Study On Polymer Parameters And Rules Of Periodic Injection In Multi-layer Reservoir

After several decades of development,some oil fields in the eastern part of China have entered the later stage of development,which is manifested by increased water content,increased polymer injection pressure,inadequate development of low-and medium-permeability layers in heterogeneous reservoirs,and large amounts of polymer injection development agents And other issues.The water content of a certain eastern oilfield studied in this paper is about 80%.In order to further improve the recovery factor,periodic polymer injection research is carried out to achieve the development goal of increasing production and efficiency of the target oilfield.In this paper,based on the actual reservoir characteristics of the target oil field,the indoor physical model is used to restore the actual development reservoir on site,the viscosity-concentration curve of the on-site polymer is determined,and the polymer mobility ratio at different concentrations is measured to obtain the polymer Injection performance.On this basis,the injection parameters such as the optimal injection concentration of the polymer,the optimal injection speed,the optimal period of the periodic injection,and the combination of the polymer concentration of the periodic injection are selected.The planar three-dimensional indoor physical model was used to study the variation law of the injection pressure field and the saturation field,and to explain the periodic injection rule from the aspects of recovery rate,flow rate,injection pressure,etc.It was found through experiments that the periodic injection pattern is more continuous than continuous.The total recovery rate of polymer injection is increased by7.24%,which shows that the cycle injection method is better than the continuous injection method.Through the above experimental research,it is concluded that the periodic polymer injection has a better displacement effect on the low permeability layer than the continuous polymer injection,which greatly improves the development level of the low permeability layer and effectively improves the recovery factor of the target oil field.