摘要
通过莺歌海盆地的烃源岩、温压特征及底辟活动规律研究,对水溶气出溶成藏的条件进行分析,并根据天然气的地球化学和同位素特征,研究水溶气出溶成藏的证据.结果表明：莺歌海盆地烃源岩气源供给充足,中浅层和深层天然气溶解度差异大,底辟构造周期性开启提供了流体向上运移的通道,具备水溶气运移出溶成藏的理想条件;在中浅层1.5～2.0 km深度范围内,天然气干燥系数较大、异构烷烃与正构烷烃含量比值大、甲烷碳同位素组成偏重、芳烃富集,表明水溶气出溶成藏是中浅层气藏形成的重要机制之一;在底辟活动期间,深层溶解大量天然气的水沿着底辟形成的断裂运移至中浅层,由于温压大幅度降低,天然气从水中释放,进入到底辟上部或附近的圈闭中形成气藏.
Based on geochemical parameters and carbon isotope values of the natural gas, the exsolution and accumulationconditions of the water-soluble gas reservoir in Yinggehai Basin were analyzed through systematic analyses of the characteris-tics of the source rock, the temperature-pressure relationship and the diapiric action. The results show that Yinggehai Basinhas perfect conditions for water-soluble gas accumulation, including a sufficient gas source, a very wide range of solubilitybetween the mid-shallow layer and the deep layer, and a fluid pathway by periodic diapiric activities. In the mid-shallow lay-er （depth ranging from 1. 5 km to 2. 0 km）, the natural gas reservoir is characterized by high dry coefficients, large contentratios of isoalkane and normal paraffin hydrocarbons, heavier methane carbon isotope δ13 C, and abundant aromatic hydrocar-bons. The exsolution and accumulation of water-soluble gas is one of the crucial mechanisms of gas reservoir formation in themid-shallow layer in Yinggehai Basin. During diapiric activities, water dissolves a great deal of gas which migrates to themid-shallow layer through faults formed by diapirs. The gas is released from water due to temperature and pressure drop, andenters into the traps in or near diapir belts to form gas reservoir.
出处
《中国石油大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2014年第1期32-39,共8页
Journal of China University of Petroleum(Edition of Natural Science)
基金
'十二五'国家科技重大专项(2011ZX05023-004-008)
关键词
水溶气
出溶
莺歌海盆地
地球化学特征
成藏
water-soluble gas
exsolution
Yinggehai Basin
geochemical characteristics
accumulation
