Generating Rel Perm tables from correlations

You can use the Rel Perm correlations to generate rel perm regions specific to your simulator.

The equations used to generate the Rel Perm tables are as follows:

k_rw = k_rwro * [(S_w - S_wc)/(1 - S_orw - S_wc)] ^nw

k_row = k_rocw * [(1 - S_orw - S_w)/(1- S_orw - S_wc)] ^now

k_rog = k_rocw * [(1 - S_org - S_wc - S_g)/(1 - S_org - S_wc)] ^nog

k_rg = k_rgro * [(S_g - S_gc)/(1 - S_org - S_wc - S_gc)] ^ng

where:

S_wc = connate water saturation, fraction

S_orw = residual oil saturation to water

S_org = residual oil saturation to gas

S_gc = critical gas saturation

k_rwro = relative permeability of water at S_w=1-S_orw, S_g=0

k_rgro = relative permeability of gas at S_w=S_wc, S_o=S_org

k_rocw = relative permeability of oil at S_w=S_wc, S_g=0

nw,now,ng,nog = exponents for analytical k_r

The calculated krw and krg values are limited by 1.0 and krwro and krgro must be 1.0 or less.

In these equations, S_w and S_g are the observed variables and k_rw, k_row, k_rog, k_rg are the calculated variables. Tables of S_w versus k_rw and k_row and S_g versus k_rg, k_rog are calculated for each simulator type.

The tables are calculated according to specified intervals of S_w and S_g.

Optionally, capillary pressures may also be calculated using the equations:

P_cwo = a1 + a2 * (1-Swn) ^a3

P_cwoi = b1 + b2 * (1-Swn) ^b3 - b4 * Swn ^b5

P_cgo = c1 + c2 * Sgn ^c3

Where:

P_cwo = drainage water-oil P_c

P_cwoi = imbibition water-oil P_c

P_cgo = drainage gas-oil P_c

S_wn = (S_w-S_wc)/(1-S_wc)

S_gn = S_g/(1-S_wc)

You provide input for the correlations by first defining the analytical rel perm coefficients and then how the deck section is to be created.

Defining analytical Rel Perm coefficients

In the first table, you specify coefficients for the equations above. The first section of the table is used to constrain what input is used. The System row is one of 3 Phase, Oil/Water, or Gas/Water. The check boxes in the next two rows determine whether capillary pressure and capillary imbibition’s pressure values are generated.

Defining Rel Perm region parameters

You use the second table to establish how the rel perm region is generated for the simulator.

You specify the region name and region ID to be used for the new region. The # of Saturation Values entry indicates how many values between 0 and 1 inclusive will be created for the S_w and S_g columns in the created table.

If the Update Existing Regions checkbox is checked, an existing region of the same name will be replaced with the newly created region.