评价干酪根生油气量的一种新方法

A NEW METHOD FOR EVALUATING HYDROCARBON GENERATED FROM KEROGEN

用压力差示扫描量热仪(PDSC)研究了我国茂名、抚顺、黄县油页岩干酪根(Ⅰ,Ⅱ型)及黄县褐煤(Ⅲ型)在热降解时的化学结构变化。试验中发现,在氧气压力为1.5MPa时,各种干酪根的PDSC图谱都出现两个放热峰。由放热峰的积分面积可计算出各干酪根的表观芳碳率。由此提出了计算干酪根生油、气量的新方法,可根据干酪根在热降解时的“残留脂碳率”与“干酪根质量系数”的演化图计算出生油岩的生油量和生气量,也可以根据干酪根热降解时的脂构碳、芳构碳的分布计算干酪根生油、气量的简化模式,由脂构碳的热解动力学参数计算出生油岩的油气生成量。

Four immature kerogens of different types from Fushun(FK), Maoming(MK), Huangxian(HSK) oil shales and Huangxian lignite(HLK) were selected as samples in the study on their chemical structures by using Pressure Differential Scanning Calorimetry(PDSC). The test shows that there are two exothermic peaks in the PDSC spectrum for each kerogen under 1,5 MPa of oxygen pressure. According to the integrated intensity of the peaks,the apparent aromaticity of kerogen may be determined. Consequently, a new method based on the change of kerogen aromaticity were suggested, and the calculation could be made in two different ways. Based on the apparent aromaticity data, an evolution diagram relating the retained aliphaticity factor of kerogen was plotted, by which the amount of hydrocarbon genetated from source rock can be estimated. According to the aromatic and aliphatic carbon distribution during the kerogen thermal-degradation, it was suggested that only the consumption of aliphatic carbon is accounted for in measuring the yields of hydrocarbon. The kinetic equations of aliphatic fraction of Maoming and Huangxian kerogens during pyrolysis were studied and the kinetic parameters were used in these in equations for calculating the amount of hydrocarbon generated from the source rock.