Abstract:

Because of structure movement, lithology diversity, morphologic prominence, etc, river system capture usually appears in modern karst drainage basin, accompanied by a series of peculiar hydrogeomorphic phenomenon like divide move- damage, capturing elbow, wind gap, beheaded river and inverted river, etc. Based on 3D seismic data, by applying flattening, accurate coherence analysis and seismic imaging, the karst palaeogeomorphology and palaeodrainage pattern are described and recognized, where the peculiar hydrogeomorphic phenomenon is discovered. In the light of the theory on modern river system capture, it had been south- confluence structure in the east of Block 4, Tahe Oilfield. Then, the base level of erosion had declined in the northwest, and the north border of south-confluence drainage basin was captured by underground way, so the inverted river was builtup. The evolutionary process of karst palaeodrainage pattern and drainage basin were reappeared, supplying a signi
ficant foundation for revealing Ordovician palaeo-karst built-up regular pattern for Tahe Oilfield.

Key words: inverted river, river system capture, palaeo-karst, Ordovician, Tahe Oilfield