Comments by on [Organic Geochemistry 36, 1717–1730]

Abstract In this short communication, we reply to the comments of Worden and Cai [Worden, R.H., Cai, C.F., 2006. Geochemical characteristics of the Zhaolanzhuang sour gas accumulation and thermochemical sulfate reduction in the Jinxian Sag of Bohai Bay Basin by Zhang et al., Organic Geochemistry 36, 1717–1730, Organic Geochemistry 37] on the data and interpretation of Zhang et al. [Zhang, S.C., Zhu, G.Y., Liang, Y.B., Dai, J.X., Liang, H.B., Li, M.W., 2005. Geochemical characteristics of the Zhaolanzhuang sour gas accumulation and thermochemical sulfate reduction in the Jixian Sag of Bohai Bay Basin, Organic Geochemistry 36, 1717–1730] concerning the origin of an Eocene sour gas and high sulfur oil accumulation from the Jinxian Sag, Bohai Bay Basin, China. We provide clarifications on the current temperature range of sour gas reservoirs and comment on the reliability of δ 34 S data of various sulfur species used by Zhang et al. (2005) and Cai, C.F., Worden, R.H., Wolff, G.A.,Bottrell, S., Wang, D.L., Li, X., 2005. [Origin of sulfur rich oils and H 2 S in Tertiary lacustrine sections of the Jinxian Sag, Bohai Bay Basin, China, Applied Geochemistry 20, 1427–1444]. We conclude that there is no verified evidence in support of bacteria sulfate reduction as the dominant geochemical process that contributed to the sour gases in the Eocene reservoirs of the Jinxian Sag, but more geological and sulfur isotope data are still needed to confirm the thermochemical sulfate reduction occurring in deeper parts of the petroleum reservoirs.