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

Fig. 6. Development of inter-salt overpressure fractures in Sha 3 Member of Dongpu sag. (a) Well Pushen 12, depth: 4284.38 m, overpressure fractures filled with oil and gas, mudstone, core photo; (b) Well Pushen 7, depth: 4309.40 m, overpressure fractures filled with calcite, mudstone, core photo; (c) Well Pushen 14, depth: 3540.60 m, overpressure fractures filled with gypsum, mudstone, core photo; (d) Well Wen 210, depth: 3906.57 m, fiber-like overpressure fractures, cast thin section; (e) Well Pushen 4, depth: 3680.45 m, dense overpressure fractures, cast thin section; (f) Well Wen 140, depth: 3307.00 m, overpressure fractures filled with hydrocarbons, cast thin section; (g) Well Hu 83, depth: 3822.70 m, overpressure fractures, scanning electron microscope; (h) Well Pushen 12, depth: 4103.20 m, overpressure fractures, fine sandstone, scanning electron microscope; (i) Well Pu 47, depth: 3045.13 m, overpressure fractures filled with hydrocarbon inclusions, fluorescence analysis.