Simulation Study Of Fracture Network And Water Injection Huff-n-puff For Stimulated Horizontal Well In Tight Oil

With the great success of shale gas revolution of America at early 20 th century,reservoir volume stimulation has aroused closed attention as an effective way of development.For ultra-low permeability reservoir and tight oil,reservoir stimulation can improve formation property and fluid flow.However,water flooding after stimulation usually causes lots of problems,such as no effective displacement,fast decline rate,these make it hard to implement efficient development.After a long time practice for stimulated horizontal well in tight oil,Changqing Oilfield puts that spontaneous imbibition is the foundation of water injection huff-n-puff.On the fully investigation of recent research,performance of horizontal well area of A83 field is analyzed and the cause of development differences are obtained.It is found that fracture network mode,dynamic imbibition,water saturation and formation pressure level are the critical factors for water injection huff-n-puff of stimulated horizontal well in tight oil.Then,simulation of fracture network is implemented by the DK-LS-LGR method of CMG and spontaneous imbibition is simulated by capillary hysteresis option.Parameters such as fracture number,cluster,fracture half-length and conductivity,secondary fracture half-length and fracture density are optimized on the basis of one horizontal well in A83 field.Also,simulating water injection huff-n-puff of single well based on the optimized fracture network,factors such as rock wettability and formation pressure level are verified,technological parameters of huff-n-puff are optimized to match the stimulated reservoir volume.Last,a horizontal well group are established to verify the influence of two fracture network type,and the application condition of synchronous and asynchronous huff-puff are determined.Above all,performance analysis and simulation results show that reservoir stimulation and huff-n-puff can effectively provide energy for formation,and EOR of tight oil can be significantly improved by proper injection paratemer matched to fracture network.