JP2011147869A - Underground storage facility for carbon dioxide and method for laying the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide useful and most suitable underground storage facilities which enable carbon dioxide to be stored in a non-structural storage layer for carbon dioxide, as well as a method for laying the underground storage facilities. <P>SOLUTION: The underground storage facilities can be laid by the following procedures: first, an artificial shielding obstacle 2 which can shield carbon dioxide is integrally formed with a shielding layer 1 by injecting a grout into a bed right under the shielding layer made up of a water non-permeable bed. Thus a storage region A for storing carbon dioxide is compartmentalized by the shielding obstacle and the shielding layer. When the shielding layer is almost flat, inclining to the horizontal plane, the shielding obstacle is formed like a wall, while the obstacle swells from the shielding layer into the bed under the shielding layer, on the lower surface side of the upper side in the inclination direction of the shielding layer. During the laying work, a forcing well 4 for forcing the carbon dioxide into the storage region, is tentatively dug upto a position where the forcing well runs through the shielding layer. After that, the grout is injected into the bed under the shielding layer from the apex of the run-through position, and thus the shielding obstacle is formed to compartmentalize the storage region. Finally, the forcing well is extended upto the deep part of the storage region. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a facility for storing carbon dioxide (CO ₂ ) as a global warming gas in the ground, and a construction method thereof.

CO ₂ capture and storage (CCS) separates and captures CO ₂ from the exhaust in order to prevent the release of CO ₂ emitted from sources such as power plants and steelworks into the atmosphere. It is a technology for injecting and storing in the ground and the sea, and is positioned as an important option for future global warming countermeasure technology.

As a storage location for CO ₂ separated and recovered by CCS, an aquifer in the deep underground (such as a sandstone layer containing many voids) is considered promising. For example, as shown in Patent Document 1 and Patent Document 2 Proposals for underground storage systems have already been made, and large-scale demonstrations are being planned both domestically and internationally.

JP 2008-248837 A JP 2008-307383 A

In a CO ₂ underground storage system, the structure of an enclosed structure such as an anticline structure (geological structure in which the formation is inclined in a convex shape) as seen in oil and gas fields as an underground storage target layer Type reservoirs are considered to be advantageous in preventing CO ₂ leakage after storage. However, in Japan, such geological structures are limited in existence. Studies on CO ₂ storage are underway.

However, when storing the CO ₂ to the unstructured reservoir layer, long term CO ₂ is expected to flow along the strata inclined by buoyancy acting on the CO _2, due to its CO ₂ tomographic Since there is a risk of leakage to the surface of the earth via an unstructured reservoir, it is necessary to suppress the flow of CO ₂ after storage as much as possible in an unstructured reservoir.

In view of the above circumstances, the present invention provides an effective and appropriate underground storage facility capable of preventing the flow of CO _{2 in} an unstructured reservoir, and also for constructing the facility. The purpose is to provide an effective and appropriate construction method.

  The invention according to claim 1 is a carbon dioxide underground storage facility in which carbon dioxide is stored in a lower layer formed from a natural layer that can shield carbon dioxide as a shielding layer, and in a layer immediately below the shielding layer An artificial shield capable of shielding carbon dioxide by injecting grout into the shield layer is formed integrally with the shielding layer, and the shielding body defines a storage region for storing carbon dioxide in the formation below the shielding layer. It is formed.

  A second aspect of the present invention is the underground storage facility for carbon dioxide according to the first aspect of the present invention, wherein the shielding layer comprises a substantially flat impermeable underground layer inclined with respect to a horizontal plane. The body is formed in a wall shape in a form that bulges from the shielding layer into the underlying layer on the lower surface side at the upper side in the inclination direction of the shielding layer.

  The invention according to claim 3 is a method for constructing the underground storage facility for carbon dioxide according to claim 1 or 2, wherein the press-in well for press-fitting carbon dioxide into the storage region is shielded. Preliminary construction up to a position penetrating the layer, the grout is injected into the lower layer of the shielding layer from the tip of the press-fitting well to form the storage area by partitioning the storage area, The press-fit well is extended to a deep part of the storage region.

According to the storage facility of the present invention, even if it is an unstructured storage layer that does not have a sealed structure in a natural stratum situation, it is possible to store CO ₂ stored only by artificially providing a simple shield at a key point. It is possible to effectively suppress the flow of water and reduce the risk of leakage to the ground surface, and it is possible to sufficiently ensure the safety and reliability of this type of facility. Thereby, the location conditions of this type of facility are greatly relaxed, and the underground storage facility of the present invention can be planned near the emission source.

  According to the construction method of the present invention, it is possible to construct a shield body easily and at low cost by performing a prior construction of the press-fit well to a position penetrating the shielding layer and constructing the shield body using the press-fit well. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the underground storage facility which is embodiment of this invention, and its construction method, and shows the construction condition of the shield prior to storage. It is a figure which shows the condition at the time of a storage start same as the above. It is a figure which shows the condition during storage similarly.

With reference to FIGS. 1-3, embodiment of the underground storage facility of this invention and its construction method is described.
Underground storage facility of the present embodiment is intended for storing the CO ₂ natural formations that can shield the CO ₂ (water impermeable strata) in the formation of the underlying as a shielding layer 1, the shielding layer 1 Is inclined with respect to the horizontal plane, and CO ₂ stored below it is assumed to flow upward. Therefore, in the storage facility of this embodiment, the lower surface side of the shielding layer 1 on the upper side in the inclination direction In addition, the wall-shaped shield 2 is artificially formed integrally with the shielding layer 1 in a form that bulges into the underlying layer, so that CO ₂ is introduced into the lower layer of the shielding layer 1 by the shielding member 2. The main purpose is to partition the storage area A for storage.
And in this embodiment, construction of this storage facility is performed according to the following procedure.

That is, the underground storage facility of the present embodiment finally stores CO ₂ by injection into the storage region A through the injection well 4 constructed so as to reach the storage region A from the discharge source 3 on the surface by control boring. However, in the construction, first, as shown in FIG. 1, the press-in well 4 is preceded to a position penetrating the shielding layer 1, and the shield 2 is constructed using the press-in well 4. To do.

Specifically, when the injection well 4 penetrates the shielding layer 1, the construction is interrupted, and the bottom surface of the shielding layer 1 is solidified by injecting grout from the tip of the injection well 4 to the lower layer of the shielding layer 1. The shield 2 is integrally formed on the side.
The shield 2 is to be formed in a range that can effectively prevent leakage to the ground surface in consideration of the CO ₂ flow range assumed from the geological conditions, and as a grout for that, the bentonite etc. It is preferable to use a material having excellent permeability.

After constructing the shield 2 as described above, if the control boring is resumed and the press-fit well 4 is extended to the deep part in the storage area A as shown in FIG. After that, the injection and storage of CO ₂ into the storage region A may be started through the injection well 4 thereafter.

Since it is supposed to be pressed and stored for several decades the CO ₂ in this type of facilities, it is assumed that the CO ₂ in between is gradually diffused in the reservoir region A, in particular as shown in FIG. 3 It is assumed that it will flow upward due to its own buoyancy and rise to the ground surface along the lower surface of the shielding layer 1, so there is a concern that leakage to the ground surface via a fault is inevitable. However, in the facility of the present invention, since the shielding body 2 is formed in advance on the upper side of the shielding layer 1, the flow of CO _{2 to} the ground surface side is naturally prevented by the shielding body.

As described above, according to the storage facility of the present invention, even in the case of a non-structural storage layer that does not have a sealed structure in a natural stratum situation, it is only necessary to artificially provide a simple shield 2 at a key point. It is possible to effectively suppress the flow of stored CO ₂ and reduce the risk of leakage to the surface, and the safety and reliability of this kind of facility can be sufficiently ensured.

Also, if it is assumed that the shield 2 is installed, the geological conditions such as the geological slope are eased when planning this type of storage facility, so that the site conditions are greatly eased. It is also possible to plan a storage facility, and as a result, a long injection well 4 is required, as in the case where it is necessary to plan a storage facility far away from the emission source 3 due to restrictions on location conditions, or far away It is possible to eliminate the trouble of transporting CO ₂ to the storage facility.

Of course, the construction of the shield 2 can be easily carried out by using the press-fit well 4 in advance and utilizing it, so that such a shield 2 is a full-fledged underground such as an underground continuous wall. Compared to the construction of a shielding wall by a structure, construction can be performed at a much lower cost.
From the above, according to the storage facility of the present invention, the storage cost of CO ₂ can be greatly reduced, and the realization and spread of this type of facility can be promoted.

In addition, when constructing the storage facility of the present invention, it is reasonable to construct the press-in well 4 up to the position penetrating the shielding layer 1 and construct the shield 2 using the same as in the above embodiment. Yes, but it is not always necessary. After the shield 2 is preliminarily applied to the important points by the appropriate method to form the storage area A, press-fitting CO ₂ into the storage area A It is also possible to construct the well 4 again.

Further, when the shielding layer 1 is inclined with respect to the horizontal plane as in the above-described embodiment, the upward flow of CO ₂ is effective by providing the shielding body 2 only at a position on the upper side of the shielding layer 1. However, when the shielding layer 1 is almost horizontal, or when it is necessary to ensure the flow of CO ₂ in each direction in consideration of various conditions, The shields 2 may be installed in various places, or may be installed continuously like an underground wall. In some cases, the shields 2 may be provided so as to surround the entire storage area A.
However, providing the shield 2 in various places or providing an excessively wide range naturally requires a cost for that purpose, so a sufficient geological survey around the storage area A is conducted in advance to determine the flow of CO ₂ after storage. Needless to say, it is preferable that the shield 2 be provided in the minimum necessary range within a range where the leakage to the ground surface can be reliably prevented based on sufficient grasp.

A storage area 1 shielding layer 2 shielding body 3 discharge source 4 injection well

Claims (3)

It is a carbon dioxide underground storage facility that stores carbon dioxide in the lower layer as a shielding layer, which is a natural layer capable of shielding carbon dioxide,
An artificial shielding body capable of shielding carbon dioxide by injecting grout into the formation immediately below the shielding layer is formed integrally with the shielding layer, and carbon dioxide is introduced into the formation below the shielding layer by the shielding body. A carbon dioxide underground storage facility characterized by partitioning a storage region for storage. The carbon dioxide underground storage facility according to claim 1,
The shielding layer comprises a substantially flat impermeable formation that is inclined with respect to a horizontal plane,
A carbon dioxide underground storage facility characterized in that the shielding body is formed in a wall shape in a form that bulges from the shielding layer into a lower formation on the lower surface side of the shielding layer in the inclination direction upper side. . A method for constructing the underground storage facility for carbon dioxide according to claim 1 or 2,
Preliminary construction of a press-in well for injecting carbon dioxide into the storage area up to a position penetrating the shield layer, and injecting grout from the tip of the press-fit well into the lower layer of the shield layer, A method for constructing a carbon dioxide underground storage facility, wherein the storage region is partitioned by construction, and then the press-fit well is extended to a depth of the storage region.

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