| Because the oil and gas accumulation conditions are complex and its reservoir forming mechanism is not clear and the main controlling factors of reservoir forming are not clear,there is an excellent exploration prospect for Qianshan in the tujiu Tuo uplift.On the basis of the predecessors' research,the organic geochemical characteristics of the source rocks,the Qianshan structure of the Shi Tuo uplift is served as the object based on the characteristics of the three large rock reservoirs,the hydrochemical properties,the chemical characteristics of the oil and gas sphere and the homogeneous temperature of the reservoir inclusions are carried out on the basis of the predecessors' research.Based on the analysis and summary of the basic data of the 427 and 428 structure of Qianshan oil and gas reservoirs,the formation mechanism of Qianshan is summarized,and the main controlling factors of the Qianshan reservoir formation are put forward,and the following understanding is obtained:1)The Qianshan hydrocarbon source rock in the shodu Tuo protruding is good,the main source rock is the three section of the Bozhong sag sand,in some areas the hydrocarbon source rocks of the Bozhong sag and the three section of the Qin Nan sag are jointly supplied by hydrocarbon source rocks,and the source rocks of the first member of the Shahejie hydrocarbon source rock have also contributed a little.The source rocks are rich in organic matter with high organic matter type,mainly type II 1and type II 2,and the maturity of source rocks is high.2)The upper Paleozoic detrital reservoir in the 428 East and 427 blocks,the 428 East and the 427 block of the Paleozoic carbonate reservoir and the Mesozoic volcanic reservoir in the 428 western region are developed in the stone mortar.The reservoir space can be divided into two types: fracture and pore.3)There are two sets of regional cap rocks in the Dongying formation and the first member of Shahejie Formation in the Paleogene Qianshan.Because of the difference of the structure between the raised body and the tilting end,the condition of the cover of the tilting end is superior to that of the Shi Jiu Tuo convex body.The regional cap rocks composed of mudstones in the lower member of the Dongying formation and the Shahe formation are important factors for the enrichment and preservation of oil and gas in Qianshan.The preservation conditions of 428E/W oilfield are good,and the preservation conditions of Shi Jiu Tuo uplift and tip end(427)are better.4)Qianshan crude oil is mainly composed of normal crude oil with a small amount of heavy oil and heavy oil.Natural gas is the associated gas of the oil layer.The salinity of water in oil field is low,and it is generally lower than the salinity of sea water.The average value is 12.05g/L.The main water forms are calcium magnesium chloride and sodium bicarbonate,which is a semi closed closed water type.427 Qianshan crude oil is mainly composed of the mixed input of the three section of the Bozhong sag and the Shishi section and the first section of the Sha 1section;the 428 structure is the mixed input of the Qinnan depression and the three section of the Bozhong sag and the mature source rock of the Shishi section,and the input of three hydrocarbon source rocks is the main input.The homogenization temperature of hydrocarbon inclusions indicates that reservoir filling time is relatively late,after 3Ma.5)The two reservoir models are estabilished: 427 Qianshan is the late accumulation type of single concave of mixed source of multiple transport,428 Qianshan is the late accumulation type of biconcave mixed source complex transporting.High quality reservoirs,strong transporting system and strong charging near oil source are the main controlling factors for hydrocarbon accumulation in Qianshan. |
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