Acknowledgements
Thanks to Daniel R. Viete (Australia) for assistance in editing and to Prof. Gordon S. Lister (ANU Research School of Earth Sciences). Thanks to Chief Geologist Cai Dongsheng for providing seismic sections for the Shengli, Liaohe and Bohai oilfields. Research for this paper was funded by NSFC (Nos. 40772121, 40172066 and 40314141) and the National 973 Project (2009CB219302).