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The
electric motors are used in the structure of the drilling rig, submersible
centrifugal pump installations, rocker-machine, objects of oil gathering and a
field oil piping, objects of preparation of petroleum, gas-compressor stations,
compression oil-well-gas, flow tank, objects of reservoir pressure maintenance,
water-distributing system, water scoop, installations on clearing waste
treatment and objects of auxiliary purpose.
The
flowing well operation stage during oil field exploitation is generally followed
by the lifting stage, which requires pumps of various types. Well distribution,
according to operation methods, depends upon the applied oil field exploitation
technology, well output, physical and chemical properties of crude. The gas lift
or electric submersible pump installations are generally used for prolific
wells. Gas lift technology requires a substantially fixed investment and it is
efficient for wells with a high enough oil output. But when water cuts approach
90%, the gas lift technology becomes non-profitable.
That
is why submersible centrifugal pump installations are predominantly used for
enhanced oil recovery. During extraction of petroleum from a productive layer,
there is a necessity to lower resistance of obliteration of actions of porous
breed, through which the petroleum is taken. A different exit of petroleum and
water can be closed by electro-osmotic interactions. The higher the speed of
extraction of petroleum through the porous breed, the more probable is the
stopping up of oil channels for very long time. For this reason, as is known, no
more than 22 % of petroleum is extracted, while 78 % remain closed in
petroliferous strata.
The
technological re-equipment calls for a raise of efficiency in the use of
electrical energy and the existing equipment at minimal expenses, also to
prevent many ecological failures, as well as the rise of efficiency already
existing in oil well industry from 22 % up to 80 % and ideally, up to 100 %.
This process is possible to operate by the regulation of volume of a taken
liquid in a wide range from a productive stratum. It will allow prolonging the
"life" of an oilfield for 35 - 40 years and possibly up to 70 - 80 years or
more.
Even
an empty oil-well can come alive with extraction of a certain adjustable mode of
water. And it can output petroleum in volumes no less than that of a new
oilfield for many years. Another example is the main oil pipelines or the
gathering lines, as a result of breakdowns, tens of thousands of tons of
petroleum are spilled annually.
Oil spills pollute the environment causing
irreparable harm and bring millions of dollars of financial loss. As a rule,
such failures are caused by hydraulic impacts arising during the start-up of
powerful pumps in the petroleum highways. Certainly, the device of a smooth
start-up partially solves this problem, but it does not solve the main problems,
which is how to optimization of process of transportation.
Regulation
in a wide range of powerful electric motors of an alternating current with the
help of semi-conductor frequency control systems is a difficult task. RPEY have
a steady high-speed range in the mechanical characteristic and a large starting
moment. This property allows the application of the circuit "generator-engine"
to regulate in a wide high-speed range of the RPEY
high-power.
One
more example is in oil-well drilling. The most known methods of drilling are:
rotaries and air-power slips, turbo-drills, screw motors and electro-drills. The
most efficient method of oil-well drilling would be with the help of an
electro-drill which has an optimum speed. Without electro-drills it is not
possible to achieve economic drilling.
But
the absence of the adjustable electric motor with the high starting moment which
is capable of working for a long time on small speeds, limits the effective and
economic drilling which is carried out by electro-drills. For this reason the
share of electro-drills makes up about five percents.
A
typical gas-well is similar in its general arrangement to an oil-well. It has to
meet more stringent standards for sealing efficiency. At the wellhead, a
gas-well is equipped with a Christmas tree type and size selected to suit the
well pressure, temperature and flow rate, plus the presence of sand and
chemically aggressive component in the product.
Energy
efficiency technologies in oil-extracting and oil refining industries are
provided, first of all by controlled technological processes. The
controllability, as is known, this is the property of technical object to have
unequivocal dependence between control action and reaction of controlled object,
and as exact reproduction of this dependence within the limits of given
dispersion on the given interval of time.
In
an ideal situation it is necessary to make all technological operation
controlled, connected with production, transportation and processing of
petroleum.
Therefore
just the adjustable electric drives are a basis of high technologies. Today many
experts understand this. Why then is the share of adjustable electric drives so
is small? Even in such a rich as well as scientifically advanced country as the
USA, the adjustable electric drives make no more than 10 % from general number
of electric drives. Attempts to make controlled technological operations in an
oil-extracting industry were undertaken for a long time.
This
idea is not new, but suitable solution until now has not been found. For about
100 years the attempts have been undertaken to modernize the process of
extracting petroleum, to increase efficiency and to lower its cost. It was offered to change not only length of a
course of a bar of the pump of the rocker-machine, to change the sizes of
pulleys on the shaft, but also to adjust frequency of rotation of the shaft of
the executive engine with phase-wound rotor by the engine of a constant current
with independent excitation.
Try
to apply rectifier drive (synchronous electric motor and control system on a
basis thyristors). The large hopes were assigned to asynchronous electric motors
with a control system regulating frequency of a current and voltage. The
experience of use American of submersible asynchronous engines adjusted on
frequency of a current, in conditions of Western Siberiaand Ural has shown
lowest reliability of a drive and high operational costs. It has appeared dearly
and unreliably.
Unsuccessful attempts to use the executive electric motors of a various
type in an adjustable drive are explained to that their choice was done without
the account of five basic criteria showed to the executive electric
motor.
1.
The starting moment should be maximal and more nominal in 2 - 3 and more
time.
2.
The capacity of start-up should be of equal rated power (in an
ideal).
3.
The power EFFICIENCY of a drive during regulation (in an ideal) should not
change in relation to nominal.
4.
The control system should have low cost and operational
charges.
5.
It is reliable to work in complex geological and climatic conditions.
The
properties of parametrical electric motors RPEY and of submersible electric
motors RPSEY completely correspond to these criteria. The more detailed
information about submersible electric motors of a type RPSEY...
An
electrically-driven submersible centrifugal oil pump unit comprises of a
submersible pump set (water-proof electric motor and pump), cable line, tubing,
wellhead assembly and surface electrical equipment (transformer and control
station, or a transformer/control package).
Wide
choice of submersible electric motors with variety of performance parameters and
design features is available on the market today along with equipment of leading
firms in the USA: REDA, Baker
Hughes-Centrilift, ESP, ODI,
in
Slovakia: ZTS, in China:
Temtex, in Ukraine: Khems, in
Russia: Alas and
Borets.
The
engine consists of two assembly units - electric motor and hydro-protection as
well as the three-phase and two-pole asynchronous motor with a squirrel-cage
rotor. The engines of each series are subdivided on size of capacity and
voltage. The engines make in one -, two and three-section performance. The constructive circuit of submersible
engines made by all firms - are identical.
The practical offers on technological re-equipment
of a petroleum industry consist in modernization of asynchronous engines of any
types traditional, submersible, protected from explosion.
And
the modernization of electric motors under the circuit RPEY can be mastered "in
place" on sites on repair of electric motors. The modernization of asynchronous
submersible engines under the circuit RPSEY is not difficult for mastering on
the bases of repair and service of submersible electro-pump installations.
The
economic preconditions of creation of new technical devices for submersible of
the electro-pump equipment raising efficiency
The
basic kind of oil-well of petroleum pumps in the world is the submersible of
centrifugal pumps installations - SCPI. They extract up to 60 % of all petroleum
in the world. SCPI is the completely delivered equipment including: of the
submersible electric motor with protector; gas-buster; 2 or 3 sections of the
multistage centrifugal pump; a cable line; station of management and
transformer.
The
small diametrical sizes oil-well have imposed constructive restrictions on the
geometrical sizes of all elements SCPI. The section of the pump at an outside
diameter of 114 mm has length of 5375 mm, and its shaft has length almost 5000
mm has a diameter only 17 mm or 22 mm (depending on productivity of the
pump).
Length
of the shaft of the electric motor by a diameter of 30 mm achieves 6000 mm. It
is simple to present, what even small diametrical deviations of the sizes within the limits of
technological fields of the admissions, not speaking even about errors of
manufacturing and the assembly, result in displacement of geometrical axes of
shaft.
While
in service of equipment it results in vibrations both separate parts, and all
installation, there are failures, the reserve maintenance period of operation,
and not only of the submersible equipment, but also oil-well is reduced.
The
small diametrical sizes of separate elements SCPI do not allow to apply known
couplings, capable to compensate misalignments especially with cross by axes.
For this reason all elements of SCPI are connected between themselves solid
couplings.
Each
technical device in structure SCPI during work (operation) has an own spectrum
of fluctuations and vibrations. Solid
coupling do not compensate of misalignments displacement of geometrical axes of
connectable of shafts on three coordinates and especially their crossings in
space.
The
gain-frequency rippling destroy joints of the connected units of the SCPI, that
results to fatigue failure of bolts, stads, by break-away of separate parts of
SCPI and fall its on the bottom of oil-well. The stoppage oil-well on repair,
installation, dismantle and start-up of SCPI in difficult accessible northern
conditions, by the sea or in desert, result in huge financial losses. Besides,
the vibrations destroy unit oil-well.
Essentially raising the cost price of production of petroleum and
reducing profit.
The
experts of the scientific project enterprise KOPEN have developed a method and
device of protection of the connected shafts of electro-pump units of a type ADC
(Articulated Double Coupling), which practically completely compensates all
marked fluctuations and vibrations at the expense of presence 12 degrees of
mobility for two shafts of the connected parts of SCPI, preventing break-away
and fall of its separate parts on the bottom of oil-well. More detail ...
On
one installation of SCPI it is required from 3 up to 5 ADC. Capacity of the
Russian market in the ADC only for the oil-extracting equipment potentially is
estimated as about 400.000 per one year. The capacity of the market of the World
oil-extracting countries is about 2.000.000 of ADC per one year. The basic
consumers of the ADC are the bases on repair and service of submersible
electro-installations, and the specialized factories making oil-extracting
equipment.
The
work has an extremely important meaning, to provide much higher energy and
financial efficiency of oil extracting and oil refining industries and to
sharply decrease the expense of operation. The submersible electro-pump
equipment makes only 3 % from general number of the machine-building equipment,
where in ADC there is a real need.
The
carried out preliminary analysis of the market has confirmed the fact, that the
ADC is required in various industries. The prompt development of mass
manufacture is necessary while analogues in the world are not present. To the
process equipment of industrial purpose in various industries, global capacity
of the market estimates about 5.000.000 ADC per one year.
The
original design of the ADC is patented in The Russian Federation. The ADC is
fulfilled, tested, produced and completely prepared for mass manufacturing.
The
submersible equipment of various types and purposes not only for rise of
petroleum and water from deep oil-wells, but also for the drilling equipment,
contains in a design one more very important element - thrust bearing of
sliding. The used thrust bearing of sliding by repeating the design of Mitchell
developed for the sea crafts 150 years ago.
However,
as well as in a case with the coupling for the connection of shafts of
submersible equipment, the diametrical restrictions of dimensions of oil-wells
have not allowed the application device with independent segments each of which
densely would adjoin to the abutment.
In
the thrust bearing of sliding for the submersible electro-pump equipment,
instead of the special device containing mobile segments, the ring from
oil-resistant rubber is used. The ring from oil-resistant rubber has not
necessary plasticity. The dynamics of deformations does not provide densely
would adjoin to abutment and there is an asymmetric destruction of
abutment.
It
rises the moment of resistance, that especially negatively has an effect for
work of the submersible equipment at start-up, in the curved oil-well and on the
large speeds, and as reduces a time between failures. At work of the submersible
electro-pump equipment on the large depths and in difficult northern areas or in
area of northern seas, cost of failure very high.
For
increase of reliability of work of thrust bearings of sliding our experts have
developed an interesting design of the self-installing thrust bearing of
sliding. More detail... |
