A letter from Bradford, Pa., says: The machinery used in boring one of
these deep oil wells, while simple enough in itself, requires nice
adjustment and skill in operating. First comes the derrick, sixty feet
high, crowned by a massive pulley.
The derrick is a most essential part of the mechanism, and its shape
and height are needed in handling the long rods, piping, casting, and
other fittings which have to be inserted perpendicularly. The borer or
drill used is not much different from the ordinary hand arm of the
stone cutters, and the blade is exactly the same, but is of massive
size, three or four inches across, about four feet long, and weighing
100 or 200 pounds. A long solid rod, some thirty feet long, three
inches in diameter, and called the "stem," is screwed on the drill.
This stem weighs almost a ton, and its weight is the hammer relied on
for driving the drill through dirt and rock. Next come the "jars," two
long loose links of hardened iron playing along each other about a
foot.
The object of the jars is to raise the drill with a shock, so as to
detach it when so tightly fixed that a steady pull would break the
machinery. The upper part of the two jars is solidly welded to another
long rod called the sinker bar, to the upper end of which, in turn, is
attached the rope leading up to the derrick pulley, and thence to a
stationary steam engine. In boring, the stem and drill are raised a
foot or two, dropped, then raised with a shock by the jars, and the
operation repeated.
If I may hazard a further illustration of the internal boring
machinery of the well, let the reader link loosely together the thumbs
and forefingers of his two hands, then bring his forearms into a
straight line. Conceiving this line to be a perpendicular one, the
point of one elbow would represent the drill blade, the adjacent
forearm and hand the stem, the linked finger the jars, and the other
hand and forearm the sinker bar, with the derrick cord attached at a
point represented by the second elbow. By remembering the immense and
concentrated weight of the upright drill and stem, the tremendous
force of even a short fall may be conceived. The drill will bore many
feet in a single day through solid rock, and a few hours sometimes
suffices to force it fifty feet through dirt or gravel. When the
debris accumulates too thickly around the drill, the latter is drawn
up rapidly. The debris has previously been reduced to mud by keeping
the drill surrounded by water. A sand pump, not unlike an ordinary
syringe, is then let down, the mud sucked up, lifted, and then the
drill sent down to begin its pounding anew. Great deftness and
experience are needed to work the drill without breaking the jars or
connected machinery, and, in case of accident, there are grapples,
hooks, knives, and other devices without number, to be used in
recovering lost drills, cutting the rope, and other emergencies, the
briefest explanation of which would exceed the limits of this letter.
The exciting moment in boring a well is when a drill is penetrating
the upper covering of sand rock which overlies the oil. The force with
which the compressed gas and petroleum rushes upward almost surpasses
belief. Drill, jars, and sinker bar are sometimes shot out along with
debris, oil, and hissing gas. Sometimes this gas and oil take fire,
and last summer one of the wells thus ignited burned so fiercely that
a number of days elapsed before the flames could be extinguished. More
often the tankage provided is insufficient, and thousands of barrels
escape. Two or three years ago, at the height of the oil production of
the Bradford region, 8,000 barrels a day were thus running to waste.
But those halcyon days of Bradford have gone forever. Although
nineteen-twentieths of the wells sunk in this region "struck" oil and
flowed freely, most of them now flow sluggishly or have to be "pumped"
two or three times a week.
"Piping" and "casing," terms substantially identical, and meaning the
lining of the well with iron pipe several inches in the interior
diameter, complete the labor of boring. The well, if a good flowing
one, does all the rest of the work itself, forcing the fluid into the
local tanks, whence it is distributed into the tanks of the pipe-line
companies, and is carried from them to the refineries. The pipe lines
now reach from the oil regions to the seaboard, carrying the petroleum
over hill and valley, hundreds of miles to tide-water.
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