diff --git a/opm/simulators/wells/BlackoilWellModelGeneric.cpp b/opm/simulators/wells/BlackoilWellModelGeneric.cpp
index c37cb75e1..20fe4efc3 100644
--- a/opm/simulators/wells/BlackoilWellModelGeneric.cpp
+++ b/opm/simulators/wells/BlackoilWellModelGeneric.cpp
@@ -1696,7 +1696,7 @@ assignMassGasRate(data::Wells& wsrpt,
     using rt = data::Rates::opt;
     for (auto& wrpt : wsrpt) {
         auto& well_rates = wrpt.second.rates;
-        const auto w_mass_rate = well_rates.get(rt::gas) * gasDensity;
+        const auto w_mass_rate = well_rates.get(rt::gas, 0.0) * gasDensity;
         well_rates.set(rt::mass_gas, w_mass_rate);
     }
 }