干旱区生态环境知识资源中心(Arid): Organic geochemistry of condensates and natural gases in the northwest Nile Delta offshore Egypt

Arid

DOI	10.1016/j.petrol.2019.106819
	Organic geochemistry of condensates and natural gases in the northwest Nile Delta offshore Egypt
	El Diasty, W. Sh 1; Peters, K. E.2,3; Moldowan, J. M.4; Essa, G., I 1; Hammad, M. M.5
通讯作者	El Diasty, W. Sh
来源期刊	JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
ISSN	0920-4105
EISSN	1873-4715
出版年	2020
卷号	187
英文摘要	Although recent gas and condensate discoveries have been achieved in the deep ultramarine Nile Delta Basin of northern Egypt, the genetic origin and formation mechanisms of these hydrocarbons remain unclear. Twenty condensate and 34 natural gas samples from Miocene-Pliocene sandstone reservoirs in the northwest Nile Delta offshore Egypt were analyzed to infer their origin, degree of thermal maturity, and extent of alteration. Based on source-related biomarkers, the condensate samples were interpreted to have originated from clayrich non-marine source rocks, based on high Pr/Ph, high Ts/Tm, low or absent C-30 n-propylcholestanes and high hopane/sterane ratios. The environment of deposition of the source rock is expected to be proximal and likely received high influx of terrigenous-dominated organic matter. Chemometrics of 12 source-related biomarker and isotopic ratios identify six genetic families. Geochemical characterization of the families shows that they are broadly similar but differ in terms of source-rock depositional paleoenvironment, organic matter precursors, thermal maturation and microbial degradation. Age and maturity biomarker fingerprints show that these hydrocarbons were generated from at least two active pods of Upper Cretaceous and Oligocene or younger source rocks, as confirmed by high oleananes, bicadinanes, and high C-26 24-norcholestane indices. Gas chemical and isotopic compositions of propane, ethane, and methane reveal a mixed microbial and thermogenic origin, where the relative proportion of biogenic component reaches up to similar to 70%. The thermogenic gas was generated from mixed Type-II/III or Type-II kerogen with a wide range of maturity between 1.0% and 1.5% R-o from primary kerogen cracking to the late stage of gas cracking. Heavier C2+ hydrocarbon isotope signatures and bulk compositions indicate that the shallower gas accumulations are severely biodegraded, unlike that in the deep hydrocarbon reservoirs. The co-occurrence of unaltered gas with biodegraded condensates may indicate different microbial communities involved in these processes, or more likely, the gas arrived in the reservoir as a second charge after biodegradation of the original condensate.
英文关键词	Norcholestanes Oleananes C-30 n-propylcholestane Biodegradation Gas condensates Nile Delta
类型	Article
语种	英语
国家	Egypt ; USA
收录类别	SCI-E
WOS记录号	WOS:000510456900058
WOS关键词	SOURCE-ROCK EVALUATION ; CRUDE OILS ; DEPOSITIONAL ENVIRONMENT ; GENETIC-CHARACTERIZATION ; WESTERN DESERT ; COAL-BED ; CARBON ; PETROLEUM ; BASIN ; BIODEGRADATION
WOS类目	Energy & Fuels ; Engineering, Petroleum
WOS研究方向	Energy & Fuels ; Engineering
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/315048
作者单位	1.Mansoura Univ, Fac Sci, Geol Dept, Mansoura 35516, Egypt; 2.Stanford Univ, Geol Sci Dept, Stanford, CA 94305 USA; 3.Schlumberger, Mill Valley, CA 94941 USA; 4.Biomarker Technol Inc, 638 Martin Ave, Rohnert Pk, CA 94928 USA; 5.Egyptian Petr Res Inst, Explorat Dept, Cairo, Egypt
推荐引用方式 GB/T 7714	El Diasty, W. Sh,Peters, K. E.,Moldowan, J. M.,et al. Organic geochemistry of condensates and natural gases in the northwest Nile Delta offshore Egypt[J],2020,187.
APA	El Diasty, W. Sh,Peters, K. E.,Moldowan, J. M.,Essa, G., I,&Hammad, M. M..(2020).Organic geochemistry of condensates and natural gases in the northwest Nile Delta offshore Egypt.JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING,187.
MLA	El Diasty, W. Sh,et al."Organic geochemistry of condensates and natural gases in the northwest Nile Delta offshore Egypt".JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING 187(2020).