Huff And Puff Parameters Optimization And Productivity Prediction Of Fractured Horizontal Wells In Tight Reservoir

At present,horizontal well fracturing technology is widely used at home and abroad to realize the effective development of unconventional tight oil and gas resources,which has been widely used in the development process of block Q.In the production process of fractured horizontal wells in block Q,there are many problems,such as rapid productivity decline and low recovery.Therefore,it is necessary to explore a new development mode of huff and puff to supplement energy to further improve recovery.This paper takes the tight reservoir in block Q as the research object,the optimization of huff and puff parameters and productivity prediction are comprehensively studied:the core porosity and permeability parameters under different overburden pressures are measured,the permeability loss ratio caused by pressure sensitive is calculated,and based on the IPR curves of horizontal wells with different stress sensitivity coefficients,the reasonable bottom hole flowing pressure range of fractured horizontal wells in this reservoir is explored.In order to optimize surfactant suitable for huff and puff development in block Q,interfacial tension measurement and imbibition oil recovery experiments were carried out for different kinds of imbibition media.According to the field,the huff and puff experiment scheme is designed,and the influence of four key parameters,energy supplement system,cycle,injection volume and soak time,on huff and puff recovery is studied.Based on the laboratory experiment of tight oil huff and puff,the huff and puff development system of block Q is established,the huff and puff production of 10 fractured horizontal wells in block Q is predicted by numerical simulation.The experimental results show that:Based on the experimental data of core stress sensitivity of two coring wells,it can be seen that,it can be seen that the core stress sensitivity of No.1 coring well is medium to strong,and that of No.2 coring well is strong,and the reasonable bottomhole flow pressure range of fractured horizontal well is 5?7Mpa.The indoor imbibition experiment shows that the optimal surfactant for Q block is betaine,the optimal concentration is 0.25%,and the static imbibition recovery is 34.9%.The oil recovery contribution rate of huff and puff experiment is mainly concentrated in the first three rounds,accounting for 90%;among the three injection systems selected in this experiment,the recovery rate from high to low is carbon dioxide,betaine surfactant,and formation water;the larger the injection amount of energy supplement system is,the better the development effect of dynamic huff and puff is,but with the increase of injection amount,the increase of recovery decreases,and the optimal injection is 0.1PV;Under the same injection conditions,the longer the soak time,the higher the recovery of huff and puff,but with the increase of soak time,the increase of EOR degree decreases,the best soak time is 7 days.Through the productivity prediction of Numerical Simulation,it shows that:The cumulative huff and puff oil production of 10 fractured horizontal wells in block Q is predicted.Among them,the cumulative production of seven horizontal wells is more than 7000m~3,and the 10-year oil production of this block is 94176.2m~3,indicating that huff and puff development mode can effectively develop tight oil in this block.The research results optimize the huff and puff production parameters of fractured horizontal wells in tight reservoir of Q block,and provide a productivity prediction method,which provides theoretical and technical support for the subsequent improvement of tight oil recovery in this block.