Experimental Study On The Optimal Fluidity Of Chemical Compound Flooding In High Condensed Reservoir Of Kongnan Area

In recent years,with the increase of oil consumption and the reduction of new proven reserves,oil companies began to attach importance to the development of high viscosity and high viscosity reservoirs.The practice shows that the effect of mobility control is very important to the development of conventional reservoirs,how to develop the high viscosity and viscous oil reservoir becomes a very important problem for petroleum science and technology personnel.The south area of Dagang oil field belongs to high temperature and high salinity and high pour point oil reservoir,the earlier research work has determined that the alkali free polymer/surface active agents two-compound system flooding is used to improve oil recovery.In this paper,Dagang Kongnan area's reservoir geology and fluid are simulation objects,the polymer/surface active agents compound system study of basic performance characteristics and driving factors of oil and its effect are performed.The results show that the reservoir water injection of calcium ion concentration is higher,which has adverse effects on the polymer/surface active agents compound system's flow control and displacement efficiency.Removal of calcium and magnesium ions in water is suggested,it can not only increase the viscosity of the two component composite system,but also reduce the interfacial tension,and oil precipitation effect is very obvious.Hydrophobically associating polymers are formed by the aggregation of hydrophobic groups on the molecular chains of polymers,and increase the viscosity of polymer solution,but it may also bring about the technical risk of poor matching relationship between polymer molecular aggregates and rock pores,and the effect of increasing oil.Under the condition of core permeability variation coefficient Vk and viscosity of crude oil,the oil displacement efficiency increases with the increase of the viscosity ratio of the polymer/surface active agents two-compound system and the crude oil(?_sp/?_o),but the increase rate decreases gradually.Under the same condition of viscosity ratio(?_sp/?_o),with the increase of permeability variation coefficient Vk,the recovery rate increases,but the final recovery rate decreases.Under the condition of viscosity ratio(?_sp/?_o)and permeability variation coefficient Vk,with the increase of the average permeability of the core,the oil displacement efficiency increases with the increase of the average permeability of the core,but the increase shows a trend of increasing first and then decreasing.Under the certain condition of viscosity ratio(?_sp/?_o)and core parameters?Kg and Vk?,with the increase of viscosity of crude oil,the oil displacement efficiency of water flooding and chemical flooding becomes worse.From the technical and economic point of view,the reasonable viscosity ratio range of the polymer/surface active agents two-compound flooding in the target reservoir homogeneous reservoir is from 0.5 to 1,and the heterogeneous reservoir is from 1 to 2.Compared with the cleaning ability,polymer/surface active agents two-compound system's mobility control ability on the recovery of chemical flooding contribution rate is larger,usually can reach more than fifty percent.Therefore,the mine should ensure that it has adequate mobility control ability in oil displacement agent composition design,which is the only way to ensure the cleaning ability to play a role.