流体包裹体在碳酸盐岩储层孔隙成因及演化研究中的应用

APPLICATIONS OF FLUID INCLUSIONS IN THE STUDY OF ORIGIN AND EVOLUTION OF POROSITY IN CARBONATE RESERVOIRS

对鄂尔多斯盆地下奥陶统硕酸盐岩储层孔隙充填矿物流体包裹体的研究证实，储层孔隙演化和油气运移、聚集的各个阶段均可形成流体包裹体，而孔隙充填 物中的流体包裹体是孔隙形成环境和发育阶段以及油气生成和运聚的直接标志。通过不同产状（期次）孔隙充填矿物中流体包裹体特征的研究，可确定储层孔隙的成因，并恢复储层孔隙演化历史及其与油气生成和运聚之间的关系。研究结果表明，区内碳酸盐岩储层孔隙的发育经历了准同生期、成岩早期和中晚期、表生期、再埋藏早、中、晚期等七个演化阶段。其中表生期岩溶孔洞缝、再埋藏早－中期深部深蚀孔洞缝和再埋藏晚期的构造裂隙构成了区内储层的聚烃期油气储集空间。油气开始生成和初次运移发生在三叠纪早期（即再埋藏中期），而油气大量运聚则发生在三叠纪中－晚期和侏罗纪（再埋藏中晚期）。区内油气生成、运移和聚集与印支－燕山斯构造运动密切相关。

Based on the research on fluid inclusions at different stages of pore-filling min- erals of oil-gas carbonate reservoirs of lower Ordovician in the eastern Ordos Basin, it is proved that fluid inclusins could be formed during each stage of reservoir poros- ity evolution and oil-gas migration and accumulation,and may directly provide evi- dence for porosity formation and development stages,and for oil-gas migration and accumulation processes.Both reservoir porosity genesis and evolution and relative oil-gas migration and accumulation can be studied in detail based on the research on characteristics of fluid inclusions at different stages of pore-filling minerals in car- bonate reservoirs.Results from the studies on fluid inclusions have proved that reservoir porosity development in carbonate rocks in the study area had undergone following several diagenetic evolution stages,namely penecontemporaneous,early —meso—late diagenetic,epidiagenetic,and early—middle—late deep buried diage- netic stages.Among which,epidiagenetic karst porosity,early—middle deep buried diagenetic dissolution porosity,and late deep buried diagenetic structure cracks constitutes the mainly significant oil-gas reservoir space of hydrocarbon-accumula- tion period in study area.Oil-gas maturity and primary migration occurred during early Triassic period (i.e.middle—deep bruied diagenetic stages).However,oil-gas extensively migrated and accumulated during midde—late Triassic—Jurassic period (i.e.,middle—late deep buried diagenetic stages).Oil-gas maturity,migration and accumulation and its driving mechanism in the study area are closely associated with Yinzhi—Yanshan tectonics.