The gaseous organic fluid inclusion in the weathering crust at the top of Ordovician in Shengli Oilfield, was a kind of secondary inclusion. The formation temperature of the organic inclusion, got by the measurements of homogenization temperature with the brine fluid inclusions lived in the same calcite vein as the organic inclusion, was 140～160 ℃, much lower than the diagenetic temperature of the host rock. The main gaseous composition of the organic inclusion was CH 4(account of 44%～49% of the total organic gas)in addition to the inorganic gas of CO2 and H2O. The δ13C1 and δD were -29.2‰(PDB)and -128‰(SMOW)respectively, almost equal to the value of the δ13C1 and δD of the nature gas from the Carbono-Permian coal. It was proposed that the Carbono-Permian coal-formed gas migrated and accumulated in the weathering crust at top of Ordovician, which could provide essential insights and help develop new exploration strategies for gas prospecting in the region, even in North China.
Li Rongxi,Hu Ruizhong,Fang Weixuan. A PRELIMINARY STUDY ON ORGANIC INCLUSIONS OF ORDOVICIAN WEATHERING CRUST IN SHENGLI OILFIELD AND ITS SIGNIFICANCE[J]. Chinese Journal of Geology, 2005, (1): 120-124.