Research On The Reservior Characteristics Of Chang 6 To Chang 8 Reservior Of Weibei Oil Field

The thesis begins with the analysis of regional geology,use core casting thin section,physical property and mercury injection data to research the reservoir characteristics and it affecting factors of Chang 6 to Chang 8 oil layer group which is the main pay zone in research area.The study found that Weibei oil field Chang6 and Chang 7 reservoir are lithic arkose and feldspathic litharenite respectively.From Chang 6 to Chang 7 reservoir carbonate cement content increases and reservoir diagenesis become stronger.Chang 6 reservoirs have high facial porosity,developmental intergranular pore and high sorting coefficient which mean its physical property is good.Reservoir oil/gas enrichment degree and its physical properties have certain relevance;in order of its physical property from good to poor are oil layer,oil-water layer,oil-bearing water layer and watery layer.The study area reservoirs are mainly in early diagenesis stage B and middle diagenesis phase stage A.In the evolution process of target stratum,dissolved pore made great contribution to reservoir porosity.From Chang 6 to Chang 8 reservoir,maximum saturation of capillary pressure curve gradually reduces which means the reservoir become compacted;distribution of pore throat radius based on twin peaks,accidentally on unimodal and multimodal peaks,which also explains the reserving space is mainly composed of dissolved pore and intergranular pore.In the target stratum,Chang 6₂² heterogeneity is strongest,Chang 6₁²,Chang 7₁¹ and Chang 8₁² heterogeneity is stronger.These strata have better property and are the advantage strata in the study area.