Exploration for unconventional gas resources from Paleozoic formations in the Sichuan Basin in South China is just getting started. Large, potential gas reservoirs are presumed to exist in the southern and southeastern Sichuan Basin where Silurian marine organic-rich shale occurs. This paper provides geochemical and mineralogical data and other relevant information on potentially economic black shale formations of the Lower Silurian. The results show that in the shale, mineral components are dominated by clay minerals and quartz with minor amounts of plagioclase, potash feldspar, calcite and pyrite. The brittle mineral content ranges from 38 to 73% by weight (average content 56.2 wt%). In general, the Lower Silurian organic-rich shale of the Longmaxi Formation in the Sichuan Basin is highly mature, with the vitrinite reflectance between 1.6 and 3%. The shale has a high content of organic carbon, with an average of 1.8%, is tens of meters thick and of large areal extent. It can be regarded as a potential gas shale target.
1. Bowker, K. A. Barnett Shale gas production, Fort Worth Basin: issues and discussion. AAPG Bull., 2007, 91(4), 523–533.
http://dx.doi.org/10.1306/06190606018
2. Chen, S., Zhu, Y., Qin, Y., Wang, H., Liu, H., Fang, J. Reservoir evaluation of the Lower Silurian Longmaxi Formation shale gas in the southern Sichuan Basin of China. Mar. Petrol. Geol., 2014, 57, 619–630.
http://dx.doi.org/10.1016/j.marpetgeo.2014.07.008
3. Zhang, J. C., Nie, H. K., Xu, B., Jiang, S. L., Zhang, P. X., Wang, Z. Y. Geological condition of shale gas accumulation in Sichuan Basin. Natural Gas Industry, 2008, 28(2), 151–156 (in Chinese with English abstract).
4. Zou, C. N., Dong, D. Z., Wang, S. J., Li, J, Li, X. J, Wang, Y., Li, D., Cheng, K. M. Geological characteristics and resource potential of shale gas in China. Petrol. Explor. Develop., 2010, 37(6), 641–653.
http://dx.doi.org/10.1016/S1876-3804(11)60001-3
5. Xu, S. L., Chen, H. D., Chen, A., Lin, L. B., Li, J. W., Yang, J. B. Source rock characteristics of marine strata, Sichuan Basin. Journal of Jilin University, Earth Science Edition, 2011, 41(2), 343–350 (in Chinese with English abstract).
6. Liang, C., Jiang, Z. X., Zhang, C., Guo, L., Yang, Y. T., Li, J. The shale characteristics and shale gas exploration prospects of the Lower Silurian Longmaxi shale, Sichuan Basin, South China. J. Natural Gas Sci. Eng., 2014, 21, 636–648.
http://dx.doi.org/10.1016/j.jngse.2014.09.034
7. Dardour, A. M., Boote, D. R. D., Baird, A. W. Stratigraphic controls on Palaeozoic petroleum systems, Ghadames basin, Libya. J. Petrol. Geol., 2004, 27(2), 141–162.
http://dx.doi.org/10.1111/j.1747-5457.2004.tb00050.x
8. Galeazzi, S., Point, O., Haddadi, N., Mather, J., Druesne, D. Regional geology and petroleum systems of the Illizi-Berkine area of the Algerian Saharan Platform: an overview. Mar. Petrol. Geol., 2010, 27(1), 143–178.
http://dx.doi.org/10.1016/j.marpetgeo.2008.10.002
9. Liang, C., Jiang, Z. X., Yang, Y. T., Wei, X. J. Shale lithofacies and reservoir space of the Wufeng–Longmaxi Formation, Sichuan Basin. Petrol. Explor. Develop., 2012, 39(6), 691–698 (in Chinese with English abstract).
http://dx.doi.org/10.1016/S1876-3804(12)60098-6
10. Jiang, Z. X., Guo, L., Liang, C. Lithofacies and sedimentary characteristics of the Silurian Longmaxi Shale in the southeastern Sichuan Basin, China. Journal of Palaeogeography, 2013, 2(3), 238–251.
11. Liang, D. G., Guo, T. L., Bian, L. Z., Chen, J., Zhao, Z. Some progresses on studies of hydrocarbon generation and accumulation in marine sedimentary regions, Southern China (Part 3): Controlling factors on the sedimentary facies and development of Palaeozoic marine source rocks. Marine Origin Petroleum Geology, 2009, 14(2), 1–19 (in Chinese with English abstract).
12. Guo, L., Jiang, Z. X., Zhang, J. C., Li, Y. X. Paleoenvironment of Lower Silurian black shale and its significance to the potential of shale gas, southeast of Chongqing, China. Energy Exploration & Exploitation, 2011, 29(5), 597–616.
http://dx.doi.org/10.1260/0144-5987.29.5.597
13. Dong, D. Z., Cheng, K. M., Wang, Y. M., Li, X. J., Wang, S. J., Huang, J. L. Forming conditions and characteristics of shale gas in the Lower Paleozoic of the Upper Yangtze region, China. Oil & Gas Geology, 2010, 31(3), 288–299 (in Chinese with English abstract).
14. Peters, K. E. Guidelines for evaluating petroleum source rock using programmed pyrolysis. AAPG Bull., 1986, 70(3), 318–329.
15. Espitalie, J., Deroo, G., Marquis, F. Rock-Eval pyrolysis and its applications. Revue de l’Institut Français du Pétrole, 1985, 40(5), 563–579.
http://dx.doi.org/10.2516/ogst:1985035
16. Sun, T., Wang, C. S., Li, Y. L., Wang, L. C., He, J. L. Geochemical investigation of lacustrine oil shale in the Lunpola Basin (Tibet): implications for paleoenvironment and paleoclimate. Oil Shale, 2013, 30(2), 101–116.
http://dx.doi.org/10.3176/oil.2013.2.02
17. Pu, B. L., Jiang, Y. L., Wang, Y., Bao, S. J., Liu, X. J. Reservoir forming conditions and favorable exploration zones of shale gas in Lower Silurian Longmaxi Formation of Sichuan Basin. Acta Petrolei Sinica, 2010, 31(2), 225–230 (in Chinese with English abstract).
18. Curtis, J. B. Fractured shale-gas systems. AAPG Bull., 2002, 86(11), 1921–1938.
19. Jarvie, D. M., Hill, R. J., Ruble, T. E., Pollastro, R. M. Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment. AAPG Bull., 2007, 91(4), 475–499.
http://dx.doi.org/10.1306/12190606068
20. Li, X. J., Lu, Z. G., Dong, D. Z., Cheng, K. M. Geologic controls on accumulation of shale gas in North America. Natural Gas Industry, 2009, 29(5), 27–32 (in Chinese with English abstract).
21. Hammes, U., Hamlin, H. S., Ewing, T. E. Geologic analysis of the Upper Jurassic Haynesville Shale in east Texas and west Louisiana. AAPG Bull., 2011, 95(10), 1643–1666.
http://dx.doi.org/10.1306/02141110128
22. Li, J. Y. Analysis on mineral components and frangibility of shales in Dongying depression. Acta Sedimentologica Sinica, 2013, 31(4), 616–620 (in Chinese with English abstract).
23. Zheng, H. R., Gao, B., Peng, Y. M., Nie, H. K., Yang, F. R. Sedimentary evolution and shale gas exploration direction of the Lower Silurian in Middle-Upper Yangtze area. Journal of Palaeogeography, 2013, 15(5), 645–656 (in Chinese with English abstract).
24. Guo, T. L., Zhang, H. R. Formation and enrichment mode of Jiaoshiba shale gas field, Sichuan Basin. Petrol. Explor. Develop., 2014, 41(1), 28–36 (in Chinese with English abstract).
http://dx.doi.org/10.1016/S1876-3804(14)60003-3
http://dx.doi.org/10.1021/ef400141m