Sinian hydrocarbon accumulation conditions and exploration potential at the northwest margin of the Yangtze region, China

YANG Yu,WANG Zecheng,WEN Long,XIE Wuren,FU Xiaodong,LI Wenzheng

Table 1. Statistics of source rocks of Lower Cambrian Maidiping-Qiongzhusi Formation in critical wells/profiles at the northwest margin of the Yangtze craton region

Well/profile Strata Thickness/m TOC/% Number of sample s Source rock with TOC>0.5% High-quality source rock with TOC>2.0% Total thickness/m Thickness in formation/% Total thickness/m Thickness in formation/% Gaoshi-17 Qiongzhusi Formation 535 0.21-5.02 1.77 51 415 78 200 48 Maidiping Formation 130 0.66-3.40 1.52 21 130 100 40 31 Pengtan-1 Qiongzhusi Formation 478 0.32-6.56 2.05 101 418 87 289 69 Maidiping Formation 55 0.67-2.99 2.16 10 55 100 36 65 Pengshen-1 Qiongzhusi Formation 386 0.61-4.84 1.82 72 380 98 229 60 Moxi-103 Qiongzhusi Formation 203 0.26-5.80 1.59 30 122 60 45 37 Gaoke-1 Qiongzhusi Formation 204 0.14-4.43 1.21 22 140 69 21 15 Gaoshi-1 Qiongzhusi Formation 210 1.00-6.57 1.78 100 130 62 25 19 Guangtan-2 Qiongzhusi Formation 131 0.37-3.89 0.96 46 81 62 11 14 Mashen-1 Qiongzhusi Formation 358 0.40-8.95 3.35 62 238 66 130 55 Chuanshen-1 Qiongzhusi Formation 382 0.44-4.58 1.88 36 300 79 168 56 Maidiping Formation 46 1.51-2.71 2.11 2 46 100 20 44 Jiaotan-1 Qiongzhusi Formation 379 0.30-3.17 1.36 55 267 70 170 64 Tianxing-1 Qiongzhusi Formation 576 0.19-3.14 0.97 159 285 49 55 19 Mianzhu Qingping Maidiping Formation 289 0.57-25.65 10.71 26 110 38 55 19 Chenjiaba, Beichuan Maidiping Formation- Qiongzhusi Formation 400 (top not exposed) 0.84-4.89 3.08 18 >400 >250 Dongxihe, Guangyuan Qiongzhusi Formation 220 (top not exposed) 0.14-6.96 2.25 66 >195 80 Southern Shaanxi-1 Qiongzhusi Formation 282 0.01-2.50 0.81 280 185 66 59 21