Numerical Simulation Of Polymer Gel System Profile Control

The oil field of east China have been developed for decades by water flooding,now they have entered into a high water cut period,and have more difficulty to develop.The main reason ia that the development of long-term water flooding has aggravated the heterrogeneity of oil layers,formed a high permeability channel between the injection and production wells.The flow of injected water is an invalid ciculation in the high permeability region between wells,and remaining oil in the low permeability region is unable to be diplaced.In recent years water flooding has not been developed more effectively.The oilfield has developed tertiary oil recovery technique according to the improvement of oil washing efficiency and increase conformance coefficient.Among them,water-plugging technique is effecive to adjust the heterogeneity of oil layers by block the high permeability area,to increasing oil production and decreasing water cut.The field experiment proves that the water plugging technique of polymer gel system can effectively improve the oil recovery.In this paper,the plugging mechanism of polymer gel system is investigated,a mathematical model of three-dimensional(oil,water)multicomponent(polymer,crosslinking agent,gel/gel,salinity)was established,which is on the basis of the black oil model,the model considered the influence of gravity,capillary pressure,fluid and rock compressibility,inaccessible pore volume of polymer,polymer adsorption,retention,diffusion,residual resistance coefficient,crosslinking reaction and the shear viscosity influence.The mathematical equations are discretized by using finite volume method,is solved by an implicit newton-raphson iterative method.Based on the influence of virtual node well technology on the distribution of matrix elements,the linear equations are solved by "matrix preordering + pretreatment technology + double conjugate gradient stability" method.Using the c++ and matlab software,the polymer gel system water-plugging simulation software is developed.The correctness and reliability of numerical simulation software are verified by comparing with commercial software and laboratory physical simulation experiment.The software can simulate water flooding,polymer flooding,weak gel flooding and gel flooding.The oil displacement efficiency of water flooding,polymer flooding and gel flooding was studied by using the numerical simulation software.It is proved that the oil displacement capacity is from large to small order: weak gel flooding > gel flooding > polymer flooding > water flooding.The sensitivity analysis of the factors affecting the blocking effect of polymer gel system was carried out.A simulation of the blocking and plugging of polymer gel in an oil field was also carried out to evaluate the development plan of the block of oilfield.It is proved by practical application that the numerical simulation software has good practicability,and it can be used for the study of the water control mechanism of polymer gel system,the formulation of the development plan and the prediction of optimization and development.