Bits ‘n Pieces – The Driller’s Blog

How to Keep from Getting Stuck in a Bore Hole

Posted by Rod McCoremick on Jul 4, 2016 10:30:00 AM


Despite years of drilling experience, sometimes unexpected things happen and you get stuck in a bore hole. This is a real pain. Everything comes to a screeching halt when your bit melts and fuses to the rock or when your rods break. No money is being made when your drill is not turning so fixing the problem, or better yet, preventing it, is crucial. There are many reasons why you can get stuck in a hole so let’s look at how we can avoid them as well as some fixes to the problem.



Ground Conditions

Ground conditions can be one of the reasons why equipment gets jammed, or stops functioning. Certain types of clay can swell enormously when they come into contact with the water used in diamond drilling. This swelling clay can literally envelop drill rods, core bits or other equipment, causing moving parts to stop.

Coming across very loose and sandy conditions can also be harmful to your drilling equipment. Flowing sand can collapse around the drilling equipment also causing it to stop operating or become trapped.

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Equipment Problems

On the other hand, the rod string can also break, either from too much pressure or by being dropped, or by being worn or damaged.  In all cases, you will need to try and retrieve it.

A bit that has melted and fused to the rock is also a bad situation that will stop operations quickly. Poor water circulation or loss of water return because of a void or fault in the ground means the bit may not be cooled properly and can lead to the bit melting. Other reasons for poor water circulation include a pump that is not working properly or rods that are leaking.

Preventing the problem

Prevention is always preferable so if you expect clay or sand, drilling fluid additives should be used to prevent problems. Products such as Sand Drill can be used to stabilize a hole in sandy conditions and prevent a collapse. In the case of clay, DD-955 is a product that is absorbed directly into the clay and shale and reduces in-hole swelling and instability. To enhance the performance of any and all polymers, Torqueless should be premixed with the products before use. It will also go a long way in preventing clay from sticking to the core bit or other tooling.

If the ground is known to have faults that could cause a loss of water circulation, a polymer that can expand in volume can be an indispensable tool. For example, DD X-Pand is a good product to fill in fissures, cracks and holes easily and efficiently. (Read this blog post to learn more about the top five drilling additives.)

To prevent equipment problems, you should always check your drill rods to make sure they don’t leak. Verify the joints for excessive wear and tear as well. A lubricating product such as Torqueless will help reduce torque and vibration, prevent rust and wear and tear on drill rods. A go/no go gauge can be used to verify the diameters of your drill rods so you can assess their condition.  Learn more about how to handle your drill rods here. Make sure to perform regular maintenance on your pump as well.

Fixing the problem

In the case of broken equipment, especially if you have achieved a significant depth in drilling over a long period of time, it is preferable to try and retrieve what equipment you can than to start over drilling a new hole. This will save some of your equipment and the time you have invested in the hole itself.

Different types of in-hole tools are available depending on the situation. If you have dropped your rod or it has broken in the hole, you can use recovery tools or fishing tools to try and retrieve the rod. In the case of a fused bit, rod or casing cutters can be used.  If you are unsuccessful in retrieving your rods, wedges can be used to deviate from your original borehole. You may forfeit some of your equipment but at least part of the hole can be salvaged. 



CONCLUSION:

Getting stuck in the hole means you have to stall operations and that means a loss of productivity. Prevention and education are the best ways to avoid this problem. Some guidance in proper hole maintenance, and how to use fluids to improve conditions can also be helpful. Our technical onsite support team can visit a drill site and offer corrective solutions quickly so you are up and running as soon as possible.


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Topics: Tips on common drilling issues



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