Abstract
N-500 type drilling rig is indigenous rig which assembling is finished at July, 1949. Its design was made by the staffs of Teikoku Oil Company's Equipment Section. This rig is complete ready-for-action on trailers……speed to move…speed to erect…speed to operate. It combines 3 3/4″ draw-works, 65' jack-knife mast, 8 3/8″ rotary maclie, 5″×10″ slush power pump. This is capable of consistantly drilling to its recommended depth 2, 000 feet with 2 7/8″ drill pipe, without undue stress or strain on any part. It is operated with equal success in open fields or mountainous terrain If necessary, it is able to break down several parts in order to convey.
