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Eric Hagenimana
A00015905
PET 410
Dr. Obioma U. Uche
Causes and Methods of Preventing Drillpipe Failures
Drilling problems can still occur even though the well planning activities have been
carefully done. Drilling is an expensive operation in oil and gas exploration and production
industry; therefore, drilling design program should focus on how to anticipate potential problems
rather than focusing on caution and containment (Amro, 2000). Understanding the causes and
how to anticipate potential drilling problems is the key to a successful drilling design program.
Drilling problems can occur at any stage of the drilling; hence, the driller and his clue should
always be vigilant in order to anticipate when needed. The most dominant drilling problems
include hole deviation, pipe sticking, borehole instability, formation damage, lost circulation,
drillpipe failures, mud contamination, as well as hole cleaning (Bourgoyne, et al., 1986). This
paper, therefore, discusses the potential causes of drillpipe failure as well as preventive methods
used to avoid such problem.
Drillpipe failure is one of the most encountered drilling problems. Drillpipe is one of the
major components of a drilling rig which transmits the rotational force from the surface to
drilling bit. It also serves as a conduit through which the drilling fluids are sent down to the base
of the well for cuttings removal and other purposes. It is of a paramount importance to know
what causes drillpipe failure as well as the preventive or remedial methods in case it happened.
Drillpipe failure is attributed to the following process: “twist off, parting, fatigue, collapse and
burst” (Azar, 2006). These are the main causes of drillpipe failure, and they are represented on
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the figure below. Details on those processes and how they induce drillpipe failure are provided
below.
Figure 1: different form of drillpipe failure
Twist off is one of the causes of drillpipe failure that takes place when excessive torque is
applied on the drillpipe. It occurs when the applied shear stress resulting from high torque
surpasses the pipe material ultimate shear stress. Although twist off is not common in vertical
well drilling under normal drilling practices, in directional and extended-reach drilling excess
torques are common and can easily induce twistoff (Azar, 2006). Twist off leads to fracturing or
complete breakdown of the drillpipe.
Parting is another potential cause of drillpipe failure which takes place as a result of
excessive tension. When the applied tensile stress exceeds the ultimate tensile stress of the pipe-
material, pipe-parting failure occurs as a result. Pipe-parting failure occurs when pipe sticking
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happens and an additional force to the weight of suspended drillpipe known as an overpull is
induced in the hole above the stuck point. In addition to parting, although they are not common
in normal drilling operation, collapse and burst can also be the causes of drillpipe failure.
Collapse and burst can occur as a result extreme conditions of high mud weight or complete loss
of circulation. Collapse failure is caused by excessive pressure exerted from outside the drillpipe
while burst failure occurs due to high pressure exerted from inside the drillpipe. Collapse and
burst can be controlled by careful choosing the drilling mud that will help to keep pressure
balance while drilling (Rabia, 1985).
Fatigue is defined as a dynamic phenomenon that initiates micro-cracks in the material
and propagates them into macro-cracks as a result of continuous application of stress. It is a
process of localized progressive structural member that may not fail under the action of dynamic
stress. It is well established that a member that cannot fail under a static load may fail when that
load is repeatedly applied. Drillpipe fatigue failure is one of the most known and costly failure in
oil and gas drilling operations. It occurs from a combined effect of cyclic stresses and corrosion.
Cyclic stresses are caused by the dynamic loads exerted by the drillstring vibration as well as
doglegs caused by rotation. Drillpipe corrosion occurs in presence of oxygen (O2), carbon
dioxide (CO2), chloride ions (Cl-), and hydrogen sulfide (H2S). Although drillpipe fatigue is the
most common drillpipe failure, it still not well understood. The lack of understanding is due to
the variation of statistical data required to determine the type of environment and service of the
drillpipe, as well as the applicability of material fatigue data (Rollins, 1966).
Although it is not possible to totally eliminate drillpipe failure, some plans need to be
developed in order to minimize the magnitude of occurrence. Fatigue failure can be reduced by
minimizing the applied cyclic (repeated) stress as well as making sure that the environment is
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noncorrosive during drilling operations. Reduction of cyclic stresses can be achieved by
controlling the magnitude of dogleg severity as well as drillpipe vibration. The use of appropriate
corrosion scavengers and controlling the pH of the drilling mud can also minimize drillpipe
corrosion as well as fatigue. Twist off and parting failure can be minimized or avoided by careful
choosing the appropriate pipe-material which can handle the torque and tension required during
drilling operations. Collapse and Burst can be avoided by careful analyzing the formation
pressure in order to design appropriate drilling mud (PetroWiki, 2015).
Regardless of the cause of the drillpipe failure, drillpipe failure is a costly failure in oil
and gas drilling operations. It is therefore advised to examine all the possible options that can
lead to the drillpipe failure. The key to successful drilling operations is to have a good plan that
will help to minimize drilling problems. As discussed in this paper, drillpipe failure occurs as a
result of twist off, parting, fatigue as well as collapse and burst. The solutions to minimize the
degree of occurrence of those processes may be well developed prior to drilling operations.
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References
A.T, B. M. (1986). Applied Drilling Engineering. Richardson, Texas: Society of Petroleum Engineers.
Amro,M. (2000). Causesand Remedies of Drillstring Failures While Drilling Medium Radius Horizontal
Wells. OnePetro. Retrieved November 28, 2015, from https://www.onepetro.org/conference-
paper/SPE-62789-MS
Azar, J. (2006). Petroleum Engineering Handbook: Drilling Problems and SOlutions (Vol. II). (L. W. Lake,
Ed.) Richardson, Texas: Society of Petroleum Engineers.
Drilling Problemsand Solutions.(2015, June).(Societyof PetroleumEngineers) Retrieved November 29,
2015, from PetroWiki:
http://petrowiki.org/PEH%3ADrilling_Problems_and_Solutions#Drillpipe_Failures
Rabia, H. (1985). Oil Well Drilling Engineering. London: Graham and Trotman Ltd.
Rollins, H. (1966, January). Drill Stem Failure. Oil & Gas Journal.
