Research On The Plugging Mechanism And Slug Combination Of Large Pores In High Water-Cut Oil Reservoirs In The High-Shallow North Area

The Ng12 sublayer in a fault block in the high-shallow north area of Jidong Oilfield belongs to a typical unconsolidated sandstone reservoir with high porosity and high permeability,with strong plane and interlayer heterogeneity,and serious development of large pores.Since it was put into development,the water cut of the oil well rose rapidly after water breakthrough,the edge and bottom water continued to advance,the water flooding situation was complicated,and the remaining oil was highly dispersed.It is urgent to discuss the plugging materials suitable for this reservoir and their matching relationship with large pores,reveal the plugging mechanism of large pores,and provide necessary theoretical and technical support for the study of enhanced oil recovery technology for Ng12 sublayer in the high-shallow north area.In this thesis,based on the development of large pores in the Ng12 sublayer in the high-shallow north area,the matching relationship between core pore radius and permeability was explored through nuclear magnetic resonance T₂ spectroscopy experiments,and a cross-linked polymer gel suitable for plugging large pores was screened.and bulking particle plugging system.On this basis,by designing a microscopic visualization glass chip displacement experiment,the microscopic blocking mechanism of the cross-linked polymer gel and the bulking particles was explored respectively.Then,a physical simulation experiment at the core scale was designed,and the cross-linked polymer gel and bulky particles were used for plugging,respectively.blocking mechanism.Then,on the basis of the Ng12 heterogeneity in fault-block reservoirs,using the method of combining physical simulation and numerical simulation of large cores,the optimal slug combination for different heterogeneity of large pores is obtained,which is a practical oil reservoir.Theoretical support for the plugging of large pores.Finally,using the typical model of fault block Ng12 established by the CMG numerical simulation software,using the numerical simulation method,for different types of heterogeneous well groups and considering different parameter combinations,the actual reservoir plugging parameters are studied.The numerical results It is shown that selecting different plugging slug combinations and injection parameters for different heterogeneous large pores can effectively improve the oil recovery factor,and the Ng12 sublayer can improve the recovery rate by 5%.