| Chaoyang Gou Oilfield is a low to ultra-low permeability reservoir with developed fractures and serious heterogeneity.At present,the water flooding efficiency is reduced due to the injection water along the fracture or high permeability layer,which affects the final recovery.Through the application of depth profile control technology to block fractures and high permeability zones,the injection pressure of injection wells is increased,the water drive sweep efficiency is improved,and the reserve production situation is improved.With the increase of water cut and recovery in the process of water injection development,the number of wells suitable for depth profile control is increasing.It is necessary to study the depth profile control technology in aspects such as reducing the cost of oil displacement,simplifying the technology and widening the scope of application.Nano-micron microsphere depth profile control agent,a gel that does not expand in oil in water,has the characteristics of adjustable original size,no oil plugging,easy injection,high sealing strength,progressive profile control and wide application range.Therefore,it is of great significance to improve the development effect of Chaoyang Gou oilfield by laboratory experimental study and field application study of depth profile control agent of nanometer-microspheres.In this paper,the injectability,expansibility,plugging ability and oil displacement effect of deep profile control agent are analyzed and studied by the performance evaluation experiment of nanometer-micron microsphere depth profile control agent.The results show that the depth profile control agent of nanometer-micron microspheres is easy to inject;it has the advantages of being independent of the water quality of wastewater,the injection concentration is adjustable,the size and deformation of the microspheres are controllable,and the salt water is helpful to the expansion of the microspheres.The salinity of formation water in Chaoyang Gou Oilfield is suitable for profile control agent of nanometer-microsphere,the experimental average plugging efficiency of nanometer-microsphere is 83.95,which is suitable for the need of deep profile control.Because of the "dynamic plugging" of nanometer-microspheres in the deep reservoir,Liquid flow redirection is produced continuously,which has little damage to low permeability reservoir and has the effect of increasing oil and precipitation.According to the principle of depth profile control and well selection,the well area suitable for profile control in C block is determined,the injection concentration suitable for depth profile control in C block is determined by core injection ability experiment,and the relation curve between profile control radius and recovery degree is used.The profile control radius is 80 m,and the injection rate of profile control agent in each well is determined according to the formula of profile control agent used in single well.After field application,water injection pressure increased,water absorption profile was improved,daily oil production and water cut decreased,indicating that depth profile control of nanometer-micron microspheres effectively plugged the second class reservoir and played a role in alleviating the interlayer.The role of plane contradictions.At the same time,it is found that the effect of profile control with nanometer-sphere depth on increasing oil production and reducing water cut in middle and low water bearing wells is not as good as that in high water cut wells,and that the effect of fracture water breakthrough wells is longer than that of matrix water injection wells.The required nanometre ball profile control agent has high concentration and high dose. |
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