Numerical Simulation Study Of Deep Profile Control By Preformed Partical Gel

Most oil fields of China are formed by terrestrial deposits,whose conditions of geological formation are complex,and the heterogeneity of the formation is serious.After long-term water injection development,the pore structure of porous media changes,and dominant channels such as high-permeability zones and large-pore channels form.The injected water along the dominant channels with small percolation resistance quickly flows into the production well and forms an invalid cycle.In the later stage of waterflooding development,there is still a large amount of remaining oil enriched in the relatively low permeability zone.How to increase the volume sweep ratio of the relatively low permeability zone becomes an important work to improve oil recovery for the old oilfields.The preformed particle gel can transport into the deep strata,and has a very good plugging effect on the high-permeability zone,large-hole tunnel and cracks in the far well zone.More subsequent injection water flows to the low-permeability zone,more residual oil is mined,and oil increase effect is obvious.The effect of deep profile control measures to increase oil production is affected by many factors.To offer better guide for onsite construction design,a mathematical model for three-dimensional oil-water two-phase preformed particle gel deep profile control was established,with the consideration of preformed particle gel deformation characteristic move to the deep strata,dynamic retention reduces the permeability of porous media and increasement of the water phase viscosity.The model was fully implicitly solved by using the MRST(Matlab Reservoir Simulation Toolbox)an open source reservoir numerical simulation software,and the numerical calculation result fit the experimental data of core displacement well,verifying the model established.A conceptual model of vertical heterogeneity positive rhythm was established to study the effect of single factor change on the profile control.The calculation results show that the larger the injection volume,the better the oil increasing effect,the higher the injection pressure and economic cost,considering the limit of construction process and economic benefit,the injection volume can not be too big.The injection concentration should not be too small,otherwise the highpermeability layer can not be well blocked,and the amount of subsequent injection water flowing into the low-permeability layer is small,and the effect of oil increase is not obvious.There is an optimal value for the particle size injected.If the particle size is too small,and the preformed particle gel enters the low-permeability layer,resulting in non-target damage,counteracting the increase of oil.If the particle size is too big,the injection pressure is too high,and preformed particle gel can not enter the layer,the profile control measures cannot be carried out.In the later stage of waterflood development,the earlier the timing of injection,the better the oil increasing effect.On the basis of single factor sensitivity analysis,an orthogonal test design method was used to select the optimal combination of multi-factor parameters under the influence of multiple factors,and the increased oil of per unit oil concentration and injection volume was used as the measure effect evaluation index.The multi-factor optimal parameter combination corresponding to the optimal solution is that the injection timing when water cut is 88%,the injection volume is 0.45 PV,the injection concentration is 0.25%,and the injection particle size is 55 ?m.This provides a guide for multi-factorial parameter combination optimization design for on-site deep profile control.