川西坳陷孝泉—新场地区天然气成因类型与运移  

Genesis and Migration of Natural Gas from Xiaoquan-Xinchang Area, Western Sichuan Depression

作　　者：谢丹[1] 王鹏[1] 张文凯[1] 罗乃菲 周瑶[1] 李延飞[1] 

机构地区：[1]成都理工大学能源学院,四川成都610059

出　　处：《天然气技术与经济》2014年第6期16-19,77-78,共4页Natural Gas Technology and Economy

基　　金：国家自然科学基金(编号:41172119)资助

摘　　要：以孝泉—新场地区天然气组分、碳同位素及轻烃等地球化学资料为基础,对该区天然气的成因类型及运移特征进行了分析。结果表明,研究区天然气以烃类气体为主,天然气中甲烷含量平均值高于94%,以干气为主。碳同位素资料证实研究区天然气主要为热成因气,且以煤型气为主。同时,天然气碳同位素与组分资料都证实了须二段存在少量的油型气,这部分油型气主要来自须二段早期的石油裂解。研究区上三叠统须二段、须四段天然气甲烷与乙烷含量的差异,主要体现了热成熟作用对天然气组分的影响,侏罗系天然气甲烷与乙烷含量差异,则体现了天然气自中侏罗统向上侏罗统的垂向运移特征。研究区上三叠统须二段、须四段及中侏罗统天然气存在水溶相与游离相两种运移相态,中侏罗统天然气的水溶相强于须二段与须四段,上侏罗统天然气则以游离相运移为主。For natural gas produced from Xiaoquan-Xinchang area, the genesis and migration were analyzed according to some geochemical data from gas composition, carbon isotope, and light hydrocarbon. Results show that the gas in the study area is dominated by hydrocarbon gas in which methane content exceeds 94 % in average, mostly belonging to dry gas. Additionally, from some carbon- isotope data, it is pointed out the gas is mainly thermogenic gas, which is dominated by coal-formed gas. Meanwhile, the carbon-isotope and composition data all confirm that there is a little oil-formed gas found in the Xujiahe 2 Member(T3x2), which primarily came from oil spitting in the early T3x2 age. A difference between methane and ethane contents in T3x2 and Xujiahe 4 Member(T3x4)represents the effect of thermo-maturation on gas composition. However, another difference between methane and ethane contents in the Jurassic reflects that gas migrated vertically from the Middle Jurassic to the Upper Jurassic. For the gas from the T3x2 and T3x4and the Middle Jurassic, there are two migration phases of water dissolving and free ones. The dissolving phase of the Middle Jurassic gas is stronger than that for T3x2 and T3x4. And the Upper Jurassic gas is dominated by free-phase migration.

关 键 词：孝泉—新场地区 天然气成因 运移相态 碳同位素 轻烃 

分 类 号：P618.13[天文地球—矿床学]