an elevated structure (usually of metal construction) over a well for lowering and raising drilling tools, face motors, casing pipes, and other equipment. The drilling derrick is generally rigged with a block and tackle, mechanized hoisting and lowering equipment, and drill-pipe holder.
The height of a drilling derrick depends on the planned well depth; derricks with a height of 9-58 m are used. Derricks are constructed from wooden beams (for shallow wells), pipes, or section rolled steel in the form of a trihedral, tetrahedral, or truncated pyramid or an A-shape (see Figure 1). Depending on the terrain and distance, drilling derricks may be transported fully assembled on trucks or by means of tractors, or they can be dismantled into separate sections for erection at a new site.