Calculation of organic carbon content in rocks with logging data is an important research field of source rocks evaluation. In the old △logR method, acoustic travel time is overlapped on resistivity curve with a fixed overlapping coefficient, and read the defined basement linc to calculate △logR. The process is tedious and the calculation accuracy is influenced, and subjective definition of organic carbon content leads to noticeable error of background value. The research reveals that the accuracy of organic carbon content is affected by overlapping coefficient of acoustic travel time and resistivity curve, and the reason is explained in theory. Therefore, the old model is improved and automatically selection of overlapping coefficient is realized. Organic carbon content is calculated rapidly and accurately by computer in absence of mature degree parameters and manual definition of organic carbon content background value and basement line. The application of the improved model in Hailaer Basin and Songliao Basin shows that the organic carbon content calculated by computer with the improved method has the highest correlation with the measured organic carbon content, and the method is easy to apply and has great prospect.%利用测井资料计算岩石中有机碳含量是烃源岩评价中的重要研究领域.此前的△logR方法以固定的叠合系数将声波时差和电阻率曲线叠合,确定基线位置后需读取基线值计算△logR,操作过程繁琐且影响计算精度,同时主观确定有机碳含量背景值误差较大.研究发现,△logR方法计算有机碳含量的精度受声波时差和电阻率间叠合系数影响,并从理论上解释了原因.为此,对原有模型改进,实现自动优选叠合系数,在缺少成熟度参数、无需人为确定有机碳含量背景值及基线值情况下,通过计算机快速、准确地计算有机碳含量.改进模型在海拉尔盆地及松辽盆地的应用结果表明,改进方法使计算有机碳含量与实测有机碳含量相关度达到最高,且方法简单,具有广泛的应用前景.
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