川东北地区富含H2S天然气烃类与CO2碳同位素特征及其成因

虽然近年来对川东北地区富含H₂S天然气的地球化学特征、成因及来源开展了广泛研究并积累了丰富的地质、地球化学资料，但由于该地区特殊的地质环境和复杂的天然气形成演化条件，天然气成因与来源问题一直备受关注并存有争议。川东北地区天然气中H₂S含量与烃类组分组成、甲烷、乙烷和CO₂碳同位素组成之间的关系表明，飞仙关组—长兴组富含H₂S的天然气主要是原油在硫酸盐催化下裂解的产物，可能主要来源于下志留统烃源岩；高含H₂S天然气中富集重碳同位素CO₂的生成，与天然气中H₂S含量的降低有关，是H₂S溶蚀储层碳酸盐岩的结果。

Carbon Isotopic Characteristics of Hydrocarbons and CO2 of H2S-rich Natural Gases and Their Origin in Northeastern Sichuan Basin

Extensive investigation on geochemical characteristics,origin and source of H2S-rich natural gas in the northeastern Sichuan basin was processed and abundant documentation was accumulated in resent years.But a great attention has been paid and controversy existed all along on the origin and source of the natural gas in the northeastern Sichuan basin because of the specific geological environment and the complicated condition of natural gas formation and evolvement of the area.The correlations between the content of hydrogen sulphide and the components of hydrocarbons,the carbon isotopic compositions of methane,ethane and carbon dioxide indicate that the H2S-rich natural gases reservoired in the Feixianguan and Changxing Formations of the northeastern Sichuan basin are the product of oil cracking under the catalysis of sulphate and possibly derived from the Silurian source rocks;and that the generation of 13C-riched CO2 in the H2S-rich natural gas is related to the reduce of H2S content in natural gas and is the result of H2S corrosion on reservoir carbonate.