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 2 Development characteristics and characterization parameters of inter-salt overpressure fractures in Sha 3 Member of Dongpu sag.

Well No. Depth/m Length/μm Opening/μm Surface density/(cm·cm-2) Pressure coefficient Formation pressure system Wen 260 3 563.10 438 15.8 0.92 1.45 Overpressure Wen 260 3 578.20 389 15.6 0.83 1.38 Overpressure Wen 243 3 742.10 320 8.3 0.42 1.30 Overpressure Wen 210 3 693.90 420 12.2 1.02 1.32 Overpressure Wen 204 3 140.00 429 13.6 0.68 1.32 Overpressure Wen 204 3 380.70 241 8.2 0.18 1.14 Weak overpressure Wen 13-358 3 382.40 303 10.1 0.93 1.28 Overpressure Wei 311 3 617.45 105 7.5 0.13 1.08 Weak overpressure Qing 65 3 824.10 521 18.6 1.85 1.46 Overpressure Pushen 7 3 524.30 480 10.2 1.23 1.41 Overpressure Pushen 4 3 982.60 679 16.3 2.12 1.56 Weak overpressure Pu 83 3 400.30 196 10.3 0.34 1.22 Overpressure Pu 141 3 674.30 82 6.8 0.11 1.06 Weak overpressure Hu 83 3 213.60 250 6.2 0.32 1.23 Overpressure Hu 7-179 3 503.20 382 9.8 0.43 1.31 Overpressure Hu 7-122 3 429.90 286 7.2 0.31 1.25 Overpressure