【摘要】 ODP1144站是南海唯一钻揭深海沉积牵引体的站位,其完整的岩芯和测井资料为开展该沉积牵引体的岩石物理模型研究提供了良好的基础。此项研究对于理解南海深海沉积物中岩性参数与弹性参数间的关系具有重要意义,并可为根据反射地震资料开展定量岩性参数预测提供依据。对现有的深海沉积物岩石物理模型包括Wood悬浮模型、等球体颗粒接触模型、Sun速度—孔隙度关系模型进行了综述。根据岩芯分析资料将1144站深海沉积物的矿物组分简化为粘土矿物、碳酸盐、陆源碎屑和硅质生物4类;其中后3种组分的弹性模量及密度值分别由其代表矿物——方解石、石英及蛋白石的理论值代替,粘土矿物组分的等效弹性模量和等效密度则分别由Voigt-Reuss-Hill平均和体积平均计算得出。将3种岩石物理模型应用于1144站,计算得出深海沉积物的纵波速度并将其与声波测井纵波速度进行比较。结果表明,Sun模型计算结果与实测结果的吻合最好,误差最小;Wood模型所得结果在浅层与实测结果较吻合,在深层与实测结果出现偏差,误差较小;而等球体颗粒接触模型计算结果整体偏高,误差较大。更多还原

【Abstract】 ODP Site 1144 is the only site for drilling into the sediment drift offshore Dongsha Islands,northern South China Sea.Integration of core and logging data from this site provides a good basis for reconstructing the rock physics model of the deep-sea sediment drift,which is of significance for understanding the relation between the lithological and elastic parameters of the deep-sea sediment and for the quantitative prediction of rock properties by reflection seismic data.The rock physical models for the deep-sea sediments are reviewed,including the Wood’s suspension model,the identical spherical grain contact model,and Sun’s velocity-porosity model for deep-sea sediments.Based on data of core smear slide analysis,the deep-sea sediments at Site 1144 are simplified as consisting of four major mineral components,which are clay minerals,which are carbonate,terrigenous clastic minerals and siliceous minerals,respectively.The elastic moduli and density of the latter three mineral components are substituted by using the corresponding values of their representative minerals,which are calcite,quartz,and opal;and the effective parameters of the clay minerals are determined by using the Voigt-Reuss-Hill and volume averaging,respectively.All the three rock physics models are applied into the deep-sea sediments at Site 1144 to estimate their P-wave velocity,which is then compared with that from the sonic logging.The result suggests that the estimated result by Sun’s model is most suitable to the measured result with the smallest error,that of Wood’s model matches the measured result in the shallow area but deviates from it with relative small error in the deep area,while that of the identical spherical grain contact model is overall higher than measured result with relative big error.更多还原