Oil-water two-phase non-darcy seepage numerical simulation method based on discrete fracture model

Abstract

The invention discloses an oil-water two-phase non-Darcy seepage numerical simulation method based on a discrete fracture model, and the method comprises the steps: determining an oil-water two-phaseseepage mode, and selecting a low-speed non-Darcy seepage model in a fracture system; selecting a low-speed nonlinear seepage model in the matrix for characterization; establishing continuity equations of an oil phase and a water phase respectively according to the law of conservation of mass; discretizing the continuity equation, and establishing a numerical simulation model; correcting the numerical simulation model by using an embedded discrete fracture model, adding a variety of non-adjacent link information, and establishing a nonlinear equation system; solving the nonlinear equation system to obtain oil-water two-phase pressure and saturation parameters; establishing a water-oil displacement model under a complex fracture condition, performing numerical simulation, and analyzing output characteristics of an injection well and an oil production well. The problem that an existing commercial numerical simulation method cannot simulate two-phase low-speed non-darcy flow in a matrix is solved, and the method has obvious advantages in the aspects of calculation precision and calculation efficiency.

Description

technical field [0001] The disclosure relates to a numerical simulation method for oil-water two-phase non-Darcy flow based on a discrete fracture model, specifically a numerical simulation method for oil-water two-phase low-velocity non-Darcy flow in tight reservoirs based on a discrete fracture model, which belongs to the field of unconventional oil and gas development . Background technique [0002] In recent years, the development of tight oil has become a hot spot in the development of petroleum resources. Due to the low permeability of tight oil reservoirs, Darcy flow has been unable to describe the flow mechanism in the reservoir. A large number of laboratory experiments and field practice have shown that the use of low-velocity non-Darcy flow can more accurately characterize the seepage mode of this type of reservoir. In order to clarify the reservoir fluid flow characteristics considering low-velocity non-Darcy seepage, a large number of low-velocity non-Darcy seep...

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Problems solved by technology

[0011] The above methods all have huge defects in the development simulation of tight oil reservoirs. The multi-continuity media model cannot characterize the complex shape of fractures. The discrete fracture model and the numerical simulation method based on PEB I grid often need to conduct grids around the fractures during the discrete process. Grid densification leads to low calculation efficiency. The embedded discrete fracture model has advantages in both calculation efficiency and calculation accuracy. However, the nonlinear seepage of the matrix cannot be considered, and the error is large

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