Readers, don’t let the title scare you. A driller operating a spudder or cable-tool machine might go months, even years, without a problem down the hole. Then, perhaps on a sunny afternoon, wham! There is trouble in the hole.
Tool catalogs list all kinds of fishing tools. One catalog I have lists as many pages of fishing tools as drilling tools. However, in small-diameter drilling — that is, 3- to 6-inch casing — the likelihood of losing tools down the hole and having to “fish” for them is not that great. (At this diameter, drillers more likely encounter stuck tools, which require loosening so drilling can resume.) However, it does happen. So, for this discussion I start with some simple tools I consider essential to a cable-tool operation. Drillers should keep these in inventory at all times and even keep some of them on the rig.
The first “fishing tool” a driller needs is not a fishing tool at all, but a jar bumper. These come in two different but effective styles. I know some drillers who wouldn’t drill a foot without jars in the tool string. They have that privilege. Others — and I’m in this category — rarely use drilling jars when working in unconsolidated drift. (Bedrock drilling is a different animal where I would recommend drilling jars at all times.) On occasion, when drilling in drift, if the drilling tools are working near the bottom of the casing and the casing shoe, a pebble or small stone will wedge between the casing and the forged-out, larger portion of the drill bit. The tool string is then stuck. No amount of pulling will loosen the pebble’s hold on the tools. Enter our friend, the jar bumper.
An eye-top bumper, as the name implies, features an eye at the top, which attaches to the sand line. For a 6-inch hole, for instance, this steel bar measures 2½-inches-thick and 12-feet-long. The top, as I said, has an eye to attach to the sand line. On this size, the bottom the 2½-inch bar enlarges to 5-inches in diameter. The tool weighs about 250 pounds. The body has a hole and slot in it so it can slide over the drill line. There are several pins that are removed, the body slipped on the drill line and the pins put back in place. This tool is supported on the sand line after any balers have been removed from that line. Slight tension is maintained on the drilling line and the bumper lowers slowly into the hole. If the hole is very deep the bumper should be lowered down about one-quarter of the depth to the drill tools and then removed. Subsequent runs of the bumper should go to one-half, three-quarters and, finally, all the way to the stuck drill tools. This is to prevent the sand line from wrapping around the drill line. The final position of the sand line should be marked with a flag or chalk or, my preference, colored tape.
The jar bumper is then raised from 5 to 10 feet and allowed to free fall to hit the top of the tools. This is a bit like a hammer driving a nail. If after several attempts the drill tools are not free, the drill line is slacked off a bit, and continued use of the bumper will almost always drive the drill tools down allowing the pebble or stone causing the stickiness to fall free. The operator then removes the jar bumper from the hole and resumes operation of the drill string. I want to make a point that you should finish this whole process as quickly and as safely as possible, as any cuttings suspended in the hole may settle around the drilling tools and really stick them.
A solid bumper serves the same purpose as the eye-top bumper, but with shorter length and larger diameter. For our 6-inch hole, this model measures 4½-inches in diameter and 6-feet-long, and weighs the same as an eye-top bumper. A solid bumper looks a bit like a drill stem with a slot cut about halfway through it. It has pins to keep it on the drill line, just like the eye-top bumper, and a fishing neck for the rare case that it might be lost in the hole. Many drillers, including myself, prefer this type, as its shorter length makes it easier to carry on the rig.
Whether using the eye-top bumper or the solid type, inspect the top of the rope socket on the drill tools after any bumping. The force of the bumping might flare out this part of the socket, making it impossible to grab with more sophisticated fishing tools (if it comes to that). I cannot over emphasize proper care of the socket neck. Generally, though, one or two good raps with a jar bumper will free the tools with little or no damage to the socket neck.
If the drilling tools become stuck twice or more in a 5-minute period, consider it the formation trying to tell the driller to add jars to the drilling string.
Another use of the jar bumper is to free the drilling jars if, on rare occasion, they get stuck in the open position. I don’t think this is very common. I never happened to me in my drilling career, but that does not mean it can’t. If the drilling tools become stuck twice or more in a 5-minute period, consider it the formation trying to tell the driller to add jars to the drilling string.
Other fishing tools essential to a cable-tool program include a latch jack, fishing jars and friction sockets. I will describe several types of friction sockets in future columns. Other, more-advanced fishing tools include a wireline grab, a wireline cutting outfit, combination sockets, slip sockets and ring collar sockets, and the rarely used center jar rein socket. A tubing spear removes plugged screen in screened wells, a handy tool to have.
With the exception of a tubing spear, I don’t think many drillers need to own all these advanced fishing tools. Operators can rent them from a number of places across the U.S. For remote projects or overseas operations, I recommend including these advanced tools in the inventory. Fishing for stuck or lost tools is simple, in my opinion, in hole from 3- through 6-inches diameter, as the tools remain upright in the hole. My understanding is that fishing for tools in large-diameter holes can prove far more complicated, but really large wells like that fall outside my drilling experience.
Next time I will discuss some of these other fishing tools.
We have had some rather cool weather here in southern Michigan lately and some rain, so my infamous lawn is not super long. Some personal issues have kept me from mowing it quite as often as I would like, but it is still looking nice and green. As I write this at the end of September our friends in Florida are expecting a really nasty storm. I hope and pray that people will be safe and damage kept to a minimum. Until next time, I hope you don’t have any fishing jobs but are prepared if you do.
A Lifetime in Drilling
We interviewed columnist and former NGWA President John Schmitt for our Drilling In-Site video series. Click here to hear him share his cable-tool expertise and wisdom earned with decades in the industry.
For more John Schmitt columns, visit www.thedriller.com/schmitt.
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