The Concentration Mechanism Of Gold In The Crude Oil From Jiyang Depression And Its Relationship With The Mantle Fluid

As the expanding of the energy,it will be an inevitable trend that the coordinated exploration of kinds of energy.The research on the noble and rare earth element(REE) in crude oil is one of the development trends of the field of high science and technology. The result has a potential value,and it will point out a new path for the coordinated exploration of energy.The Bohai Bay Basin is the largest rift basin in China.Jiyang Depression belongs to the basin.It is a complicated double-entry oil-gas area.The oil in Bohai Bay Basin has a higher content of gold.The abnormal phenomena attract lots of geologists to study it.So we choose the Jiyang Depression for our research area,and take the oil and gold in an uniform system to research by the organic and inorganic experiment,at the sake of finding a new way for the coordinated exploration of energy.The purposes of this research are:finding the function of organic matters to the concentrating,migrating and depositing of gold,finding the relation between gold and deep fault and mantle fluid,and exploring the condition and origin of gold in crude oil. To seek the fact,we collect samples around the deep fault in the depression,do a series of experiments such as,chromatogram mass spectrum,infrared spectrum and the analysis of trace element,and so on.Then by discussing the organic geochemical characteristic and distribution of the REE,based on the research of chemical property of Au and the geologic background,we do a comprehensive research,and give several conclusions such as:First,heavy oil in the shallow layers contains higher Au abundance than light oil. In Jiyang Depression most gold-rich samples are from the reservoirs in Paleogeno sand stone and granite gneiss.Second,further study indicates that gold mostly occurs in the bituminite and colloidal components of the crude oil,which are little in the crude oil.It maybe relate to the high active unpaired electron in bituminite.Third,the organic geochemistry characters of oil and racks from research area reveals that,the depositional environment of Jiyang Depression is continental-lake reduction-strong reduction deposition,and the amino acid checked in the depression, such as glycine,leucine,serine and glutamic-lysine is in favor of the solution and redeposition of gold.Forth,organic matter and the gold's activation,migration and redeposition are affinity.The gold's organic-complex compound may be an important form of gold entering the basin brine from the site of depositing.Fifth,the TanLu fracture zone cuts the upper mantle deeply,and the fluid activity is frequent.This gives a powerful support to the mantle-origin of gold.With the character of REE,we conclude that the gold in the crude oil in Jiyang Depression has two possible sources,those are mantle and hydrocarbon source rock.No matter which possibility is closely related with the mantle fluid.