摘要
天然气和石油的形成相比具有多种地质来源性,表现在成因类型的多样性、成气机制的多样性和成气母质赋存状态的多样性。天然气成因类型的多样性主要体现在有机来源和无机来源、单一来源和复合来源以及单一来源有机质成气演化过程的多阶段性和连续性。而成气机制的多样性主要表现为在天然气形成的不同阶段,由于气源岩母质和物理化学条件的差异,不同的成气机制(如生物化学、脱羧、缩聚、热解、裂解、力化学,以及催化和加氢等多种化学反应)发挥着不同的作用。在成气母质赋存状态的多样性中,除生物可利用物质的水溶有机质,CO2及早期形成的有机质外,分散和聚集型不溶和可溶有机质均是成气母质的主要赋存状态。在叠合盆地中,分散型可溶有机质沥青伴随盆地的再次沉降,由于其具有更好的催化条件,使石油裂解的活化能降低,更利于干酪根裂解形成气态烃。
Natural gas has multi-origin compared with oil, which can be expressed as multiple genetic types, multiple gas genetic models and multiple occurrences of gas-generating material. Multiple genetic types include organic origin and inorganic origin, single origin and multiple origins, as well as the multistage and continuous gas-generating and evolutional processes from organic matter. Multiple gas genetic models, including mainly various gas-generating mechanisms （such as biochemistry, decarboxylation, polycondensation, pyrolysis, cracking, mechanical chemistry, catalysis and hydrogenation, as well as other chemical reactions） would play different roles in different stages of gas generation, due to the differences in source rock＇s kerogen and physico-chemical conditions. Multiple occurrences of gas-generating material include the dispersed and accumulative, dissoluble and insoluble organic matters, as well as the water-soluble organic matters that can be used by organisms, CO2 and the previously formed organic matter. In superimposed basins, accompanying the resubsidence and resedimentation, the better catalytic condition of dispersed and dissoluble organic matter or asphaltene would lower the activation energy for cracking which would be favorable for cracking of kerogen into gaseous hydrocarbons.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2005年第4期393-401,共9页
Oil & Gas Geology
基金
国家重点基础研究项目(2001CB209102)
关键词
成因类型
成气机制
成气母质
可溶有机质
genetic type
genetic model
gas-generating material
dissoluble organic matter
