Sedimentary Evolution in the Framework of High Resolution Sequences of Dongying Formation and Prediction of Favorable Zones in Qingshui Sag, Liaohe

Key words: 
• Qingshui Sag /
• Dongying Formation /
• highresolution sequence stratigraphy /
• sedimentary system /
• favorable zones

Abstract: On the principle of baselevel cycling and through the integrated analysis of cores, well logs and 3D seismic data, we divided the Dongying Formation (Ed) in Qingshui Depression into 4 thirdorder sequences, namely Lower Ed3, Upper Ed3, Ed2 and Ed1, and recognized three types of sedimentary systems, i.e. the semideep lacustrine subaqueous fan system, the shallow lacustrinedelta system and the alluvialfloodplain system. On the basis of the sequence identification and the sedimentary system recognition, we then studied the configuration of sedimentary systems and the development of reservoir sandbodies in the sequential context. Finally, after evaluating the oilgeneration, preservation and seal conditions, we concluded that, Lower Ed3 and Upper Ed3 sequences are the most favorable sections vertically, and exploration targets are subwater fans and delta front sands, mainly channel sands, mouth bars and sheet sands.