Non-Darcy Flow Numerical Simulation for Low-Permeability Reservoirs

Abstract

Abstract With further progress of oilfields' development all over the world, more and more low permeability reservoirs are being put in production. However, fluid flow in low permeability porous media no longer obeys Darcy's law and instead conforms to the one of low-velocity non-Darcy seepage. Most commercial numerical simulation software may cause inaccuracy in simulating development performance of low permeability reservoirs. So the non-Darcy flow numerical simulation software has been developed. In this paper, non-Darcy flow mathematical model was presented. Then, on the basis of practical field and laboratory experiment data, an ideal model of five-spot well pattern was established. Under the same reservoir condition, the non-Darcy simulation, Darcy simulation and quasi-linear simulation were conducted. At last, the simulation results of pressure gradient distribution, accumulative oil production and remaining oil distribution for Darcy flow, quasi-linear flow and non-Darcy flow were given. Research shows that flow of most regions in low permeability reservoir belongs to the curve segment which indicate the rationality of the non-Darcy software; compared with the results of Darcy flow, when considering non-Darcy flow, the accumulative oil production is lower, and the quasi-linear flow is the lowest, so Darcy flow model overstates the reservoir flow capability, and quasi-linear flow model overstates the reservoir flow resistance; analysis of remaining oil saturation indicates that for non-Darcy flow model simulation and quasi-linear flow model simulation, different flow regions exist including dead oil region and flow region which makes the flow patterns more complex in low permeability reservoir.