A semi-closed loop system for producing liquefied natural gas (LNG) that combines certain advantages of closed-loop systems with certain advantages of open-loop systems to provide a more efficient and effective hybrid system. In the semi-closed loop system, the final methane refrigeration cycle provides significant cooling of the natural gas stream via indirect heat transfer, as opposed to expansion-type cooling. A minor portion of the LNG product from the methane refrigeration cycle is used as make-up refrigerant in the methane refrigeration cycle. A pressurized portion of the refrigerant from the methane refrigeration cycle is employed as fuel gas. Excess refrigerant from the methane refrigeration cycle can be recombined with the processed natural gas stream, rather than flared.