In order to improve the resolution of sequence stratigraphic analysis and accuracy of reservoir forecasting, datum cycle identification and high?frequency sequence classification are done in Guangbei 12?Xie 1 well of Bamianhe oilfield using stratigraphic datum principle proposed by Cross T A et al.

The oilbearing rock series are mostly made up of the second and third members of the Paleogene Shahejie Formation in the Bonan oil field, of which 0-9 sandstone beds in the middle and upper parts of the third member have been well documented, and may be divided into hierarchical stratigraphic baselevel cycles by using apparent resistivity curves.

The authors suggest that the stratigraphic base level is a unifying concept in analysis of continental sequences and the base level transit cycle is control of the change of accommodation as well as distribution of major sequences.

The selection of benthic macroinvertebrate-based multimetrics and preliminary establishment of biocriteria for the bioassessment of the water quality of Taihu Lake;