Time–depth relationships (TDR) are required for correlating geological information from drill sites with seismic reflection profiles. Conventional time–depth domain conversion is implemented using P-wave velocity data, derived from downhole sonic logs, calibrated with vertical seismic check-shots. During scientific ocean drilling expeditions, immediate seismic correlation is carried out using laboratory velocities measured on recovered core material. As these three velocity measurements vary significantly in signal frequency, resolution and acoustic pathways, they carry potential for substantial TDR differences and consequent miscorrelation to seismic profiles. Our analytical work uses the comprehensive scientific ocean drilling dataset to quantify these differences in core-seismic integration. TDRs are calculated and compared at sites where check-shot, sonic log, and laboratory velocity measurements cover the same depth segments of the drill hole. We find that the maximum differences between the TDRs (TDR \(diff_{max}\)) reach up to 55%, which can cause fundamental errors in the seismic correlation. No direct relationship to porosity and bulk density of the cored material is observed. Instead, higher TDR variability is found at sites with carbonate content > 70%, particularly with coarser grain texture. Sites containing primarily igneous and siliciclastic sequences show less than 10% TDR \(diff_{max}\). This semi-quantitative criterion indicates that downhole logging should be conducted during drilling expeditions, especially at sites with carbonate sequences, or low core recovery, to ensure accurate core-seismic integrations.

中文翻译：

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科学海洋钻探探险得出的时深关系的比较分析

将钻探地点的地质信息与地震反射剖面关联起来需要时间深度关系（TDR）。传统的时深域转换是使用P波速度数据实现的，该数据是从井下声波测井获得的，并用垂直地震检查镜头进行了校准。在科学的海洋钻探探险期间，使用对回收的岩心材料测得的实验室速度来进行即时地震关联。由于这三个速度测量在信号频率，分辨率和声波路径上有显着变化，因此它们具有潜在的TDR差异以及与地震剖面的不相关性。我们的分析工作使用全面的科学海洋钻探数据集来量化岩心-地震整合中的这些差异。在检查点，声波测井和实验室速度测量值覆盖钻孔的相同深度段的站点上计算和比较TDR。我们发现TDR之间的最大差异（TDR\（diff_ {max} \））最高可达55％，这可能会导致地震相关性出现基本误差。没有观察到与有芯材料的孔隙率和堆积密度直接相关。取而代之的是，在碳酸盐含量> 70％的部位发现更高的TDR变异性，尤其是具有较粗晶粒纹理的部位。主要包含火成岩和硅质碎屑序列的站点显示不到10％的TDR \（diff_ {max} \）。该半定量标准表明，在钻探探险期间应进行井下测井，尤其是在碳酸盐岩层序或岩心采收率低的地点，以确保准确的岩心地震整合。