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横波和纵波测井曲线由与岩性特性相对应的核测井响应推导来的,推导过程如下,中子—密度交会图确定岩性、孔隙度和气体含量,自然伽码测井确定泥质量含量。已发表的文献中提出了岩性—孔隙度—泥质含量和横波—纵波速度两者之间的关系。以前,岩性、孔隙度和泥质含量是由核测井确定的,而横波和纵波速度则由计算得到。这项技术有两项重要的应用,测井资料与地震资料的结合,并扩大了地层评价的能力。声波测井并不适用于所有的井,这就很需要由其它测井精确地推导出声波速度来。当能够测得声波测并资料时,把计算得到的速度与实测的声波测井速度作比较,这两者差别反映了次生孔隙度(裂缝、晶簇等等),或泥质分布状态(分散的、层状的等)。值得注意的是该技术具有与声波测井一样的精度,它能预测出四个参数,即岩性、孔隙度、泥质含量和泥质种类。由于要用四个参数来计算横波和纵波速度,仅用横波和纵波测量值评价地层变就得困难。
The S-wave and P-wave logs are derived from core log responses corresponding to lithology characteristics and are derived as follows. The neutron-density cross plot determines lithology, porosity, and gas content, and natural gamma logging determines mud mass content. The published literature has proposed the relationship between lithology, porosity, shale content and shear wave-compressional wave velocity. Previously, lithology, porosity and shale content were determined by nuclear logging, while shear and longitudinal wave velocities were calculated. There are two important applications of this technology, the combination of well data and seismic data, and the expanded ability to evaluate formations. Sonic logging is not suitable for all wells, which requires precise acoustic derivation from other logs. When measured sound waves can be measured, the calculated velocities are compared to the actual sonic logging velocities, and the differences between the two reflect the secondary porosity (cracks, clumps, etc.) or mud distribution ( Scattered, layered, etc.). It is noteworthy that this technique has the same accuracy as sonic logging and predicts four parameters, lithology, porosity, shale content, and shale type. Due to the four parameters used to calculate the S-wave and P-wave velocities, it is difficult to evaluate the formation only by the S-wave and P- wave measurements.