渤海湾盆地东营凹陷示烃成岩作用及其演化特征*

富含有机酸的烃类流体在由泥质烃源岩进入储集层后将发生一系列的示烃成岩反应。研究发现有6类成岩现象与烃类活动密切相关,即酸性烃类流体的溶蚀作用、蒙脱石脱水与伊利石化、碳酸盐矿物的铁离子浸染、沥青—铁核的轨迹、自生高岭石的形成以及耗水、底积碳酸盐胶结层的隔层分布。这些特殊的成岩现象是含油气盆地内特有的标识,对指示油气初次侵入程度、运移的方向与轨迹、工业聚集度以及最终成藏场所的确定具有重要的参考价值。基于所发现的示烃成岩矿物而建立的“含油气盆地碎屑岩成岩演化规律”,对胜利油区复杂油气藏勘探起到了指导作用,也可为今后含油气区储集层的有效性确定提供借鉴。

Diagenesis and evolution characteristics of hydrocarbon-traced minerals in Dongying sag,Bohai Bay Basin

A series of diagenetic reaction will occur after hydrocarbon-bearing fluid,which is rich in organic acids,entered the reservoir from source rock. The study indicates that six diagenetic phenomena were closely related to hydrocarbon activities,namely dissolution of acidic hydrocarbon fluid,montmorillonite dehydration and illitization,iron ion impregnation of carbonate mineral,track of asphalt and iron-concretion,the formation of authigenic kaolinite and water consumption,bottom interlayer distribution of carbonate cementation layer. These special diagenetic phenomena were characteristic identification signals in petroleum-bearing basin which indicate the degree of first invasion,the direction and trajectory of hydrocarbon migration,and the industrial concentration. Those have great reference value for finally confirming the accumulation place. Based on the hydrocarbon-traced diagenetic minerals in petroleum-bearing basin,a clastic diagenetic evolution pattern was established. The evolution pattern can guide the exploration of complicated reservoirs in Shengli oil-field,and can also provide reference for determining the effectiveness of reservoirs in the future.