5.1.1 Preperation and Inspection Before Running
New tubing is delivered free of injurious defects as
defined in API Specification 5CT and within the practical
limits of the inspection procedures therein prescribed. Some
users have found that, for a limited number of critical well
applications, these procedures do not result in tubing suffi-ciently
free of defects to meet their needs for such critical
applications. Various nondestructive inspection services have
been employed by users to ensure that the desired quality of
tubing is being run. In view of this practice, it is suggested
that the individual user:
a.Familiarize himself with inspection practices specified in
the standards and employed by the respective manufacturers,
and with the definition of “injurious defect” contained in the
standards.
b. Thoroughly evaluate any nondestructive inspection to be
used by him on API tubular goods to assure himself that the
inspection does in fact correctly locate and differentiate injurious
defects from other variables that can be and frequently
are sources of misleading “defect” signals with such inspec-tion
methods.
CAUTION: Due to the permissible tolerance on the outside
diameter immediately behind the tubing upset, the user is cau-tioned
that difficulties may occur when wrap-around seal-type
hangers are installed on tubing manufactured on the high side
of the tolerance; therefore, it is recommended that the user
select the joint of tubing to be installed at the top of the string.
5.1.2 All tubing, whether new, used, or reconditioned,
should always be handled with thread protectors in place.
Tubing should be handled at all times on racks or on wooden
or metal surfaces free of rocks, sand, or dirt other than normal
drilling mud. When lengths of tubing are inadvertently
dragged in the dirt, the threads should be recleaned and ser-viced
again as outlined in 5.1.9.
5.1.3 Before running in the hole for the first time, tubing
should be drifted with an API drift mandrel to ensure passage
of pumps, swabs, and packers.
5.1.4 Elevators should be in good repair and should have
links of equal length.
5.1.5 Slip-type elevators are recommended when running
special clearance couplings, especially those beveled on the
lower end.
5.1.6
Elevators should be examined to note if latch fitting is
complete.
5.1.7 Spider slips that will not crush the tubing should be
used. Slips should be examined before using to see that they
are working together.
Note: Slip and tong marks are injurious. Every possible effort should
be made to keep such damage at a minimum by using proper up-to-date
equipment.
5.1.8 Tubing tongs that will not crush the tubing should be
used on the body of the tubing and should fit properly to
avoid unnecessary cutting of the pipe wall. Tong dies should
fit properly and conform to the curvature of the tubing. The
use of pipe wrenches is not recommended.
5.1.9 The following precautions should be taken in the
preparation of tubing threads:
a. Immediately before running, remove protectors from both
field end and coupling end and clean threads thoroughly,
repeating as additional rows become uncovered.
b. Carefully inspect the threads. Those found damaged, even
slightly, should be laid aside unless satisfactory means are
available for correcting thread damage.
c. The length of each piece of tubing shall be measured prior
to running. A steel tape calibrated in decimal feet (millimeters)
to the nearest 0.01 feet (millimeters) should be used. The measurement
should be made from the outermost face of the
coupling or box to the position on the externally threaded end
where the coupling or the box stops when the joint is made up
power tight. The total of the individual lengths so measured
will represent the unloaded length of the tubing string.
The actual length under tension in the hole can be obtained
by consulting graphs that are prepared for this purpose and
are available in most pipe handbooks.
d. Place clean protectors on field end of the pipe so that
thread will not be damaged while rolling pipe onto the rack
and pulling into the derrick. Several thread protectors may be
cleaned and used repeatedly for this operation.
e. Check each coupling for makeup. If the stand-off is abnormally
great, check the coupling for tightness. Loose
couplings should be removed, the thread thoroughly cleaned,
fresh compound applied over the entire thread surfaces, then
the coupling replaced and tightened before pulling the tubing
into the derrick.
f. Before stabbing, liberally apply thread compound to the
entire internally and externally threaded areas. It is
recommended that a thread compound that meets the
performance objectives of API Bulletin 5A2 be used;
however, in special cases where severe conditions are
encountered it is recommended that high pressure silicone
thread compound as specified in API Bulletin 5A2 be used.
g. Connectors used as tensile and lifting memebersshould
have their thread capacity carefully checked to ensure that
the connector can safely support the load.
h. Care should be taken when making up pup joints and
connectors to ensure that the mating threads are of the same
size and type.
5.1.10 For high-pressure or condensate wells, additional precautions should be
taken to ensure tight joints as follows.
a. Couplings should be removed, and both the mill-end pipe
thread and coupling thread thoroughly cleaned and inspected.
To facilitate this operation, tubing may be ordered with
couplings hankling tight, or may be ordered with the couplings
shipped separately.
b. Thread compound should be applied to both the external
and internal threads, and the coupling should be reapplied
handling tight. Field-end threads and the mating coupling
threads should have thread compound applied just before
stabbing.
5.1.11 When tubing is pulled into the derrick, care should
be taken that the tubing is not bent or couplings or protectors
bumped.
5.2 STABBING, MAKING UP, AND LOWERING
5.2.1 Do not remove thread protector from field end of tubing until ready to stab.
5.2.2 If necessary, apply thread compound over entire sur-face
of threads just before stabbing. The brush or utensil used
in applying thread compound should be kept free of foreign
matter, and the compound should never be thinned.
5.2.3 In stabbing, lower tubing carefully to avoid injuring
threads. Stab vertically, preferably with the assistance of a
man on the stabbing board. If the tubing tilts to one side after
stabbing, lift up, clean, and correct any damaged thread with
a three-cornered file, then carefully remove any filings and
reapply compound over the thread surface. Care should be
exercised, especially when running doubles or triples, to pre-vent
bowing and resulting errors in alignment when the tub-ing
is allowed to rest too heavily on the coupling threads.
Intermediate supports may be placed in the derrick to limit
bowing of the tubing.
5.2.4 After stabbing, start screwing by hand or apply regu-lar
or power tubing tongs slowly. To prevent galling when
making connections in the field, the connections should be
made up at a speed not to exceed 25 rpm. Power tubing tongs
are recommended for high-pressure or condensate wells to
ensure uniform makeup and tight joints. Joints should be
made up tight, approximately two turns beyond the hand-tight
position, with care being taken not to gall the threads. When
the additional preparation and inspection precautions for
high-pressure or condensate wells are taken, the coupling will
“float” or make up simultaneously at both ends until the
proper number of turns beyond the hand-tight position have
been obtained. The hand-tight position may be determined by
checking several joints on the rack and noting the number of
threads exposed when a coupling is made up with a torque of
50 ft-lb (68 N • m).
5.3 FIELD MAKEUP
5.3.1 Joint life of tubing under repeated field makeup is
inversely proportional to the field makeup torque applied.
Therefore, in wells where leak resistance is not a great factor,
minimum field makeup torque values should be used to prolong
joint life. The use of power tongs for making up tubing
made desirable the establishment of recommended torque
values for each size, weight, and grade of tubing. Table 3 con-tains
makeup torque guidelines for nonupset, external upset,
and integral joint tubing, based on 1 percent of the calculated
joint pullout strength determined from the joint pullout
strength formula for 8-round-thread casing in API Bulletin
5C3. All values are rounded to the nearest 10 ft-lb (13.5 N •
m). The torque values listed in Table 3 apply to tubing with
zinc-plated or phosphate-coated couplings. When making up
connections with tin-plated couplings, 80 percent of the listed
value can be used as a guide. When making up round-thread
connections with PTFE (polytetrafluoroethylene) rings, 70
percent of the listed values are recommended. As with standard
couplings, makeup positions shall govern. Buttress
connections with PTFE seal rings may make up at torque val-ues
different from those normally observed on standard but-tress
threads.
Note: Thread galling of gall-prone materials (martensitic chromium
steels, 9 Cr and 19 Cr) occurs during movement stabbing or pulling
and makeup or breakout. Galling resistance of threads is
primarily controlled in two areas—surface preparation and
finishing during manufacture and careful handling practices
during running and pulling. Threads and lubricant must be clean.
Assembly in the horizontal position should be avoided. Connections
should be turned by hand to the hand-tight position before slowly
power tightening.The procedure should be reversed for disassembly.
5.3.2 Spider slips and elevators should be cleaned fre-quently,and slips should
be kept sharp.
5.3.3 Finding bottom should be accomplished with extreme caution. Do not set
tubing down heavily.
5.4 PULLING TUBING
5.4.1 A caliper survey prior to pulling a worn string of tub-ing will provide a
quick means of segregating badly worn lengths for removal.
5.4.2 Breakout tongs should be positioned close to the cou-pling. Hammering
the coupling to break the joint is an injurious practice. When tapping is
required, use the flat face, never the peen face, of the hammer, and tap
lightly at the middle and completely around the coupling, never near the
end or on opposite sides only.
5.4.3 Great care should be exercised to disengage all of thethread before
lifting the tubing out of the coupling. Do not jump tubing out of the
coupling.
Tubing stacked in the derrick should be set on a firm wooden platform
and without the bottom thread protector since the design of most
protectors is not such as to support the joint or stand without damage to
the field thread.
5.4.5 Protect threads from dirt or injury when the tubing is
out of the hole.
5.4.6 Tubing set back in the derrick should be properly supported to prevent
undue bending. Tubing sizes 2 3 / 8 and larger preferably should be
pulled in stands approximately 60 feet (18.3 meters) long or in doubles of
range 2. Stands of tubing sizes 1.900 OD or smaller and stands longer
than 60 feet (18.3 meters) should have intermediate support.
5.4.7 Before leaving a location, always firmly tie a setback of tubing in place.
5.4.8 Make sure threads are undamaged, clean, and well coated with
compound before rerunning.
5.4.9 Distribute joint and tubing wear by moving a length from the top of the
string to the bottom each time the tubing is pulled.
5.4.10 In order to avoid leaks, all joints should be retight-ened occasionally.
5.4.11 When tubing is stuck, the best practice is to use a calibrated weight
indicator. Do not be misled, by stretching of the tubing string, into the
assumption that the tubing is free.
5.4.12 After a hard pull to loosen a string of tubing, all joints pulled on should be
retightened.
5.4.13 All threads should be cleaned and lubricated or should be coated with a
material that will minimize corrosion. Clean protectors should be placed
on the tubing before it is laid down.
5.4.14 Before tubing is stored or reused, pipe and threads should be inspected
and defective joints marked for shopping and regauging.
5.4.15 When tubing is being retrieved because of a tubing failure, it is
imperative to future prevention of such failures that a thorough
metallurgical study be made. Every attempt should be made to retrieve
the failed portion in the “as-failed” condition. When thorough etallurgical
analysis reveals some facet of pipe quality to be involved in the failure,
the results of the study should be reported to the API office.
