Study On The Parameters Optimization Of Weak Gel In-depth Profile Control In Fractured Tight Oil Reservoir

It is very difficult to develop fractured tight oil reservoir because of water channeling and flooding along the fracture,and then reduce the water injection efficiency.Step by step in-depth profile control is the main way to deal with the problems of this kind reservoir.It is very important to go on in-depth profile control seepage law kinetics study to improve field plugging effect and recovery oil production.However,weak gel in-depth profile control seepage law kinetics studies are mainly concentrated on single fracture medium,and there are less studies on numerical simulation and rule analysis for tight oil reservoir which include multiple fractures.Therefore,going on the study of the parameters optimization of the fractured tight oil reservoir can provide conduction for field construction.Taking Yaoyingtai oil field,belonging to typical fractured tight oil reservoir with three different levels fractures,as an example,basing on double medium model coupling motion equation,continuity equation and state equation,this paper establishes a numerical model for weak gel in-depth profile controlling in fractured tight reservoir containing three stages fractures.Then,plugging effect and recovery effect of step by step in-depth profile control in fractured tight reservoir are analysed after the numerical model is corrected by experimental,and according to injection parameters sensitivity analysis reveal influence law of profile control parameters on profile control effects.Finally,based on real geological model of Yaoyingtai oil field fractured tight oil reservoir and water flooding history matching,the real step in-depth profile control process in real fractured tight reservoir is simulated,real injecting parameters are optimized.It can provide reference for step by step in-depth profile control process in similar reservoir.The results show that fractured tight oil reservoir step by step in-depth profile control technology can plug each stage fractures,it can increase crude oil recovery rate by 10% and reduce water cut by 20%;The earlier the profile control goes on,the better of the displacement effect is;With the increase of injecting slugs and injection rate,the enhanced recovery will increase at first and then decreases,and thus there is an optimal value;With the increase of injection volume and concentration of injected polymer,improved recovery range will gradually increase,when it increase to a certain value,the degree of improve recovery tends to be a constant.