【摘要】 莺歌海盆地异常地层压力的分布状况、异常地层压力条件下的流-岩相互作用以及其对储层成岩演化影响方面的研究尚未展开,综合应用岩石薄片鉴定、扫描电镜分析、稳定同位素分析、流体包裹体均一温度测试等技术,系统分析了莺歌海盆地LD区现今压力分布特征、超压环境下储层成岩作用特征及超压流体活动对储层成岩演化的影响.结果表明:(1)地层超压驱动深层热流体向上释放,富含碳酸盐类离子成分的热流体运移到超压顶界面附近时由于温压条件变化而重新沉淀,形成高含量的碳酸盐胶结物致密层;(2)地层超压通过抑制粘土矿物的转化来减少碳酸盐胶结物的生成和石英次生加大,使原生孔隙得以有效保存;(3)LD区块储层普遍富含CO2,在超压环境下CO2在流体中溶解度增大,会大量生成H+;另外一方面,超压增加了LD区块有机酸的释放空间和时间,促进溶蚀作用的产生.由此可知,造成研究区中深部超压储层具有较高的孔隙度的主要因素为超压抑制了胶结物的生成,其次为超压降低了机械压实作用及促进了次生孔隙的发育.更多还原

【Abstract】 As to the Yinggehai basin,there is much room for further studies on the following issues including the distribution of abnormal pressure,the interaction of fluid and rock under the condition of abnormal pressure and the effect on diagenetic evolution.A systematic analysis on the distribution of overpressure,the effect on geological fluid activities and diagenetic evolution in Yinggehai basin is carried out by means of microscopy,scanning electron microscopy,isotope analysis and fluid inclusion homogenization temperature measurement based on the previous studies.The results show follows:(1)Overpressure drives the deep thermal fluid to release up.The thermal fluid which contains carbonate minerals is driven to the top interface of the overpressure and then deposits again with the changing pressure and temperature.The thermal fluid forms tight plugged zone of carbonate cementation with high content.(2)The overpressure reduces the material sources of carbonate cements and quartz secondary enlargement by inhibiting the transformation of clay minerals,so that the primary pores can be effectively preserved.(3)The reservoirs in LD block generally contain high content of CO2.In condition of overpressure,the solubility of CO2 in thefluid increases,which generates a large number of H+.On the other hand,overpressure increases the space and time for the release of organic acids in LD block and promotes the dissolution.It is concluded that the main reason for the high porosity in middle-deep overpressure reservoir of study area is that the overpressure constrains the forming of carbonate cement,and the other reason is that the decrease of compaction and the promotion of secondary pores.更多还原