Evaluation Of Oil Displacement Effect By CO₂ Flooding Of FUYANF Reservoirs In DAQING Oilfield

At present,one of the important objects of oil and gas exploration and development is extra-low permeability reservoir with low-permeability,poor physical property and low production capacity,which is also one of the main types in Fuyang oil layer of Daqing Peripheral Oilfields and usually exploit by CO₂ flooding or other gas flooding.A set of mature oilfield development evaluation standard have been formed in Daqing oilfield for water flooding reservoir,but evaluation index is relatively simple for CO₂ flooding,and there is not a set of molding method which is used to evaluate oil development effect by CO₂ flooding.Therefore,It is helpful for evaluation of early development and the later period of the development adjustment to establish a set of evaluation system of CO₂ flooding for Fuyang reservoir of Peripheral low permeability Oilfield of Daqing.This paper has confirmed the weight of the evaluation index by table of orthogonal test and grey relational analysis method on the basis of the research of numerical simulation,which is based on geological characteristics of typical block by CO₂ flooding of extra low permeability Fu Yang reservoir of Daqing peripheral oil fields.Combined with the evaluation index,evaluation criteria and evaluation methods and field development experience of low permeability reservoir by water flooding,a set of evaluation method that is used of development effect analysis for Fu Yang reservoirs of Daqing Peripheral Oilfield by CO₂ flooding has been established by fuzzy evaluation system and membership function.The evaluation method of development effect has been applied in three typical block which development time is longer in Daqing Peripheral Oilfield Fu Yang reservoir by CO₂ flooding.The results show that S101 test block displacement effect is best and F48 pilot test displacement effect is better,F48 expansion test displacement effect is common.This method can be used in development effect evaluation of Fu Yang reservoir of CO₂ flooding in Daqing Peripheral Oilfield,which has theoretical guiding significance for ultra low permeability block development effect evaluation of Daqing Peripheral Oilfield.