Solve well equation for the first iteration

flow/flow_ebos_gasoil.cpp

@@ -38,6 +38,10 @@ struct EclFlowGasOilProblem {
     using InheritsFrom = std::tuple<EclFlowProblem>;
 };
 }
+template<class TypeTag>
+struct EnableDiffusion<TypeTag, TTag::EclFlowGasOilProblem> {
+    static constexpr bool value = true;
+};
 
 //! The indices required by the model
 template<class TypeTag>