W=7.758 Ahooi U.S.A Boi where Boi is oil volume factor in reservoir barrels per stock tank barrel or bbl/STB.dimensionless N-< hooi china Boio i s o i B A h S N   7.758 where Boi is oil volume factor in reservoir barrels per stock tank barrel or bbl/STB. dimensionless oi s oi B A h S N   china U.S.A