Drill Pipe Back-Off Operation

For back-off operations to be successful on the first try, plans must be devised and then carefully followed; this should also keep the risk of injury low for rig floor personnel. Of course, the Contractor Driller/Tool pusher and the Fishing Tool Supervisor need to oversee the process since it’s considered a non-routine operation.

Steps for Safety

1) Firstly, a safety meeting, coordinated by the Drilling Supervisor, should take place before the procedure itself. With all rig personnel in attendance, the meeting will explain the no-go areas during torque application (and when torque is held on the drill string), the hazards of the operation, and the proper use of equipment in order to prevent injury.

For personnel not essential to the task at hand, they should stay well away from the rig floor until completion.

2) To hold right or left-hand torque in the string, sometimes rotary slips and rig tongs will be used. If this is the case, the slip insert dies need to be sharp (while also fitting into the slots themselves). If any dies have signs of wear during an inspection, they should be replaced. Continue reading

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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Determine Stuck Pipe Depth Based on Real Example

This is the real example of how to determine stuck depth using the stuck depth calculation.

Well Information:

  • TD = 8,900’MD/5,600’ TVD
  • Bit Size = 8.5”
  • Drilling fluid = water based mud (PHPA system)
  • Formation: sand shale sequence
  • BHA: 7” mud motor + 9 stands of 5” HWDP S-135, 4-1/2” IF connection
  • Drillstring: 5” DP S135, 4-1/2” IF connection
  • Neutral weight @ 6,850’MD = 175 Klb

While tripping out of hole to 6,850’MD, observe over pull 40 Klb over pick up weight. Stop tripping out and attempt to go down no issue. Attempt to rotate, pipe is able to rotate at 30K ft-lb. Attempt to circulate, observe restricted flow.

Figure 1 - Stuck While Pulling Out

Figure 1 – Stuck While Pulling Out Continue reading

How To Free Stuck Pipe (Oilfield)

This article is a summary of how to free stuck pipe caused by three main mechanisms which are wellbore geometry, differential sticking and packing/bridging off. It will give you some ideas which you can apply for your operation.

How-to-free-a-stuck-pipe2

 

Free Stuck Pipe Caused By Wellbore Geometry

These following instructions are guide lines on how to free the stuck drill string caused by wellbore geometry.

What should you  do to free the stuck pipe caused by wellbore geometry ?

• If the drill string gets stuck while moving up, jar down with maximum trip load and torque can be applied into drill string while jarring down. Be caution while applying torque, do not exceed make up torque.

• On the other hand, if the drill string gets stuck while moving down, jar up with maximum trip load. DO NOT apply torque in the drill string while jarring up.

• Flow rate must be reduced while attempting to free the drill string. Do not use high flow rate because it will make the stuck situation became worse and you will not be able to free the pipe forever.

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Tectonic Stress Causes Stuck Pipe

Tectonic stress is a nature phenomenal and it naturally occurs due to lateral force from the formation. Typically, if the rig is close to mountains, there is high chance to face with the tectonic stress issue. 

The later force will create stress which will squeeze sandstone causing under gauge hole. Moreover, the lateral stress will fracture shale and create additional cuttings. 

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