普光气田高密度甲烷包裹类型与油气演化和H2S成因  

Occurrence and Genesis of Multiple Types of High Density Methane Inclusions in Puguang Gas Field

作　　者：刘德汉[1] 肖贤明[1] 田辉[1] 戴金星 王一刚 杨春 胡安平 米敬奎 

机构地区：[1]中国科学院广州地球化学研究所有机地球化学国家重点实验室,广东广州510640 [2]中国石油石油勘探开发研究院,北京830000 [3]中国石油四川分公司,四川成都610081

出　　处：《地球科学期刊（中英文版）》2013年第1期1-10,共10页Scientific Journal of Earth Science

基　　金：本文得到国家科技重大专项（2011ZX05008-002）,中科院知识创新工程项目（KZCX2-YwQ05-03,KZCX2-YW-05-06）,国家自然科学基金（41072095）,中国科学院广州地球化学研究所三期创新项目（批准号：5407341801）联合资助.

摘　　要：根据矿物包裹体的显微激光拉曼光谱分析，先后在普光气田储层中发现3种类型的高密度甲烷包裹体。其中第1类产于气藏碳酸盐储层的方解石矿物中高密度甲烷包裹体的拉曼位移在2910-2912cm^-1特征峰的强度很大，同时也含比较明显H2S的特征峰以及微量C02峰，但是不含固体焦沥青峰；第2类为产于碳酸盐储层早期方解石矿物中的高密度甲烷包裹体，在拉曼谱图中除了富含高密度的甲烷特征峰以外，明显含固体焦沥青D峰和G峰，但是基本不含H2S峰；第3类是产于上部碎屑岩储层石英中的高密度甲炕包裹体，在拉曼谱图中存在有焦沥青峰或不含焦沥青峰的高密度甲炕包裹体。但是这类包裹体都基本不含HzS的特征峰。研究结果表明：上述第1类高密度甲烷包裹体捕获于油藏高温极端裂解阶段，储层中既有大量甲烷生成，也伴随有硫酸盐热化学反应（TSR）含H2S的流体，被同期方解石矿物所捕获的信息；第2类为油藏阶段方解石矿物捕获的石油包裹体，经后期高温极端裂解作用形成的高密度甲烷包裹体，由于石油包裹体裂解产物可能保留在未破裂的包裹体封闭体系中，因此拉曼谱图中除了富含高密度甲烷以外，也含原油裂解残余的焦沥青“D”峰，和“G”峰，但是基本不含与储层流体“TSR”作用有关的H2S特征峰；第3类为赋存于上部非碳酸盐地层石英中都不合H2S的高密度甲炕包裹体，反映了气藏上部存在与油裂解气作用成因有关的高密度甲烷流体运聚的重要信息，但不存在与“TSR”作用有关的地质地球化学环境。方解石和石英中高密度甲烷包裹体拉曼光谱中焦沥青“D”和“G”峰的位移和比值，分别与储层空隙中焦沥青的“D”和“G”十分相似，用研究的拉曼反射率方程计算了与镜质组反射率对应的拉曼反射率（RMRo％）分别为3．2-3．6％和2．2-2．6�Based on micro-Raman spectroscopic analysis of a great quantity of inclusions, three types of high density methane inclusions were identified in the petroleum reservoir of Puguang gas field. Type I inclusions occur in calcite minerals of carbonate rocks in gas reservoir, and their Raman spectra show 2910-2912cm1 peaks characteristic of high density methane and apparent peaks characteristic of H2S as well as peaks characteristic of trace amount of CO2, but do not show peaks characteristic of solid pyrobitumen; Type II inclusions occur in early-formed calcite minerals in carbonate reservoir, and their Raman spectra not only show peaks characteristic of high density methane, but also show D and G peaks characteristic of solid pyrobitumen, basically with no peaks for H2S; Type III inclusions are high density methane inclusions trapped in quartz minerals in the upper clastic reservoir, their Raman spectra may or may not show peaks characteristic of pyrobitumen, but basically exhibiting no peaks characteristic of H2S. It can be concluded that Type I high density methane inclusions may by formed at the stage of high temperature cracking of oil reservoir, since in well cemented reservoirs, not only a great amount of methane would be generated but also H2S-bearing fluid would be formed as a result ofthermalchemical sulphate reduction （TSR）, and they will be both trapped by calcite minerals formed at the same stage; Type II inclusions are high density methane inclusions, resulted from high temperature cracking of oil inclusions trapped in calcite at the stage of petroleum reservoir formation. Since products due to cracking of oil inclusions could be preserved in the closed system of untracked inclusions, their Raman spectra would show Peak D and Peak G characteristic of relic pyrobittunen resulted from cracking, in addition to peaks of high density methane, but basically contain no peaks of H2S resulted from TSR processes related to fluids in the reservoir. Type III methane inclusions demonstrate that oil cracking may

关 键 词：高密度甲烷包裹体 显徽激光拉曼光谱分析 原油高温裂解作用 普光气田 

分 类 号：P618.510.4[天文地球—矿床学]