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.
For this example, we use 5” DP, S-135, NC50 (4-1/2” IF connection) to be a reference figure.
- 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
This is the real example of how to determine stuck depth using the stuck depth calculation.
- 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 Continue reading
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.
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.
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.
I have posted several stuck pipe articles and I would like to summarize all articles in one page so you can use it for future reference.
Stuck pipe categories
There are 3 categories of stuck pipes as follows:
1. Packing off and bridging: There are seven cases in this category.
• Cutting settling in near well bore wells and cutting setting in deviated wells
• Shale instability
• Unconsolidated formations
• Fractured formations
• Soft cement
• Cement Blocks