Formation of inter-salt overpressure fractures and their significances to shale oil and gas: A case study of the third member of Paleogene Shahejie Formation in Dongpu sag, Bohai Bay Basin

LIU Weibin,ZHOU Xingui,XU Xingyou,ZHANG Shiqi

Table 1 Structural characteristics of formation pressure system of Sha 3 Member in Dongpu sag (data source: measurement).

Area Depth of transition interface between weak overpressure and overpressure/m Depth of transition interface between overpressure and strong overpressure/m Average pres- sure coefficient Structure of the pressure system Wenliu 3100 4200 1.39 Weak overpressure - overpressure - strong overpressure Puwei 3000 4100 1.23 Weak overpressure - overpressure - strong overpressure Huqing 2900 2900 1.18 Weak overpressure - overpressure