西湖凹陷新生代煤系烃源岩生烃动力学研究

Study on kinetics of hydrocarbon generation from Cenozoic Coal Measures of Xihu Depression

为了探究西湖凹陷平湖组煤系烃源岩生烃潜力,优选出平湖组煤系烃源岩中煤、炭质泥岩和暗色泥岩样品各2块进行热模拟试验和生烃动力学研究,并模拟了2口井的生烃史。研究表明,煤和炭质泥岩活化能分布范围在20 k J/mol之内,体现了快速生烃过程;暗色泥岩活化能分布分布范围在60 k J/mol之内,反应生烃持续时间较长;暗色泥岩有机质在距今37 Ma进入生烃门限,煤和炭质泥岩在距今30 Ma开始进入生烃期,10 Ma以后开始进入大量生烃阶段,同时在生烃热演化过程中存在明显的二次生烃作用,可以此说明该区煤系烃源岩具有较大的生烃潜力。

In order to investigate the hydrocarbon generation potential and evolution of Pinghu Formation,coal,carbonaceous shale anddark mudstone samples each two were preferred to apply thermal simulation experiment and kinetics calculation,and two wells hydrocarbongeneration history were simulated. The results demonstrated that the activation energy of coal and carbonaceous mudstone distribution waswithin 20 kJ / mol,and reflecting a rapid hydrocarbon generation. the activation energy of dark mudstone distribution was within 20 kJ / mol,and reflecting a longer hydrocarbon generation. The organic material from dark mudstone reached oil and gas threshold in 37 Ma,while coaland carbonaceous shale reached oil and gas threshold in 30 Ma. Additionally gas peak was in the last 10 Ma. Finally,the second hydrocar-bon-generation was present in thermal evolution of hydrocarbon. The coal measures in Xihu Depression have large hydrocarbon potential.