济阳坳陷花沟地区高含He气藏成藏分析

ACCUMULATION ANALYSIS ON A HELIUM-ENRICHED GAS RESERVOIR IN HUAGOU AREA, THE JIYANG DEPRESSION

曹忠祥 车燕 李军亮 李鸿文

CAO Zhong-xiang CHE Yan LI Jun-liang LI Hong-wen

胜利油田有限公司地质科学研究院, 山东, 东营, 257015

Research Institute of Geological Sciences, Shengli Oilfield Limited Company, Dongying, Shandong 257015, China

He气在天然气藏中的含量很低,一般小于01%.它既有重要的工业价值,又是天然气尤其是非烃类天然气成因的重要区分标志.济阳坳陷花沟地区上第三系明化镇组(Nm)发现的花501气藏,He气含量达3.08%.气藏中气体成分复杂,既有以N2和CO2气为主的非烃类气层,又有以CH4为主的气层,是一个多元复合成因的特殊气藏.δ13CCO2=-8.3‰,3He/4He=447×10-6,这些代表性指标表明N2、CO2和He等非烃气主要是幔源成因;δ13C1=-48.8‰,表明CH4气是下第三系生成的有机成因的油型气.气藏位于济阳坳陷和鲁西隆起的结合部,受高青断层这一中生界以来长期活动的深大断裂控制,与多期次岩浆活动密切相关.CH4气层与N2、CO2及He气等非烃气层是两期成藏的产物.CH4聚集成藏早,而高含He的非烃类气的聚集成藏发生在距今3Ma以内.

Helium content in natural gas reservoirs is very low,usually smaller than 0.1%.Gas helium not only has inmportant industrial values,but also is a major differential mark for the origin of natural gas especially nonhydrocarbons natural gas.In Hua-501 gas reservoir discovered in the Upper Tertiary Minghuazhen Formation(Nm)of Huagou area,the Jiyang Depression,the gas He content is up to 3.08%.The gas components of the gas reservoir is complex.It has not only nonhydrocarbons gas layers dominated by N2and CO2,but also gas layers dominated by CH4.It is a special gas reservoir of multiple and composite origins.δ13CCO2 is equal to-8.3‰,and 3He/4He is 4.47×10-6.These representative indexes reveal that N2,CO2,He and other nonhydrocarbons gases are mainly of mantle-source origins.δ13 Cl is equal to -48.8‰.This shows that gas CH4 is organic genetic oil-type gas generated in the Lower Tertiary.The gas reservoir is located in the joint of the Jiyang Depression and the Luxi Uplift.It is controlled by the Gaoqing Fault which is a deep and large rift long activated since the Mesozoic,and is closely related to muti-stage magmatic activities.CH4 gas layers and N2,CO2,He and other nonhydrocarbons gas layers are the products of two stages of accumulation.CH4 accumulated early,and the accumulation of helium-enriched nonhydrocarbons gases happened within 3Ma from now.

https://doi.org/10.11781/sysydz200104395