Abstract
Commercial oil flow has been obtained from the sandstone reservoir of the Lower Silurian Kelpintag Formation in the Well Shun-9 prospect area. In the present studies, 10 Silurian oil and oil sand samples from six wells in the area were analyzed for their molecular and carbon isotopic compositions, oil alteration (biodegradation), oil-source rock correlation and oil reservoir filling direction. All the Silurian oils and oil sands are characterized by low Pr/Ph and C21/C23 tricyclic terpane (<1.0) ratios, “V”-pattern C27-C29 steranes distribution, low C28-sterane and triaromatic dinosterane abundances and light δ13C values, which can be correlated well with the carbonate source rock of the O3l Lianglitage Formation. Different oil biodegradation levels have also been confirmed for the different oils/oil sands intervals. With the S1k2 seal, oils and oil sands from the S1k1 interval of the Kelpintag Formation have only suffered light biodegradation as confirmed by the presence of “UCM” and absence of 25-norhopanes, whereas the S1k3-1 oil sands were heavily biodegraded (proved by the presence of 25-norhopanes) due to the lack of the S1k2 seal, which suggests a significant role of the S1k2 seal in the protection of the Silurian oil reservoir. Based on the Ts/(Ts+Tm) and 4-/1-MDBT ratios as reservoir filling tracers, a general oil filling direction from NW to SE has been also estimated for the Silurian oil reservoir in the Well Shun-9 prospect area.
Article PDF
Similar content being viewed by others
References
Corman J. Biodegradation of crude oils in reservoirs. In: Brooks J and Welte D H (eds.), Advances in Petroleum Geochemistry. London: Academic Press. 1984: 298–335
Galimov E M. Isotope organic geochemistry. Organic Geochemistry. 2006. 37: 1200–1262
Huang G H. The Origin and Geochemical Significance of Fluorene and its Derivatives in Fossil Fuels. Beijing: Science Press. 1987. 211–220 (in Chinese)
Hughes W B. Use of thiophenic organosulfur compounds in characterizing crude oils derived from carbonate versus siliciclastic sources. American Association of Petroleum Geologists, Tulsa. 1984. 18: 181–196
Jia J H, Zhang M, Zhu S H, et al. Stratigraphy, sedimentary characteristics and lithofacies palaeogeography of the Silurian in Tarim Basin. Journal of Palaeogeography. 2006. 8(3): 339–351 (in Chinese)
Jiang Z X, Pang X Q, Liu L F, et al. Quantification of the hydrocarbon destroyed by Silurian bituminous sandstone in the Tarim Basin. Science in China (Series D: Earth Sciences). 2008. 38(S1): 89–94 (in Chinese)
Lin R Z, Wang P R, Dai Y J, et al. Petroleum Geochemical Significance of PAH in Fossil Fuel. Beijing: Geological Publishing House. 1987: 129–140 (in Chinese)
Ma Q Y, Sha X G, Li Y L, et al. Characteristics of strike-slip fault and its controlling on oil in Shuntuoguole region, middle Tarim Basin. Petroleum Geology and Experiment. 2012. 34(2): 120–124 (in Chinese)
Philp R P, Gilbert T D and Friedrich J. Bicyclic sesquiterpenoids and diterpenoids in Australian crude oils. Geochimica et Cosmochimica Acta. 1981. 45(7): 1173–1180
Philp R P, Gilbert T D and Friedrich J. Geochemical correlation of Australian crude oils. APEA J. 1982. 22: 188–199
Quan Y, Hou H, Qi L X, et al. Analysis of geological conditions and exploration potential of Silurian pools in the Liangshun region, northern slope of Tazhong. Journal of Mineralogy and Petrology. 2008. 28(4): 100–108 (in Chinese)
Sofer Z. Stable isotopes in petroleum exploration. In: Merrill R K (ed.), Source and Migration Processes and Evaluation Techniques. AAPG, Tulsa. 1991: 103–106
Wang C G, Wang T G, Zhang W B, et al. Molecular geochemistry and classifications of genetic types of petroleum from Tahe Oilfield of the Northern Tarim Basin. Acta Sedimentologica Sinica. 2006. 24(6): 900–907 (in Chinese)
Wang T G, He F Q, Wang J, et al. Oil filling history of the Ordovician oil reservoir in the major part of the Tahe Oilfield, Tarim Basin, NW China. Organic Geochemistry. 2008. 39(11): 1637–1646
Xiong W L, Chen H H, Yun L, et al. Hydrocarbon charging history for Silurian reservoirs of Shuntuoguole block in the north slope of Tazhone Uplift, Tarim Basin: Constraints from fluid inclusion of Well Shun 9. Acta Petrolei Sinica. 2013. 34(2): 239–246 (in Chinese)
Zhai G M and Wang J J. Analysis of petroleum geology in Tazhong region. Acta Petrolei Sinica. 1999. 20(4): 1–6 (in Chinese)
Zhang H L, Wang Z M, Zhang R H, et al. Controlling factors of Silurian high-quality reservoirs in Tarim Basin and selection of exploration direction. China Petroleum Exploration. 2004. 9(5): 21–25 (in Chinese)
Zhu R K, Luo P, He D B, et al. Sedimentary facies and models of the Kepingtage Formation of Silurian in Tazhong area, Tarim Basin. Journal of Palaeogeography. 2005. 7(2): 197–205 (in Chinese)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Song, D., Li, M. & Wang, TG. Geochemical studies of the Silurian oil reservoir in the Well Shun-9 prospect area, Tarim Basin, NW China. Pet. Sci. 10, 432–441 (2013). https://doi.org/10.1007/s12182-013-0293-2
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12182-013-0293-2