测井资料反演南海北部陆坡渐新统的矿物组分

南海1148站是大洋钻探计划（ODP）184航次惟一钻揭渐新统的站位，但该段地层取芯收获率低，影响了根据岩芯地质和地球化学分析对地层性质的了解．利用1148A孔连续测井曲线，反演矿物组成，旨在建立渐新统地层剖面．根据岩芯分析资料，将渐新统地层简化为陆源碎屑、碳酸盐、粘土矿物和孔隙四种组分．选取与岩性和孔隙度关系密切的无铀自然伽玛、地层体积密度、光电吸收截面指数和中子孔隙度四种测井曲线，建立测井响应方程组，用线性最小二乘法求解地层组分体积含量，其结果与岩芯分析数据能较好地对比．将反演结果回代至测井响应方程组，所得模拟测井曲线与实际测井曲线能很好吻合，从一个侧面证明了根据测井曲线反演的地层组分结果的合理性．

Oligocene Mineral Component Inversion Based on Geophysical Well Logs from ODP Hole 1148A, South China Sea

Site 1148 is the only site during ODP Leg 184 driling into the deep-sea Oligocene strata affects in the South China Sea.Unfortunately,a low core recovery in the Oligocene strata affects understanding of the oligeocene strata based on geological and geochemical analyses of the core and core samples.In the paper,continuous geophysical well logs from Hole 1148A are used to inverse the mineral components and porosity.Based on the statistics of core analysis data,the Oligocene sediment is simplified as four formation components: terrigenous clastic minerals,carbonate,clay minerals,and porosity.Four well-log curves which are sensitive to lithology and/or porosity are chosen to construct the well-log response equation set,from which the volumetric percents for all the stratal components are solved with the least-squares method.The four well-log curves stand for uranium-free gamma ray,bulk density,photoelectric effect,and neutron porosity,respectively.Results matches well with the data from core analyses.The component solutions being substituted to the equation set,four modeled well logs are computed.Results are close to the corresponding measured well logs.Although a further refinement is needed,the method shows good potential for future application.