川西北下三叠统飞仙关组泥灰岩的油气及H_2S生成模拟实验研究

Thermal Simulation Experiment on Generation of Oil-gas and H_2S from Marlite in Lower Triassic Feixianguan Formation in Northwestern Sichuan

由于川东北飞仙关组海相烃源岩成熟度高、有机质丰度低,在讨论天然气来源时多不考虑飞仙关组自身的贡献。对采自川西北剑阁县上寺下三叠统飞仙关组泥灰岩样品进行烃类生成的热压模拟实验,再现了飞仙关组烃源岩的生烃演化过程及特点,证实了四川盆地飞仙关组烃源岩在成熟程度适当的条件下具有较大的生烃潜力:泥灰岩最大产油率为142.2kg/t,生油高峰范围在Ro=0.63%～1.2%之间;累计产气率为793.9m3/t。同时,通过模拟实验证实了烃源岩在生烃过程中也能生成较高含量的H2S气体,为川东北飞仙关高含硫天然气中H2S的成因解释提供了一种新的思路。

In consideration of the characteristics of high-maturity and low organic matter abundance of Feixianguan Formation carbonate rocks found in Sichuan Basin,thermal simulation experiments has carried out on marlite samples collected from the fresh outcrops of Feixianguan Formation,Lower Triassic,at Shangsi,Jiange County,Northwest Sichuan. Not only revealed the evolving process and characteristics of hydrocarbon generation but also provided important parameter for the external estimation of Feixianguan Formation marls in Sichuan Basin. According to the results, the maximum yield ratio of oil hydrocarbon was up to 142.2kg per ton and the figure of Ro (0.63%~1.2% ) is the peak of oil generation; and the maximum yield ratio of gas hydrocarbon was up to 793.9 cubic meters per ton, and the H2S has been detected by the instrument of Agilent 6890N TCD in the gases collected from the different simulation temperature. All of these indicate that the marlite source rocks are of great hydrocarbon- generating potential and H2S under suitable maturity conditions in Sichuan Basin.