Quantitative Characterization Of Macro-heterogeneity And Its Effect On Oil Of Chang-7 Tight Reservoir In H-well Area Of Northern Shaanxi

Compared with conventional reservoirs,the heterogeneity of tight sandstone reservoirs is stronger and has a greater impact on the oil-bearing property in the reservoirs.Therefore,further study on the heterogeneity of tight sandstone reservoirs has important guiding significance for tight oil exploration.Taking chang7 tight sandstone in well H area of ordos basin as an example,this paper studies the distribution characterization of macroscopic heterogeneity of tight reservoir and its relationship with oil and gas distribution,and summarizes the influence of macroscopic heterogeneity on the distribution and enrichment law of tight oil,so as to provide guidance for the exploration of this type of tight oil.By studying the physical evolution process of each of diagenetic facies in chang7 and yanchang formation in the research area,the densification process of diagenetic facies was analyzed,and the influence of diagenetic relative reservoir heterogeneity was determined.At the same time,combined with the analysis and test results and electrical data,the various parameters affecting the reservoir heterogeneity are analyzed,and the degree of reservoir heterogeneity is analyzed.Finally,combining with the distribution rules of the reservoirs in the chang7 and yanchang formation in the study area,this paper explains the specific influence of reservoir macroscopic heterogeneity on the reservoir.The results show that among the parameters reflecting heterogeneity in the study area,the interlayer thickness,number of layers,continuity and permeability gradient have obvious control on the oil-bearing property of the reservoir.The thicker the interlayer is,the smaller the effective thickness of the oil layer is;otherwise,the larger the effective thickness is.The unsaturated oil water interface is developed when the interlayer continuity is good.When the permeability gradient is larger,the oil-bearing area and oil-bearing saturation of the reservoir with a large permeability value are larger,and the reservoir with a small permeability value is screened without oil-bearing.The thickness and continuity of the interval in the parameters characterizing the inter-layer heterogeneity have obvious influence on the oil distribution.The inter-layer heterogeneity in the study area is strong,and the oil mostly accumulates under the interval with greater thickness and better continuity,so that the oil layer on the upper part of the interval is relatively small or even without oil.For plane parameters characterizing the heterogeneity,sand body thickness,the continuity of sand body in the plane and plane distribution of sedimentary microfacies has great influence to the there is distribution,oil thickness of sand body and continuity in more good article region of zonal distribution,and parallel to the river direction and effective thickness change is small,effective thickness changes in a direction perpendicular to the river.