Abstract: A rotary well drilling system employs a drill string with a drill bit affixed at its lower end for the drilling of a borehole. Drilling fluid is circulated through the drill string to remove drill cuttings. To break out a section of drill pipe from the drill string, the drill string is raised to a point where the drill string joint to be broken is above the drilling rig floor. Compressed gas is injected into the drill string to displace the column of drilling fluid to a level below such drill string joint. The compressed gas is vented and the drill pipe is broken out of the drill string.

Abstract: A method and apparatus are disclosed for removing and counting artificial drill cuttings from a returning drill mud containing a mixture of both artificial and natural drill cuttings. The artificial drill cuttings are injected into the drilling fluid and supplied to a drill string and have magnetic properties, while the natural drill cuttings do not. A rotary magnetic drum having a first endless belt travelling therearound receives the cuttings mixture and the magnetic artificial cuttings adhere to the first belt by being attracted to the drum, while the natural drill cuttings do not, thereby permitting separation of the two. The artificial cuttings are removed from the drum by a second endless belt cooperating with the first endless belt to define a nip between them. The belts positively engage with and remove the artificial cuttings from the drum.