Study On The Migration Law Of Heterogeneous Composite Flooding System In Porous Media

Polymer oil displacement agent and pre-crosslinked particle profile control agent have been widely used to stabilize oil production and control water cut in oilfield. In order to solve the limited swept volume of polymer solution in serious heterogeneity reservoir, and the complicated injection process of pre-crosslinked particle, research group has developed a kind of heterogeneous composite oil displacement agent with gel and water soluble polymer double characteristics. This paper, simulating the actual conditions of a district in Gudao oil reservoirs, studies migration of the heterogeneous composite flooding system in porous media, and provides a theoretical basis for the research and application of non homogeneous composite flooding system.According to the migration law of heterogeneous composite flooding system in porous media. Firstly, we have synthesized the displacing agent and studied its solution properties. Secondly, the migration law was studied by the laboratory physical simulation device. Finally, the visualization migration rule of heterogeneous composite flooding system in porous media were discussed.The results show that: ①Heterogeneous composite flooding system with the branched chain and soft solid particles shows good viscoelasticity; the solution has a noteworthy three-dimensional network structure, which strengthens certain shear stability.②The speed of heterogeneous composite flooding system transport in media transport has great influence on the solution of viscoelasticity. The reasonable migration velocity is 0～2mL/min; the heterogeneous composite flooding system transferring in a "accumulation jams, pressure increased, deformation and movement" alternate blocking drive way transports in porous media and medium pressure hysteresis phenomenon occurs; solution particles occur deformation, fracture during migration and when particle size and pore throat ratio is 40.49-97.73, the system has the good compatibility. Solution can obtain a high resistance during the migration process, the resistance coefficient of 77.14, and the residual resistance coefficient of 20.71 in porous media. ③Heterogeneous composite flooding system start-up pressure gradient is large in low permeability reservoir. Solutions give priority to the high permeability layer which has less resistance, which can change the followed shunt volume, start low permeability layer and divert the followed fluid effectively. The solutions improve the plane heterogeneity effect obviously, make the fluid balance forward and enlarge swept volume;④Heterogeneous composite flooding system occurs stack, deformed and broken when transporting in a single microscopic pore, and the system built the resistance in the large pore of micro etching model, which makes the fluid flow to small pore and solution forward evenly and expand swept volume effectively. The residual oil film in the pore wall is gradually stripped in a portable solution under a filament and floccule, and then is driven out along with the solution. The residual oil in "the Blind Side" is gradually driven out by the "Pull, Drag" effect of viscoelastic particles. So solutions rely on the synergistic effects to enhance oil recovery.