Study On The Optimum Selecting Of Polymer Injection Parameter In Different Stages And Well Pattern Optimization In Well Block Ta2

Polymer flooding is an important EOR technology. Oil regions of domestic majoroilfields have already stepped into the high water-cut stage nowadays, and manyindustrialized field experiments of polymer flooding are carried out with the increasingdifficulty of stable yields, obtaining good technical and economic benefits. Because of thephysical and chemical properties of polymer, polymer flooding is more complicated thanwater flooding, and many factors have mutual influence on the final results of polymerflooding when the polymer is injected into the oil layers, including the injected polymerconcentration, the injected polymer rate, the injected polymer time, the polymer input and theinjector producer distance and so on. In recent years, a lot of new progress has been made onthe study of influencing factors of polymer injection and the optimization of polymerinjection parameters, but it is only focused on the whole process, and it is not considered thatdifferent polymer injection parameters should be used in different stages where the changes ofoil production and water cut are larger during the polymer injection process, which has aneffect on the final oil recovery to some degree; In the aspect of well pattern adjustments, thenumber of programs and research methods of polymer flooding is relatively small. Thus thework below is done that is focused on the polymer injection parameters and well patternadjustments during the polymer flooding process of Well Block Ta2in this paper.Firstly, with the geological model of Well Block Ta2being established and numericallysimulated, the distribution changes of the residual oil saturation are compared in differentsedimentary units at different time and the vertical distribution of the residual oil saturation isanalyzed; meanwhile, the development effectiveness of water flooding and polymer floodingis predicted by current development conditions.Secondly, with current injected polymer concentration and rate of Well Block Ta2asreference, the adjustment plans in the early stage of polymer injection, the low water-cut stageand the rising water-cut stage are worked out by using the uniform design method and takingthe injected polymer concentration and rate as influencing factors; the final plan is evaluatedby taking the incremental degree of reserve recovery, water cut, the incremental oil per tonand the comprehensive index as optimizing evaluation indexes after the developmenteffectiveness of these plans is predicted.Thirdly, the reasonable injected concentration, rate and time during the early stage ofpolymer injection, the low water-cut stage and the rising water-cut stage are determineddepending on reasonable polymer injection parameter plans in different stages, thus thepolymer consumption can be optimized.Fourthly, the encryption plans are determined by analyzing the current well pattern, wellspacing density and production situation of Well Block Ta2and taking the distribution ofproduction and injection wells, the distribution and accumulation of the residual oil intoconsideration. The development effectiveness of different plans is predicted and the encryption adjustment method is optimized by evaluating the final recovery efficiency, theincremental oil per ton and the comprehensive index.