DRILL PIPE SPINNER Russian patent published in 1994 - IPC

FIELD: repairs of oil and gas wells. SUBSTANCE: driving 3 and driven 4 gears have the form of worm wheels. The driven worm wheel has internal teeth. The intermediate gear has the form of a barrel-shaped worm 5 installed inside the driven worm wheel. After gripping the string stuck in the well, washing fluid is injected into the working string. Passing through a throttle hole said fluid builds up a pressure differential which moves out the dies. The latter fix the spinner rigidly in the well. Then the string is rotated to the right. Due to the action of intermediate worm wheels the R. H. rotation of the pipe string is reversed into the L.H. rotation of the driven wheel with the fishing tool. During its L.H. rotation the pipes remaining in the well are screwed off. A splined sub moves upward through the length of the threads of the unscrewed pipe. Then circulation of fluid is discontinued, pressure drops in the pipes and releases them. The unscrewed pipes are lifted to the surface complete with the spinner. EFFECT: higher reliability of spinner. 3 dwg