济阳坳陷热液流体活动特征及其油气地质意义

Characteristics of hydrothermal fluid activity and its petroleum geological significance in Jiyang Depression

针对济阳坳陷中热液流体活动标志及油气地质意义不明确的问题,综合运用薄片、微量元素、稀土元素、碳氧同位素和压汞等资料,明确了济阳坳陷中热液流体活动发育标志及其油气地质意义。研究结果表明:济阳坳陷中热液流体活动发育,指示标志包括多种热液矿物和热碎裂结构,砂岩中绿泥石和伊利石含量异常高,黄铁矿的Co/Ni比大于1,稀土元素表现出明显的Eu正异常,砂岩中铁白云石胶结物的碳氧同位素数据投影在低温热液成因区。热液流体活动有利于储层中次生孔隙的形成,同时也有利于裂缝型储层和成岩圈闭的形成。以上成果不仅可以丰富和完善对含油气盆地中热液流体活动特征的认识,而且对于热液改造型隐蔽油气藏的勘探具有一定的指导意义。

Aiming at the problem that hydrothermal fluid activity signs and hydrocarbon geological significance are not clear in Jiyang Depression,based on the data of thin section,trace element,rare earth element,carbon and oxygen isotopes,and mercury injection test,the author analyzed the development marker of the hydrothermal fluid activity and its geological significance in Jiyang Depression.The results show that hydrothermal fluid activity is developed in Jiyang Depression,a variety of hydrothermal minerals and thermal cataclastic structures are found,the contents of chlorite and illite in sandstones are unusually high,the Co/Ni ratio of pyrite is greater than 1,rare earth elements show obvious Eu positive anomaly,the carbon and oxygen isotope data of the ferrite cement in the sandstone are projected in the epithermal zone.Hydrothermal fluid activity is conducive to forming secondary pores in the reservoir and forming fractured reservoirs and diagenetic traps.These results can enrich and improve the understanding of hydrothermal fluid activity characteristics in petroliferous basins and have a certain guiding significance for the exploration of hydrothermally modified subtle reservoirs.