Study On Reservoir Characteristics Of Chang 8₁ Section In Well 92 Of Honghe Oilfield

Since Honghe Oilfield was established in the Zhenjing region and put into development,the development effect of the Chang 81 formation has been very good,and many high-capacity oil-gas flows have been drilled.Furthermore,the oil production of the horizontal wells of the Honghe 92 well area is very good,which has great oil-gas exploration potential.However,some wells had poor oil production effects,and even only produced water.This shows that the reservoir heterogeneity of the research area is strong,the controlling factor of the high yield well remains unclear,and the distribution law of the favorable reservoir facies belt is difficult to determine.Therefore,there is positive significance on the further exploration and development of oil reservoirs,in order to research the controlling factor of the favorable reservoir facies belt of the Honghe 92 well area,and clarify its distribution law.Based on the core,thin section and logging data,combined with single-well and logging facies analysis,this research considers the Chang 81 formation in the research area as a front-delta deposition of delta deposits with four microfacies:subaqueous distributary channel,subaqueous crevasse splay,mouth-bar and subaqueous interdistributary embayment.The lithology of the reservoir is dominated by lithic feldspar sandstone and feldspar lithic sandstone.However,it has poor physical properties such as low porosity and extra-low permeable reservoir,in which pore sorting and connectivity is poor.Furthermore,local fissures also developed,and the pore structure was mainly a fine pore-micropore throat type,which was followed by a small pore throat type.Under the research of the relationships among lithology,porosity and permeability characteristics,electric properties and oil-bearing properties,a log interpretation model suitable for this exploration area has been established;and a comprehensive well logging interpretation has been carried out for the Chang 81 formation of all wells in the research area.It has been considered from the analysis of the main controlling factor of the reservoir that the compaction effect is the main cause of the decrease in reservoir porosity,and its dissolution is the important factor for forming the induced porosity in the research area.In summarizing the studies above,it was considered that the beneficial reservoir region are concentrated in areas of the zone of well Honghe 92 to well Honghe 190 and nearby well Honghe 190 in the research area.