基于岩石热解参数图版的烃源岩内部排烃效率计算方法

排烃效率是研究排烃作用的关键地质参数，准确计算烃源岩排烃效率对常规和非常规油气资源评价都有重要意义。在原始生烃潜力恢复法基础上，介绍了一种热解图版法。该方法是利用氢指数与最大热解峰温关系划分有机质类型的经典图版，将有机质类型分界线和成熟度趋势线均匀插值网格化，然后将样品的氢指数和最大热解峰温数据投点于图版中，沿着类型线向左追踪至与R_o为0.2%的成熟度线交点作为生烃指数的原始值，从而计算出排烃效率。通过南襄盆地泌阳凹陷泌页1井66个烃源岩实测数据，研究了排烃效率与烃源岩有机质丰度、类型、成熟度（ATM）特性以及页岩油富集程度的关系。结果表明，与人为赋值法相比，热解图版法获得的排烃效率与有机质ATM特性更具规律性，与页岩油富集程度的吻合度较高，而且计算过程与结果不会出现负值和排烃效率大于100%的现象。该方法计算的烃源岩内部排烃效率合理可行，可作为原始生烃潜力恢复法计算排烃效率的补充。 

A calculation method for the efficiency of hydrocarbon expulsion based on parameter-diagram of source rock pyrolysis

The efficiency of hydrocarbon expulsion acts as a key geological factor for the study of hydrocarbon expulsion of conventional oil and gas, also, it indicates the enrichment degree of unconventional oil and/or gas. Based on the method of recovering the original hydrocarbon generation potential, a method according to pyrolysis chart was proposed in this paper. A classic diagram for classifying organic matter types based on hydrogen index (I_H) and maximum pyrolysis peak temperature (T_max ) was introduced in this study. The dividing line of organic matter type and the maturity trend line were evenly interpolated and gridded. The I_H and T_max data were plotted into the chart, and then traced to the left along the type line to the intersection point of maturity line R_o=0.2% as the original value of hydrocarbon generation index, thus, the hydrocarbon expulsion efficiency can be calculated. Based on the results of 66 source rock samples from the well BYHF1 of Biyang Sag, the relationship between hydrocarbon expulsion efficiency and characteristics of organic matter (ATM) was studied. In addition, the correlation between hydrocarbon expulsion efficiency and shale oil enrichment degree was studied. The results indicated that the hydrocarbon expulsion efficiency and ATM characteristics of organic matter obtained by the pyrolysis chart method were more regular than those obtained by the artificial assignment method, and it had a higher consistency with the enrichment degree of shale oil (OSI). The calculation process and results will not to be negative value or hydrocarbon expulsion efficiency greater than 100%. Therefore, it is reasonable and feasible to calculate hydrocarbon expulsion efficiency by the pyrolysis chart method, which is a complement to the original hydrocarbon generation potential recovery method.