In recent columns, we’ve gone over the wire lines of spudder rigs, namely the drilling line and the bailing line. The casing line is the third and last wire line we need to consider.
Spudders of many years ago were two-line rigs: a drill line and sand line. These rigs served well, particularly in high rock areas where not much casing gets used. In the area I have drilled, we ran casing pretty much 100% the depth of the well — not including the screen. We handled a lot of casing. If you drill a small well like a 3- or 4-inch with a spudder, and it was a two-line machine, you could handle 10 feet of casing by hand. That hand work gets pretty tough if you do a 6- or 8-inch well with the same machine. Removing the baler from the sand line and attaching a hook would make that line useable as a light duty casing line. Even the smallest spudder could probably handle one single length (21 feet) of casing with the sand line.
I once saw a rig that had two “steps” in the sand reel. The drum on which it spooled had two diameters. For about three quarters of the reel’s width, it had a normal sized drum, while the remaining quarter was much, much smaller. By switching the sand line to the small part of the reel, the driller had, in effect, a light-duty casing line. By using the large part of the reel, he still had an effective sand line. While an interesting innovation, it doesn’t replace having three dedicated lines. I have run both two-line rigs and three-line rigs, and I will tell you the latter is much, much handier. Three-line rigs come equipped with a third reel called (no kidding) the “casing” reel.
The safest, most effective way to run casing line is what we call “double.” From the reel, the casing line goes up the mast and over a sheave at the top. Then, it runs back down to the ground and through the sheave on a traveling block. It then goes back up to the top of the mast and over a second sheave there, before coming down to an anchor point somewhere on the rig frame. (Some rigs have a non-moveable support, shaped like one-half of a sheave, in place of the second sheave.) This double setup distributes the strain on the mast evenly. Another advantage is the traveling block doubles the hook load the casing reel can handle. The traveling block was usually equipped with a heavy hook to attach to elevators, chains or what-have-you.
Traveling blocks on larger rigs, like those found in the oil fields, could have two, three or even four sheaves. A casing reel with a six-part line (that is, with three sheaves on the traveling block) can lift pretty significant loads. On these rigs, a device called a casing tackle strut was attached to the mast. This acted as, in effect, a second upper section of the mast. It sat on top of the lower section and was attached near the top of the upper section. This strut had several sheaves at the top, and they were at 90 degrees to the regular casing sheaves on the main part of the mast. I don’t believe I’ve ever heard of a casing tackle strut for a small spudder like a Bucyrus-Erie 20W or 22W; a Speedstar 55, 61 or 71; or a Cyclone 36.
The wire rope that works best for casing line is quite different from what one would use for drilling and sand lines. We need to select non-rotating wire rope. This rope will have two distinct sets of small wires: a traditional 6 x 7 inner circle wire line encased in a 12 x 7 outer covering. In other words, the outer section of this rope has 12 strands of seven smaller wires. (I hope you understand. I have a little trouble with the terminology.) This non-rotating rope will be just that: relatively easy to bend with a tendency not to twist. If we set up a multi-sheave traveling block with anywhere from one to three lines and use regular wire rope, it will try to twist itself into a pretzel. Non-rotating wire rope acts something like manila hemp, as it does not tend to wrap around itself.
Our non-rotating casing line can be plow steel, since it won’t be bending like the drill line. Plow steel line will be a little stronger than mild plow steel — no kidding. The capacity charts I have list the working strength of plow steel non-rotating wire rope as anywhere from 2,700 pounds for 7/16-inch, to 5,300 pounds for ⅝-inch. One-inch rates ate 13,500 pounds. The size of the casing line depends on the rig. Oddly (or perhaps not oddly), recommendations have quite a range between Bucyrus-Erie rigs and Speedstar rigs. In resources I’ve seen, B-E recommends ⅝-inch for a 20W, and ¾-inch for a 22W or 60L. For the big 36L — not often used in water well drilling, they recommended 1-inch casing line. The 36L could handle casing loads up to 120,000 pounds with the proper derrick equipment.
Speedstar, on the other hand, recommends slightly smaller lines: 7/16-inch on the 55, ½-inch on the 61, ⅝-inch on the 71 and ¾-inch on the 72. Like the Bucyrus-Erie 36L, we don’t see many Speedstar 72s drilling water wells in Michigan.
Whatever the rig, err on the side of caution for casing line size and capacity. A broken line can result in bad accidents happening quickly.
After these recent columns, we now we have our spudder (whatever the brand or size) set up with three kinds of lines: drill, sand and casing. Each has its own purpose and needs to be cared for properly. Next time, I’ll write a few lines about proper maintenance and lubrication of wire lines and then get into selecting drilling tools, which is the heart of any spudder drilling operation.
I apologize if these topics seem over technical, maybe even a little confusing. If you have questions, contact your rig manufacturer or, if you can find them, the makers of your wire rope.
We have had variable weather here in Michigan in late spring. We have had nice warm sunny days, some windy days and some that were downright cold. The corn crop seems to be off to a good start despite the cool weather. The lawns are growing at a reduced rate. Until next time, as always, work hard, work safe and take time to enjoy life.
For more John Schmitt columns, visit www.thedriller.com/schmitt.