DIRECTIONS FOR APPLYING NATIONAL SPUDDING SHOE

The jerk line and bridle line should be carefully measured as indicated in figure No. 33.

The jerk line may be made of wire or Manila cable. If Manila is used, splice an eye in the end fastened to spudding shoe, as a knot adds weight which may cause tipping of the shoe.

If wire line is used, wire rope clips Fig. 32. National Wire Line may be used to make the loop or eye.

Spudding Shoe

The bridle line should be made of good sand line, 1⁄2-inch or larger in diameter.

Make the jerk line according to length indicated in Fig. No. 33 and attach it to wrist pin and spudding shoe.

Slack drilling cable and hook spudding shoe over it.

Make loop about 2 feet long on one end of the bridle line.

Pass this loop between the double girts above the bull wheels

and put a short block of wood through it. This block should rest about 2 feet from the center of the girts on the tug side of the derrick.

Pass bridle line back of and under bull wheel shaft and measure for length as shown at C and D in Fig. No. 33.

Fasten bridle line to spudding shoe as shown at (E) in Fig. No. 33 and be sure to bring it up under the part of the cable which passes from bull wheel shaft to spudding shoe on the forge side of the derrick. This is necessary in order that when shoe is unhooked and dropped to the floor, the bridle line will fall clear of the cable.

In spudding or drilling through the surface soil, or in soft formations, the tools should be turned; otherwise if the bit is allowed to drill without turning a "flat hole," as the drillers say, may result. The tools are turned by simply twisting the cable several turns in one direction, and then in the opposite direction. If, on twisting the cable, it has a tendency at once to twist back, it is an indication that the tools are not turning and the driller

Fig. 33.

Illustration of Spudding Operation, using a National Wire Line Spudding Shoe.

Note: Length of jerk line should be 26 inches shorter than distance from center of jack post to center of hole.

should pull out and resume drilling a few feet above where he stopped in order to avoid a flat hole. At intervals, as the hole deepens, the bull wheel brake is released and sufficient slack of the cable is let out to reach bottom and "make hole." Enough water is poured in the hole to mix the drillings and they are removed with the bailer or sand pump as described on page 122. When spudding has proceeded to a sufficient depth, 85 to 125 feet, the temper screw is suspended from the walking beam, then clamped to the cable, and drilling with the walking beam is begun.

DRIVING PIPE

Drive pipe, so threaded that the ends of the pipe will meet in the coupling, should be used. For shallow driving of only a few joints of pipe, casing may be used, but for driving 100 feet or more regular heavy drive pipe is necessary. A steel drive shoe should always be screwed to the lower joint, and the inside of the

shoe below the shoulder should be exactly the same diameter as the inside of the pipe. In ordering the shoe it is best to state the weight per foot of the pipe or the exact inside diameter of it. Otherwise, should the pipe be larger inside than the shoe, the resulting projection of the shoe might cause the bits to lodge in it or the shoe to break.

The driving is done with a pair of drive clamps which are clamped on the wrench square of the stem below the pin. A hol

low or a drop drive head fitted to the top of the pipe receives the blow delivered by the stem and the clamps.

For very long drives a wood maul is recommended, for thus the blow is cushioned and danger of the pipe collapsing or telescoping is minimized. In driving with a maul a solid drive head

is used and a pair of guides is sometimes erected in the derrick, similar to those used in driving piles.

In both methods of driving the stroke is obtained in the same way as in spudding and the spudding shoe is used.

When driving pipe ahead of the tools, the driller should adjust the stroke of the tools so that the blow delivered is just enough to move the pipe. If, after several blows, the pipe does not drive or appears to spring back, it would be advisable to stop driving and run the tools, for it may be found that a stratum of soft shale, hard clay or a boulder has been encountered.

If it is shale or clay that has retarded the pipe, it is suggested that the driller pour about a barrel of water in the hole, run the tools and drill a few inches. This should mix and soften the formation sufficiently to drive the pipe into or through it.

If a boulder has impeded the progress of the pipe, it should be drilled through, if possible, and the pipe pulled back five to ten feet and the boulder broken up by a shot of dynamite. Water should be poured in to a depth of twenty feet over the explosive

to direct its force downward. The charge may be detonated by means of water-proof fuse or an electric battery.

An effective way to shoot a boulder is to use a string of tubing reaching to the boulder, in the bottom joint of which a charge of dynamite is confined by means of a cast iron bushing screwed into the lower coupling. Water should be poured into the tubing to tamp the charge, and the explosion should break both the bushing and the boulder, without damaging the tubing.

Two strings of drive pipe should be used for extremely long drives, the larger pipe being driven as far as practicable, the core cleaned out, and the smaller pipe driven inside the larger. As the pipe is driven it becomes necessary to clean out the core of soil or sand. This is done with the drilling tools by the ordinary spudding or drilling operation and, by using water in drilling, the cuttings may be removed with the sand pump or bailer.

Refer to table of sizes for drive pipe in Chapter XV, General Information.

In drilling soft formations it sometimes becomes necessary to drive the casing, which might collapse under ordinary driving methods. Long strings of casing may be driven by using an inverted or drive down trip casing spear, Fig. 106, whose slips are engaged in the lower joint of casing. The driving is done with long stroke jars on a heavy stem.