JPS6015108B2 - 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 underground in order to increase the fluidity of hydrocarbons that exist underground, with high viscosity and low fluidity, when produced from wells. It is something. "Hydrocarbons" here refer to betrolium or oil, bityumen (B skin men) contained in oil sands (also called tar sands), and kerogen (K skin men) contained in oil shells.
For 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, fluid transfer, etc. If the oil that exists underground has fluidity, a well is dug to reach the oil layer from the surface of the earth, and the gas that coexists in the oil layer is ejected.
Alternatively, oil can be produced by pumping, or by introducing liquid such as salt water into one well and letting it flow out from the other well.

However, if the fluidity of underground oil is low, production cannot be achieved unless a means is purchased for 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. . Possible methods for heating oil layers include injection of hot water, injection of high-temperature, high-pressure steam, underground electrification, underground combustion (igniting the underground oil layer and blowing air to burn it), and the use of explosives. , the latter two are difficult to control and lack generality.

The thermal or high-temperature, high-pressure steam injection method heats the oil layer to zero and increases the fluidity of the oil, while at the same time allowing the fluidized oil to flow to the surface. If there is a spot, there is a risk that the oil will pass through that spot and not spread throughout the entire body, and if the opposite oil layer is hard and dense, hot water or steam will not diffuse and the temperature will be difficult to rise.

The current heating method involves drilling multiple wells in an oil layer, installing electrodes in these wells, and applying a potential difference between each electrode to heat the oil layer using its conductivity. 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 through electrically conductive fibers, and when the oil layer softens, hot water or high-temperature, high-pressure steam is injected to continue heating and extract the fluidized oil. ing. In order to efficiently heat the oil layer, the electrode device used in this method must be air-insulated to avoid current leakage outside the oil layer as much as possible. 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 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 partly exposed in narrow valleys and river glands, but most of it is underground.
The oil sands exist at a depth of 0 to 500 m and a thickness of several tens of m., and since digging out oil sands and separating the oil on the ground is constrained by economics and environmental protection, 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 that it is desirable to extract oil from the following layers 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 casings 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 '3, 8 is the ground, 9 is the upper oil sand layer, and 1 is the lower oil sand layer.

When a voltage is applied to the electrodes 3 and 13 buried in the oil sand layer 6 from the power source 5 on the ground through the cables 4 and 14, a current 7 flows according to the electrical resistance in the oil sand layer 6, resulting in Joule loss. occurs, and 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 current is turned off and one of the casings 0 of the electrode device
If hot water or high-temperature, high-pressure steam is introduced from the upper part of electrode device 1, it passes through oil sand layer 6 and flows out from casing 11 of the other electrode device along with oil. In order to improve the outflow of hot water or high-temperature, high-pressure steam, the electrodes 3 and 13 are usually provided with pores. FIG. 2 is a sectional view showing the follower device, and in FIG. 2, 3, 6, and 9 are the same as the conventional one.

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, a second insulating member which covers the first insulating member 16 and surrounds the entire outer periphery of the main pipe 15 near the first insulating member 16. ing.

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 pipe opened near the partition member 19, 2
A water pipe 2 is disposed within the main pipe 15, penetrates the partition part in a watertight manner, and is opened within the electrode 3.

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, as shown in FIG. 2, salt water is sent in the direction of arrow A from the water pipe 22, passes through the electrode 3, and is dug from the opening 3a in the direction of arrow B for insertion of the electrode 3. 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 is turned off, and hot water instead of salt water is sent to the first water pipe 22 to perform heating with the hot water. Thereafter, the oil sand layer 6 is heated and oil is taken out in the same manner as in FIG. However, in the conventional device as described above, at the beginning of flowing hot water after electrical heating, the hot water is cooled by brine, etc. that accumulates inside the electrode 3 or near the outside of the electrode 3, and the low-temperature heat is released. Water is sent to the oil sand layer 6, the temperature of the oil sand layer 6 does not rise, and therefore the permeability of hot water does not improve, so the amount of permeation of hot water is small. Since the amount of heat supplied is small, a vicious cycle occurs in which the temperature does not rise, resulting in a disadvantage that the heating efficiency of the oil sand layer is poor.

The object of the present invention is to eliminate the drawbacks of the conventional devices as described above and to obtain an efficient electrode device.

3 and 4 are sectional views showing one embodiment of the present invention, with FIG. 3 showing the lower part of the electrode device and FIG. 4 showing the upper part.

In Figures 3 and 4, 3, 4, 6, 8, 9, 15~
25 is exactly the same as the conventional device, and 26 is the electrode 3.
, is a second water pipe that penetrates the water pipe 22, and 27 is a second water pipe that penetrates the water pipe 22.
When inserting or extracting the water pipe 26 into or out of the water pipe 2, be careful not to contact the inner wall of the water pipe 22. Also, when flowing hot water into the water pipe 22, the water pipe 26 may vibrate or become uneven, causing water flow resistance. This is a centralizer that fixes the water 26 at the center of the water pipe 22 so that it does not rise. Numeral 28 is a bolt that securely fixes the water pipe 26 to the water pipe 22.

In the electrode device configured as described above, the operation of heating the oil sand layer 6 and taking out the oil is the same as that of the same machine.
In the figure, hot water is sent in the direction of arrow A, arrows B, E, F.
This circuit expels water and cooled hot water. When the temperature of the hot water at the outlet of the upper part of the electrode rises to a predetermined temperature as shown in FIG. Allow it to flow into layer 6.

The water pipe 26 becomes a flow resistance when extracting oil after heating the oil sand layer 6 with hot water, or when using an oil extraction pump, it becomes a disadvantage that a pump with a large diameter cannot be used. It is more efficient to extract it.

Therefore, a centralizer 27 is provided in this water pipe 26,
The upper part of the water pipe 26 is connected to the water pipe 22 by a flange, so that it can be easily taken out by removing the bolt 28. As explained above, in this invention, by providing the water pipe 26, high temperature hot water can be supplied to the oil sand layer 6, enabling efficient heating, and when extracting oil, the water pipe 26 is provided.
6 can be easily extracted, the water pipe 22 can be used effectively, which has the effect of increasing oil extraction efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the device, FIG. 2 is a sectional view showing a conventional device, and FIGS. 3 and 4 are sectional views showing an embodiment of the present invention. In the figure, 3 is an electrode, 15 is a main pipe, 20 is an electric conductor, 22 is a water pipe, and 26 is a water pipe that penetrates inside the water pipe 22. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A circular main pipe, an electrode insulated and connected to the main pipe, an electric conductor that passes through the main pipe and is connected to the electrode, and a first water pipe that passes through the main pipe. An electrode device for electrically heating hydrocarbon-based underground resources, comprising a second water pipe penetrating the first water pipe. 2. The electrode device for electrically heating hydrocarbon-based underground resources according to claim 1, wherein the second water pipe passes through the electrode. 3. The electrode device for electrically heating hydrocarbon-based underground resources according to claim 1, wherein the second water pipe is configured to be able to be extracted from the first water pipe.