JPS6015109B2 - 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 a reservoir to increase the fluidity of hydrocarbons that exist underground, with high viscosity and low fluidity, when produced from wells. be. “Hydrocarbon” here refers to vetrolium, oil, oil sands (
bitumen (also called tar sands)
B skin men), kerogen (Ke) contained in the oil shell
For the sake of simplicity, these hydrocarbons will be referred to as oil hereinafter.

In addition, "production" refers to the extraction of fluid oil from an oil well, such as artesian injection, pumping, and fluid transfer. If the oil that exists underground has fluidity, a well is dug to reach the oil layer from the surface, and the pressure of the gas coexisting in the oil layer is used to self-inject, pump up, or pump liquid such as salt water 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 the fluidity of underground oil is low, production cannot be achieved unless a means is purchased 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 methods for heating the oil layer, the following methods have been proposed: injection of hot K, injection of high-temperature, high-pressure steam, underground electrification, underground combustion method (igniting the underground oil layer and blowing air to combust it), and the use of explosions. However, the latter two are difficult to control and are generally scarce.

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 spread throughout the area.On the other hand, if the oil layer is hard and dense, hot water or steam will not diffuse and the temperature will be difficult to rise.

In the current 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 utilize the conductivity of the oil layer and heat it. Even though it is delicate, it has the advantage of being easy to heat.

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 by applying electricity, and when the oil layer becomes soft, hot water or high-temperature, high-pressure steam is injected to continue heating and extract the fluidized oil. There is. In order to efficiently heat the oil layer, the electrode device used in this method must be electrically insulated to avoid leakage of current outside the oil layer as much as possible, and must be electrically insulated to avoid leakage of current to areas other than the oil layer. It is necessary that the product not be destroyed by the pressure of heated hot water or high-temperature, high-pressure steam.
Furthermore, it is necessary that hot water or high-temperature, high-pressure steam does not leak. In order to explain this electrode device more specifically, an example in which oil is produced from oil sand will be described below.

Oil sands, also known as tar sands, have been found in Canada, Venezuela, and the United States.

Oil in oil sands coexists with salt water on the surface of the sand and between the sands, but it has extremely high viscosity and has no fluidity in its natural state. The oil sand layer is mostly underground, with some parts exposed in narrow valleys and riverbanks.
The oil exists at a depth of 0.00 to 500 skin and is several tens of centimeters thick, and digging out oil sands and separating the oil on the ground is constrained by economics and protection from remote areas, so it is difficult to extract only the oil from underground. I need to take it out. Furthermore, since oil production from shallow underground layers is at risk of cave-ins, it is said to be desirable to extract oil from layers less than 300 deep underground. The first example shows the case of heating the oil sand layer by applying electricity.
The electrode device is arranged as shown in the figure.

In Fig. 1, 1 and 11 are casings made of steel pipes, 2 and 12 are insulators joined to the casing 1 and 11,
3, 13 are electrodes bonded to insulators 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 on the ground, 9 is the upper oil sand layer, and IQ is the lower oil sand layer.

When a voltage is applied to the electrodes 3, 13 buried in the oil sand layer 6 through the cables 4, 14 from a power supply device on the ground, a current 7 flows according to the electrical resistance in the oil sand layer, generating Joule loss, and the oil Sand layer 6 is heated. At this time, part of the current 7 also flows to the oil sand upper layer 9 and the oil sand lower layer 10, but since the insulated casings 2 and 12 are interposed between the casings 1 and 11 and the electrodes 3 and 13, the current 7 leaks. can be kept small. 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 on one side of the electrode device.
It flows out from the casing 11 together with oil. In order to improve the outflow of hot water or high temperature and high pressure steam, electrode 3,
13 is Zendo, who has Tsumugi-kou. Figure 2 is a sectional view showing a conventional device.
is the same as before.

15 is a main pipe consisting of the first and second pipe bodies 15a and 15b, and 16 is the exchange body 15 interposed between the exchange bodies 15a and 15b.
A first insulating member 17 insulates between a and 15b is a second insulating member that covers the first insulating member 16 and extends around the outer periphery of the main pipe 15 near the first insulating member 16. There is.

18 is a continuous coupling between 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 electromagnetic member 3 via the cutting member 19; Insulating oil supply arranged and connected near the partition member 19, 22
is a water pipe disposed within the main pipe 15, penetrating the partition member in a watertight manner and opening within the electrode 3.

23 is a hole 24 dug to insert the electrode 3 into 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 was sent in the direction of arrow A from the water pipe 22, passed through the inside of the fin pole 3, and was excavated for insertion of the electrode 3 from the entrance 3a as shown by arrow B. fill the hole.

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, the electricity supply is stopped, and hot water instead of salt water is poured into the water pipe 22, and heating is performed using the hot water. Thereafter, the oil sand layer 6 is heated and oil is taken out in the same manner as in FIG. In the conventional device as described above, when making a fake electrode bag, the electrical conductor 20, the water pipe 22, and the insulating oil supply pipe 23 are connected to each other, and after they are fixed and insulated from each other, the main pipe 15 is connected. This operation is repeated to assemble an electrode device of a predetermined length. Therefore, there is a drawback that assembly requires a great deal of labor and time. An object of the present invention is to obtain an electrode device that is easy to assemble.

FIG. 3 is a cross-sectional view showing an embodiment of the present invention, FIG. 4 is a cross-sectional view of the first tube body of the present invention, and FIG. 5 is a cross-sectional view of the second tube body of the present invention. FIG. 6 shows a sectional view of the third tube body of the present invention, FIG. 7 is an explanatory diagram of the connection of each tube body, and FIG. 8 shows a diagram of the connection state of the tube bodies.

In each figure, 3, 6, 9, 15 to 18, and 23 to 25 are the same conventional devices, and 26 is the first tube, which provides insulation in all directions as shown in Figure 4. It is connected to the main conduit 15 via an insulating material 16, and a part of the coupling connecting the 31 main conduits 15 is insulated by an insulating material 17, and the insulating material 16 and the outer periphery of the main conduit 15 are insulated.

There are 30 water pipes coaxially arranged in the main pipe 15 and 35 water pipes 30.
One end of the water pipe 30 is connected and fixed with a PT screw using a water pipe coupling, and the end of the water pipe 30 is freely expandable and contractable in the axial direction. The water pipe covering 35 is provided with 36 seals, and has a structure that can be sealed when the other part of the water pipe 30 is inserted. Reference numeral 32 denotes an electric conductor, which is coaxially provided outside the water pipe 30 and inside the main pipe 15.

A connector 33 electrically connects the electric conductor 32.

34 is filled with a heat insulating material between the water pipe 30 and the main pipe 30. Reference numeral 27 denotes a second tube body, which has a cross section as shown in FIG.
It is completely the same as the first tube except that it has changed to .

Reference numeral 28 denotes a third tube which is completely the same as the first and second tubes except for the absence of insulating materials 16 and 17, and has a cross section as shown in FIG.

29 is an insulating cover that electrically insulates the outside of the cup IJ ring 18, and as shown in FIG. 8, it is a holding metal fitting that holds the lip-type V packing 37 and the V packing 38, and presses and fixes the V packing 37. The press fitting is a sleeve that insulates the coupling 18, and the inner ring surface of the V packing 37 is in close contact with the outer surface of the insulating material 17, and the insulating material 17, the V packing 37, and the sleeve 40 provide electrical insulation between the pipe bodies. This is the foundational structure.

41 is a protective layer.

To set up the electrode device of this invention, as shown in FIG. 3, fit the connector 33 onto the electrode 3 as shown, and then
When 7 is screwed in as shown in FIG. 7, the water pipe 30 and electric conductor 32 are automatically connected as shown in FIG. Next, the first tubular body 26 is connected in the same manner as above, and the third tubular body is further connected in succession to assemble the electrode device to a predetermined length. The insulating cover is attached to the connection between the first tube and the second tube as shown in FIG. In the electrode device configured as described above, the operation of heating the oil sand layer 6 and taking out the oil is completely the same as in the conventional device except for the operation of circulating the insulating oil. Therefore, in this invention, the above-mentioned circulation operation is unnecessary.

According to the present invention, on-site assembly time can be significantly shortened compared to conventional devices.

[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 showing an embodiment of the present invention, Fig. 4 is a first tube body, and Fig. 5 is a sectional view showing a conventional device. FIG. 6 shows the second tube, FIG. 6 shows the third tube, FIG. 7 is an explanatory diagram showing the connection, and FIG. 8 is a sectional view showing the connection state. In the figure, 3 is an electrode, 15 is a main pipe, 26 is a first pipe, 27 is a second pipe, 28 is a third pipe, 3 water pipes, and 32 is an electric conductor. Note that the same reference numerals in each figure indicate the same or equivalent parts. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. A circular main conduit and an electrode are connected, and an electrical conductor passing through the main conduit and the electrode are connected,
The main pipe has a first pipe body whose axial direction and outer circumference are insulated;
A second pipe whose outer circumference is insulated only, a third pipe whose outer circumference and axial direction are not insulated, a water pipe housed in each of the above tubes and connectable to each other, and a water tube housed in each of the above tubes and electrically connected to each other. Electrode device for electrical heating of hydrocarbon-based underground resources with an electrical conductor connectable to. 2. A claim characterized in that the outer surface of the coupling connecting the first tube and the second tube or the first tube and the electrode is provided with a coupling insulating cover capable of electrically insulating the outer surface of the coupling. An electrode device for electrically heating hydrocarbon-based underground resources according to item 1. 3. The electrode device for electrically heating hydrocarbon-based underground resources according to claim 2, wherein the coupling insulating cover is composed of an insulating cylinder, a V-packet, and a V-packet holding fitting.