diff --git a/opm/parser/eclipse/Parser/UnitSystem.cpp b/opm/parser/eclipse/Parser/UnitSystem.cpp
index 5b50531de..433522ced 100644
--- a/opm/parser/eclipse/Parser/UnitSystem.cpp
+++ b/opm/parser/eclipse/Parser/UnitSystem.cpp
@@ -114,7 +114,7 @@ namespace Opm {
         system->addDimension("Pressure" , 100000 );
         system->addDimension("K" , 9.869233e-10 );
         system->addDimension("Viscosity" , 0.001); // viscosity. ECLiPSE uses cP for metric units
-        system->addDimension("Rs" , 1); // Gas dissolution factor. ECLiPSE uses m^3/m^3 for metric units
+        system->addDimension("GasDissolutionFactor" , 1); // Gas dissolution factor. ECLiPSE uses m^3/m^3 for metric units
         
         return system;
     }
@@ -131,7 +131,7 @@ namespace Opm {
         system->addDimension("Pressure" , 6894.76 );
         system->addDimension("K" , 9.869233e-10 );
         system->addDimension("Viscosity" , 0.001); // viscosity. ECLiPSE uses cP for field units
-        system->addDimension("Rs" , 28.316847/0.15898729); // Gas dissolution factor. ECLiPSE uses Mscft/stb for field units
+        system->addDimension("GasDissolutionFactor" , 28.316847/0.15898729); // Gas dissolution factor. ECLiPSE uses Mscft/stb for field units
         
         return system;
     }
diff --git a/opm/parser/eclipse/Units/ConversionFactors.hpp b/opm/parser/eclipse/Units/ConversionFactors.hpp
index 8de6451c7..963c552d0 100644
--- a/opm/parser/eclipse/Units/ConversionFactors.hpp
+++ b/opm/parser/eclipse/Units/ConversionFactors.hpp
@@ -51,7 +51,8 @@ namespace Opm {
         const double Time              = 86400;
         const double Mass              = 1.0;
         const double Permeability      = 9.869233e-16;
-        const double DissolvedGasRatio = 1.0;
+        const double GasDissolutionFactor = 1.0;
+        const double OilDissolutionFactor = 1.0;
         const double LiquidVolume      = 1.0;
         const double GasVolume         = 1.0;
         const double Density           = 1.0;
@@ -66,7 +67,8 @@ namespace Opm {
          const double Time              = 86400;
          const double Mass              = 0.45359237;
          const double Permeability      = 9.869233e-16;
-         const double DissolvedGasRatio = 178.1076;            // Mscf / stb -> m^3/m^3
+         const double GasDissolutionFactor = 178.1076;         // Mscf / stb -> m^3/m^3
+         const double OilDissolutionFactor = 1.0/178.1076;     // stb / Mscf -> m^3/m^3
          const double LiquidVolume      = 0.158987294;         // STB -> m^3
          const double GasVolume         = 28.316847;           // MCFT -> m^3
          const double Density           = 16.01846;            // lb/ft^3 -> kg / m^3
diff --git a/opm/parser/eclipse/Units/UnitSystem.cpp b/opm/parser/eclipse/Units/UnitSystem.cpp
index 203607ff9..9e74ab116 100644
--- a/opm/parser/eclipse/Units/UnitSystem.cpp
+++ b/opm/parser/eclipse/Units/UnitSystem.cpp
@@ -136,16 +136,17 @@ namespace Opm {
         UnitSystem * system = new UnitSystem("Metric");
         
         system->addDimension("1"         , 1.0);
-        system->addDimension("Pressure"         , Metric::Pressure );
-        system->addDimension("Length"         , Metric::Length);
-        system->addDimension("Time"         , Metric::Time );
+        system->addDimension("Pressure"  , Metric::Pressure );
+        system->addDimension("Length"    , Metric::Length);
+        system->addDimension("Time"      , Metric::Time );
         system->addDimension("m"         , Metric::Mass );
         system->addDimension("K"         , Metric::Permeability );
-        system->addDimension("Rs"        , Metric::DissolvedGasRatio);
+        system->addDimension("GasDissolutionFactor", Metric::GasDissolutionFactor);
+        system->addDimension("OilDissolutionFactor", Metric::OilDissolutionFactor);
         system->addDimension("LiquidVolume", Metric::LiquidVolume );
-        system->addDimension("GasVolume", Metric::GasVolume );
+        system->addDimension("GasVolume" , Metric::GasVolume );
         system->addDimension("Rho"       , Metric::Density );
-        system->addDimension("Viscosity"        , Metric::Viscosity);
+        system->addDimension("Viscosity" , Metric::Viscosity);
         system->addDimension("Timestep"  , Metric::Timestep);
         return system;
     }
@@ -156,12 +157,13 @@ namespace Opm {
         UnitSystem * system = new UnitSystem("Field");
         
         system->addDimension("1"    , 1.0);
-        system->addDimension("Pressure"    , Field::Pressure );
-        system->addDimension("Length"    , Field::Length);
-        system->addDimension("Time"    , Field::Time);
+        system->addDimension("Pressure", Field::Pressure );
+        system->addDimension("Length", Field::Length);
+        system->addDimension("Time" , Field::Time);
         system->addDimension("m"    , Field::Mass);
         system->addDimension("K"    , Field::Permeability );
-        system->addDimension("Rs"   , Field::DissolvedGasRatio );
+        system->addDimension("GasDissolutionFactor" , Field::GasDissolutionFactor);
+        system->addDimension("OilDissolutionFactor", Field::OilDissolutionFactor);
         system->addDimension("LiquidVolume", Field::LiquidVolume );
         system->addDimension("GasVolume", Field::GasVolume );
         system->addDimension("Rho"  , Field::Density );
diff --git a/opm/parser/share/keywords/P/PVDG b/opm/parser/share/keywords/P/PVDG
index 221d4cc83..e24e15d2b 100644
--- a/opm/parser/share/keywords/P/PVDG
+++ b/opm/parser/share/keywords/P/PVDG
@@ -1,4 +1,4 @@
 {"name" : "PVDG" , "size" : {"keyword" : "TABDIMS" , "item" : "NTPVT"} , "items" : [
-        {"name" : "data" , "size_type" : "ALL" , "value_type" : "FLOAT"  , "dimension" : ["Pressure","1/Rs","Viscosity"]}]}
+        {"name" : "data" , "size_type" : "ALL" , "value_type" : "FLOAT"  , "dimension" : ["Pressure","OilDissolutionFactor","Viscosity"]}]}
         
 
diff --git a/opm/parser/share/keywords/P/PVTG b/opm/parser/share/keywords/P/PVTG
index d68d4c429..7e132f650 100644
--- a/opm/parser/share/keywords/P/PVTG
+++ b/opm/parser/share/keywords/P/PVTG
@@ -1,6 +1,6 @@
 {"name" : "PVTG" , "num_tables" : {"keyword":"TABDIMS" , "item":"NTPVT"},
         "items" : [
             {"name":"GAS_PRESSURE", "value_type" : "FLOAT", "dimension":"Pressure" },
-            {"name":"DATA", "size_type" : "ALL" , "value_type":"FLOAT" , "dimension" : ["1/Rs","1","Viscosity"]}
+            {"name":"DATA", "size_type" : "ALL" , "value_type":"FLOAT" , "dimension" : ["OilDissolutionFactor","1","Viscosity"]}
          ]
 }
diff --git a/opm/parser/share/keywords/P/PVTO b/opm/parser/share/keywords/P/PVTO
index 2b392f3ad..112eeeabc 100644
--- a/opm/parser/share/keywords/P/PVTO
+++ b/opm/parser/share/keywords/P/PVTO
@@ -1,6 +1,6 @@
 {"name" : "PVTO" , "num_tables" : {"keyword" : "TABDIMS" , "item" : "NTPVT"}, 
         "items" : [
-            {"name":"RS", "value_type" : "FLOAT", "dimension":"Rs" },
+            {"name":"RS", "value_type" : "FLOAT", "dimension":"GasDissolutionFactor" },
             {"name":"DATA", "value_type":"FLOAT", "size_type" : "ALL" , "dimension" : ["Pressure","1","Viscosity"]}
          ]
 }
diff --git a/opm/parser/share/keywords/R/RS b/opm/parser/share/keywords/R/RS
index 11e21e55d..fb83cff70 100644
--- a/opm/parser/share/keywords/R/RS
+++ b/opm/parser/share/keywords/R/RS
@@ -1 +1 @@
-{"name" : "RS" , "data" : {"value_type" : "FLOAT", "dimension" : "Rs"}}
+{"name" : "RS" , "data" : {"value_type" : "FLOAT", "dimension" : "GasDissolutionFactor"}}
diff --git a/opm/parser/share/keywords/R/RSVD b/opm/parser/share/keywords/R/RSVD
index 75afed930..96fcdec4e 100644
--- a/opm/parser/share/keywords/R/RSVD
+++ b/opm/parser/share/keywords/R/RSVD
@@ -2,6 +2,6 @@
         "items" : [{"name" : "table" , 
                    "value_type" : "FLOAT" , 
                    "size_type" : "ALL",
-                   "dimension" : ["Length" , "Rs"]}]}
+                   "dimension" : ["Length" , "GasDissolutionFactor"]}]}