Fracture development and hydrocarbon accumulation in tight sandstone reservoirs of the Paleogene Huagang Formation in the central reversal tectonic belt of the Xihu Sag, East China Sea

ZHOU Xinhuai,XU Guosheng,CUI Hengyuan,ZHANG Wu

Table 2 Statistics of logging fracture identification in single wells in the study area.

Well Tectonic fractures Interlayer fractures Unfilled fractures Filled fractures Total Linear fracture density/ (item/m) A-1 116 180 74 222 296 0.235 A-2 16 55 20 51 71 0.147 A-3 81 129 63 147 210 0.276 A-4 115 127 31 211 242 0.443 B-1 42 93 30 105 135 0.257 B-2 117 136 28 225 253 0.398 B-3 66 98 66 98 164 0.160 C-1 41 103 75 69 144 0.130 D-2 17 106 34 89 123 0.141 D-3 4 17 9 12 21 0.111 D-4 10 8 11 7 18 0.047 D-5 22 71 41 52 93 0.208 Total 647 1123 482 1288 1770 0.215 (average)