Vibration Mechanisms In Drillstring by SperrySun

Vibration in drillstring is one of major downtime associated with drilling operation. Therefore, it is very important to learn and understand what each vibration mechanism is. This VDO created by Sperry Drilling Services well explains various of vibration modes that is happened downhole with the drillstring. You can watch the VDO here and we also provide full VDO transcription to help learns get more understanding about the content if the learners cannot catch all wordings from this VDO.

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Using Combined Load Chart For Stuck Pipe Situation

When the drill string get stuck, there are several ways to free the string as using Jar (up and/or down), straight pull, working torque down, etc. Pulling stuck pipe with torque in the drill string is one of those technique which often utilize to free the stuck drill string. However, there are some concerns that you should know before doing this because torque in the string will reduce a tensile capacity of tubular. This is very important to read and understand the combined load chart (Torque‐Tension Graph) in order to determine the limitation before pulling the pipe.

combined-load-chart-for-stuck-pipe

For this example, we use 5” DP, S-135, NC50 (4-1/2” IF connection) to be a reference figure.

Pipe information

  • Pipe Size and Weight: 5.000″ 19.50ppf 0.362″ wall IEU
  • Pipe Grade: S-135
  • Range: 2
  • Tool Joint: 6.625″ X 3.250″ NC50
  • Tool Joint 120,000 psi Material Yield Strength
  • Premium class

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Drill String Components – VDO Training

This is a great VDO Training about drill  string components. We also added the detailed transcripts so you can learn from the VDO effectively.

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Transcription of Drill String Components 

drillstring component

There are many components that make up the drill string as shown in this graphic. Drill pipe is a strong but relatively lightweight pipe. Crew members attach it to a top drive or Kelly. Drill pipe forms the upper part of the drill string. Usually the drill pipe rotates which also rotates the bit. Each section of pipe is called a joint. Crew members screw together or make up several joints and put them in to the hole as the bit drills.

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Why Does Drillstring Fail? Basic Understanding of Drill String Failure

In drilling industry, it is common that drill string will fail while drilling. Two main factors causing drillstring failure are stresses and corrosion.

Stress Affects on Drillstring

Drillstring is exposed to the following stresses:

Tension – Suspended weight of drillstring sometimes can be several thousand pounds. Additionally, overpull weight while pulling out can be over drill string limit resulting failure (see Figure 1).

 

Drillpipe-Stress-and-Failure-1

Figure 1 – Drillstring in Tensile

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Basic Understanding about Drill Pipe

Drillpipe is seamless steel pipe made up in the drill string and it is the major component of the entire drillstring. Typically, 90% – 95% of the total length is drill pipe. Thread connection of drill pipe is called “Tool Joint”. One end of drill pipe has a female end which is named as “Box” (see Figure 1).

basic-Understanding-About-Drill-Pipe-1-Box-Connection

Figure 1 – Box End of Tool Joint

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