Combination and superimposition of source kitchens and their effects on hydrocarbon accumulation in the hinterland of the Junggar Basin, west China
Tóm tắt
In the hinterland of the Junggar Basin, there are multiple depressions with multiple sets of source rocks. Therefore, the conditions of hydrocarbon sources are complex, and the geochemical characteristics and sources of hydrocarbon vary in different structural belts. The evolution of the Che-Mo palaeohigh affected the formation of hydrocarbon source kitchens and hydrocarbon migration. We studied the combination and superimposition of hydrocarbon source kitchens, using as an example the hinterland of the Junggar Basin (including the Yongjin, Zhengshacun, Moxizhuang and Luliang uplift areas). The study was based on geochemical analyses of crude oil and fluid inclusions, and the histories of tectonic evolution and hydrocarbon generation. The results indicated that before the Paleogene there were two hydrocarbon-generating depressions: the Western Well Pen1 depression and the Changji depression on the south and north sides of the Che-Mo palaeohigh, respectively. The Permian source kitchen had been generating hydrocarbon continuously since Triassic and reached high maturity stage in the Cretaceous period. After Paleogene, the adjustment of the Che-Mo palaeohigh led to the subsidence of the Changji depression and the Jurassic source rocks reached mature stage and became the main source kitchens. However, the Jurassic source rocks in the Western Well Pen1 depression were still in a low maturity stage and did not generate oil because of the adjustment of tectonic movements. As a result, in the central and southern parts of the Junggar Basin, Jurassic source rocks generated oil, but in the Luliang uplift, the crude oil was from the Permian source rocks in the Western Well Pen1 depression and the Jurassic source rocks did not contribute. The crude oil in the central Zhengshacun-Moxizhuang belt was from the Permian source rocks in two depressions, and partially from the Jurassic source rocks. The crude oil in the Luliang uplift was from the source rocks of the lower Permian Fengcheng Formation and middle Permian Wuerhe Formation, which is characterized by superimposition of two sets of source kitchens and three accumulation stages. The crude oil in the Yongjin tectonic belt was from the lower Permian, middle Permian and Jurassic source rocks, which is characterized by superimposition of three sets of source kitchens and two accumulation stages. The crude oil in the Zhengshacun tectonic belt was from a combination of source kitchens of lower Permian and middle Permian in the Western Well Pen1 depression in the early stage and from the superimposition of Jurassic source rocks in the Changji depression in the late stage.
Tài liệu tham khảo
Cai X Y and Liu C H. Main factors for controlling formation of oil-gas reservoir in central part of Junggar Basin. Acta Petrolei Sinica. 2005. 26(5): 1–9 (in Chinese)
Chen Z H, Zha M, Wu K Y, et al. Hydrocarbon migration direction in Luliang section of Junggar Basin. Journal of China University of Petroleum. 2003. 27(2): 19–22 (in Chinese)
Gao X K, Hu W X, Cao J, et al. Study of hydrocarbon migration and accumulation in the Mosuowan-Mobei area, Junggar Basin. Oil & Gas Geology. 2007. 28(2): 250–256 (in Chinese)
Hao F, Jiang J Q, Zou H Y, et al. Inhibitory effects of overpressure on organic matter thermal evolution. Science in China, Series D. 2004. 34(5): 443–451 (in Chinese)
Kuang J, Liu D G and Li S H. Geologic characteristics and distribution framework of natural gas reservoirs in Junggar Basin. Xinjiang Petroleum Geology. 2001. 22(5): 390–392 (in Chinese)
Liao J D, Kang S F, Li M H, et al. Geochemistry research of oil reservoirs in Luliang Oil Field. Petroleum Geology and Recovery Efficiency. 2003. 10(4): 29–31 (in Chinese)
Liu G B and Zhang H R. The hydrocarbon occurrences and characteristics of geothermal field in Junggar Basin. Xinjiang Petroleum Geology. 1992. 13(2): 99–107 (in Chinese)
Pan C C, Zhou Z Y, Fan S F, et al. Thermal history of Junggar Basin. Geochimica. 1997. 26(6): 1–7 (in Chinese)
Pan C C, Zhou Z Y and Wang Q L. Study of thermal history of source beds in Junggar Basin by apatite fission-track. Oil & Gas Geology. 1989. 10(1): 35–39 (in Chinese)
Qiu N S, Wang X L, Yang H B, et al. The characteristics of temperature distribution in the Junggar Basin. Chinese Journal of Geology. 2001. 36(3): 350–358 (in Chinese)
Qiu N S, Zha M and Wang X L. Simulation of geothermal evolution history in Junggar Basin. Xinjiang Petroleum Geology. 2000. 21(1): 38–41 (in Chinese)
Qiu N S, Zhang Z H and Xu E S. Geothermal regime and Jurassic source rock maturity of the Junggar Basin, northwest China. Journal of Asian Earth Sciences. 2008. 31(4–6): 464–478
Qiu N S. Characters of thermal conductivity and radiogenic heat production rate in basins of northwest China. Chinese Journal of Geology. 2002. 37(2): 196–206 (in Chinese)
Wang S J, Hu S B, Li T J, et al. The heat flow in the Junggar Basin. Chinese Science Bulletin. 2000. 45(12): 1327–1332 (in Chinese)
Wang X L and Kang S F. Analysis of crude origin in hinterland and slope of northwestern margin, Junggar Basin. Xinjiang Petroleum Geology. 1999. 20(2): 109–112 (in Chinese)
Wang X L, Yang H B, Kang S F, et al. Analysis on oil sources and reservoir formation of Well Lu 9 in Luliang Uplift in Junggar Basin. Xinjiang Petroleum Geology. 2001. 22(3): 213–216 (in Chinese)
Wu X H, Xiang B L and Liu G F. Geochemical study for oil-gas pools of Shixi Oilfield. Xinjiang Petroleum Geology. 2001. 22(1): 35–37 (in Chinese)
Wu X H, Yi H S and Wang C S. Reservoir geochemical characteristics of Shinan Oil Field in Junggar Basin. Natural Gas Industry. 2004. 24(12): 24–27 (in Chinese)
Zhang L P, Wang S J and Qu H. Geochemistry of crude oil and oilsource analysis of Junggar Basin. China Petroleum Exploration. 2000. 5(3): 30–35 (in Chinese)
Zhou Z Y, Pan C C, Fan S F, et al. Geothermal characteristics of the Junggar Basin and its significance to oil searching. Xinjiang Petroleum Geology. 1989. 10(3): 67–74 (in Chinese)