Organic petrology and hydrocarbon generation of potential source rocks in Permian formation of Junggar Basin, Northwest in China

Abstract

From the outcrops in the Yaomoshan and Hongyanchi sections, oil shales, deep dark mudstones or black mudstones with better organic richness were found. Through the analysis of the samples in the organic petrology method, the microscope features of the sedimentary organic matter were studied. The results indicate that three types of kerogens present in the measured samples. Kerogen type I consists of the laminate algainite, abundant sporinite and only little content of cutinite, which can mainly generate oil. The generation hydrocarbon components of the type II kerogen are dominated by the sporinite, cutinite and little the exinite debris. The type III kerogen is comprised of the sporinite and debris of the exinite with some components of gas generation. Through the analysis of the experiments, the organic kerogen of the Lucaogou formation is mostly comprised of the type I, partially type II, and particularly type III. In Hongyanchi formation, the organic type is mixed by the types II and III. The plot of the (S₁+S₂) or TOC value and the content of exinite show two trends. From the evolution of burial and the Permian source rocks in Changji Depression, the Permian formation source rock has ended the generation of hydrocarbon. A significant difference in constituents of the organic macerals among three kerogens in these samples leads to the distinction of the potential hydrocarbon generation. The Lucaogou formation for kerogen type I has better potential hydrocarbon generation. It can reach the oil peak with R_o ratio of 0.9%. For the kerogen II, the oil peak of the source rocks comes late with the R_o ratio of 1.0% with less quantity of the generation hydrocarbon than the kerogen I. For type III, it can mainly generate gas and reach the gas peak with the R_o ratio of 1.3%. In a word, the Lucaogou formation and Hongyanchi formation source rocks with high organic richness in Permian source rocks have well exploration prospects.

Keywords

organic macerals / hydrocarbon generation potential / Permian source rocks / southern Junggar Basin

References

[1] Suárez-RuizI, FloresD, FilhoJ G M, HackleydP C. Review and update of the applications of organic petrology: Part 1, geological applications [J]. International Journal of Coal Geology, 2012, 99(1): 54-112

[2] HackleyP C, SanfilipoJ R, AziziG P, DaviscP A, StarrattdS W. Organic petrology of subbituminous carbonaceous shale samples from Chalāw, Kabul province, Afghanistan: Considerations for paleoenvironment and energy resource potential [J]. International Journal of Coal Geology, 2010, 81(4): 269-280

[3] FloresD, Gama PereiraL C, RibeiroJ, PinabB, MarquesaM M, RibeiroaM A, Pinto de JesusaA. The Buçaco Basin (Portugal): Organic petrology and geochemistry study [J]. International Journal of Coal Geology, 2010, 81(4): 281-286

[4] TaoS, WangY-b, TangD-z, WuD-m, XuH, HeWei. Organic petrology of Fukang Permian Lucaogou formation oil shales at the northern foot of Bogda Mountain, Junggar basin, China [J]. International Journal of Coal Geology, 2012, 99(1): 27-34

[5] BalbinotM, KalkreuthW. Organic geochemistry and petrology of the Gomo Member, Reconcavo basin, Brazil [J]. International Journal of Coal Geology, 2010, 84(3/4): 286-292

[6] MagdalenaM-k, MonikaJ. Fabiańska. Application of organic petrology and geochemistry to coal waste studies [J]. International Journal of Coal Geology, 2011, 88(1): 1-23

[7] YossifovaM G, EskenazyG M, ValčevaS P. Petrology, mineralogy, and geochemistry of submarine coals and petrified forest in the Sozopol Bay, Bulgaria [J]. International Journal of Coal Geology, 2011, 87(3/4): 212-225

[8] DaiS-f, WangX-b, SeredinV V, HowerJ C, WardC R, OkeefeJ M K, HuangW-h, LiT, LiX, LiuH-d, XueW-f, ZhaoL-xin. Petrology, mineralogy, and geochemistry of the Ge-rich coal from the Wulantuga Ge ore deposit, Inner Mongolia, China: New data and genetic implications [J]. International Journal of Coal Geology, 2012, 90/91(1): 72-99

[9] MohammedH H, WanH A, MohamedR S. Source rock characterization and oil generating potential of the Jurassic Madbi formation, onshore East Shabowah oilfields, Republic of Yemen [J]. Organic Geochemistry, 2010, 41(5): 513-521

[10] López-DíasV, BorregoÁ G, BlancoC G. Las Dueñas mire (Cantabrian Coast, North Spain) [J]. International Journal of Coal Geology, 2010, 84(3/4): 179-189

[11] CarrollA R, BrassellS C, GrahamS A. Upper Permian Lacustrine oil shales, Southern Junggar Basin, Northwest China [J]. AAPG Bulletin, 1992, 76(12): 1874-1902

[12] WangD-y, TangD-z, GouM-f, WangF, TaoS, GaoG-feng. Oil-shale geology of Lucaogou formation in Fukang area on southern margin of Junggar basin [J]. China Petroleum Exploration, 2007, 12(6): 18-22

[13] LiJ-j, TangD-z, XuH, WangD-y, TaoS, ZhouC-y, GaoG-feng. Pyrolysis-gas chromatography of the oil shale in Lucaogou formation, Dahuangshan, southern Junggar basin [J]. Petroleum Exploration and Development, 2008, 356: 674-679

[14] JiangDA, YanSONG, Shao-boLIU, FengHONG, Meng-junZHAO, Guo-youFU. Hydrocarbon play and controlling factors in fold-thrust belt of the southern Junggar foreland basin [J]. Petroleum Geology & Experiment, 2007, 29: 355-360(in Chinese)

[15] KuangJ, QiX-feng. The structural characteristics and oil-gas explorative direction in Junggar foreland basin [J]. Xinjiang Petroleum Geology, 2006, 27: 5-9

[16] Dong-taoWEI, Ying-chengZHAO, TaoCHEN, Hai-boYANG, Liang-yuWU, Shi-hongLI. Difference of hydrocarbon accumulation in the foreland thrust-fold belt of the southern Junggar basin [J]. Geological Journal of China, 2010, 16: 339-350(in Chinese)

[17] WangY-t, GuB, WangL-hong. Pool-forming history of oil and gas in south margin of Junggar basin [J]. Oil & Gas Geology, 1998, 19: 291-295

[18] TeiehmullerM. Organic petrology of source rocks: history and state of art [J]. Organic Geochemistry, 1986, 10: 581-599

[19] TissotB P, WelteD HPetroleum formation and occurrence [M], 1984BerlinSpringer Verlag200-220

[20] CookA C, StruckkmeyerH. The role of coal as a source rock for oil [C]. Second South-Eastern Australia Oil Exploration Symposium. Petroleum Exploration Society of Australia, Melbourne, 1986419-432

[21] WangT-g, SimoneitB R T. Organic geochemistry and coal petrology of tertiary brown coal in the Zhoujing mine, Baise basin, South China: 2. Biomarker assemblage and significance [J]. Fuel, 1990, 69(1): 12-20