【摘要】 根据天然气扩散原理、物质平衡原理和烃浓度封闭机理建立了多套源岩天然气扩散损失评价模型。选取松辽盆地北部浅层多套生物气源岩为例进行应用,结果表明,研究区4个层位现今累积生气量达385.7×1012m3,浅层生物气源岩主要生气层位中嫩江组二段生气量最大,主要生气期在嫩江组沉积末期。实际扩散气量计算表明,嫩二段实际扩散气量最大,其次为嫩一段、青山口组一段和青山口组二三段,不考虑烃浓度封闭和考虑烃浓度封闭的累积实际扩散气量分别达199.42×1012m3和105.44×1012m3。考虑烃浓度封闭时各时期的评价扩生比(实际扩散气量和生气量比值)都低于不考虑烃浓度封闭时的扩生比,后者约为前者的2～3倍。更多还原

【Abstract】 Based on principles of natural gas diffusion,mass balance and hydrocarbon concentration sealing,a model was established to assess natural gas diffusion loss from multiple source rocks.The model was applied to the shallow multiple source rocks in the north of the Songliao Basin.There are four shallow gas source rock intervals with a total accumulative gas volume generated of 387.5TCM,in which the 2nd member of the Cretaceous Nenjiang Formation (K1n2) is the largest in gas volume generated.Peak gas generation occurred at the end of the Nenjiang age.Calculation of the actual gas diffusion loss shows that K1n2 is the highest in diffusion loss,followed by the 2nd and 3rd member of the Cretaceous Qingshankou Formation (K1qn2+3),K1n1 and K1qn1.The actual cumulative gas diffusion loss with and without hydrocarbon concentration sealing effect considered are 199.42TCM and 105.44TCM,respectively.The ratio of diffusion loss to generation with hydrocarbon concentration sealing effect considered is lower than that without hydrocarbon concentration sealing effect considered.The latter is around 2-3 times as the former.更多还原