JPS6015107B2 - Electrode device for electrical heating of hydrocarbon underground resources - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode device used for electrically heating hydrocarbon underground resources.

More specifically, it relates to an electrode device used to heat and energize the underground in order to increase the fluidity of hydrocarbons that exist underground and have high viscosity and low fluidity when produced from wells. It is. “Hydrocarbon” here refers to vetrolium, oil, oil sands (
Pichumen (also known as tar sands)
kerogen (K) contained in the oil shell
For simplicity, these hydrocarbons will be referred to as oil hereinafter.

Furthermore, "production" refers to the extraction of fluid oil from an oil well, such as artesian injection, pumping, and fluid transfer. If the oil existing underground has fluidity, a well is dug to reach the oil layer from the surface of the earth, and a liquid such as chloride is pumped out by self-injection using the pressure of the gas coexisting in the oil layer, pumped up, or liquid such as chloride is pumped from one well. It is possible to produce oil by injecting it into one well and letting it flow out of the other well.

However, if underground oil has low fluidity, it cannot be produced unless a means is used to allow the oil to flow. A common method for fluidizing oil is to reduce the viscosity of the oil by heating.The temperature suitable for fluidizing varies depending on the individual properties of the oil, but it becomes necessary to heat the underground oil layer. . As a method of heating the oil layer, injection of hot water,
Injection of high-temperature, high-pressure steam, underground electrification, underground combustion method (igniting an underground oil layer and blowing air to burn it), and the use of explosives have been proposed, but the latter two are difficult to control and are not widely used. poor. Hot water or high-temperature, high-pressure steam injection methods can heat the oil layer to increase the fluidity of the oil and at the same time allow the fluidized oil to flow to the surface, but there are places in the oil layer with low passage resistance, such as cracks. If this happens, there is a risk that the oil will pass through only that area and not diffuse throughout the area.On the other hand, if the oil layer is dense, hot water or steam will not diffuse and the temperature will be difficult to rise.

In the energization heating method, multiple wells are dug in the oil layer, electrodes are installed in these wells, and a potential difference is applied between each electrode to heat the oil layer using the conductivity of the oil layer. It has the advantage of being easy to heat the whole thing even if it is dense. However, other means are required to remove the fluidized oil. Therefore, as a method to increase the efficiency of oil production, a method has been considered that first heats the oil layer using an electric current method, and when the oil layer softens, hot water or high-temperature, high-pressure steam is injected to continue heating and take out the fluidized oil. There is.

The fin pole device used in this method must be electrically insulated to avoid leakage of current outside the oil layer as much as possible in order to heat the oil layer for efficiency. It is necessary that the pressure of the injected hot water or high-temperature, high-pressure steam does not cause damage, and furthermore, it is necessary that the hot water or high-temperature, high-pressure steam does not leak. To explain this electrode device more specifically,
An example of producing oil from oil sands will be described below. Oil sands, also known as tar sands, have been found in Canada, Venezuela, and the United States. Oil in oil sand coexists with salt water on the surface of the sand and in the gaps between the sand, but it has extremely high viscosity and has no fluidity in its natural state. The oil sand layer is mostly exposed at a depth of 200 to 500 m underground, with a thickness of several dozen skins, except for some exposed areas such as narrow valleys and river banks.
Excavating oil sands and separating the oil above ground is limited by economics and environmental protection, so it is necessary to extract only the oil from underground. In addition, since oil production from shallow underground layers is at risk of cave-ins,
It is said that it is desirable to collect from the layer below 00. To schematically show the case where an oil sand layer is heated by electricity, an electrode device is arranged as shown in FIG.

In Fig. 1, 1 and 11 are casings made of steel pipes, 2 and 12 are insulators joined to the casings 1 and 11,
3, 13 are electrodes joined to the insulating parts 2, 12, 4, 14
is a cable that sends current to the electrodes 3 and 13, and these are collectively called an electrode device. 5 is a power supply device 6 is an oil sand layer, 7
is the current between the electrodes 3 and 13, 8 is the ground, 9 is the oil sand upper layer, and 10 is the oil sand lower layer.

When a voltage is applied to the electrodes 3, 13 buried in the oil sand layer 6 from the ground power supply 5 through the cables 4, 14, a current 7 flows according to the electrical resistance in the oil sand layer 6, generating Joule loss. Then, the oil sand layer 6 is heated. At this time, a part of the current 7 also flows to the oil sand upper layer 9 and the oil sand lower layer 10, but the casings 1, 11
Since the insulators 2 and 12 are interposed between the electrodes 3 and 13,
Leakage of current 7 can be suppressed to a small level. When the oil sand layer 6 warms up, the electricity is turned off and hot water or high-temperature, high-pressure steam is injected from the top of the casing 1 of one of the electrode devices. It flows out along with the water. In order to improve thermophoresis or the outflow of high-temperature, high-pressure steam, the electrodes 3 and 13 are usually provided with holes. FIG. 2 is a sectional view showing a conventional device, and in FIG. 2, 3, 6, and 9 are the same as the conventional device. 15 is a main pipe consisting of the first and second pipe bodies 15a and 15b; 16 is a first insulating member interposed between the exchange bodies 15a and 15b to insulate the exchange bodies 15a and 15b;
7 is a second insulating member that covers the first insulating part 16 and
The outer periphery of the main pipe 15 near the insulating member 16 is covered.

18 is a coupling connecting the main pipe 15 and the electrode 3;
19 is a partition member that partitions the electrode 3 and the main pipe 15 in a watertight manner, 20 is an electric conductor that penetrates the main pipe 15 and is connected to the electrode 3 via the partition member 19, and 21 is arranged inside the main pipe 15. an insulating oil supply joint pipe connected near the partition member 19;
Reference numeral 22 denotes a water pipe which is opened within the electrode 3 and penetrates a partition member disposed within the main pipe 15 in a watertight manner.

23 is a hole 24 dug to insert the electrode 3 and the main pipe 1
The cement fills the gap between electrode 5 and the bottom reaches near electrode 3.

A blocker 25 is provided to prevent salt water or hot water from rising through the gap between the cement 23 and the main pipe 15.

To heat the oil sand layer 6, in FIG. 2, salt water is sent from the water pipe 22 in the direction of arrow A, passes through the electrode 3, and is drilled into a hole for inserting the electrode 3 as shown by arrow B from the entrance 3a. satisfy. Next, insulating oil is fed from the insulating oil supply pipe 21 in the direction of arrow C and circulated in the direction of arrow D, and a current is applied to electrically heat the oil sand layer 6. After electrical heating for a certain period of time,
Turn off the electricity, send hot water instead of salt water to the water pipe 22,
Heating with hot water. Thereafter, the oil sand layer 6 is heated and oil is taken out in the same manner as in FIG. but,
In the conventional device as described above, the cross section of the device is as shown in FIG.
Furthermore, since the insulating oil supply pipe 21 and the water pipe 22 are arranged near the outside of the electric conductor 20, the impedance becomes even larger, increasing the power transmission loss of the device.

In addition, since the electrical conductor 20 is not flexible or flexible, in the conventional device, as the temperature of the device increases, the main conduit 15 and the electrical conductor 20
Due to the difference in thermal expansion between the two, the electrical conductor 20 was damaged. Furthermore, it has been necessary to connect the electrical conductor 20 at several dozen locations in the device, requiring a great deal of effort to assemble the device. Conventional devices had the above-mentioned drawbacks. This invention eliminates the above drawbacks,
The purpose of the present invention is to obtain an electrode device that is electrically efficient, simple, and inexpensive to assemble.

FIG. 4 is a sectional view showing one embodiment of the present invention, and FIG.
The figures are cross-sectional views taken in a direction perpendicular to the axis of FIG. 4, FIG. 6 is an explanatory view of connections of the electrode device of the present invention, and FIG. 7 is a partial view of connections. In each figure, 3, 6, 9, 15-19
, 23 to 25 are exactly the same as the conventional device, and 26
is a water pipe, 27 is arranged in the same manner as the main pipe 15,
It is an electric conductor that has a cylindrical shape and a net-like structure that can expand and contract in the direction of the ball, and when the temperature rises when electricity is applied, the thermal expansion of the electric conductor 27 is caused by the contraction due to the structure of the body. It has a structure that allows the vertical height to be kept constant and prevents damage due to the difference in thermal expansion with the main pipe 15. 28 is a connector in which a plurality of reinforcing contacts are arranged in a cylindrical shape, the contacts are movable in the radial direction, and are in contact with the ring-shaped connection terminals 29 and 30 with a predetermined contact pressure. .

The connection terminals 29 and 30 are arranged coaxially with the main pipe 15. Note that 28 to 30 constitute a connecting body 31. FIG. 6 shows the state before connecting the main pipe 15. When the PT screw at the end of the main pipe 15 is screwed and connected to the coupling 18, it becomes as shown in FIG. 7, and the electrical conductor 27 is connected via the connector 28. Connected automatically. As shown in FIG. 5, compared to the cross section of the conventional device shown in FIG. 3, the electric conductor 27 is not eccentric.

Furthermore, since there is no magnetic water pipe or the like near the outside of the electric conductor 27, the impedance is reduced, and power transmission loss can be reduced. In the electrode device configured as described above, the operation of heating the oil sand report 6 and taking out the oil is exactly the same as in the conventional device except for the operation of circulating the insulating oil, and in this invention, the above circulation operation is not performed. It is essential.

According to this invention, the impedance within the electrode device can be made smaller compared to the conventional diamond-backed device, and an efficient electrode device with less power transmission loss can be obtained. Furthermore, the drawback of the conventional device in that the electrical conductor is damaged due to thermal expansion is eliminated, and the work of connecting the electrical conductor is not required during assembly, making it easy to assemble the electrode device and greatly reducing labor.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the device, Fig. 2 is a sectional view showing a conventional device, Fig. 3 is a sectional view taken perpendicular to the axis of Fig. 2, and Fig. 4 shows an embodiment of the present invention. 5 is a sectional view of a plane perpendicular to the axis of FIG. 4, FIG. 6 is an explanatory diagram of device connections, and FIG. 7 is a partial diagram of connections. In the figure, 15 is a main pipe, 27 is an electric conductor, and 30 is a connecting body. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 3 Figure 5 Figure 1 Figure 2 Figure 4 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1 A circular main pipe and an electrode are connected to each other, and a plurality of electrical conductors pass through the main pipe and are connected to each other via a connecting body. An electrode device for electrically heating hydrocarbon-based underground resources, characterized in that it has a circular tubular shape and is arranged within the main pipe concentrically with the axis of the main pipe. 2. The electrode device for electrically heating hydrocarbon-based underground resources according to claim 1, wherein the electric conductor has flexibility in the axial direction of the main pipe. 3. Claim 1, characterized in that the connecting body is configured of a pair of ring-shaped contacts disposed coaxially with the main pipe and is slidable in the axial direction and circumferential direction of the main pipe. An electrode device for electrically heating hydrocarbon-based underground resources according to item 1 or 2.