JPS6015105B2 - 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. “Hydrocarbon” here refers to vetrolium, oil, oil sands (
bityumen (also called tar sands)
B et al.), kerogen (Ke) contained in the oil shell
For the sake of 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 salt water is pumped out by self-injection using the pressure of the gas coexisting in the oil layer, pumped up, or liquid such as salt water 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 the fluidity of underground oil is low, production cannot be achieved unless a means is taken to make the oil flow. A common method for fluidizing oil is to reduce the viscosity of the oil by heating.The optimal temperature for fluidizing varies depending on the individual properties of the oil, but it becomes necessary to heat the underground oil layer. . Proposed methods for heating the oil layer include 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 burn it), and the use of explosives. However, the latter two are difficult to control and lack generality.

The heating method or high-temperature, high-pressure steam injection method heats the oil layer and increases the fluidity of the oil, and at the same time allows the fluidized oil to flow to the surface, but it is possible to flow the fluidized oil to the surface of the earth if there are places with low passage resistance such as cracks in the oil layer. If it exists, there is a risk that it will pass through only that area and not diffuse 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 bottle 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 that even if it is hard and delicate, it is easy to heat the whole thing.

However, other means are required to remove the fluidized oil. Therefore, as a way to increase the efficiency of oil production, a method has been considered that first heats the oil layer using the energization method, and when the oil layer becomes soft, hot water or high-temperature, high-pressure steam is injected to continue heating and remove the fluidized oil. It is being In order to efficiently heat the oil layer, the pole equipment used in this method must be dovetail insulated to avoid current leakage to sources other than the oil, and must be insulated from underground soil or steam generated by heating or injection. It is necessary that it not be destroyed by the heat K or the pressure of high-temperature, high-pressure steam, and furthermore, it is necessary that hot water or high-temperature, high-pressure steam cannot 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 partially exposed in narrow valleys, riverbanks, etc., but most of the oil sand layer exists at a depth of 200 to 500 layers underground and several tens of layers thick. Separation 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 preferable to collect from the layer below 0. 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 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 10 is the lower oil sand layer.

When voltage is applied to the electrodes 3 and 13 buried in the oil sand layer 6 from the ground power supply 5 through the cable 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 by 4. oil sand layer 6
When the casing 1 of the electrode device is warmed up, the current is turned off and the casing 1
If hot water or high-temperature, high-pressure steam is injected from the top of the
It passes through the oil sand layer 6 and flows out from the casing 11 of the other electrode along with the oil. In order to improve the outflow of hot water or high-temperature, high-pressure steam, it is a good practice to provide pongee holes in the electrodes 3 and 13. FIG. 2 is a cross-sectional view showing the slave device. In FIG. 2, numerals 3, 6, and 9 are the same as the slave.

15 is a main pipe consisting of first and second pipe bodies 15a and 15b; 16 is a main pipe interposed between both pipe bodies 15a and 15b;
a, 15b, and 17 is a second insulating member that covers the first insulating member 16 and screens the outer periphery of the main pipe 15 near the first insulating section 16. There is.

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,
A water pipe 22 is disposed within the main pipe 15, penetrates the partition member in a watertight manner, and is closed within the electrode 3.

23 is a hole 24 drilled 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.

In order to heat the oil sand layer 6, in the second step, 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 ○, 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 the water pipe 22 sends hot water K instead of salt water, and heats with 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, in order to use insulating oil to cool the electrical conductor, when hot water is passed through the water pipe 22 and the oil sand layer 6 is heated, the insulating oil absorbs the heat of the hot water. It becomes a conductor and requires cooling to reduce the high temperature of the insulating oil itself.

Therefore, heat from the hot water escapes from the insulating oil to the ground through the main pipe 15, and heat loss occurs due to cooling of the insulating oil, resulting in a device with poor heating efficiency. The present invention aims to eliminate the drawbacks of the conventional devices as described above and to obtain an electrode device with good heating efficiency.

FIG. 3 is a sectional view showing an embodiment of the present invention.

In the figure, 3, 3a, 6, 9, 15-19, 22-2
5 is the same as the conventional device. 26 is an electric conductor arranged coaxially with the main pipe 15; 27 is an inner wall of the main pipe 15 and the water pipe 2;
A solid insulation material that fills the space between two exterior walls.

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 in the conventional device, and the operation of circulating the insulating oil as in the conventional device is unnecessary.

The solid heat insulating material 27 described above is made of a fiber material such as glass wool or a molding material, but it can be made cheaper if an inorganic solid powder is used.

According to this invention, by using a solid heat insulating material and further a solid powder heat insulating material for the insulating oil of the subordinate equipment, the solid powder has a better heat insulating effect than the insulating oil. Since there is no need for cooling, it is even more efficient.

In addition, solid powder heat insulating material is cheaper than insulating oil, so it has the effect of lowering manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the device, FIG. 2 is a sectional view showing a subordinate device, and FIG. 3 is a sectional view showing an embodiment of the present invention. In the figure, 3 is the electrode, 3a is the entrance part, 15 is the main pipe,
19 is a partition member, 22 is a water pipe, 26 is an electric conductor, and 27 is a heat insulating material. Note that the same reference numerals in each figure indicate the same or equivalent parts. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. An electrode having an opening and a main conduit are watertightly configured with a partition member, an electric conductor passing through the main conduit is connected to the electrode, and the partition member is disposed within the main conduit. A water tube that penetrates the member in a watertight manner and opens in the electrode, characterized in that a solid heat insulating material is filled in a container consisting of the inner wall of the main tube, the outer wall of the water tube, and the partition member. Electrode device for electrical heating of hydrocarbon underground resources. 2. The electrode device for electrically heating hydrocarbon-based underground resources according to claim 1, wherein the heat insulating material is a solid powder.