Streamline Simulation Of Polymer Flooding For Five-Spot Patterns In Homogeneous Reservoirs

The thesis focuses on problems of five spot polymer flooding in homogeneousreservoirs. Based on the deep study of one-dimensional flooding, complextwo-dimensional problems are simplified into a series of one-dimensional ones byintroducing streamlines, thus avoids the solving of complicated equations.Based on the assumption of unchanged streamlines, the distribution ofstreamlines for five spot wells is analytically obtained according to steady-state flowtheory. Then the non-linear convection-diffusion mathematical models of waterflooding and polymer flooding are solved by using TOF function. The changingregularity of major parameters such as water cut and recovery percentage, areobtained by numerical method. Finally, a field example from Daqing polymer pilotarea is performed to obtain the optimal parameters and prediction of raised recovery.Main conclusions obtained in the thesis are as follows,1、One dimensional water flooding problems can come down to the solving ofone dimensional B-L function. Saturation distribution is obtained by characteristicline theory. It is shown that recovery grows with the increase of injected pore volumemultiple at first, and then the curve becomes flat later.2、The mathematical model of two dimensional and two phase flooding isestablished, then mechanism and methods of streamline simulation are expoundedexplicitly. The transforming process from two dimensional parabolic equation to twodimensional hyperbolic equation and then to1-D convection control equation isdeduced in detail. Besides, two solution methods are provided in this thesis, namelycharacteristic line method and numerical solution.3、Potential function, stream function and streamline distribution of five spotwells in homogeneous reservoirs are analytically obtained according to flow fieldtheory. Under the same condition, the results of streamline simulation for five spotwater flooding in this thesis agree with the ones obtained from Eclipse.4、With considering the effect of polymer solution on viscosity increasing,adsorption, inaccessible pore volume and the water phase permeability coefficient of decline, one dimensional mathematical model of polymer flooding is established. It isshown that numerical results (TVD) and analytical solutions of the model have goodagreement.5、Two dimensional and two phase mathematical model for polymer flooding isset up. With TOF function, the equation in streamline coordinate is obtained.Unchanged streamline simulation of five spot polymer flooding is achieved bynumerical method. Results show that polymer concentration, the time of polymerflooding injection and injection slug impact recovery on different levels.6、Taking experimental block in Daqing Oilfield for an example, favorablepolymer concentration and optimal injection slug size are provided, also theimprovement of recovery degree level is predicted.