Characteristics Of Hydrocarbon Fluid Inclusions And Analysis Of Reservoir Formation In Ordovician Reservoir Of TaZhong 45 Borefild

Well TaZhong 45 is a hige-yield well in the TaZhong No.1.break belt,its hydrocarbon fluid inclusions of Ordovician reservoir can divided into four periods. PeriodⅠ,inclusions are dark liquid hydrocarbon inclusions,mainly distribute in the early calcite veins and adglutinates; PeriodⅡ,inclusions are colourless liquid hydrocarbon inclusions,have yellow-white and white fluorescences,mainly distribute in early calcite adglutinates of corroded hollow and calcite briquettes in bilateral of sature,and in well 45 of TaZhong distribute along the fluorite growth striations; PeriodⅢ,inclusions are grey gas-liquid hydrocarbon inclusions and gas hydrocarbon inclusions,have stong white blue fluorescence,mainly distribute in the healed fractures;PeriodⅣ,inclusions are gas-liquid and gas hydrocaibon inclusions and asphalt inclusions,liquid phase have moderate brown fluorescence,mainly distribute along tensional fractures.Reservoir rock characteristics of Well Tazhong 45 hydrocarbon inclusions: type of reservoir is fracture-pore,the diagenesis included cementation packing action,metasomatic reaction,dissolution and cataclasis. Most hydrocarbon inclusions in well TaZhong 45 is liquid hydrocarbon inclusions,also there is a small amount of liquid hydrocarbon inclusions,gaseous hydrocarbon inclusions and minute quantity of asphaltic inclusions. Most hydrocarbon inclusions present white-blue and white-yellow,small amount present reddish-brown by UV fluorescence.According the Oxygen Isotopes analysis,Strontium Isotopes analysis,Quantitative Grain Fluorescence analysis,Confocal Microscopy analysis,Laser Raman analysis,GC chromatographic analysis,and the Geochronology study,combined with the field observation,Petrography observation and Microthermometry experiment of the well TaZhong 45 hydrocarbon inclusions,a comprehensive analysis obtained: the chron of periodⅡinclusions filling in is about 22.9Ma ago; the oil of the periodⅠin the fluorite of hydrocarbon inclusions major origined from O2+3 mother rocks; PeriodⅡof the hydrocarbon inclusions from the Cambrian-Lower Ordovician source rocks; theⅡandⅢperiod of hydrocarbon fluid inclusions play a major role Accumulation of oil and gas. Combined with the thermal evolution analysis,accounting that three periods of the hydrocarbon inclusions correspond to three phases of oil and gas breakthrough: mature oil and gas injection of the periodⅡat Neo-Hercynian; high mature condensate gas injection at Early Himalayan and mature oil injection at Neo-Himalaya.