Page 92 - Air and gas Drilling Field Guide 3rd Edition

4.4 Drill Pipe 83

the drill string in order for the compass to give accurate azimuth readings. This is
why nonmagnetic drill collars are placed at the bottom of the drill string. When
running the single-shot survey, care must be taken to make sure that the single-
shot instrument is located approximately midway along the nonmagnetic drill col-
lar length section before the camera film is allowed to be exposed.
More details regarding directional drilling operations and surveys are dis-
cussed in Chapter 12.

4.4 DRILL PIPE
There are four types of drill pipe used in air and gas drilling operations. These are
standard API drill pipe, heavyweight drill pipe, drill rod, and dual wall pipe.

4.4.1 Standard API Drill Pipe
Standard API drill pipe is used in most rotary drilling operations (shallow and
deep). API drill pipes are fabricated by various API-certified manufacturers around
the world, principally for use in the drilling of deep wells for the recovery of oil
and natural gas. The nominal weight per unit length defines the wall thickness
and the inside diameter of the pipe body. When tool joints (box and pin) are
added to a pipe body, the average actual weight per unit length of the drill pipe
element is increased above the pipe nominal weight per unit length. API drill
pipe is also classified by API material (steel) grade. Tables 4-2a and 4-2b give

Table 4-2a. API Drill Pipe Steel Grade Minimum and Maximum Mechanical Properties
in USCS Units [1, 7]
API Grade E75 X95 G105 S135
Minimum yield (psi) 75,000 95,000 105,000 135,000
Maximum yield (psi) 105,000 125,000 135,000 165,000
Minimum tensile (psi) 100,000 105,000 115,000 145,000

Table 4-2b. API Drill Pipe Steel Grade Minimum and Maximum Mechanical Properties
in SI Units

API Grade E75 X95 G105 S135
Minimum yield (MPa) 517 655 724 931
Maximum yield (MPa) 724 862 931 1138

Minimum ultimate tensile (MPa) 690 724 793 1000