Study And Evaluation On The Features Of Reservior Of Chang6Section Of The Yanchang Formation In The Eastern Ansai Oilfield

This paper investigates the Chang6section of the Yanchang formation in the eastern Ansai oilfield of Ordos basin,using Multidisciplinary research as the guiding ideology,analysis core,logging,well logging date,on the basis of predecessors’s achievements,learns from previous experience of neighboring regions,combined with actual production,analysis the facies sequence profile of key wells and appraisal wells, conducts comprehensive and detailed study on the reservoir characteristics of the area,analysis the oil and gas enrichment regularity,provide the foundation for the oilfield expansion of production in this area.Studies suggest that,in the yanchang formation period of Erdos Basin,Ansai delta was in the edge of the shoreline,toward the lake basin center in chang6peride,the sediments brout into the rivers through sedimentary reformation,redistribution,formated of sorting,pure elements of sand sediment concentration,so that it hae good natural reservoir.Study area of Chang6rock type is mainly arkose and syrosem arkose, Chang6reservoir has experienced strong diagenesis in the deposition process.Compaction and cementation is one of the main reasons for porosity and permeability reduction in the sediments.The easily dissolution part of the cements was dissolved by the organic acid generated in the hydrocarbon generation process and secondary porosity was produced.so that the pore structure of the study area was improved, access to oil and gas enrichment became better.The development of the reservoir is mainly affected by the deposition and diagenesis.Reference to previous studies, the effective reservoir was classified by the reservoir properties, the microscopic pore structure parameters and the combination of pore-throat type of the reservoir,the study area belongs to the ultra-low (Class Ⅱ) and low permeability (Ⅲ class) two types of reservoirs.