JPS6034680B2 - 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 in electrocuting 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 (
bitumen (also called tar sands)
Kerogen (K) contained in the oil shell
For simplicity, these hydrocarbons will be referred to as oil hereinafter.

In addition, "production" refers to extracting fluid oil from an oil well, such as artesian injection, pumping, and fluid movement. If the oil in the ground has fluidity, it is possible to dig a well from the surface of the earth to reach the oil layer, and use the pressure of the gas coexisting in the oil layer to pump it out, or pump up liquid such as salt water from one well. It is possible to produce oil by entering one well and letting it flow out from the other well.

However, if the fluidity of the oil underground is low, production cannot be achieved unless there is a means for the oil to flow. A common method for fluidizing oil is to reduce the viscosity of the oil by heating.The temperature at which the oil is fluidized varies depending on the individual properties of the oil, but it becomes 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 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 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 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 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 Nile sand coexists with salt water on the surface of the sand and in the interstices between the sand, but it is extremely viscous and has no fluidity in its natural 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 meters underground, with a thickness of several tens of meters. Separation is limited by economics and environmental protection, so it is necessary to extract only the oil from underground. 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 layers less than 30 meters underground. A conventional device for heating an oil sand layer by applying electricity is schematically shown in which electrode devices are arranged as shown in FIG.

In Fig. 1, 1 and 11 are casings made of steel pipes, 2 and 12 are insulated casings joined to casing 11, and 3 and 13 are insulated casings 2 and 1.
Electrodes 4 and 14 connected to electrodes 2 and 14 are cables that send current to 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 a current between the electrodes 3 and 13, 8 is the ground, 9 is an oil sand upper layer, and 10 is an 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 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 9 warms up, the electricity is turned off and hot water or high-temperature, high-pressure steam is injected from the upper part 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 usually includes Tsumugi-kou. In the conventional device as shown in FIG. 1, there is a large power loss flowing through the casing 11 and into the upper layer 9 of the oil sand.

Furthermore, in order to reduce this power loss, it is necessary to lengthen the insulated casings 2 and 12, which increases manufacturing costs. In addition, when electricity is applied, the electrodes 3 and 13 are overheated, and the insulation of the casings 2 and 12 cannot withstand the heat.Furthermore, when passing hot water, the casings 1 and 11 and the insulated - Things 2 and 12 had the disadvantage of large heat loss due to insufficient insulation.The present invention eliminates the above disadvantages and provides an electrode device for heating hydrocarbon-based underground resources that efficiently heats oil sand layers. do.

The figures will be explained below.

In FIG. 2, 3, 6, and 9 are the same as the conventional one. 15
is a main pipe consisting of first and second pipe bodies 15a and 15b,
16 is interposed between the exchange bodies 15a and 15b, and is connected to both the exchange bodies 15a.
, 15b, and 17 is a second insulating member that covers the first insulating member 16 and insulates the first insulating member 1.
The outer periphery of the main pipe 15 near the main pipe 15 is lined with stripes.

18 is a coupling connecting the main pipe 15 and the electrode 3;
Reference numeral 19 denotes a partition that watertightly partitions the electrode 13 and the main pipe 15; an electric conductor passes through the main pipe 15 between the two rivers and is connected to the electrode 3 via the partition member 19; and 21 indicates a part inside the main pipe 15. an insulating oil supply pipe disposed in and closed 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 opened 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.

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, the electricity is turned off, and hot water is sent instead of salt water to the water pipe 22 to heat the hot water. Thereafter, the oil sand layer 6 is heated and oil is taken out in the same manner as in the conventional apparatus. According to this invention, since the pipe bodies constituting the main conduit are insulated by the first insulating member, it is possible to block the current flowing through the main conduit, thereby eliminating power loss due to heating the upper layer of the oil sand.

Additionally, by circulating the insulating oil, overheating is alleviated, improving the durability of the insulating material. Furthermore, the insulating oil acts as a heat insulator, making it possible to reduce heat loss when the oil sand layer 6 is heated by hot water. Therefore, compared to conventional equipment, thermal efficiency was significantly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional device, and FIG. 2 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,
15a, 15b are tube bodies, 16 is a first insulating member, 17 is a second insulating member, 19 is a partition member, 20G electric conductor,
21 is an insulating oil supply pipe, and 22 is a water pipe. 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 pipe in which a plurality of pipe bodies are connected, a tubular electrode that is watertightly connected to the main pipe and has an opening, a partition member that partitions the electrode and the main pipe in a watertight manner, and the main pipe. an electric conductor that penetrates through the main conduit and is connected to the electrode; a water pipe that watertightly penetrates the partition member disposed within the main conduit and opens within the electrode; a water pipe disposed within the main conduit and opens in the vicinity of the partition member. an insulating oil supply pipe, a first insulating member interposed between each of the pipe bodies and insulating each of the pipe bodies, covering the first insulating member and covering the outer periphery of the main pipe in the vicinity of the first insulating member; An electrode device for electrically heating hydrocarbon-based underground resources, characterized by comprising a surrounding second insulating member.