DOI: 10.1306/01031110103
Scopus记录号: 2-s2.0-79960677338
论文题名: Gas isotope reversals in fractured gas reservoirs of the western Canadian foothills: Mature shale gases in disguise
作者: Tilley B. ; McLellan S. ; Hiebert S. ; Quartern B. ; Veilleux B. ; Muehlenbachs K.
刊名: AAPG Bulletin
ISSN: 0149-1841
EISSN: 1558-9571
出版年: 2011
发表日期: 2011
卷: 95, 期: 8 起始页码: 1399
结束页码: 1422
语种: 英语
Scopus关键词: Devonians
; Fractured gas reservoirs
; Gas fields
; Gas isotopes
; Gas pool
; Gas release
; Gas yields
; Laramide
; Negative values
; Permian
; Shale gas
; Tectonic events
; Thermal history
; Thermochemical sulfate reduction
; Thrust faulting
; Triassic
; Western canada sedimentary basins
; Carbon dioxide
; Carbonates
; Ethane
; Gas industry
; Isotopes
; Lakes
; Methane
; Oil shale
; Petroleum reservoirs
; Propane
; Shale
; Shale oil
; Gases
; alkane
; carbon dioxide
; carbon isotope
; carbonate rock
; Devonian
; fracture
; gas field
; isotopic analysis
; kerogen
; magnitude
; methane
; reservoir
; sedimentary basin
; shale
; sulfide
; Triassic
; volume
; Canada
Scopus学科分类: Energy
; Earth and Planetary Sciences
英文摘要: Isotopically reversed gases (δ13 C methane > δ13 C ethane > δ13C propane) occur in fractured mixed clastic-carbonate reservoirs of the Permian and the Triassic in the foothills at the western edge of the Western Canada sedimentary basin (WCSB). The δ13C methane values (-42 to-24%o), gas dryness, and organic maturity (Ro > 2.2) are indicative of mature gases, and gas maturity generally increases with reservoir age and from the southeast to the northwest. The δ13C ethane values range from-44 to-25, with the less negative values in isotopically normal gases to the northeast of the gas fields we studied. To explain the gas isotope reversals observed in the WCSB foothills, we adopt the concept of a closed-system shale, in which simultaneous cooking of kerogen, oil, and gas yields gas with light δ13C ethane and heavy δ13C methane. This gas was released from shales and trapped in fractured folds of brittle clastic-carbonate rocks during deformation and thrust faulting of the Laramide orogeny, creating some of the most prolific gas pools. These gases are actually mature shale gases. Local high abundances of H2S and CO2 are most likely the products of thermochemical sulfate reduction (TSR) reactions in anhydriterich interbeds and underbeds that admixed to the released shale gas during the tectonic event. No evidence exists that TSR is responsible for the isotope reversals. Variations in δ13C ethane are likely caused by local differences in thermal history, the timing of gas release from shale, and the timing of the fault and fold development. Less negative δ13 C ediane values (resulting in isotopically normal gases) to the northeast of the fields and in the underlying Devonian carbonates likely reflect a more open shale system where the earliest generated gas was lost. We suggest that isotopic reversals are restricted to closed-system maturation, and that their magnitude may be related to the relative volume of gas retained in shales. Copyright © 2011. The American Association of Petroleum Geologists. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960677338&doi=10.1306%2f01031110103&partnerID=40&md5=d7a6a49489cb9fa864163beadd8e165d
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/13410
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
There are no files associated with this item.
Recommended Citation:
Tilley B.,McLellan S.,Hiebert S.,et al. Gas isotope reversals in fractured gas reservoirs of the western Canadian foothills: Mature shale gases in disguise[J]. AAPG Bulletin,2011-01-01,95(8)