A gate valve includes a valve body having a through-bore and a gate cavity that are substantially orthogonal to each other, a gate disposed within the gate cavity operable to translate along a length of the gate cavity to move between an open position and a closed position, an annular seat pocket formed within the valve body proximate to the intersection of the through-bore and the gate cavity and concentric with the through-bore, an annular seat disposed within the annular seat pocket, a skirt disposed within the gate cavity and in contact with the annular seat and in contact with the surface of the gate, and a plurality of skirt energizers coupled to the skirt to provide a biasing force for biasing the skirt towards the gate. A substantial fluid seal is formed between the surface of the seat and the surface of the gate when the gate is closed.