Study On Enhanced Oil Recovery Technology Of Chemical Flooding Quasi-Equilibrium Flooding In JZ Oilfield

Bohai JZ oilfield chemical flooding has large-scale industrial application,but at a certain stage of mining,because well pattern adjustment of reservoir remaining oil distribution is more dispersed,and in the later of the injection Wells to get together after the well caused by the water transfer interference phenomenon makes the reservoir sweep efficiency of the whole is not high,which reduces the efficiency of polymer flooding,and is different from the mining land,offshore oil field is limited by platform operation can only use general injection general production mode of operation,so we can not on the horizon of finely divided into liquid quantity,makes the high permeable zone first breakthrough and invalid water cycle,and the use of the low permeability layer.Therefore,the sweep efficiency of displacement fluid can only be improved by adjusting well pattern and injection parameters.As much as possible to achieve in the polymer flooding stage to make the balance of the horizon and the upward forward,so as to carry out chemical flooding quasi equilibrium displacement research,this article is based on reservoir engineering theory foundation and seepage mechanics,combined with the polymer flow characteristics,through the water flooding displacement equilibrium concept built on the basis of the theory of mathematical model,this paper derived the equilibrium displacement of polymer flooding plane constraint equation,verify the feasibility plane equilibrium displacement,and put forward the revised thayer index as evaluation index of its equilibrium level,through the pattern model experiment of the late for validation.In this paper,through a large number of indoor static experiments of different polymer solution,polymer microspheres and gel formula,performance tests the strength and through the single tube small core experiment study of prescription compatibility with reservoir,drag coefficient and residual resistance coefficient was determined by different poor injection system,provide the basis for reservoir adaptability after evaluation.Based on injection experiment scheme,according to different well spacing pattern,different row spacing deployment and interference of water,under the condition of different ratio of polymer injection water in large flat-panel physical model experiment,well selected five network optimal well spacing pattern,and well spacing adjustment based on this research,think the longitudinal spacing adjustment based on permeable zone delamination can improve the overall displacement effect;At the same time,in the case of water polymerization co-flooding,that is,after the conversion of water injection well to polymer injection well,it is considered that the displacement is more balanced when the water polymerization ratio is 1:0.8.After to achieve on the longitudinal displacement under the conditions of different permeability differential equilibrium,based on this carried out under the condition of different differential double core parallel experiment,finally out of polymer/microspheres with alternating slug system for differential 3 conditions of strata displacement,the differential 6 conditions by the combination of the gel/polymer microspheres of grading block system for deep profile control.The research is of great significance for improving polymer flooding effect and greatly reducing polymer flooding cost in offshore oilfield.