Paleo-Oil-Reservoirs Reconstruction and Oil Correlation of Changxing Formation in the Yuanba Gas Field,Sichuan Basin
Li Pingping
Guo Xusheng
Hao Fang
Zou Huayao
Yu Xinya
Wang Guangwei
Abstract：The natural gases from the Changxing Formation (P2ch)in the Yuanba gas field are mainly derived from oil cracking, but the volume of oil-cracking-gas has not been evaluated quantitatively and the source of the paleo-oil has not been studied sys-tematically.Solid bitumen,commonly developed in the P2ch reservoirs,is a direct product of oil cracking which had finished before the regional uplift and structure deformation in the Yuanba gas field.As a result,the paleo-oil zone can be recognized by the solid bitumen.Basing on the lateral and vertical distribution of solid bitumen,seven reliable and four probable paleo-oil res-ervoirs have been found out.The paleo-oil accumulated in these reservoirs by volumetric method is about 6.14×108 t,and the corresponding oil-cracking-gas is about 3 807.08×108 m3 .The volume of oil-cracking-gas is much larger than the natural gas found in the Yuanba gas field,which indicates that the oil-cracking-gas can supply sufficient gases for the present gas reser-voirs,and further proves that the natural gases are mainly derived from oil cracking.Theδ13 C correlation of solid bitumen and kerogens from different source rocks,and total organic carbon (TOC)data show that the paleo-oil was derived from type-Ⅱsource rock mainly in the Upper Permian Wujiaping Formation,and then in the Changxing/Dalong Formation.The latter is mainly developed in Guangyuan-Nanjiang-Tongjiang area,and the hydrocarbon generated by this source rock cannot be neglec-ted during the natural gas exploration in this area.
Keywords：paleo-oil reservoiroil correlationpetroleum geologyYuanba gas fieldSichuan basin
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 452-462 )