The Enrichment Mechanism Of Gold In The Crude Oil In Jiyang Depression

Oil is the most important energy in the world. The research of precious metal which is enriched in crude oil has the potential utilization value at the same time it is compatible with the current high-tech field .Gold contents in crude oils and source rocks samples is very high in Shengli Oilfield .So we choose the Jiyang Depression for our research area,synthetical analyse and evaluate the source, exist state and economy value of precious metals in Jiyang Depression .The purposes of this research are: finding the function of organic matters to the enrichment, migrating and depositing of gold, finding the relation between gold and mantle fluid.To seek the fact, 48 samples were collected .we collect crude oil and source rock samples which is enriched in precious metals do a series of experiments such as, chloroform extraction, separation of group composition, gas chromatographic, gas chromatography-mass spectrometry and inductive coupling plasma mass spectrometry and so on. The abundance characteristice and exist state of precious metals in crude oil were got by the experience of separation of group composition. Explore the source and the pattern of migration by the degree change of crude oil and source rock.Analyze the crude oil and source rock samples by geochemical methods.The results indicate that the gold accumulation in Jiyang Depression is closely related to the mantle fluids and sulfur polycyclic aromatic hydrobarbon in oil and source rocks. The analysis of ICP-MS indicates that the gold contents of the samples near the deep faults are higher compared with samples far from the deep faults, together with corresponding geological, we can conclude that the gold enrichment was influenced by Tanlu fault. At the same time, the activity of mantle fluids is frequent and promotes the dissolution and migration of gold. All source rocks should have similar gold contents if they are from the same sedimentation stage. Therefore, gold elements could come from the mantle fluids because they enriched near the faults.