Research On The Method For Classifying Internal Structural Units Of Distributary Channel Sandbody

The Daqing oilfield has entered into the later period of high water cut development.The remaining reserves are very difficult to reach,60%of which in the fiver sancbodies.Especially 40-50%of the main layers' reserves haven't been produced even after the polymer flooding.It is the key technique to research the inner residual oil distribution,and enhance the recovery to establish 100-year oilfield.To research the residual oil and their distribution inside the distributary channel sandbody, the reservoir character must quantitatively get the internal heterogeneity,and fulfill the structural unit model building.This paper points out the discrimination mode among four sub-facies with 24 micro-facies and establishes the internal architecture of the dividing channel sandbody.This conclusion is based on a lot of modern sediments and ancient outcrop research;guided by the detailed anatomical achievements of the modem meander belts in the Qianguoshizhong part of the Second Songhuajiang River area,which is simi far with Daqing oi ifield and combined with the lithologic and electric log characters.Aimed at the complexity of fluvial strata,such measures as well cyclical comparison,step control and geological analysis of reference beds have been applied.Moreover the paper has developed a set of methods the techniques to extract the parameters(tilt angle,dip,and dimension) controlling the formation of intra-sandbody thin interbeds.The present study has examined how thin interbeds affect the frame property and heterogeneity of individual sandbodies;revealed the permeability space distribution mode of meandering distributary channel's single side lithosomic body and straight distributary channel's aggrading lithosomic body. Through applying the distributary channel sandbody structural unit classifying and identifying method achievement,some horizontal wells have been deployed to dig the residual oil in the top of hick pay zone in the xing8-9 area,which shows better effect after they have been put into production.