碳酸盐岩油源岩有机质丰度分级评价标准

碳酸盐岩油源岩分级评价标准研究具有重要的理论和实际意义。以塔里木、渤海湾、鄂尔多斯盆地地质参数（地层、地史、热史）为例分别计算了不同地质条件下单位面积碳酸盐岩的生油量及源岩和围岩的残留油量，进而根据物质平衡原理（排油量＝生油量－残油量）计算出排油量，以排油量为指标给出划分油源岩分级评价的标准，并计算出其对应的有机质丰度。模拟计算显示油源岩有机质丰度工业下限值TOCgy随源岩厚度的增加而减小；随成熟度的增加先减小后增加；随有机质类型（生烃潜力）的变好而减小，碳酸盐岩油源岩评价标准随地质条件的不同变化很大。建立了塔里木、渤海湾、鄂尔多斯盆地碳酸盐岩油源岩的分级评价表。经过分析综合，归纳出我国碳酸盐岩沉积区有机质类型为Ⅱ型的成熟油源岩“非、无效、差、中、好”各级对应的TOC界限值分别为“0.25、0.5、0.8、1.5”。

Standard Related to TOC Classification Evaluation of Carbonate Oil Source Rocks

The study of evaluation criterion of carbonate oil source rocks is a basic research subject which has significant influences on exploratory decision and has important theoretical and practical value. In this paper, calculations have been performed about amount of oil generation, remained oil of unit area carbonate rocks at different geologic conditions by the parameters (strata, geohistory, and thermal history) in Tarim basin, Bohai Bay basin, and Ordos basin. According to the material balance principle, oil expulsion amount has been worked out (oil expulsion amount = amount of oil generation － amount of remained oil). We regard it as an index to present the classification evaluation of oil source rocks, figure out the corresponding organic enrichment, and establish the classification evaluation tables of carbonate oil source rocks in Tarim basin, Bohai Bay basin, and Ordos basin. Based on the simulating calculation, find that TOC industrial threshold value (TOCgy ) decreases with the increasing source rocks thickness; decreases at first and then increases with the increasing maturity and decreases with the better type of organic matter. Investigations indicate that the evaluation Standard of carbonate oil source rocks have great variance with the differences of geologic conditions. Based on the analysis, we induce the threshold values, TOC are "0.25, 0.5, 0.8, 1.5", which correspond with the classes, "non, ineffective, poor, moderate and good source rocks" of mature carbonate oil source rocks whose organic matter type is Ⅱ.