Drillstring

DRILLSTRING DESIGN PGE 471 Oil and Gas Well Drilling Engineering –IRig Components: 1- Power system, 2- Derrick and substructure 4- Rotary equipment 5- Circulation system 3- Hoisting system 6-Pressure control system (BOP)

The main components of a drill string include: Kelly, Drillpipe, Drill collars, Accessories and Drill bit. The SWIVEL: The functions of the swivel: 1supports the weight of thedrill stem during drilling, 2permits the drill stem to rotate (more than 200 rpm), and 3provides a passageway for the drilling mud to get into the drill stem

The KELLY The Kelly is a flat-sided,heavy steel pipe that attached to the bottom of the swivel. Kellys are manufactured from high grades of chrome molybdenum steel and heattreated. The Kelly is usually 40 feet (12.2 meters) and 54 feet(16.5 meters) long and has either four (square) or six (hexagonal) flatted sides. The attachments to the Kelly include upper Kelly cock, lower Kelly cock (drill pipe safety valve), and the Kelly saversub. Functions of the kelly: Transmits the rotation of the rotary table to the drill string 12Conducts drilling fluid from the swivel to the drill stem. Upper Kelly cock: is installed between the swiveland the Kelly. It protects the equipment above the Kelly in emergencies and stops the flow of fluids up the drill stem. Lower Kelly cock: installed below the Kelly and is like a standby safety valvefor blowout prevention. Kelly saver sub: is short threaded pipe that fits below the Kelly. It minimizes the wear on the Kelly’s threads.

The master bushing performs two jobs: 1 2 During drilling, itconnects the rotary table to the Kelly bushing and transfers rotation from one to the other. When drilling stops, the master bushing holds the slips.

DRILLPIPE The main functions of drillpipe are totransmit rotary motion and drilling mud under high pressure to the drill bit. 1

The drillpipe must be capable of withstanding all types of imposed loading, such as axial loading, radial forces due...