Charles George Warnford Lock.

Economic mining: a practical handbook for the miner, the metallurgist and ... online

. (page 32 of 76)
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more boys or girls to assist in pulling. As soon as the bucket fills
these persons run down a beaten path, and the bucket is thus drawi
to the mouth of the weU, when it is emptied by another person.

In Wallaohia and (3alioia dug wells exist, and in Moldavia an
dug wells more than 130 ft. deep, lined with woven sticks.

Most perfectly constructed dug wells exist in Italy, at Montechino
Piaoenza ; they are perfectly cylindrical in form, and lined with larg*
bricks firmly cemented together. Some of these wells are 240 ft
deep and 8 to 10 ft. diam. They yield 160 to 180 lb. of oil each pei
day. The oil, which is drawn up in buckets, is of very remarkabk
character, being so pure that it can be burned in its crude state ii
suitable lamps, though in consequence of the presence of a largi
quantity of tne more volatile hydrocarbons it is very inflammable, «i
once taking fire upon the application of a flame. These wells cann<7
be dug deeper in consequence of the presence of petroleum gas am
vapour, several lives having been lost m attempts to deepen them.

The first operation in the sinking of a petroleum well in Ameria
is the erection of what is termed a "derrick," a timber structun
(Fig. 89), pyramidal in form, and consisting, in the main, of 4 upright?
held in position by the necessary ties and diagonal braces. At th
present time the derrick is usually about 70 ft. high, 20 fu squaie a
the base, and costs about lOOZ.

The height of the derrick has necessarily been increased paripau
with the depth of the wells and length of the tools, but where ^
wells are shallow, derricks not more than 30 ft. high are still m
ployed. The lower part is usually boarded up when drilling is beii(
done in winter, in order to protect the workmen. Immediatdy (m(
side the derrick stands the "samjpson post" a, a massive pillar «
wood which supports the " walking-beam " 6. Inside the derrid
stands a smaller upright termed the " headache post " or *' life ^
server " c, desimed, as its name implies, to save the driller from boiij
struck on the head by the end of the walking-beam in the event i
the connection breaking. The end of the wa&ing-beam outside til
derrick is connected by means of a rod termed the " pitman " #i, ^
a crank attached to the axle of what is known as the " band-wheel*!
This band-wheel runs in bearings on a couple of uprights /i and
caused to revolve through the medium of a band g driven bjj
steam-engine A in an adjoining shed, a rocking movement being Ud
imparted to the walking-beam. The steam-engine is now usualljl
12 to 15 h.p., and steam is generated in a boiler of the loocxnotr
type, fired with natural gas. To the opposite side of the deni
are fixed the bearings of the '* bull- wheel " t, a windlass of i
construction, used for lowering and raising the drilling took,
supporting cable passing over a grooved wheel, termed the **ct
pulley " ib, at the top of the derrick, and being coiled on the drnffiJ
axle of the bull-wheel. Between the band-wheel and the bnll-v^
the " bull-rope," made of 2-in. plain-laid cable, joined by iron cou|^

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MM8. This rope runs in a groove in both wheels, and imparts
Botion to the windlass. The latter is provided with a powerful



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brake. A seocmd windlass, termed a ^sand-reel," is also profrided.
This smaller windlass, which is used for raising the detntos frum
the welU is fixed near the band- wheel, and can be bron^ht into
contact with the face of the band-reel, by pulling a lever inside th^
derrick, and the driller can thns from the mouth of the well start or
stop the revolutions of the sand-reel. An endless cord, termed ** the
telegraph," passes round a pulley on the throttle-valve of the engine
steam-pipe and a similar pulley in the derrick, so that the driller csnj
also start or stop the engine. The reversing link is also operated \>j
a cord from the derrick. The bull-wheel being, as explained, drivea
through the medium of the band-wheel, it is necessary to disconneot
the pitman when the bull-wheel is used, and to throw the rope off
the bull-wheel when the walking-beam is to be set in motion. Thfl
cable used to support the drilling tools is a 6-in. (2 in. diam.) untarred
Manilla rope. Wire rope is not used, as it is not sufficiently pliaUe
to admit of its being coiled on the shaft of the bull-wheel.
The lengths and weights of a string of tools are : —

Leogth. WH^it.

ft. In. n».

Bope socket 8 90

Sinker bar 12 400

Jars 6 300

Aagerstem 32 1050

Bit 3 4 140

56 4 1960

In addition, the following are required to complete the 8et:-H
Temper-screw, large jars, large bits, reamers, and two wreni^es.

The tools are made of the best steel and Norway iron. The cost
of the complete set of drilling tools is about 200Z. A *' saud-pump,"
or bailer, to remove the detritus from the well, often cjnsiBts simply
of a plain cylinder of thin galvanised iron, usually about 6 ft. long,
but sometimes as long as 15 or 20 ft., provided at the bottom with a
valve opening inwards. The valve is provided with a stem projeciin||
downwards, so that, when the filled cylinder is lowered into a trough^
the valve is pushed open, and the contents of the cylinder are dis-
charged. A better sort of sand-pump consists of a wronght-iron
cylinder, having, in addition to the bottom valve, a plunger attadied
to an iron rod passing through a stirrup spanning the top of th«
cylinder. The sand-pump is, in the latter form, suspended froiE
the end of the plunger-rod, and when it reaches the bottom of the
well, the slackening of the rope allows the plunger to descend ic
the bottom of the cylinder; on tightening the cord, the plunger u
first raised, and the entrance of the detritus into the cylinder is faoili
tated; when the plunger has reached the. stirrup, the cylinder itseli
begins to rise, and the valve closes. The rope attached to the sand-
pump passes over a small pulley at the top of the derrick, to the sand
reel already described. Besides the drilling tools referred to, a large
number of so-called "fishing tools" are employed, when, through
breakage of the cable or otherwise, the tools, or any of them, remaii]
in the well.

The first step in the drilling of a well is to sink a " condactor *

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dirongh the snr&oe gronnd to the '* bed-rook." When the superficial
clmjs and gravelB are not more than 10 to 15 ft. thiok, a oommon
well-fihaft, 8 to 10 ft. square, is dug to the surface of the rock. A
wooden conductor, 8 in. square in the clear, is then set up perpen-
dicularly between the rook and the boarded floor of the derrick, the
junction between the rock and the conductor being so made as to
keep out gravel and mud. When the depth of surface ground is
too great to admit of digging down to the rock, iron piping, termed
" driving-pipe," is driven in by means of a " mall," working in guides,
as in pile-driving. V\ hen 200-300 ft. have to be thus dbriven, as is
sometimes the case, a good deal of skill is required. When the con-
ductor is sunk to the bed-rock, the operation of drilling is commenced.
The composition of the string of tools has already been stated. The
jars practioJly divide the string into two parts, the one dulivering
its luow downwards and the other upwards. The auger or drill
which cuts and pulverises the rock, consists of the bit, the auger-stem,
ind the lower link of the jars, while the function of the sinker-bar
ind upper link of the jars is to deliver a blow on the upward stroke,
H> that the " jar " may loosen the drill in case it should have become
[unmed in the rock. This appliance, which is of the greatest value,
nay be likened to two flat links of a chain, the cross-head of the upper
me passing through the slot of the lower. The length of the slots
B such that there is a play of 9 in., though a longer play has some-
imes been given. A skilful driller never aUows the jars to strike
ogether on the downward stroke. The various members of the string
f tools are connected together by male and female screws. The
' temper screw," inserted between the walking-beam and the cable,
dmit8 of letting out the latter gradually, as the drill enters the rock,
rhe '* ropo-socket " firmly grasps the cable at the required point, and
nom it the tools are suspended to the end of the walking-beam.

If the bed-rock is reached at a less distance than about 60 ft.
xsyxa, Borface, the drilling of the rock is commenced by the operation
irmed ^ spudding," which cunsists in alteniately raising and drop-
mg the tools by tightening and then slackening the cable, which
>r this purpose is simply coiled 2 or 3 times round the revolving
all-wheeL A sufficient depth having been reached to admit of the
^gular use of the drilling tools, the cable is properly coiled on the
fldl-wheel shaft, the bull-rope is thrown off, the pitman is connected,
[id the string of tools is lowered into the well by releasing the
lU-wheel brake, and suspended from the walking-beam. The tools
Lving run to the bottom of the well, and the jars having closed by
te Blackening of the cable, the slack is taken up by turning the bull-
heel bj hand until the cross-heads of the jars come together, this
»ing plainly indicated by a tremulous motion imparted to the cable,
bout 4 in. of cable being then paid out, the tools are in the right
flition^ and the walking-beam is started. If the vertical motion be
\ in., the sinker-bar first moves 4 in. on the up-stroke ; the cross-heads

the jars then come together with a sharp blow, and the auger-stem
lifted 20 in. On the down-stroke the auger-stem falls 20 in. and
'livers its blow on the rock, while the sinker-bar goes down 24 in.

teksoope the jars. An unskilled workman sometimes closes the

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jars (especially if the well be deep and nearljr full of water), and
works for hours without aocomplisning anything, as the tools may
be resting on the bottom or remaining suspended ; but an expert can
tell, by placing his hand on the cable, whether the drill is working
properly or not. Before the well reaches a great depth, the move-
ment of the tools can be distinctly recognised by grasping the cable.
As the jar grows feeble, it is " tempered " to the proper strength by
slightly altering the position of the temper-screw, and thus letting
out a Httle more cable. The best drillers now, however, often drill
by the spring of the cable, only using the jars when the bit sticks.

Under these circumstances, the tools are suspended so that the
bottom of the bit is from 5 in. to 3 ft. from the bottom of the hole, the
distance depending on the length and consequent spring of the cable.
The walking-beam being set in motion, the tools rise and feJl, and
the elasticity of the cable allows them to touch the bottom and boond
from it. This operation is termed " bouncing the drill," and the rock
is thus cut faster than by the old method. As the drilling proceeds,
the driller slowly rotates the temper-screw so as to cause the ohisd
end of the bit to do its work evenly. When the whole length of the
temper-screw has been unscrewed, or the bit requires sharpening,
the buU-rope is placed on the bull-wheel, and the string of tools is
drawn up. The sand-pump is then lowered into the well, some water
being first thrown down if necessary, and the pulverised rock is thus
removed. Drilling and sand pumping thus proceed alternately day
and night, unless a breakdown occurs, one driller and one engineer
working from noon till midnight, and another pair from midnight
till noon. At nieht the derrick is lighted with a primitive form of
lamp, something like an iron kettle with a spout on each side, in
which crude petroleum is burned. The operation of drilling sddon^
however, proceeds very long without the aid of the "fishing tods'
being required. Perhaps the cable breaks, or one of the tools becomei
detached, and the operation of extraction, which is termed "fishing,"
is often very tedious. Considerable skill has, however, been expended
in devising tools to meet almost all conceivable cases, and there are
now hundreds of tools available; from the delicate "grab" designed
to pick up a small piece of valve-leather, to the ponderous string erf
" pole tools " containing tons of iron, by means of which a set of took
can be unscrewed at a depth of 1600 ft., and brought up one by one,
or a thread can be cut on the broken end of a sinker-bar or auger-staa*

Every oil-well is naturally divisible into three sections, vit :—
(1) surface clays and gravels, (2) stratified rocks containing more oi
less water, (3) stratified rocks, seldom water-bearing, including th«
oil-sands. The first division requires the conductor already deembe^
and the second division requires casing to shut off the water from the
third section. The earlier method of excluding the water, by pladn|
a seed-bag round the tubing, has been found unsatisfiactory, as tbi
tubing could not be removed for repairs without disturbing the seed
•bag, and letting water into the well. Cast-iron drive pipe wn
adopted as a substitute for the wooden conductor used in the earlid
wells. An important alteration was the introduction of Sj-in. casini
as a permanent fixture. This casing extended to the bottom of tiv

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water-bearing rooks, and was famished either with the seed-bag or
with a leather oup, which was foroed open against the sides of the
well bj the pressure of the water. The tubing, of 2f-in. external
diam., and extending nearly to the bottom of the well, was then
placed inside and suspended from the casing. To obtain a supply of
water for the boiler, a small pipe was often inserted, between the
tubing and the casing, into the water-chamber above the seed-bag.
Although this well was a great improvement, it possessed defects.
Thus the casing being 3|-in. internal diam., while the uncased part
bdow it was 5^ in., fishing tools oould not be easily introduced, and if
it became necessary to deepen the well, only d^in. bits could be used.
The modem well has an 8-in. wrought-iron drive-pipe, armed at the
bottom with a steel shoe. The pipe is driven down to the bed-rock,
uid an 8-in., or, strictly speaking, 7^in., hole is drilled in the base of
the water-bearing strata. At this point, the bore is gradually reduced
to 5^in., and there a bevelled shoulder is made ; 5^in. casing, pro-
vided at the lower end with a collar to fit the bevelled shoulder, is
then inserted, and a sufficiently water-tight joint is thus made.
Drilling with 5]^in. bits is then continued until the required depth
has been reached. When gas is obtained in sufficient quantity to
famish fuel for the boiler, it is conveyed through a 2-in. pipe con-
oeoted with the casing beneath the derrick floor, and passing into the
ioor of the furnace. A ^-in. steam-pipe, fitted with an elbow and
jhin. jet, is inserted in the gas-pipe, close to the fire-box, and a blast
Cff steam is thus caused to issue with the gas. The apparatus acts

15 an exhauster, drawing the gas from the well, and preventing the
lame from running bac£ The cost of a well is about 6002.

The ^water-packer'* is a device to prevent water that may pass
into a well below the casing from gaining access to the oilnsand, and
Eo stop the ascent of gas on the outside of the tubing. It is applied
tmnd the tubing at aoy desired point, and its effect is to shut on all
tommnnication between the annular space outside the tubine above
t and the oil chamber below. The oil and gas are thus confined in
he well chamber, and many wells are thus caused to flow that would
itherwise require pumping. Under these circumstances the flow is
atermittent, taking place when sufficient gas-pressure has accumu-
Ued. There are many forms of water-packer, but one of the simplest
tmsists of a band of rubber which, on compression, is forced against
tie walls of the well. If the well does not flow, the oil requires to
e raised to the surface by a pump. The working barrel of the pump
I placed at the bottom of the well on the end of the tubing, a per-
>rated pieoe of casing of proper length, termed the ** anchor," being
ttacbed to the lower end of the working barrel. To the sucker of

16 pomp the required number of wooden sucker-rods, screwed
>g6tber, are attached, the upper end of the string of rods being con-
acted with the walking-beam. There is, of course, a valve at the
[)tt(nn of the working barrel, and in the sucker. The sucker is pro-
ided with a series of 3 or 4 leather cups, which are pressed against
le working barrel by the weight of the column of oU. The sucker
ids are of ash, 1\ in. diam. by 24 ft. to 28 ft. long. When a number
' oontigtious wells are to be pumped^ an arrangement termed a

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" grasshopper " apparatus is employed. By this means several wells
oan be pumped by the action of a single walking-beam.

Most petroleum wells in the United States are " torpedoed " on
the completion of the drilling, in order to increase the flow of oil
The torpedo is a charge of nitro-glyoerine in a suitable shell, which
is lowered to the oil-bearing rock, and there exploded, with the effect
of opening fissures into the surrounding rock. The shells, which are
of tin plate, are of two kinds. One form is lowered to the bottom of
the well by a string that can easily be detached, and rests on what is
termed an " anchor," which is simply a cylindrical tin tube of such
length as will bring the torpedo to the required petition. To the
upper end of the shell is fitted a *' firing head " consisting of a oircalar
plate of iron, only slightly smaller than the bore of the well, having
projecting verticjJly downwards from its lower surface a rod on which
a percussion cap is placed. Beneath the cap is an anvil. The lower-
ing cord having been detached and drawn up, a cast-iron weight,
termed a '* go devil," is dropped into the well, and this weight strikiiij?
the disc explodes the percussion cap and fires the torpedo. The oth»
form of shell is suspended by a cord, which serves as a guide for &

Serforated weight running on it The usual size of the former
escription of shell is S^ in. diam. by 10 ft. long, a shell of these
dimensions holding 20 quarts of nitro-glycerine. Frequently as large
a charge as 80 quarts is used, and it is then usual to employ 4 shells
of the dimensions given, the lower end of one fitting into the upper
end of another, and only the top shell of the series having the firing
head. Shells of the otner description are commonly termed sqtiiha.
They are of much smaller dimensions, holding only about 1 quart of
the explosive liquid, and are now generally used to bring about the
explosion of the large torpedo.

The torpedo is usually exploded under about 50 ft. of water.
Little or no sound is heard, but a slight quiver of the ground is c^ta
perceptible. A few moments after the explosion, however, the fliii<i
in the well is shot into the air with great violence, forming a magnifi-
cent fountain, and small pieces of rock are also thrown out. The
torpedo and exploding weight are blown into small fragments.

Some authorities are of opinion that the effect of the torpedo v
simply to clear the pores of the rock of obstructions, the apparent
increase in the yield of oil being due to reaction from the immeme
gas pressure produced by the explosion. Many wells, however, thil
produced no oil on the completion of the drilling (technioaUy tennei
" dry-holes ") have, through the use of the torpedo, been caused to
yield abundantly. In Bussia the torpedo is never used.

A modification of the rope system of drilling, known as the rn(
system, is adopted in Canada, Bussia, and Galicia. It consists in thi
substitution oi 2-in. ash rods, 16 ft. long, screwed together, f<»r tbi
portion of the drilling cable which passes from the end of the walking
beam to the string of tools. Iron rods are used in Bussia. The rodit'
in some cases, work in guides. The rod system is apparently preio^
able to the rope system, where the well is not very deep.

In Bussia it is usual to commence drilling with a bit as much tf
15 to 16 in. diam., but it is generally found necessary to gradiul^

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tliTninish ihe size of the bit as the drilling proceeds. The average
rate of sinking is 140 ft per month. In oonsequenoe of the extreme
preGSiire of the gas, amounting sometimes to as much as 300 lb. per
Bq. m., it is found difficult to prevent the oil from escaping between
the casing and the ground. This difficulty has been overcome by
iinking an octagonal well about 6 ft. diam. and 40 ft. deep, down to
the hiffd ground, and filling in the space round the casing with
masonry in cement ; or by tamping the space with puddled clay, after
the joint between the casing and the hard ground has been caulked
with rope-packing.

When wells have ceased to yield oil in remunerative quantity in
the United States, it is usual to draw out the iron casing for use in
other wells ; but as this operation allows surface water to gain access
to the oil-sand, and as it has been found that the yield of adjacent
wells is prejudicially a£fected by this ** flooding " as it is termed, the
Pennsylvania Legislature enacted that abandoned wells should be
"" plugged" by fimng them with sand. The prejudicial e£fect of the
flooding of the oil-bearing strata has been experienced in the Caucasus,
the neroentage of water in the oil raised in tnat locality being steadily
on Uie increase.

When the oil has reached the surface, either by flowing or being
pomped, it is conducted into a tank, usually of wood, holing about
250 barrels. In America, quantities of crude petroleum are always
itated in •* barrels " of 42 gal. (6 American gal. = 4 Imperial gal.),
[n the early days of the industry, the only method of transporting
the oil was in oak barrels holding 40 or 50 gal., coated internally
rith glue ; but the small quantity of water present in the oil was
bond to dissolve the glue, and cause the barrels to leak. The tank
ar now employed consists of a cylinder of boiler-plate, Iving upon a
t-wheeled truck, and provided with a dome similar to that which a
lorizoDtal steam-boiler has. The tank is famished with means of
Uling at the top, and with a valve beneath by which it can be
mptied ; it is usually about 24 ft. 6 in. long by 66 in. diam., and
olds 4500 to 5000 gsl

Gradually a system of pipe-lines, running from the wells to
entral stations and thence to loading stages on the railway lines,
ras constructed, and at the present time uiere is in the oil regions
r the United States a complete network of 2-in. piping connecting
le various wells with storage tanks and trunk lines, aggregating
lousands of miles.

The first trunk line extended from the lower oil country to Pitts-
^M^^ a distanoe of 60 miles, and was 4 in. diam. The New York line
midsta of two 6-in. tubes for the entire distance, with a third 6-in.
the for a portion of the way, and is provided with 11 pumping
alionB about 28 miles apart; its transporting capacity is about
iJ,000 barrels a day. The greatest elevation of the pipe between
ations above tide-water is 2490 ft. The Philadelphia pipe has a
dimeter of 6 in. with 6 stations ; the Baltimore pipe is 5 in. diam.
ithoat a break ; the Cleveland pipe 5 in. with 4 stations ; and the
offiJo and Pittsburg pipes. 4 in. with 2 stations.

The pipe is made specially, and is of wrought iron, lap-welded.

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It is tested to a pressure of 1500 lb. per sq. in., the worldng [
being 900 to 1200, or even sometimes 1500 lb. The pipe is in leogtl
of 18 ft, provided at each end with ooarse and shu^ taper thread
9 to the inoh, and the lengths are connected with long sleeve ooui^infl
also screwed taper. The line is nsnally laid 2 or 3 fL below ti
surface of the ground, though in some places it is exposed, and i
intervals bends are provided to allow for contraction and expansia
At the different pumping stations there are storage tanks of li^
boiler plate, usually 90 ft. diam. by 30 ft. high, the oil being ptanpc
irom the tanks at one station to those at the next, though sometiiiM
loops are laid round the stations, and oil has thus been pumped
distance of 110 miles with one engine. The primping engines chiei
employed are the Worthington engines, constructed at the Worthingtc
Works in New York, and at each station there is usually a dnplicaj

Online LibraryCharles George Warnford LockEconomic mining: a practical handbook for the miner, the metallurgist and ... → online text (page 32 of 76)