The Optimization Of Compound Fracturing Fluid And Experimental Study On Oil Production In The Same Layer Of Same Well

The permeability and porosity of tight oil reservoir is low,fracturing technology is often used in such reservoir.With the long-term development of oil field,the energy of the formation can not be supplemented in time,what's more,the oil recovery will be reduced in a short period time,the recovery of crude oil is low,which is unfavorable to the rational and economical development of the oil field.Therefore,it is urgent to find effective measures for exploring potential of oil reservoir and improving the recovery of tight oil reservoir.Because the tight oil reservoir has the characteristics of small pore radius,large capillary force and poor permeability.The combination of imbibition and huff-puff is considered to improve the recovery of such reservoir in this paper.According to the actual needs of the field,tight oil reservoir is taken as the research object.In order to optimize the compound fracturing fluid and improve the oil recovery,this paper,used the theory of oil field chemistry and oil layer physics,instrument detecting and physical simulation experiments.The properties of infiltration fluid to reduce the interfacial tension and to change the wettability of core have been evaluated.At the same time,the development effects of static imbibition and dynamic imbibition have been analyzed and the optimization of compound fracturing fluid has been completed.The physical simulation experiments of the same layer of same well have been carried out.The results show:(1)The interfacial tension can be reduced by surfactant and the wettability of core surface can be changed by the infiltration fluid with surfactant;(2)The more the core is hydrophilic,the higher the static imbibition recovery is;(3)The wettability of the core surface is better than the low interfacial tension in improving the static imbibition recovery;(4)Under the condition of reservoir temperature,static imbibition can conduct when the interfacial tension of oil and water reaches 1×10-1~10-2m N/m;(5)The static imbibition recovery of the compound fracturing fluid is higher than that of the simple fracturing fluid;(6)With the increase of temperature,the recovery of static imbibition increases;(7)With the reduce of crude oil viscosity,the recovery of static imbibition increases;(8)The dynamic imbibition recovery of the compound fracturing fluid is higher than that of the simple fracturing fluid;(9)The dynamic imbibition recovery increases first and then decreases with the increase of injection velocity;(10)The dynamic imbibition recovery increases with the increase of alternating injection times but the increasing extent is less;(11)The oil recovery of compound fracturing fluid is higher than that of the simple fracturing fluid in the experiments of same layer of same well;(12)The oil recovery in the experiments of the same layer of same well increases with the increase of injection pressure;(13)The oil recovery in the experiments of the same layer of same well increases first and then decreases with the increase of soaking time,therefore,the optimization soaking time of this paper is 5h;(14)The optimization compound fracturing fluid is the slickwater+SDBS,its dynamic imbibition recovery of the seamless cores is higher than that of the static imbibition recovery and its average huff-puff recovery of slotted cores is higher than that of the average dynamic imbibition recovery.