【摘要】 川东北普光气田和毛坝气田高含硫化氢气藏中储层沥青显微镜下光学特征、沥青反射率值及S/C原子比均具有明显的非均质性,这说明在由古油藏原油高温热裂解形成现今气藏的过程中硫酸盐热化学还原(TSR)反应不充分。同时,飞仙关组和长兴组气藏中硫化氢相对含量与烃类气体组分及碳同位素之间没有明显的相关性,进一步说明TSR反应还没有明显波及到烃类气体。这一研究结果表明这些气藏中烃类气体组分及碳同位素没有受到TSR反应的明显影响,因而能够基本反映母源性质和演化程度,在天然气成因分析及气源对比研究时可能不需要经过人们以往所建议的大幅度校正,这对于该地区天然气藏的成因与成藏机制解剖具有重要的指导意义。更多还原

【Abstract】 Solid bitumens in the Feixianguan-Changxing reservoirs of the Puguang and Maoba gas fields with high H2S content exhibits clear heterogeneities in the optical properties,reflectance values and S/C atomic ratios,which indicates that the reservoir bitumens have only been partially affected by the thermo-chemical sulfate reduction(TSR).This evidence as well as the general lack of correlation between the chemical composition and stable carbon isotopes of the gaseous alkanes and the hydrogen sulfate content in the produced gases suggests that the gaseous alkanes in the Feixianguan-Changxing reservoirs have not been severely altered by the TSR reactions.Therefore,the chemical composition and stable carbon isotopes of these gaseous alkanes may still largely show the characteristics and thermal evolution of their source rocks.Thus,the significant calibration on these data as suggested previously appears unnecessary,which is significant for the study of gas genesis and trapping mechanism in the Puguang and Maoba gas fields.更多还原