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通过采集羌塘盆地中央隆起带二叠系展金组白云岩油苗及烃源岩样品,对其族组成、饱和烃、芳烃色谱—质谱以及单体碳同位素进行了研究,并进行了油源对比。研究结果表明:白云岩油苗中饱和烃含量最高,其次为非烃,芳烃和沥青质含量较低,饱芳比大于1;白云岩油苗的正构烷烃主要为前高单峰型分布特征,碳数分布范围n C_(15)~nC_(36),主峰碳为nC_(17)~nC_(20),nC_(21)-/nC_(22)+值为1.0~4.56,C_(27)-C_(28)-C_(29)规则甾烷表现为不规则的“V”型的分布并且C29甾烷占优势,升藿烷从C_(31)~C_(35)均有检出,显示出白云岩油苗的生烃母质主要来源于藻类和细菌等低等水生生物;白云岩油苗的Pr/Ph值为0.91~1.30,伽马蜡烷指数值为0.42~0.88,三芴系列化合物中以硫芴含量最高(平均67.39%)而氧芴含量(平均7.89%)较低,4-MDBT/DBT比值为0.97~4.26,(2+3)-MDBT/DBT值为0.37~1.62,表明白云岩油苗生烃母质为形成于具有一定盐度还原环境为的海相页岩;白云岩油苗的OEP值接近平衡值1,甾萜烷异构参数C_(29)ααα20S/ααα(20S+20R)、C_(29)αββ/(ααα+αββ)和C_(31)22S/(22S+22R)等接近或达到平衡值,芳烃标志物成熟度参数MPI_1、F_1和4,6/1,4-DMDBT计算出的等效镜质体反射率表明白云岩油苗为成熟原油。白云岩油苗的生物标志物和展金组泥岩具有较好对比性,反映了白云岩油苗主要来源于展金组烃源岩;其单体碳同位素与二叠系展金组烃源岩分布形式和变化趋势基本相似,但也有一定的差异,反映了其具有混合来源的特点。
By collecting the dolomite oil source and source rock samples from the Permian Zhanjin Formation in the central uplifted belt of the Qiangtang Basin, the authors investigated the carbon isotope composition, saturated hydrocarbon, aromatics, aromatics and their carbon isotopes. Compared. The results show that the content of saturated hydrocarbon in dolomite oil is the highest, the next is non-hydrocarbon, the content of aromatics and asphaltene is lower, and the saturation aromatic ratio is more than 1. The n-alkanes in dolomite oil are mainly single peak distribution and carbon The distribution of nC_ (15) ~ nC_ (36) in the number distribution ranged from nC 17 to nC 20, nC 21 - / nC 22 + 1.0-4.56, C 27 C - (28) -C (29) regular steranes showed irregular “V ” type distribution and the C29 steranes predominated, and the hopanes were detected from C 31 C 35, The dolomitic oil-derived parent material is mainly derived from lower aquatic organisms such as algae and bacteria; the Pr / Ph value of dolomite oil seedlings is 0.91-1.30, the gamma-chiral alkane index is 0.42-0.88, The highest fluorene content (average 67.39%) and the lower fluorene fluorene content (average 7.89%) were obtained with 4-MDBT / DBT ratio of 0.97 to 4.26 and (2 + 3) -MDBT / DBT of 0.37 to 1.62 The dolomitic oil-bearing parent hydrocarbon is a marine shale formed in a salinity-reducing environment. The OEP value of dolomite oil seed oil is close to the equilibrium value of 1, the isomerism parameter C 29 ααα20S / ααα (20S +20 R), C_ (29) αββ / (ααα + αββ) and C_ (31) 22S / (22S + 22R) , Aromatic marker maturity parameters MPI_1, F_1 and 4,6 / 1,4-DMDBT calculated equivalent vitrinite reflectance showed dolomite crude oil into mature seedling. The dolomite oil biomarkers and Zhanjin group mudstone are comparatively well contrasted, which shows that the dolomite oil source is mainly derived from the source rocks of the Zhanjin Formation. The carbon isotope of dolomite and the Permian Zhanjin Formation source rocks Distribution patterns and trends are similar, but there are some differences, reflecting the characteristics of its mixed source.