Accumulation Distribution Characteristics And Controlling Factors Of Chang 6 Reservoir Of Yanchang Formation In Panlong Oilfield

Based on a comprehensive understanding of the basic petroleum geological conditions in the Chang 6 reservoir of the Panlong Oilfield,Combining data from core analysis,comprehensive logging,laboratory analysis,and oil testing,the Reservoir type,distribution characteristics and controlling factors of the Chang 6 reservoirs in the study area were studied from the conditions of the oil source,sand body distribution,structural characteristics,reservoir characteristics,and sdimentary microfacies characteristics.The Chang 6 reservoir is a lithologic reservoir with no obvious oil-water interface,no pure oil layer,and most oil production layers are the same layer of oil and water.There are 4sand groups in Chang 61-Chang 64,of which Chang 61 and Chang 62 are more developed.The thickness of the downward oil layer gradually becomes thinner,and the oil distribution area gradually decreases.The distribution of oil layer in the longitudinal direction is characterized by thin layer and many layers,while the horizontal feature is change rapidly,poor connectivity and mostly isolated lens body distribution.The Chang 6 sedimentary microfacies are mainly Underwater distributary channel at delta front and the inter-distributary bay.The distribution of the oil layer mainly appeared in the main sand body of the river distributed in the direction of the northeast-southwest.Reservoir permeability,interlayer and plane properties mainly affect the distribution of oil layers,Simultaneously,the combination of reservoir cover and lithology has an important role in controlling the distribution of oil and water;The vertical,lateral migration and accumulation of oil and gas are separated and blocked by interlayer separation,when the physical properties of the plane channel sand body are good,the oiliness is generally better.In the study area,the oil content of the Chang 61 and Chang 62 is better than that of the Chang 63 and Chang 64;When the reservoir rhythm distribution is obvious,the middle and lower parts of the positive rhythm and the middle and upper part of the anti-rhythm are generally developed.