Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
OIL EXTRACTION SYSTEM AND OIL EXTRACTION SUPERVISORY
SYSTEM
TECHNICAL FIELD
[0001]
The present invention relates to an oil extraction system for recovering oil
forcibly and an oil extraction supervisory system for supervising an oil
extraction system.
BACKGROUND ART
[0002]
At first, the oil extraction from an underground oil field is performed in the
form of production using only natural oil discharge energy or production by
artificial oil
extraction (e.g., gas lift extraction or pumping extraction) that is not
associated with EOR
(described later). This is primary extraction.
[0003]
Then, after the oil production by the primary extraction has decreased, it is
attempted to increase the extraction efficiency by applying oil discharge
energy to an oil
layer artificially by pressure-injecting water or natural gas into the oil
layer (water flooding
or a gas injection method), which is secondary extraction.
[0004]
Furthermore, after the secondary extraction, an artificial enhanced oil
recovery
method is employed to extract oil remaining in the underground crude-oil-
containing layer.
The enhanced oil recovery method is an extraction method that aims to attain
higher
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replacement efficiency than the ordinary water flooding and gas injection
method.
Examples of the enhanced oil recovery method are a micelle injection method in
which
crude-oil is recovered by forming microemulsion by adding surfactant to water
and oil
such as petroleum or heavy oil and then pressure-injecting the microemulsion
into an
underground crude-oil-containing layer and a polymer injection method in which
the oil
extraction efficiency is increased by increasing the viscosity of water by
adding, to
injection water, a water-soluble polymer substance such as polyacrylamide,
poly(aJkyl
acrylate), poly(alkyl methacrylate), polyacrylonitrile, or xanthan gum (see
e.g., Patent
document 1). Another example is a microorganism injection method which uses
microorganisms. In the microorganism injection method, a microorganism is used
which
produces a metabolite such as a polymer, a surfactant, carbon dioxide, a
methane gas, or an
acid. It is expected to attain the same function as the above-described EOR
technology.
(see e.g., Patent document 2).
As described above, the conventional oil extraction methods are attempting to
extract oil efficiently by making full use of various extraction techniques.
[0005]
Incidentally, as a typical example of a pump for extracting oil, a sucker rod
pump 300 as shown in Fig. 3 is used. The sucker rod pump 300 extracts oil in
such a
manner that a rod 301 to whose tip a plunger (not shown) connected is lowered
through a
tubing and moved vertically by ground facilities and the movement of the rod
is
transmitted to the plunger. By virtue of its simplicity, the sucker rod pump
300 is used
most widely in land oil fields (see e.g., Patent document 3).
A pump-off phenomenon may occur in the sucker rod pump. A pump-off
control method is known in which occurrence of a pump-off phenomenon is
detected
under prescribed conditions and control is made (see e.g., Patent document 4).
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Patent document 1: JP-A-11-236556 (pages 2-5)
Patent document 2: JP-B-6-13699 (pages 2-9)
Patent document 3: Japanese Patent No. 3,184,229 (pages 9-11 and Fig. 7)
Patent document 4: WO 00/66892 (pages 9-17)
DISCLOSURE OF THE INVENTION
Problem to Be Solved by the Invention
[0006]
In recent years, it has come to be studied when to employ extraction methods
of what principles in the development of an oilfield to work out a most
economical plan as
a whole. However, there may occur a case that a clear solution cannot be
obtained, that is,
a most appropriate production plan cannot always be obtained.
The present invention has been made in view of the above problem, and an
object of the invention is to provide an oil extraction system and an oil
extraction
supervisory system capable of extracting oil efficiently by using a pump-off
signal in
secondary and tertiary extraction.
Means for Solving the Problem
[0007]
To solve the above problem, the present invention have been made as follows.
According to the invention set forth in claim 1, an oil extraction system
comprises: a sucker rod pump provided for a production well so as to pump up
crude oil;
a signal detecting section for detecting a pump-off signal sent from the
sucker rod pump;
and an injection pump provided for an injection well so as to pressure-inject
fluid which is
used for secondary extraction or tertiary extraction, wherein the injection
pump is operated
based on the pump-off signal detected by the signal detecting section.
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According to the invention set forth in claim 2, the signal detecting section
is
an inverter for driving a power source of the sucker rod pump.
According to the invention set forth in claim 3, the signal detecting section
is a
superior controller of an inverter for driving a power source of the sucker
rod pump.
According to the invention set forth in claim 4, the pump-off signal is
transmitted to an inverter for driving a power source of the injection pump.
According to the invention set forth in claim 5, the fluid is water, a gas, or
a
surfactant.
According to the invention set forth in claim 6, a microorganism is used in
place of the fluid.
According to the invention set forth in claim 7, in an oil extraction system
comprising a sucker rod pump provided for a production well so as to pump up
crude oil; a
signal detecting section for detecting a pump-off signal sent from the sucker
rod pump; and
an injection pump provided for an injection well so as to pressure-inject
fluid which is used
for secondary extraction or tertiary extraction, an oil extraction method
comprises:
detecting the pump-off signal with the signal detecting section; and operating
the pressure
injection pump based on the detected pump-off signal.
According to the invention set forth in claim 8, the signal detecting section
is
an inverter for driving a power source of the sucker rod pump.
According to the invention set forth in claim 9, the signal detecting section
is a
superior controller of an inverter for driving a power source of the sucker
rod pump.
According to the invention set forth in claim 10, the pump-off signal is
transmitted to an inverter for driving a power source of the injection pump.
According to the invention set forth in claim 11, the fluid is water, a gas,
or a
surfactant. 4
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According to the invention set forth in claim 12, a microorganism is used in
place of the fluid.
According to the invention set forth in claim 13, an oil extraction
supervisory
system comprises: a sucker rod pump provided for a production well so as to
pump up
crude oil; an inverter for driving the sucker rod pump; a remote supervisory
unit for
manipulating the inverter; a first radio communication section connected to
the remote
supervisory unit; a second radio communication section for performing a radio
conununication with the radio communication section; and a computer connected
to the
radio communication section.
According to the invention set forth in claim 14, the command is transmitted
at
a prescribed cycle.
According to the invention set forth in claim 15, in an oil extraction
supervisory system comprising a sucker rod pump provided for a production well
so as to
pump up crude oil; an inverter for driving the sucker rod pump; a remote
supervisory unit
for manipulating the inverter; a first radio communication section connected
to the remote
supervisory unit; a second radio communication section for performing a radio
communication with the radio communication section; and a computer connected
to the
radio communication section, an oil extraction supervisory method comprises:
sending a
certain command from the computer to the inverter via the second radio
communication
section; receiving, with the remote supervisory unit, the certain command via
the first radio
communication section; manipulating the inverter in response to the certain
command; and
transmitting the manipulation result to the computer via the first and second
radio
communication sections.
According to the invention set forth in claim 16, the certain conunand is
transmitted at a prescribed cycle.
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Advantages of the Invention
[0008]
According to the inventions recited in claims 1 to 12, in secondary or
tertiary
extraction, the pump for pressure-injecting water, gas, or surfactant (fluid)
or
microorganisms and the sucker rod pump for extracting oil can be operated so
as to
cooperate with each other by using a pump-off detection signal of the
inverter. This
enables efficient oil extraction.
The inventions recited in claims 13 to 16 make it possible to perform oil
production/maintenance management at a distant place.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
Fig. 1 shows the configuration of an oil extraction system according to a
first
embodiment of the present invention.
Fig. 2 shows the configuration of an oil extraction supervisory system
according to a second embodiment of the invention.
Fig. 3 illustrates a conventional sucker rod pump.
DESCRIPTION OF SYMBOLS
[0010]
1: Underground crude-oil-containing layer (oil layer)
2: Production well
3: Injection well
10: Sucker rod pump
11: Motor
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12: First inverter
20: Injection pump
21: Motor
22: Second inverter
23: Signal transmission section
51: Communication interface
52: Remote supervisory unit
53: Radio communication section
60: Central supervisory system
61: Radio communication section
62: Communication interface
63: Computer
300: Sucker rod pump
301: Rod
BEST MODE FOR CARRYING OUT THE INVENTION
[0011]
Embodiments of the present invention will be hereinafter described with
reference to the drawings.
Embodiment 1
[0012]
Fig. 1 shows the configuration of an oil extraction system according to the
invention. The following description will be made with an assumption that oil
is extracted
by water flooding. However, the invention can be applied to any injection
method in the
case of secondary or tertiary extraction.
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In FIG. 1, reference numeral 1 denotes an underground crude-oil-containing
layer (oil layer), numeral 2 denotes a production well to be a well for
extracting oil, and
numeral 3 denotes an injection well for injecting water.
Reference numeral 10 denotes a sucker rod pump for pumping up crude oil
and numeral 11 denotes a motor serving as a power source of the sucker rod
pump 10.
Reference numeral 12 denotes a first inverter for driving the motor 11. The
first inverter 12
can detect a pump-off signal according to a known technique.
Reference numeral 20 denotes an injection pump for injecting water, numeral
21 denotes a motor serving as a power source of the injection pump 20, and
numeral 22
denotes a second inverter for driving the motor 21. Reference numeral 23
denotes a signal
transmission section for transmitting a pump-off signal from the first
inverter 12 to the
second inverter 22 and is composed of a transmitter, a signal line, and a
receiver (not
shown).
[0013]
The operation of the above-configured oil extraction system according to the
invention will be described below.
As the sucker rod pump 10 continues to pump up crude oil, the oil layer
pressure gradually decreases, and thus the oil extraction efficiency gradually
lowers. As
the oil layer pressure decreases, a pump-off-phenomenon becomes more prone to
occur.
When a pump-off signal is detected by the first inverter 12, the signal is
transmitted to the second inverter 22 via the signal transmission section 23.
That is, the
first inverter serves as a pump-off signal detecting section. When receiving
the pump-off
signal, the second inverter 22 starts pressure-injecting water (fluid).
As a result, the oil layer pressure is recovered and stable oil extraction is
enabled in the production well.
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[0014]
Although in this embodiment the first inverter detects a pump-off phenomenon,
a superior controller (not shown) may detect the pump-off phenomenon or a
sensor
provided for the sucker rod pump may detect the pump-off phenomenon directly.
Although a pump-off signal detected by the first inverter is transmitted to
the second
inverter 22 directly, there is no problem if a condition is met that the
second inverter can be
operated based on the pump-off signal. That is, there is no problem if the
pump-off
phenomenon is detected by a certain means and then pressure injection of water
is
performed based on the detection result.
It is not indispensable to start operating the second inverter immediately
after
detecting the pump-off phenomenon. Operation of the second inverter may be
started when
the pump-off phenomenon has been detected a prescribed number of times or when
the
number of times of detection per unit time has exceeded a prescribed value.
[0015]
As described above, in secondary or tertiary extraction, the pump for
pressure-injecting water, gas, or surfactant (fluid) or microorganisms and the
sucker rod
pump for extracting oil can be operated so as to cooperate with each other by
using a
pump-off detection signal of the inverter. This enables efficient oil
extraction.
Embodiment 2
[0016]
Fig. 2 shows the configuration of an oil extraction supervisory system
according to a second embodiment. A component having the same component in the
first
embodiment is given the same reference numeral and will not be described below
in detail.
In the figure, reference numeral 51 denotes a communication interface, which
is a communication interface card that allows the first inverter 12 to
exchange data with a
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remote supervisory unit (described later). Reference numeral 52 denotes the
remote
supervisory unit which receives a command from a central supervisory system
and
manipulates the inverter in response to the content of the command. Reference
numeral 53
denotes a radio communication section which serves to send and receive a radio
signal.
Reference numeral 60 denotes the central supervisory system which is
composed of a radio communication section 61, a communication interface 62,
and a
computer 63.
[0017]
With the above configuration, when a certain command is sent from the
computer 63, command data is transmitted to the remote supervisory unit 52 via
the radio
communication sections 61 and 53.
The remote supervisory unit 52 manipulates the inverter in response to the
command and returns result data to the computer 63.
For example, if the computer 63 sends out a rotating speed read command, the
remote supervisory unit 52 reads out rotating speed information that is
managed by the
inverter and returns it to the computer 63.
If commands are transmitted periodically, result data are acquired
periodically
and hence data monitoring is enabled.
Accordingly, the operation state of the inverter is checked regularly by the
computer 63, so that it is made possible to supervise and manage the oil
extraction
amount/variation of the entire oil field, the oil extraction amount/variation,
operation state,
maintainability, availability, etc. of each sucker rod pump.
[0018]
Although in this embodiment the communication interface is provided inside
the first inverter, it may be provided outside the first inverter.
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[0019]
As described above, the supervision using radio communication makes it
possible to perform oil production/maintenance management at a distant place.
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