Oil and natural gas are important strategic resources in China.Deep oil and gas due to its abundant reserves but complex geological conditions,have become a hot topic of widespread concern in the oil and gas industry in recent years,and are still thriving to this day.As the first oil and gas project in Sinopec named after the"Deep Earth Project",the basic theoretical research on deep oil and gas exploration in the Shunbei oil and gas field is of great significance for China to better secure its energy rice bowl.It is selected the industrial oil and gas flow well SB47 drilling core(debris)samples collected from the control oil and gas reserves area in Shunbei area of Tarim Basin for elemental geochemical analysis.Combining well logging,mud logging,actual drilling conditions,and mineralogical and petrological data,the article explores the geochemical characteristics of Ordovician carbonate rocks in Shunbei area,as well as the mechanism of pore and fissure construction and oil and gas enrichment,in order to provide theoretical support for oil and gas exploration and development work in the area.The main results of this article are as follows:(1)The geochemical characteristics of well SB47 can effectively indicate the widespread dolomitization phenomenon of Ordovician carbonate rocks in the Shunbei area.The"mirror change"trend of Ca and Mg elements in the Ordovician carbonate rocks in the Shunbei area reflects the strength of dolomitization;The synergistic changes in Fe,Mn,Sr,Ba content and Ca,Mg content reflect the controlling effect of dolomitization on element enrichment and migration.(2)By combining logging data such as acoustic time difference,resistivity,gas logging of all hydrocarbons,and imaging logging,the geochemical characteristics of well SB47 can effectively determine the genesis and filling material types of Ordovician carbonate pores and fissures in the Shunbei area.A large acoustic time difference,low electrical resistivity,and high total hydrocarbon value in gas logging indicate the development of pores and fissures in the formation or accompanied by oil,gas,and water filling.The"mirror image"changes of Ca and Mg elements indicate the development of dolomite induced pores and fissures in the formation.An increase in the content of Si,Fe,Mn,Ti,Al,and K indicates that the pores and fissures are filled with mud.Based on the research results and the objective fact that oil and natural gas reservoirs are developed along fault zones in the Shunbei area,the mechanism of pore and fissure construction in the Ordovician carbonate rocks and the mechanism of oil and gas enrichment in the Shunbei area are proposed:On the one hand,the formation of low-pressure zones through structural fractures is conducive to the enrichment and production of oil and gas;On the other hand,structural fractures provide channels for the upward migration of surface water,the upward migration of hydrothermal fluids,and the lateral migration of deeply buried sealed fluids,leading to significant diagenesis and the development of pores and fissures near the fault zone,thereby becoming an oil and gas accumulation zone.
elemental geochemistrycarbonate rockpore and fissure identificationoil and gas enrichment mechanismShunbei areaTarim Basin
维普
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