川东北毛坝气藏含自然硫包裹体的发现及其地质意义  

Discovery and Geological Significance of Natural Sulfur-bearing Aqueous Inclusions in the Maoba Gas Reservoir,NE-Sichuan,China

作　　者：李保华[1] 顾雪祥[2] 李黎 付绍洪[4] 徐仕海[1] 赵甫峰[1] 肖德长[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610059 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]南达科他州州立大学,南达科他州布鲁金斯57007 [4]中国科学院地球化学研究所,贵州贵阳550002

出　　处：《矿物学报》2011年第3期541-549,共9页Acta Mineralogica Sinica

基　　金：四川省教育厅自然科学基金项目;国家自然科学基金项目(批准号:40873036;40930423)

摘　　要：根据流体包裹体显微观察,均一温度、盐度测定和激光拉曼分析结果,毛坝气藏储层中存在多种类型包裹体,包括气液H2O包裹体、烃-H2O包裹体、气相烃包裹体、沥青包裹体和含自然硫气液H2O包裹体。在含自然硫气液H2O包裹体中,自然硫的特征激光拉曼峰值是151.1 cm-1、217.9 cm-1和473.3 cm-1。根据包裹体的产状、分布以及组合特征,可将本区下三叠统储层流体包裹体划分为3期。晚成岩期方解石中气液H2O包裹体均一温度变化范围为104～206℃,盐度为4.03%～19.29%NaCl。温度和盐度呈一定的负相关关系,反映随着成岩环境的埋藏深度增加,地层中孔隙水的温度趋于升高,同时烃类与流体中SO42-发生热化学还原反应(TSR),生成H2S和H2O,使盐度降低。在区域抬升降温、降压期,由于外来流体的不均匀混合,流体温度、盐度进一步降低(均一温度为31～108℃,盐度为0.35%～4.03%NaCl),在低温及硫主要以H2S形式存在的条件下,O2与H2S反应生成大量自然硫。在自然硫形成过程中,随着温度的降低,pH值趋向于升高,lg f(O2)趋向于降低。当温度为100℃时,自然硫在pH=2.9～3.4,lg f(O2)=-50.61～-49.92的环境中形成;25℃时,自然硫形成于pH=1.9～6.5,lg f(O2)=-69.30～-63.11的环境中。Based on the petrographic observation, homogenization temperature and salinity determination and Laser Rarnan analysis of fluid inclusions, various types of fluid inclusions are recognized in the Maoba gas reservoir rocks, including gas-liquid H20 inclusions, hydrocarbon-H20 inclusions, gas-phase hydrocarbon inclusions, asphalt inclu- sions and natural sulfur-bearing gas-liquid H20 inclusions. The homogenization temperatures of gas-liquid H20 inclu- sions at the late diagenetic stage range from 104°C to 206°C, and salinities vary between 4. 03% and 19. 29% NaC1. Temperatures and salinities are negatively correlated to a certain extent. The temperature of pore water in res- ervoir rocks increased with increasing buried depth in diagenetic environment, resulting in the thermoehemical sulfate reduction between hydrocarbons and SQ2, the generation of H2S and HE0, and the decrease in fluid salinity. Heter- ogeneous mixture of external fluids （ meteoric water） during the regional uplift resulted in further decrease in temper- ature （31 °C - 108°C ） and salinity （0. 35% -4. 03% NaC1） of the pore fluid. At the low temperature, 02 reacted with HES to produce natural sulfur. At the temperature around 100 ~C , natural sulfur formed under the conditions of pH = 2. 9 - 3.4 and lgf（ 02 ） = -49. 92 - -50.61, while at the temperature of 25 ~C , natural sulfur formed under the conditions of pH = 1.9 - 6. 5 and lgf（ 02 ） = -69.30 - -63.11.

关 键 词：含自然硫气液包裹体 均一温度 盐度 显微激光拉曼分析 毛坝气藏 川东北 

分 类 号：P579[天文地球—矿物学] P599[天文地球—地质学]