Study On Carboniferous Volcanic Reservoirs And Fluid Identification In Shixi Oilfield

In this paper,carboniferous volcanic reservoir in the Shixi oil field based on using the predecessor's research achievements,combined with well drilling,well logging,mud logging,core analysis test and oil-testing and so on,using geophysical techniques and geological methods,through various means,multidisciplinary cross analysis,to developing the study of Shixi oil field Carboniferous reservoir and fluid identification research.The carboniferous volcano rocks in Shixi oil field is divided into overflow facies and explosive facies,and overflow facies is primary.In the study area.the lithology give priority to the banded lava,agglomerate,breccia lava and dense tuff,the reservoir space types give priority to matrix dissolved pores,within the seam dissolved pore fillings,pore filling solution pores,between breccia solution pores,which belongs to fracture-pore type reservoir with medium-high porosity and low permeability and strong heterogeneity.The "four property" of the reservoir there is good correlation between property and lithology,and the agglomerate and breccia lava shows high porosity and permeability characteristics;while banded lava shows characteristics with low permeability and high property;the oil bearing grade of the study area shows high fluorescence;resistivity logging curve increases with the increase of oil content;the positive difference of natural potential indicates the existence of oil and gas;weathered clay layer natural potential indicate negative difference,the resistivity shows low baseline and oil and gas are not displayed.Identification of reservoir fluid properties by five methods.The resistivity and porosity intersection method is the best method to identify oil,water and dry layer,the coincidence rate is 80%;The normal probability distribution method and the Rt/Rxo and Rt intersection method are better for oil layer and water layer,which the coincidence rate is 63.63%;The porosity logging curve overlapping method is better for dry layer and water layer;The depth and shallow of resistivity difference method of identification.Reservoir parameter log interpretation model and fluid identification chart,we can see that the lower limit of porosity is 9%,the permeability is the lower limit of 0.2mD,the lower limit of oil saturation is about 45%.To sum up,based on the volcanic reservoirs in the study area about the physical characteristics,the relationship between the four properties,reservoir parameter model,the lower limit of physical property,the identification of single well fluid,oil wells contrast section,combined with the analysis of dynamic data,the reservoir is mainly distributed in the B section of the lithofacies.The thickness of the oil layer on the plane and the surplus recoverable reserve map can be seen that the well with the production capacity of more than 10×104t oil and gas accumulation area in the single wells are mainly in the SH1031,SH1026,SH1037,SH1106,SHW10 and so on.The wells with the production capacity distribution less than 10×104t are in SH1041,SH1020,SH1109,SH1035 and other wells within the scope of.The oil and gas are mainly concentrated in the area east of SH1034-SH1035-SH1040-SH1041,and the area of SH1040 and SH1031 wells is the best area for further excavation.SH1025 well and SH1037 wells can fill the hole.