COLLAPSIBLE SUBSTRUCTURE FOR A MOBILE DRILLING RIG

摘要

Generally, the present disclosure is directed to a collapsible substructure of a mobile drilling rig. In one illustrative embodiment, a drilling rig substructure is disclosed that includes a base having a fixed drill floor mounted thereon, wherein an upper surface of the fixed drill floor is positioned at an operating height above the base for performing drilling operations at a wellbore location of a drilling site. Furthermore, a raisable floor is also included that is adapted to be positioned in a lowered transportation position for transportation of the substructure to the drilling site and raised to an operating position adjacent to the fixed drill floor for performing drilling operations, wherein a height level of an upper surface of the raisable floor is lower than a height level of the upper surface of the fixed drill floor when the raisable floor is positioned in the lowered transportation position.