Method for operating a gas turbine plant with a compressor, a turbine, and a sequential combustor arrangement comprising a first burner, a first combustion chamber, and a second combustor the method comprising the steps of - compressing the inlet gas in the compressor, - separating a fuel gas into a rich fuel having a concentration of higher hydrocarbons which is higher than the concentration of higher hydrocarbons of the fuel gas, and a lean fuel having a concentration of higher hydrocarbons which is lower than the concentration of higher hydrocarbons of the fuel gas, - feeding a first fuel comprising at least one of the rich fuel, the lean fuel, and the fuel gas or a mixture thereof to at least one first burner wherein the concentration of higher hydrocarbons in the first fuel differs from the concentration of higher hydrocarbons of the fuel gas, - burning the first fuel and the compressed gas in the first combustion chamber to obtain first combustion products, - feeding a second fuel comprising at least one of the rich fuel, the lean fuel, and the fuel gas or a mixture thereof to at least one second combustor wherein the concentration of higher hydrocarbons in the second fuel differs from the concentration of higher hydrocarbons of the fuel gas and of the first fuel, - burning the second fuel with the first combustion products to obtain second combustion products, and - expanding the second combustion products in the turbine, wherein for low load operation the first fuel which is fed to the first burner is provided with a concentration of higher hydrocarbons which is lower than the concentration of higher hydrocarbons of the fuel gas, and the second fuel which is fed to the second combustor is provided with a concentration of higher hydrocarbons which is higher than the the concentration of higher hydrocarbons of the fuel gas for stabilizing the combustion; while for high load operation the first fuel which is fed to the first burner is provided with a concentration of higher hydrocarbons which is higher than the concentration of higher hydrocarbons of the fuel gas, and the second fuel ( ̇13) which is fed to the second combustor is provided with a concentration of higher hydrocarbons which is lower than the concentration of higher hydrocarbons of the fuel gas for reducing the flame speed characterized in that during operation in an intermediate load range the fuel separation is bypassed and the fuel gas is directly fed to the first burner, and to the second combustor. - compressing the inlet gas in the compressor, - separating a fuel gas into a rich fuel having a concentration of higher hydrocarbons which is higher than the concentration of higher hydrocarbons of the fuel gas, and a lean fuel having a concentration of higher hydrocarbons which is lower than the concentration of higher hydrocarbons of the fuel gas, - feeding a first fuel comprising at least one of the rich fuel, the lean fuel, and the fuel gas or a mixture thereof to at least one first burner wherein the concentration of higher hydrocarbons in the first fuel differs from the concentration of higher hydrocarbons of the fuel gas, - burning the first fuel and the compressed gas in the first combustion chamber to obtain first combustion products, - feeding a second fuel comprising at least one of the rich fuel, the lean fuel, and the fuel gas or a mixture thereof to at least one second combustor wherein the concentration of higher hydrocarbons in the second fuel differs from the concentration of higher hydrocarbons of the fuel gas and of the first fuel, - burning the second fuel with the first combustion products to obtain second combustion products, and - expanding the second combustion products in the turbine, wherein for low load operation the first fuel which is fed to the first burner is provided with a concentration of higher hydrocarbons which is lower than the concentration of higher hydrocarbons of the fuel gas, and the second fuel which is fed to the second combustor is provided with a concentration of higher hydrocarbons which is higher than the the concentration of higher hydrocarbons of the fuel gas for stabilizing the combustion; while for high load operation the first fuel which is fed to the first burner is provided with a concentration of higher hydrocarbons which is higher than the concentration of higher hydrocarbons of the fuel gas, and the second fuel ( ̇13) which is fed to the second combustor is provided with a concentration of higher hydrocarbons which is lower than the concentration of higher hydrocarbons of the fuel gas for reducing the flame speed characterized in that during operation in an intermediate load range the fuel separation is bypassed and the fuel gas is directly fed to the first burner, and to the second combustor.