DETERMINATION OF DEAD AND SLIGHTLY DRAINED OIL ZONES IN HETEROGENEOUS RESERVOIRS Russian patent published in 2014 - IPC E21B49/00 G01N15/00 

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises filtration experiments with cores under stationary conditions, plotting of fluid filtration rate against pressure gradient, determination of ultimate pressure gradient corresponding to fluid filtration pattern variation. Additionally, filtration experiments with different-permeability cores are carried out under non-stationary conditions to define dependence of ultimate pressure gradient on permeability and to construct formation pressure gradient modulus map and permeability map. Quadratic net is applied on seam pressure gradient modulus map and permeability map. Seam pressure gradient modulus and permeability factor are evaluated for every cell of the net. Dependence of limiting pressure gradient on permeability is used to calculate the limiting pressure gradient for every cell of the net. Obtained magnitudes are compared with seam pressure gradient modulus. Cells are isolated wherein seam pressure gradient is lower than limiting pressure gradient to define dead and slightly drainage zones of oil deposit.

EFFECT: determination of dead and slightly drained zones of oil low-permeability deposits.

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