Surface Machinery and Methods for Oil-Well Pumping Page: 55

POWER-TRANSMITTING MACHINERY.

Motor cost a year:
Electricity, 5 kw. required at 1.04 per kw. h _-__ $453. 00
Oil, 10 gallons a year, at 40 cents per gallon____ 4. 00
Fixed charges, sinking fund, 20-year life, taxes
and insurance, at 2 per cent .63. 50
Cost of motor accidents - -- _-- 1. 00
Loss of 2 days' production, 40 barrels, at $2 per
barrel ------------------------------------- 160. 00
Total cost ------------------------------- 798. 94
OIL ENGINE.
The oil engine has high thermal efficiency. It generally con-
sumes less than one-fifth of the oil that would be required to pro-
duce the same amount of power with an oil-field steam boiler and
engine using the oil as a fuel. Like the gas engine, it needs only
enough water for cooling.
ELECTRIC MOTORS.
The development of the two-speed, two-power electric motor for
use at oil wells has given a source of power well suited to pumping,
pulling, bailing, or swabbing. This development, like that of the
oil engine, has been largely the result of the failure of the natural
gas supply.
With the electric motor, advantage can be taken of the higher
thermal and general efficiency of the central power plant, as com-
pared with smaller and scattered power installations.
POWER-TRANSMITTING MACHINERY.
EQUIPMENT FOR PUMPING INDIVIDUAL WELLS.
PUMPING ON THE BEAM.
In the early days of the petroleum industry, all wells were pumped
on the beam. Later, in order to decrease costs, methods for op-
erating a number of wells from one power unit were developed,
such as pumping by "jerk line," and by a central "jack plant "
or "power." The adaptability of any method of production, other
than pumping on the beam, depends on the depth of the well, the
frequency of pulling jobs, and the distance between wells. Many
operators claim that wells in which the fluid has to be raised more
than 2,500 feet can not be successfully pumped by jack plants or
powers. However, wells 3,500 feet deep are being successfully op-
erated by this method in the Humble field, Texas.
In the Mid-Continent and California fields, at many of the deep
wells drilled by rotary tools, standard equipment is installed after

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