Organic matter sources and depositional environment analysis of continental shale oil:a case study of Paleogene sec-ond member in Funing Formation in the Huazhuang Area,Gaoyou Sag,Subei Basin
The Gaoyou Sag in the Subei Basin is rich in oil and gas resources,with high potential for ex-ploration and development.This study focuses on typical shale samples from the second member of the Funing Formation(E1f2)in the Huazhuang Area of the Gaoyou Sag.Gas chromatography-mass spec-trometry(GC-MS)was used to analyze biomarkers,X-ray diffraction(XRD)was employed for quantita-tive analysis of clay minerals,and inductively coupled plasma mass spectrometry(ICP-MS)was applied for trace element analysis to determine the organic matter sources and depositional environment.The re-sults indicate that the organic matter in the study area primarily originated from lower aquatic organisms and was deposited in a reducing environment.During the early deposition of E1f2,the climate was pre-dominantly cold and arid with low precipitation,transitioning to a warm and humid climate with increas-ing rainfall in the later stage.The early depositional environment was characterized by saline water,while salinity gradually decreased in the later stage.The formation of lakes under humid conditions was a prerequisite for oil shale deposition,while an anoxic reducing environment and saline depositional con-ditions were critical for organic matter enrichment.These findings provide valuable guidance for shale oil exploration in the Huazhuang Area of the Gaoyou Sag in the Subei Basin.
shale oilorganic matter sourcepaleoenvironmentcontinental faciessecond member of Funing FormationPaleogeneHuazhuang AreaGaoyou SagSubei Basin
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