Abstract: A well drilling apparatus includes multiple, transportable, modular, pre-assembled sections which include a substructure and multiple mast sections. These pre-assembled sections allow for a quicker complete rig-up of the well drilling apparatus at ground level in a horizontal direction, without the use of a crane. Once the assembly has been completed at ground level, the mast is raised to its vertical operating position via mechanisms for raising and lowering dog tails. During transport, the guide rails are built-in to the mast sections and the crown block is attached to the traveling block, thereby facilitating the rigging-up process. The mast may be lowered after the drilling operation has been accomplished without interfering with any blow-out preventer devices that may have been placed on the wellhead while the structure was at its raised operational level.

Abstract: A well drilling apparatus includes multiple, transportable, modular, pre-assembled sections which include a substructure and multiple mast sections. These pre-assembled sections allow for a quicker complete rig-up of the well drilling apparatus at ground level in a horizontal direction, without the use of a crane. Once the assembly has been completed at ground level, the mast is raised to its vertical operating position via mechanisms for raising and lowering dog tails. During transport, the guide rails are built-in to the mast sections and the crown block is attached to the traveling block, thereby facilitating the rigging-up process. The mast may be lowered after the drilling operation has been accomplished without interfering with any blow-out preventer devices that may have been placed on the wellhead while the structure was at its raised operational level.