JPS6034678B2 - 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. The term "hydrocarbon" here refers to bitumen (B
itumen), Keroken (K) contained in the oil shell
For simplicity, these hydrocarbons will be referred to as oils hereinafter.

In addition, "production" refers to the extraction of fluid oil from an oil well through artesian injection, suction, fluid transfer, etc. If the oil in the ground has fluidity, a well is dug to reach the oil layer from the surface of the earth, and the oil is pumped up by the pressure of the gas coexisting in the oil layer, pumped up, or a liquid such as salt water is injected from one well. It is possible to produce oil in other ways, such as by draining it from the other well.

However, if the fluidity of underground oil is low, production cannot be achieved without taking measures to make the oil flow. The general method for fluidizing oil is to lower the viscosity of the oil by reducing the viscosity of the oil.The temperature suitable for fluidizing varies depending on the individual properties of the oil, but it is necessary to heat the underground oil layer. occurs. 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.

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.

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. It has the advantage that even if it is delicate, it is easy to heat the entire body.

However, other means are required to remove the fluidized oil. Therefore, one possible 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 soft, hot water or high-temperature, high-pressure steam is injected to continue heating, and the fluidized oil is extracted. In order to heat the oil layer efficiently, the electrode device used in this method must be electrically insulated to avoid current leakage 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 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 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 does not have 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 h 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. Also, since oil production from shallow underground layers is at risk of cave-ins, it is said that it is desirable to collect oil from layers less than 30 layers underground. A conventional apparatus for heating an oil sand layer by applying electricity is schematically shown in FIG. 1, in which electrode bags are arranged.

In Fig. 1, 1 and 11 are casings made of steel pipes, 2 and 12 are insulated casings joined to the casings 1 and 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 through the cables 4, 14 by 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. The oil sand layer 6 is heated. At this time, part of the current 7 also flows to the upper oil sand layer 9 and the lower oil sand 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 does not leak. Can be kept small. When the oil sand layer 6 warms up, the electricity is turned off, and if hot water or high-temperature, high-pressure steam is injected from the upper part of the casing 1 on one side of the electrode device, it passes through the oil sand layer 6 and passes through the casing 1 of the other electrode device. It flows out from No. 11 along with oil. In order to improve the outflow of hot water or high-temperature and high-pressure steam, the electrode 3
, 13 usually include pores. In the electrode device, salt water is usually fed into the electrodes 3 and 13 through a pipe (not shown) to improve the contact resistance with the oil sand layer 6, and the electrode 3 is fed to separate the salt water casings 1 and 11 from each other. , 13 is provided with a partition plate (not shown), and the upper part of the partition plate is filled with an insulating liquid.

Regarding these matters regarding electric heating, for example, U.S. Patent No. 3,946,80 and Canadian Patent No. 1,
No. 022,062' describes this.

In the conventional device as shown in Fig. 1, the casing 1
, 11, it is necessary to incorporate a large number of parts such as cables 4, 14, supply pipes for salt water and hot water, and supply pipes for insulating liquid, resulting in a complicated structure. Furthermore, while heating the oil sand layer 6 with hot water, the insulating liquid sealed in the casings 1, 1 serves as a heat insulator that reduces heat loss escaping from the hot water supply pipe to the upper oil sand layer 9. However, this liquid does not have a sufficient heat insulating effect and has the disadvantage of increasing heat loss. The 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 oil sand layers.
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, and 16 is an electric conductor that suspends the electrode 3 and sends electricity to the electrode 3 from a power source 5 installed on the ground. There is a certain leadership. The outer surface of this main conduit is covered with an electrical insulator 17. The electrode 3 and the main pipe 16 are integrally formed into a tubular shape. A water pipe 18 for supplying salt water and hot water passes through the main pipe 16 and opens at one end within the electrode 3 . A partition member 19 is provided near the boundary between the main pipe 16 and the electrode 3 portion to provide a watertight structure to prevent hot water or salt water from flowing back into the main pipe 1. 20 is a covering that connects the main pipe 16 and the electrode 3; 21 is a cement part 15;
This is a blockage installed to prevent salt water and hot water from rising from the space between the main pipe 16 and the main pipe 16 and spouting out to the ground.

A heat insulating material 22 is inserted into the space between the water pipe 18 and the main pipe 16, and serves to reduce heat loss transmitted from the water pipe 18 to the upper layer 9 of the oil sand.

To heat the oil sand layer 6, as shown in FIG.
Salt water is sent from the water pipe 18 in the direction of arrow A, passes through the electrode 3, and is blown out from the entrance 3a in the direction of arrow B.
Fill the hole dug for insertion.

Next, a current is passed through the main conduit 16 and reaches the electrode 3 to heat the oil sand layer 6. After electrical heating for a certain period of time, electricity is stopped, the water pipe 18 is replaced with salt water, and heated with hot water. Thereafter, the oil sand layer 6 is heated and oil is taken out in the same manner as in the conventional apparatus. In the above example,
Although the electrode 3 is connected to one end of the main pipe 16 in the explanation, the main pipe and the electrode may be connected as a body.

According to this invention, the structure can be simplified by arranging the water pipe within the main pipe made of an electric conductor and partitioning the closed part of the main pipe with a partition member so that one end of the water pipe is open.

Furthermore, thermal efficiency can be improved by providing a heat insulating material between the main pipe and the water pipe.

[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 electric insulator, 18 is a water pipe, 19 is a partition member, and 22 is a heat insulating material. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A main conduit made of an electrical conductor whose outer periphery is insulated and has an opening at one end so that one end is exposed; a partition member that makes the opening of the main conduit watertight with the other end; 1. An electrode device for electrically heating hydrocarbon-based underground resources, comprising a water pipe arranged to penetrate the partition member in a watertight manner and open in the electrode. 2. A main conduit made of an electrical conductor whose outer periphery is insulated so that one end is exposed and has an opening at one end; a partition member that makes the opening of the main conduit watertight with the other end; and a partition member disposed within the main conduit. A water pipe that penetrates the main pipe in a watertight manner and opens at one end of the main pipe, and a heat insulating member provided on the other end side of the partition member between the main pipe and the water pipe. Electrode device for electrical heating of underground resources.