Source rock evaluation and gas genesis of well Yican 1 in Southeastern Ordos Basin
LIU Lihong1,2, ZHOU Xingui1, ZHAO Shengmin1, DU Zhili1, TIAN Ya1, HAN Miao1
1. Oil & Gas Survey, China Geological Survey, Beijing 100083, China; 2. School of Earth and Space Sciences, Institute of Oil & Gas, Peking University, Beijing 100871, China
Abstract:A breakthrough in natural gas exploration has been made in well Yican 1 of Southeastern Ordos Basin, while the hydrocarbon potential of its source rocks hasn’t been studied. Several source rock samples collected from Shanxi and Majiagou Formation were used for relative study. The results show that the TOC content of four mudstone samples from Shanxi Formation varies from 0.54% to 2.31%, with the average content of 1.65%. (S1+S2) value varies from 0.12 mg/g to 0.46 mg/g, with the average value of 0.34 mg/g. Shanxi Formation mudstone source rocks have a high abundance of organic matter and strong hydrocarbon generation potential. The TOC content of dolomitic (calcareous) mudstones from Majiagou Formation varies from 0.09% to 0.33%, with the average content of 0.17%. (S1+S2) value varies from 0.03 mg/g to 0.17mg/g, with the average value of 0.12mg/g, which is evaluated to be poor to non-hydrocarbon source rocks. The compositions of carbon isotope in CH4 and C2H6 were compared, and the results show that well Yican 1 has the characteristic of δ13C1>δ13C2, which indicates that the natural gas is mainly coal type gas mixed by a small amount of oil type gas. And the coal type gas is mainly from the coal layers of Upper Paleozoic, whereas the oil type gas is mainly from premium marine facies source rocks of Taiyuan Formation in Upper Paleozoic. The investigation of the hydrocarbon potential and gas genesis of Ordovician Majiagou Formation is favorable to study its gas generation and formation characteristics, and it is of great significance to the study of gas field formation model, resource prospects and exploration.
刘丽红, 周新桂, 赵省民, 杜治利, 田亚, 韩淼. 鄂尔多斯盆地东南部宜参1井烃源岩评价及气源分析[J]. 中国地质调查, 2019, 6(4): 95-103.
LIU Lihong, ZHOU Xingui, ZHAO Shengmin, DU Zhili, TIAN Ya, HAN Miao. Source rock evaluation and gas genesis of well Yican 1 in Southeastern Ordos Basin. , 2019, 6(4): 95-103.