The neutral point is usually defined as the point in the drillstring where the axial stress changes from compression to tension. The location of this neutral point depends on the weight-on-bit and the buoyancy factor of the drilling fluid. In practice, since the WOB fluctuates, the position of the neutral point changes. It is therefore quite common to refer to a "transition zone" as the section where axial stress changes from compression to tension.
Drillstring components located in this "transition zone" may, therefore, alternately experience compression and tension. These cyclic oscillations can damage downhole tools. A prime example is drilling jars, whose life may be drastically shortened if the jars are located in the transition zone. It is also important, as previously explained, to know if any drill pipe is being run in compression. Therefore it is important to know the location of the neutral point.
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