Abstract
This paper deals mainly with descriptions of certain oil-well drilling and servicing equipment carrying its own derrick as well as the necessary hoisting and rotary drilling equipment. Such equipment is mounted permanently and integrally on wheels, making it completely mobile over highway and across country. The equipment described is of two types, i.e., self-propelled or trailer-mounted. In either case, the entire machine is transportable, virtually with no disassembly; and moving from one well to another has proved to be a matter of minutes. Design and design requirements of this equipment and records showing its usefulness are discussed. Figures are given concerning the saving of steel. Safety requirements and their effect upon the design are also considered, as well as the requirements concerning the use of such equipment over state highways.
