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油气不同组分的物理化学特性差异及地层中岩石、矿物选择性吸附造成的色层效应使油气在运移过程中其组分和同位素组成发生一定的变化 ,这为利用油气地化特征探讨油气运移提供了理论基础。利用该原理对莺琼盆地崖 13 1气藏天然气甲烷δ13C1值及凝析油族组分 (烷烃、芳烃、胶质 )、C6化合物 (正构烷烃、异构烷烃、环烷烃、芳烃 )等的相对含量和碳同位素组成进行了研究。结果表明 ,该气藏中天然气甲烷及凝析油族组分的δ13C1值由西到东呈现逐渐变轻的趋势 ;凝析油中极性相对弱的组分含量逐渐增加 ,极性相对强的组分含量逐渐降低。这表明崖13 1气藏中的油气应主要来自一号断层西侧的莺歌海盆地 ,其运移方向是由西以东。对莺琼盆地东方 1 1气藏天然气甲烷δ13C1值的研究表明 ,该气藏主要是由下覆烃源岩生成的天然气向上运移到浅层形成的 ,气藏中大部分天然气的垂向运移距离在 2km以上
The difference of physico-chemical characteristics of different oil and gas components and the color-effect caused by the selective adsorption of rocks and minerals in the formation make the composition and isotopic composition of oil and gas undergo some changes during migration. The migration provides the theoretical basis. Based on this principle, δ13C1 values of natural gas methane and condensate components (alkanes, aromatics, colloids), C6 compounds (normal paraffins, isoparaffins, naphthenes and aromatics) Relative content and carbon isotope composition were studied. The results show that δ13C1 values of natural gas methane and condensate components in gas reservoirs tend to decrease gradually from west to east. Relatively weak polar components in condensate oil gradually increase and their polarities are relatively strong The content of the ingredients gradually decreased. This indicates that the oil and gas in the Yanya 13 gas reservoir should come mainly from the Yinggehai Basin on the west side of Fault No.1 and its migration direction is from east to west. The study on the δ13C1 value of natural gas methane in Dongfang-1 gas pool in the Ying-Qiong Basin shows that the natural gas generated from the underlying source rock migrated upwards to the shallow layer, and the vertical transport of most natural gas in the gas reservoir Move more than 2km away