Characteristics of newly discovered crude oil in the Weihe Basin and its petroleum geological significance

被引：0

作者：

Li Y. ^{[1
]}

Gao G. ^{[2
]}

Wang X. ^{[3
]}

Qu T. ^{[2
]}

Han W. ^{[1
]}

Gong Z. ^{[3
]}

Zhang W. ^{[4
]}

Dang W. ^{[2
]}

机构：

[1] Xi'an Geological Survey Center, China Geological Survey, Xi'an, 710054, Shaanxi

[2] State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing

[3] Weihe Energy Co. Ltd. of Shaanxi Gas Group Ltd., Xi'an, 710016, Shaanxi

[4] China University of Mining & Technology (Beijing), Beijing

来源：

Oil and Gas Geology | 2019年 / 40卷 / 02期

关键词：

Biomarker; Crude oil; Geochemistry; Geothermal well; Weihe Basin;

D O I：

10.11743/ogg20190213

中图分类号：

学科分类号：

摘要：

The unexpected production of oil from the geothermal wells in the Weihe Basin breaks the conclusion of history that there is no oil distributed in the region. We made a systematic study of the crude oil in terms of its physical property, group composition, content of saturated hydrocarbon, composition of sterane and terpane, as well as carbon isotope composition of saturated hydrocarbon monomer, with a view to explore the characteristics of crude oil and its petroleum geological significance for the basin. The results show that the crude oil compositions are predominated by saturated hydrocarbons, followed by arene and asphaltene, and with the colloid coming last, thus it belongs to a kind of low-sulfur crude oil with light colloid and normal content of wax. Its saturated hydrocarbon chromatogram is bimodal, with the main peaks corresponding to C15 and C22, and the CPI and OEP values are 0.93 and 0.90 respectively. The organic matters of the crude oil are high in maturity, and mainly sourced from planktons, followed by certain higher plants and algaes. The carbon isotope value of low n-alkanes (C14-C22) decreases from -27.1‰ to -30.3‰ along with the increase of carbon number. When the carbon number is higher than C22, the carbon isotope value varies between -29.3‰ and -30.4 ‰.In addition, the carbon isotope values of pristane (Pr) and phytane (Ph) are relatively heavy at 26.1‰ and 24.9‰, respectively. Higher content of gammacerane indicates that the organic matters are produced in an environment of higher salinity. Compared with the adjacent areas, the crude oil has a great difference with that from the Permian, the Triassic Yanchang Formation and the Jurassic in the Ordos Basin in terms of geochemistry and origin. The newly discovered crude oil indicates that the Weihe Basin may still have source rocks undiscovered, which is of great significance to guide the petroleum exploration of the basin. At the same time, it is also of referential meaning for oil and gas survey in the unexplored sequences in Ordos Basin. © 2019, OIL & GAS GEOLOGY Editorial Board. All right reserved.

引用

页码：346 / 353

页数：7

共 43 条

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