency. Complete illitization prior to bitumen generation is common for Paleozoic source rocks (e.g., Woodford Shale and Retort Phosphatic Shale Member of the Phosphoria Formation), and expulsion efficiencies can be determined on immature samples by hydrous pyrolysis. Conversely, smectite is more common in Cenozoic source rocks like the Kreyenhagen Shale, and expulsion efficiencies determined by hydrous pyrolysis need to be made on samples that reflect the level of illitization at or near bitumen generation in the subsurface. Copyright © 2014. The American Association of Petroleum Geologists. All rights reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903643050&doi=10.1306%2f10091313059&partnerID=40&md5=9f269d6fdbfbc0eac792d87a9a882ee0
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/13108
Appears in Collections: 过去全球变化的重建 影响、适应和脆弱性 科学计划与规划 气候变化与战略 全球变化的国际研究计划 气候减缓与适应 气候变化事实与影响
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Recommended Citation:
Lewan M.D.,Dolan M.P.,Curtis J.B.. Effects of smectite on the oil-expulsion efficiency of the Kreyenhagen Shale, San Joaquin Basin, California, based on hydrous-pyrolysis experiments[J]. AAPG Bulletin,2014-01-01,98(6)