I live in an unconsolidated sandy area of Virginia Beach, Va. I think mud rotary drilling is the hardest method of drilling there is. A driller must know more about the proper muds and additives to keep the drilled hole open, prevent washouts, remove the cuttings from the hole, and allow the hole to stay open until the casing can be installed, gravel packed and grouted. It takes years of experience to become a proficient mud-rotary driller. Then some never do.
Recently, my son Chris (“Piglet”) went to Haiti to teach mud-rotary drilling. The previous driller was young and only experienced with unconsolidated formations. In Haiti, much of the drilling is in consolidated formations (hard rock). When Piglet arrived, he first saw that the roller cone bit bearings were shot, but the teeth were hardly worn. This wear pattern told Piglet that the driller was turning the bit too fast and not using enough weight on the bit.
Rotary-air and downhole hammer drilling requires its own specific drilling knowledge and experience requirements. Air drilling is much easier in that the hole is less apt to cave in and lock your tools in the hole. However, you still must have the proper drilling equipment and experienced people to operate and service the equipment, lots of fuel and compressed air – plus the proper additives to lubricate the tools, stabilize the hole and remove the cuttings. I love downhole hammer drilling.
Cable-tool drilling is an old and reliable drilling method that works anywhere in the world with a minimum of support equipment, but it is too slow for most people in the United States. Developing countries usually are not in such a hurry, and often don’t have access to all of the required support equipment, such as water, fuels and muds, so it usually is the preferred method. There is one drawback to cable-tool drilling in that it sometimes requires advancing the hole with steel casing.
Recently, Piglet went to Nigeria to teach cable-tool drilling. We knew before he left that the drill owner had purchased the improper (cable tool) equipment for his requirements. Not only that, the drill owner had purchased two of these drills. Unfortunately, when people contact us to teach them to drill, it usually is after they have purchased their equipment. Piglet was able to teach them to drill wells with their equipment, and only then could he advise them that they needed downhole hammer drills to compete in their markets.
In my years of drilling in all types of formations with all types and makes of drilling equipment, mud rotary is my favorite; however, I do like downhole hammer drilling when drilling consolidated formations. Because when you get the rig adjusted to drill the formation that you are drilling in, it is the nearest to “set it and watch it” that I’ve seen.
Update on Our Failing 250 DrillI’ve had several rigs in my life, but a small Failing 250 was my favorite. Recently, I found one, and I wanted it. Not that I plan to drill with it – you just can’t take away an old man’s toys.
In June, my sons and I purchased the drill, and had it shipped to my son Randy in North Carolina, where he is rebuilding it and mounting it on a late-model Ford F-350 diesel 4-by-4 truck.
Since July, Randy, without any help, has removed the rig from the existing truck, removed the mast and removed the mud pump. He currently is rebuilding the mud and gear end of the mud pump. He’s rebuilding the gear boxes and rotary table. He’s pressure-washed the whole rig. He’ll rebuild the frame, side plates, flooring, drill stem box and mud pan. Once it’s all rebuilt, he’ll mount it on the new truck, and will test it for a time drilling geothermal loops.
Once it is tested, we’ll paint and detail it. Our goal is to have it on display it at the South Atlantic Well Drillers Jubilee in Virginia Beach in 2013.