Reservoir Quality Difference Research And Development Effect Analysis Of Tight Sandstone On Chang6 Oil Formation In Hua Qing Oilfield

Chang 6 oil formation of Yanchang Formation of Huaqing oilfield in Ordos Basin has rich oil and gas resources,developing typical tight sandstone reservoir,which has great potential for development.But the strong heterogeneity within the reservoir leads to the problems of worse waterflood effect and intensifiedly invalid injection.Therefore,the key to improve the development effect is to study the quality difference of the reservoir carefully.Taking Yuan284 Block of Huaqing Oilfield as an example,which develops Chang 6₃sand group,this paper aims to analyse pore structure feature and its reservoir quality difference mechanism,then characterizes distribution of the reservoir quality difference and analyses effects of the reservoir quality difference on oilfield development result.This goal is accomplished by comprehensive analysis of core,logging and dynamic data.This research obtains many achievements and understandings as follows.(1)This research makes pore-throat configurations and reservoir quality levels about tight sandstone of the study area clearly,and then reservoir quality is classified into four types.I type of reservoir has intergranular pore and wide sheet-like throat,and its permeability is more than 0.30×10^-3?m².?type of reservoir has intragranular-intergranular pore and wide sheet-like throat,and its permeability is between 0.10×10^-3?m²to 0.30×10^-3?m².?type of reservoir has intragranular-intergranular pore and narrow sheet-like throat,and its permeability is between 0.05×10^-3?m²to 0.10×10^-3?m².?type of reservoir has micropore group-intragranular pore and extremely narrow sheet-like throat,micropore group and extremely narrow sheet-like throat,and its permeability is less than 0.05×10^-3?m².(2)This research clarifies mechanism about the study area reservoir's quality difference.Compaction and calcareous cementation are the main diagenesis,determining final physical property of the target region objective reservoir,which are controlled by the reservoir sedimentary components and fabric,and sedimentary components and fabric are controlled by sedimentary microfacies.(3)The study establishes spatial distribution style about the reservoir quality difference of the target area.Vertically,?and?type of reservoir relatively centralize centre of the sand,but the top and bottom of sand,which has finer granularity or relatively near the adjoining mudstone,usually form calcareous cement,so it usually form?and?type of reservoir.In plane,due to development of different sedimentary microfacies,reservoir quality of lobate group deteriorates from interior to edge part.(4)The research makes the influence about distribution of reservoir quality difference on oilfield development result clearly.Vertically,main water intake layer of water injection wells and main fluid producing layer of production wells mostly focus on the relative high-grade reservoir.In plane,injected water firstly displace towards the relative high-grade reservoir,so production wells from other directions can only receive the slow waterflood susceptibility,so it leads to obvious production capacity difference of production well.