莺歌海盆地泥底辟带高温热事件与储层成岩作用

为了探讨莺歌海盆地泥底辟带的高温热事件与储层成岩作用的关系,以泥底辟带的形成、演化特征为切入点,通过薄片、探针、流体组分及包裹体等资料寻找泥底辟带与底辟事件相关热流体活动存在的依据,总结分析了其形成期次,研究了与热流体活动有关的主要成岩作用。研究结果表明,泥底辟带储层中存在高温矿物组合,地层水中的钙、镁离子质量浓度和天然气中的二氧化碳体积分数均高于非泥底辟带;包裹体测试古地温高于现今温度,古地温的分布及其中的流体成分显示热液活动具有期次性;泥底辟带较非泥底辟带,地层水中二氧化碳溶蚀长石、碳酸盐等物质生成的K+、Ca2+和HCO-₃质量浓度高;长石溶孔、粒间溶孔和铸模孔等次生孔隙发育,占总孔隙比例较高,溶蚀作用较强;泥底辟带储层中的碳酸盐岩胶结物体积分数高,胶结作用相对发育;泥底辟带主要存在3期热流体活动,与之有关的影响储层质量的成岩作用主要有溶蚀作用和胶结作用。 

High-Temperature Thermal Events and Diagenesis of the Reservoir of the Diapiric Structure Zone in Yinggehai Basin

In order to explore the relationship between the high-temperature thermal events and diagenesis of the diapiric structure zone in Yinggehai Basin,the authors regard the formation and evolution of the mud diapirs in Yinggehai Basin as the cutting point,analyze the basis and periodicities of high-temperature thermal fluid activities,and study the main diagenesis related with the high-temperature thermal fluid activities using the information such as sheets,probes,the compositions of formation water and gas,inclusion and so on.It is found that there are high temperature mineral assemblages,and calcium,magnesium ions in high salinity formation water,high carbon dioxide content of natural gas are richer than in diapiric structure zone.Paleo geothermal temperature of the inclusions is higher than today,and its distribution and fluid ingredients show that hydrothermal activities have periodicity.Compared with the non-diapiric zone,there is a high ion concentration of K+,Ca2+ and HCO-₃ in formation water,which generated from dissolution of feldspar,carbonate and other substances,and a higher proportion of the secondary porosity such as feldspar dissolved pore,intergranular solution pore,mold holes and so on in the diapiric zone.The content of carbonate cement located near the diapiric area is high,in which the cementation is comparative developed.The study concludes that there are mainly three high-temperature thermal fluid activities in the mud diapirs,and the main diagenesis which related to high-temperature thermal event are dissolution and cementation.