JPS6034679B2 - 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, when producing hydrocarbons with high viscosity and low fluidity that exist underground from wells, electrodes are used to heat and conduct electricity underground in order to increase the fluidity of the hydrocarbons. It is related to the device. The term "hydrocarbons" used here refers to vetrolium or oil, bitumen contained in oil sands (also called tar sands), and kerogen contained in oil shells. Let's call hydrocarbons oil.

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 it can be self-injected by the pressure of the gas coexisting in the oil layer, pumped up, or injected with liquid such as salt water from one well. It is possible to produce oil by draining one well from the other.

However, if the fluidity of underground oil is low, production cannot be achieved unless measures are taken to make the oil fluid. The general 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 is necessary to heat the oil layer underground. . 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 sending air to burn it), and the use of explosives have been proposed, but the latter two are difficult to control and are not common. 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 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 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 add up 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, a method to increase the efficiency of oil production is to first heat the oil layer using an electric current method, and when the oil layer becomes hot, hot water or high-temperature, high-pressure steam is injected to continue heating and take out the fluidized oil. ing. In order to efficiently heat the oil layer, the polar laminated layers used in this method must be electrically insulated to avoid current leakage outside the oil layer as much as possible. It is necessary that the pressure of the heated 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. 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 chloride on the surface of the sand and in the interstices between the sands, but the oil is extremely precise and has no fluidity in its naturally existing state. The oil sand layer is partially exposed in valleys, riverbanks, etc., but most of the oil sand layer exists at a depth of 200 to 50 h underground with a thickness of several tens of meters. Separating oil is subject to economic and environmental protection considerations, 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 necessary to
It is said that it is desirable to collect from n layers or less. If a conventional device for heating an oil sand layer by electricity is schematically shown, 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 insulated casings 3 and 13 joined to the casings 1 and 11, and 3 and 13 are insulated casings 2 and 12.
Electrodes 4 and 14 connected to the electrodes 4 and 14 are cables that send current to the electrodes 3 and 13, and these are collectively called an electrode device. Reference numeral 5 indicates a power supply device 6 in the oil sand layer, 7 indicates a current between the electrodes 3 and 13, 8 indicates the ground, 9 indicates an upper layer of oil sand, and 10 indicates a lower layer of oil sand.

When a voltage is applied to the electrodes 13, 3 buried in the oil sand layer 6 through the cables 4, 14 from the power supply device 5 on the ground, 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 insulated casings 2 and 12 are interposed between the electrodes 3 and 13, leakage of the 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 the outflow of hot water or high-temperature and high-pressure steam, the electrode 3
, 13 are usually pores. In the conventional device as shown in FIG. 1, the power loss flowing through the casings 1 and 11 to the upper oil sand layer 9 is large;
Casing 2, 1 due to overheating of electrodes 3, 13
The disadvantage was that the insulator in No. 2 could not withstand heat.

In addition, when hot water is passed through, the casings 1 and 11 and the insulated casings 2 and 12 are not sufficiently insulated, so heat is generated. Another drawback was that the space was large. An object of the present invention is to provide an electrode device for heating hydrocarbon-based underground resources that can eliminate the above-mentioned drawbacks of conventional devices and can efficiently heat an oil sand layer.

The configuration of this invention will be explained with reference to the drawings.

FIG. 2 is a diagram showing an embodiment of the present invention. The figure shows the electrode inserted into the oil sand layer 6. In FIG. 2, 15 is a cement part that is closed after inserting the electrode 3 into the oil sand layer 6, 16 is a main pipe from which the electrode 3 is suspended, and there is electrical insulation between the main pipe 16 and the electrode 3. An insulating tube 17 made of an alumina guy tube is connected to the insulating tube 17. An electrode 3 is connected to the main pipe 16 and the insulating pipe 17 from the ground power source 5.
Electrical conductor 18 leading to and water pipe 1 supplying salt water and hot water
An insulating oil supply pipe 20 that supplies insulating oil for electrically insulating between the electrical conductor 18, the main pipe 16, and the water pipe 19 passes through the pipe.
A partition member 21 is provided between the insulator 17 and the electrode 3, and the partition member 21 has a structure that prevents insulating oil from leaking to the outside. The partition member 21 and the electrode 3 are electrically connected.
The insulating oil supply pipe 2 is open near the partition member 21, and is arranged to facilitate the circulation of the insulating oil. During heating, it acts as a heat insulator to reduce the amount of heat transmitted to the upper oil sand layer 9 through the main pipe 16. The water pipe 19 penetrates the partition member 21 and has an open end inside the electrode 3, and sends salt water when electrically heating the oil sand layer 6, and sends hot water when heating the oil sand layer 6 with hot water. Reference numeral 22 denotes a connecting fitting for connecting the electrode 3 and the insulating tube 17 or the insulating tube 17 and the main conduit 16.

A blocker 23 is provided to prevent salt water or hot water from rising between the cement part 15 and the insulator 17.

To heat the oil sand layer, in FIG. 2, salt water is sent from the water pipe 19 in the direction of arrow A, passes through the electrode 3, and is blown out from the closed part 3a in the direction of arrow B to form a trench for inserting the electrode 3. Fill the ivy hole.

Next, insulating oil is fed in the direction of arrow C from the insulating oil supply pipe 20 and circulated in the direction of arrow D, and a current is applied to the oil sand layer 6.
is heated electrically. After electrical heating for a certain period of time, the tortoise is stopped,
Hot water is sent to the water pipe 19 instead of salt water, and heating is performed by the hot water. Thereafter, the oil sand layer 6 is heated and the oil is extracted using the same machine as the conventional device. According to this invention, by interposing an insulating tube made of porcelain between the main conduit and the electrode and supplying insulating oil into the main conduit and the insulating tube, it is possible to prevent current leakage to the upper layer of the oil sand. Heat loss during layer heating can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional device, and FIG. 2 is a sectional view showing an embodiment of the present invention. In the figure, 16 is a main pipe, 17 is an insulating pipe, 18 is an electric conductor, 19 is a water pipe, two insulating oil supply pipes, and 21 is a partition member. Note that the same reference numerals in each figure indicate the same or equivalent parts. Figure 1 Figure 2

Claims (1)

[Claims] 1. A main conduit, a tubular electrode having an opening, an insulating tube made of porcelain watertightly connected between the main conduit and the electrode, an electric conductor penetrating the main conduit and connected to the electrode, the electrode and the above a partition member that makes the space between the main pipe watertight and the insulating oil supply pipe watertight; an insulating oil supply pipe that penetrates the main pipe and opens near the partition member; An electrode device for electrically heating hydrocarbon-based underground resources, characterized by comprising a water pipe with one end open.