Adjustment of `B_(o)` and `R_(s)` from Separator Test

Amyx et al. (1960) and Dake (1978) adjustment of `B_(o)` and `R_(s)`

Amyx et al. (1960) and Dake (1978) proposed a procedure for constructing the oil formation volume factor and gas solubility curves by using the DL test data in conjunction with the experimental SEP (flash) test data for a given set of separator conditions:

Step 1: Calculate the differential shrinkage factor `S_(od)` (bbl/bbl) at various pressures by

`S_(od) = B_(od)/B_(odb)`
where,
`B_(od)` = Differential relative oil volume factor at pressure p, bbl/STB
`B_(odb)` = Differential relative oil volume factor at `P_(b)`, bbl/STB

* `S_(od)` will be 1 (one) at `P_(b)` and less than one at p < `P_(b)`

Step 2: Adjust the relative volume data

`B_(o) = B_(ofb) * S_(od)`
where, `B_(o)` = Oil FVF bbl/STB
`B_(ofd)` = Oil FVF at `P_(b)` as obtained from SEP (flash) test = `V_(sat)/(V_(o))_(st)`

Step 3: Calculate Oil FVF above `P_(b)` by

`B_(o) = V_(rel) / B_(ofb)`
where,
`V_(rel)` = relative oil volume as generated CCE test.

Step 4: Adjust the differential gas solubility data `R_(sd)` to give the required gas solubility factor `R_(s)`

`R_(s) = R_(s fb) - (R_(sdb)-R_(sd))*B_(ofb)/B_(obd)`
`R_(s)` = gas solubility, scf/STB
`R_(s fb)` = bubble-point solution gas-oil-ration from SEP test , scrf/STB
`R_(sdb)` = solution gas-oil-ratio at bubble point pressure as measured by the DL test, scf/STB
`R_(sd)` = solution gas-oil-ratio at various pressure levels as measured by the DL test, scf/STB

Notes

These adjustments will typically,

• Lower Bo (FVF) as Rs as compared to the DL test data
• May produce Bo < 1.0 and Rs < 0. These needed to be manually corrected as Bo=1 and Rs=0.

Step 5: Calculate the two phase (total) FVF, `B_(t)` by

`B_(t) = B_(ofb)/V_(rel)`
where,
`V_(rel)` = Relative oil volume below `P_(b)`
Similar values can be obtained from DL test by
`B_(t) = B_(td) * B_(ofb)/B_(odb)`
where, `B_(td)` = relative total volume