What drill pipe failures occur when oil well drilling operations are performed?

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The drill pipe is a key equipment or tool in the drilling of oil wells, since without it it would be impossible to reach certain depths, where in order to reach a greater and greater depth we have to add more drill pipes.

Given the importance of drill pipe in oil well drilling operations, it is important to know all the possible ways in which drill pipe can fail and also to know why this represents a serious problem in well drilling operations.

The ways in which drill pipe can fail involve several categories including: high torque, burst or collapse failure, fatigue due to mechanical loads. The important thing about being able to diagnose a drill pipe failure is that behind its cause there is also a possible solution.

High torque failure does not occur in all cases of well drilling, for example when drilling vertically it is seen that the allowed torque values are not exceeded, however when drilling directionally torques can exceed values above 80,000 lb-ft which can easily cause torques that cause the drill pipe to fail.

The solution to this type of failure is to correctly monitor the torque and drag values when drilling directionally and keep the torque values below the allowable values supported by the drill pipe in use.

Tension failure generally occurs when tension is applied to the drill pipe to free it from a pipe stick, it is not that the tension is wrong, but when the permissible tension values are exceeded, the pipe gives way and breaks at some point of it, so it can be left at the bottom of the well the drill bit, a certain length of drill pipe, and the downhole motor if it is being drilled in a directional way.

To avoid this type of failure, the problems of sticking of the pipe must be avoided, since if the drill pipe does not stick, it is not necessary to try to detach it by exerting tensile stresses that may exceed the permissible values of the drill pipe.

It is very rare that the drill pipe fails by bursting or collapse, however when suddenly the density of the drilling fluid has to be increased, the pressure inside the drill pipe increases causing a burst pressure that causes the pipe to fail by bursting.

When the failure is by collapse is because drilling fluid is lost to the formation, so the formation pressure is not counteracted by the pressure of the drilling fluid, causing a crushing of the drill pipe caused by collapse pressure.

In order for these failures by bursting and collapse not to occur, it is necessary to take care of the drilling fluid density values and avoid circulation losses.

In addition to all the types of failures explained, it should be taken into account that even if a failure does not occur at first sight, in the same way due to all the movements and mechanical stresses to which the drill pipe is subjected, it is suffering wear that a priori are translated into wear failures, so it is recommended the supervision and certification of the drill pipe every time its work is completed in the construction of an oil well..

References

Drilling problems

PEH:Drilling Problems and Solutions