Abstract Condensates and natural gases are significant resources that frequently occur together in many petroleum systems. Unraveling their origins is crucial for effective petroleum exploration and exploitation. This is often a challenge because light crudes are volatile, deficient in biomarkers, and commonly altered. The origin of condensates and natural gases in the Upper-Cretaceous Almond Formation in southwestern Wyoming was unraveled through use of improved analytical and interpretative geochemical approaches constrained by regional geologic perspectives and basin modeling. Here, an improved GC–MS/MS method allowed simultaneous determination of saturate and aromatic biomarkers, diamondoids, and organo-sulfur compounds in the whole crudes. Furthermore, basin-specific calibration of diamondoid-based thermal maturity parameters, through correlation of measured indices for diamondoids in rock extracts versus measured reflectance of vitrinite from the same rocks, allowed reliable interpretation of maturity of the most likely source rocks. Modified interpretation schemes for C7-hydrocarbon distributions, and compositions of C1-C30 alkanes, aromatic and organosulfur compounds, and δ13C1-C5 together indicated that the condensate and natural gas from each well are likely co-generated and thermogenic products from non-marine source rocks, although methane is partially biogenic. The bulk thermogenic petroleum are too mature to have originated in the rocks adjacent to the producing reservoirs. The geochemical, geologic, and modeling interpretations collectively indicate that the condensates and associated natural gases were most likely generated, expelled, and migrated from the downdip, highly mature, near-shore/transitional humic source rocks of the Almond Formation/Mesaverde Group in the Washakie Basin and Great Divide Basin at >1.3% Ro and ∼30 Ma.

中文翻译：

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美国怀俄明州西南部杏仁组储层中凝析油和天然气的成因

摘要 凝析油和天然气是许多石油系统中经常同时出现的重要资源。解开它们的起源对于有效的石油勘探和开采至关重要。这通常是一个挑战，因为轻质原油易挥发，缺乏生物标志物，并且通常会发生改变。通过使用受区域地质观点和盆地建模约束的改进的分析和解释地球化学方法，揭示了怀俄明州西南部上白垩统杏仁组中凝析油和天然气的来源。在这里，改进的 GC-MS/MS 方法允许同时测定整个原油中的饱和和芳香生物标志物、类金刚石和有机硫化合物。此外，基于金刚石的热成熟度参数的特定盆地校准，通过将岩石提取物中类金刚石的测量指数与来自相同岩石的镜质体的测量反射率相关联，可以可靠地解释最可能的烃源岩的成熟度。C7-烃分布、C1-C30烷烃、芳香族和有机硫化合物以及δ13C1-C5组成的修正解释方案表明，每口井的凝析油和天然气可能是非海洋源的联产和热成因产品岩石，尽管甲烷是部分生物成因的。大量产热石油太成熟，无法起源于生产储层附近的岩石。地球化学、地质和建模解释共同表明凝析油和伴生天然气最有可能是生成、排出、