What happens when drilling pipes get stuck in borehole drilling

When drilling pipes get stuck in borehole drilling, it can pose significant challenges and may require specialized techniques to resolve the situation. 

Here are some common scenarios and potential solutions:

1. Differential Sticking: 

This occurs when the drill pipe becomes stuck due to the pressure difference between the drilling fluid inside the pipe and the formation fluid outside. To address this, techniques such as applying additional drilling fluid or using chemical additives to reduce friction might be employed. Alternatively, the drill string can be rotated or reciprocated to free it from the stuck position.

2. Hole Instability: 

In some cases, the borehole itself may collapse or become unstable, trapping the drill pipe. This can happen when drilling through weak or fractured formations. To overcome this, drilling mud can be circulated to stabilize the hole, or specialized tools like casing or liners can be used to reinforce the wellbore.

3. Mechanical Failure: 

Equipment failures or malfunctions can result in the drill pipe getting stuck. For example, a part of the pipe may break or become detached, causing it to become wedged in the wellbore. In such cases, fishing tools—which are specifically designed to retrieve stuck objects—can be employed to engage and extract the stuck pipe.

4. Lost Circulation: 

This occurs when the drilling fluid escapes into highly permeable formations, leading to a loss of hydraulic pressure and subsequent sticking of the pipe. Various techniques can be used to combat lost circulation, such as using specialized lost circulation materials, adjusting the drilling fluid properties, or employing wellbore strengthening techniques.

5. Geological Obstructions: 

Sometimes, the drill pipe may encounter unexpected obstructions, such as boulders or hard rock formations, which can cause it to become stuck. In such cases, specialized tools like rotary hole openers, underreamers, or percussion tools can be utilized to remove or break through the obstructions.