柴达木盆地绿参1井烃源岩芳烃组成及地球化学意义

Composition Features and Geochemical Significance of Aromatic Hydrocarbons in Oil Source Rock from Well Lucan 1in Qaidam Basin

绿参1井是评价柴达木盆地第三系(E+N)咸水湖相烃源岩重要的参数井。通过对该井烃源岩抽提物芳烃色谱-质谱分析与研究,发现在已检测到的芳烃化合物中,萘系列、菲系列占优势,分别达到6.96%～46.08%和23.63%～59.64%。∑SF/∑(F+SF+OF)值随埋深增加而逐渐增大,与∑OF/∑(F+SF+OF)的变化呈镜像关系,硫芴/氧芴比值大多数大于0.7,表征向深部还原性增强的咸水湖相环境。卡达烯、惹烯、萤蒽、芘的相对含量都随深度增加而减小,说明高等植物输入量逐渐减少,水体逐渐加深。可能受沉积环境和物源的影响,萘系列、菲系列、二苯并噻吩系列的成熟度参数在深度剖面上部发生了异常变化,但当镜质体反射率Ro大于0.62%时(3695m以下),各参数都随深度增加而升高,说明该深度段热演化是主导因素,这几个参数对达到成熟阶段的咸水湖相烃源岩仍然是有效的。

Well Lucan 1was a typical parameter well of Tertiary saline lacustrine source rocks in Qaidam Basin.By analyzing the aromatic hydrocarbon GC-MS,it was found out that the compounds of naphthalene series(6.96%～46.08%) and phenanthrene series(23.63%～59.64%) were domined.The ratio of∑SF / ∑(F+SF+OF) gradually increased with the increase of depth,but in a mirror symmetry relation with the changes of∑OF / ∑(F+SF+OF),the major value of SF / OF was more than 0.7,it was represented that the reducibility of saline lacustrine was gradually enhanced to the deep bed.Meanwhile,the contents of cadalene,retene,fluoranthene and pyrene are decreased slowly,it displays a reduced input of higher plants and water is deepened.It is possibly affected by sedimentary environment and provenance,the maturity parameters(DNR-1,TNR-3,MPI-1,MDBI,etc.) reveal abnormal changes in the upper part of the formation.While for R o >0.62%,all parameters increase progressively,which indicates that these parameters are effective for mature oil source rock in saline lacustrine environment.