中国海相层系油气成藏过程与储层沥青耦合关系:以四川盆地为例

Coupling Relationship Between Oil&Gas Accumulation Process and Reservoir Bitumen of Marine System:Taking Sichuan Basin as An Example

鄂尔多斯盆地、塔里木盆地和四川盆地三大海相盆地在古生界均不程度地发育古油藏,古油藏中储层沥青是藉以恢复和重建油藏成藏过程的重要中间产物。在对四川盆地海相层系油气成藏分类的基础上,对四川盆地碳酸盐岩储层沥青特征开展了详细的产出形态分析,总结了储层沥青产出形态与油气成藏过程的关系。四川盆地海相天然气藏储层岩类页岩、致密砂岩、碳酸盐岩均有分布,多期生烃、多期构造调整导致天然气与古油藏耦合关系复杂。总体上讲,四川盆地海相天然气气藏构建了一个原生与次生兼备、原油裂解气藏占主导、页岩气藏和致密砂岩气藏为辅的复式成藏系统。储层沥青分布特征可揭示古油藏和气藏成藏调整过程。

Ordos,Tarim and Sichuan basins are the import marine basins with abundant paleo oil reservoirs.The reservoir bitumen in paleo oil reservoirs is the intermediate product of buildup and reconstruction of the oil gas accumulation process.Based on the classification of oil gas accumulation of marine system in Sichuan Basin,the shape of carbonate reservoir bitumen has been analyzed in detail,and relationship between reservoir bitumen shape and oil gas accumulation process has been obtained.Shale,tight sand and carbonate are in a wide range,and coupling relationship between gas and paleo oil reservoirs is very complex.In a word,primary and secondary oil-cracking gas in mainshale gas,and tight gas in minor composite accumulation system is the basic characteristic of marine system in Sichuan Basin.The characteristics of bitumen can reveal the paleo oil pools and gas reservoir accumulation and adjustment process.