Drill stems must be designed to transfer drilling torque for combined lengths that often exceed several miles down into the , and also must be able to resist pressure differentials between inside and outside (or vice versa), and have sufficient strength to suspend the total weight of deeper components. For deep wells this requires tempered steel tubes that are expensive, and owners spend considerable efforts to reuse them after finishing a well.
[pdf] Both high-pressure mud pumps are utilized on rigs to circulate the drilling fluidaround. Each type, however, has its operating limits,. .
The speed of the piston is not constant during the suction and discharge strokes. During each stroke, the speed increases from zero to maximum at approximately the halfway position. .
Mud pumps must be equipped with pressure relief valves. These valves prevent too high a pressure from being built up in the circulating system. The relief valves most.
[pdf] An automated drill rig (ADR) is an automated full-sized walking land-based drill rig that drills long lateral sections in horizontal wells for the oil and gas industry. ADRs are agile rigs that can move from pad to pad to new well sites faster than other full-sized drilling rigs. Each rig costs about $25 million. ADR is used extensively in the . According to the "Oil Patch Daily News", "Each rig will generate 50,000 man-hours of work during the construction phase and up.
[pdf] 
