Thermochemical sulphate reduction in Cambro-Ordovician carbonates in Central Tarim

	Thermochemical sulphate reduction in Cambro-Ordovician carbonates in Central Tarim
	Cai, CF ; Hu, WS ; Worden, RH
刊名	MARINE AND PETROLEUM GEOLOGY
	2001-06-01
卷号	18 期号:6 页码:729-741
关键词	H2S CO2 thermochemical sulphate reduction organic sulphur pyrite Tarim Basin
ISSN号	0264-8172
文献子类	Article
英文摘要	H2S and CO2 are found in elevated concentrations in Palaeozoic reservoirs in the Tarim Basin in China. We have carried out analyses on gas, petroleum, mineral cement and bulk rock compositions and isotope ratios together with petrography and fluid inclusion to assess the origin of the H2S. A deep crustal (e.g. volcanic) origin of the H2S and CO2 is unlikely since the inert gases, N-2 and He, have isotope ratios totally uncharacteristic of this source. Organic sources are also unlikely since the source rock has low a sulphur content and the sulphur isotope ratio of the petroleum correlates positively with the sulphur content, the opposite of what would be anticipated from petroleum-derived H2S. Bacterial sulphate reduction is unlikely because temperatures are too high for bacteria to have survived. Thermochemical sulphate reduction of petroleum fluids by anhydrite in Lower Ordovician and Cambrian carbonate reservoirs is the most likely source of both the H2S and the CO2 causing isotopically characteristic Pyrite, CO2 gas and calcite cement. H2S, and possibly CO2, migrated into Silurian sandstone reservoirs by cross formational flow. The H2S, with the same sulphur isotope ratio as Ordovician anhydrite, was partially lost from the fluid phase by extensive growth of late diagenetic pyrite. Similarly the CO2 was partially lost from the fluid phase by precipitation of late diagenetic calcite. The H2S that resulted from TSR underwent reaction with the remaining petroleum resulting in locally elevated organic sulphur concentrations in the petroleum and the progressive adoption of the Ordovician anhydrite sulphur isotope ratio. (C) 2001 Elsevier Science Ltd. All rights reserved.
WOS关键词	NATURAL-GAS ACCUMULATIONS ; SULFATE REDUCTION ; SMACKOVER FORMATION ; MOLECULAR NITROGEN ; BURIAL DIAGENESIS ; KHUFF FORMATION ; ORGANIC-MATTER ; ABU-DHABI ; BASIN ; DIOXIDE
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER SCI LTD
WOS记录号	WOS:000170827300005
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/77151]
专题	中国科学院地质与地球物理研究所
通讯作者	Cai, CF
作者单位	1.Univ Liverpool, Dept Earth Sci, Jane Herdman Labs, Liverpool L69 3GP, Merseyside, England 2.Jainghan Petr Inst, Jinzhou 434102, Hubei, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Cai, CF,Hu, WS,Worden, RH. Thermochemical sulphate reduction in Cambro-Ordovician carbonates in Central Tarim[J]. MARINE AND PETROLEUM GEOLOGY,2001,18(6):729-741.
APA	Cai, CF,Hu, WS,&Worden, RH.(2001).Thermochemical sulphate reduction in Cambro-Ordovician carbonates in Central Tarim.MARINE AND PETROLEUM GEOLOGY,18(6),729-741.
MLA	Cai, CF,et al."Thermochemical sulphate reduction in Cambro-Ordovician carbonates in Central Tarim".MARINE AND PETROLEUM GEOLOGY 18.6(2001):729-741.