Method and apparatus for cavernizing salt caverns for recycling deep brine

Abstract

The application belongs to the technical field of salt cavern cavity construction, and discloses a salt cavern cavity construction method and equipment for recycling deep brine. The method comprises the following steps: S0, drilling a cavity well above a target salt layer and drilling a water well above a deep brine layer; S1, first pumping brine from the deep brine layer, filtering impurities in the brine, and forming brine for salt cavern cavity construction; S2, injecting the brine for salt cavern cavity construction into the target salt layer to dissolve salt and form cavity brine; S3, pumping out the cavity brine, filtering impurities in the cavity brine, and then injecting the cavity brine into the deep brine layer; and S4, repeating steps S1-S3 to recycle the brine from the deep brine layer to dissolve salt and construct a salt cavern gas storage, thereby greatly improving the cavity construction speed, not being restricted by the digestion capacity of a salt chemical enterprise, and further improving the construction speed of the salt cavern gas storage.

Description

Technical Field

[0001] This invention relates to the field of salt cavern construction technology, and in particular to a method and apparatus for salt cavern construction that recycles deep saline water. Background Technology

[0002] Salt cavern gas storage is an infrastructure that utilizes cavities left after underground salt mine mining or creates cavities through water injection to store natural gas. Compared to other types of gas storage (such as depleted oil and gas reservoir storage, aquifer storage, and mine pit storage), salt cavern gas storage features excellent sealing, stable physical properties, and robust structure. Large-volume salt cavern cavities can be constructed within underground salt layers, effectively storing liquid and gaseous hydrocarbons with minimal geological loss. In particular, salt cavern gas storage offers advantages such as flexible injection-production switching and high single-well throughput, playing an increasingly important role in national natural gas supply security and peak-shaving.

[0003] Currently, domestic salt cavern gas storage facilities primarily utilize fresh water or low-concentration brine to dissolve salt layers. After drilling to the salt layer, a cavern-building tubing is lowered, and fresh water or low-concentration brine is injected into the target salt layer through this tubing. The brine is dissolved in the salt rock and then drained back to the surface. It is then transported through pipelines to salt chemical enterprises, which use it as a raw material for salt, alkali, or other chemical products. After desalination, the brine becomes fresh water or low-concentration brine, which can then be used again as injection water for cavern construction.

[0004] This cavity-building method is limited by the brine processing capacity of salt chemical enterprises, and the slow brine digestion speed results in a long cavity-building time for salt caverns, making it difficult to meet the needs of rapid construction of salt cavern gas storage facilities. Summary of the Invention

[0005] The purpose of this invention is to provide a method and equipment for creating salt caverns for recycling deep saline water, so as to solve the problem that the construction speed of salt cavern gas storage is constrained by the brine digestion capacity of salt chemical enterprises, and to improve the construction speed of salt cavern gas storage.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A method for creating salt caverns by recycling deep saline water includes the following steps:

[0008] S0, drill a cavity well above the target salt layer and a water well above the deep saline aquifer;

[0009] S1, salt water is pumped from the deep saline layer through the well, and the salt water is filtered to remove impurities, forming water for salt cavern creation;

[0010] S2, the water used for creating the salt cavern is injected into the target salt layer through the cavity-creating well to dissolve salt and create a cavity, generating cavity-creating brine;

[0011] S3, the cavity-forming brine is extracted and filtered for impurities before being reinjected into the deep saline layer;

[0012] S4. Repeat steps S1-S3 to recycle the saline water from the deep saline layer for salt dissolution and cavity creation until the cavity creation is completed.

[0013] In some embodiments, the impurity filtration process employs a membrane filtration method.

[0014] In some embodiments, in step S1, fresh water is first injected into the target salt layer to dissolve salt and build a tank. During the process of dissolving salt and building the tank, the fresh water generates cavity-forming brine, which is then extracted and injected into the deep saline layer. Then, the saline water is extracted from the deep saline layer.

[0015] In some embodiments, the deep saline layer includes a first saline layer and a second saline layer at different depths, wherein one of the first saline layer and the second saline layer is used to extract the saline water and the other is used to inject the cavity-forming brine.

[0016] A salt cavern creation device for recycling deep saline water includes:

[0017] The first bidirectional tubing string includes a first water injection tubing string and a first water pumping tubing string disposed in the cavity well and connected to the target salt layer.

[0018] The second bidirectional tubing string includes a second injection tubing string and a second pumping tubing string installed in the well and connected to the deep saline aquifer.

[0019] The bidirectional pipeline includes a first pipeline and a second pipeline installed on the ground. The two ends of the first pipeline are respectively connected to a first pumping pipe and a second injection pipe, and the two ends of the second pipeline are respectively connected to the second pumping pipe and the first injection pipe. The saline water in the well enters the cavity-forming well sequentially through the second pumping pipe, the second pipeline, and the first injection pipe. The cavity-forming brine in the cavity-forming well enters the well sequentially through the first pumping pipe, the first pipeline, and the second injection pipe, thus achieving bidirectional circulation.

[0020] In some embodiments, the salt cavern cavity-making device for recycling deep saline water further includes a first water treatment station and a second water treatment station located on the ground. The first water treatment station is configured to extract the cavity-making brine from the cavity-making well, filter out impurities, and then inject it into the well. The second water treatment station is configured to extract the saline water from the well, filter out impurities, and then inject it into the cavity-making well.

[0021] In some embodiments, the first water treatment station is provided with a first water pump, which is connected to the pumping end of the first bidirectional tubing to extract the cavity-forming brine; the second water treatment station is provided with a second water pump, which is located at the pumping end of the second bidirectional tubing to extract the saline water.

[0022] In some embodiments, both the first water treatment station and the second water treatment station are equipped with membrane filtration devices, which are located at both ends of the bidirectional pipeline.

[0023] The beneficial effects of this invention are:

[0024] The present invention provides a method for creating salt caverns by recycling deep saline water. This method involves extracting saline water from deep saline layers and injecting it into the target salt layer to create a cavity. The brine formed in the cavity is then reinjected into the deep saline layer. This method utilizes the saline water from the deep saline layer to construct salt cavern gas storage facilities, greatly increasing the cavity dissolution rate and eliminating the constraints imposed by the brine digestion capacity of salt chemical enterprises, thereby accelerating the construction speed of salt cavern gas storage facilities.

[0025] The salt cavern cavity-forming device for recycling deep saline water provided by this invention achieves bidirectional circulation of saline water from the deep saline layer and brine formed during cavity formation by drilling a cavity-forming well and a water well, installing a first bidirectional tubing string in the cavity-forming well and a second bidirectional tubing string in the water well, and connecting the first and second bidirectional tubing strings with a bidirectional pipeline. This enables the recycling of saline water from the deep saline layer to construct salt cavern gas storage facilities, greatly improving the cavity-forming speed and eliminating the constraint of brine digestion capacity of salt chemical enterprises, thereby increasing the construction speed of salt cavern gas storage facilities. Attached Figure Description

[0026] Figure 1 This is a flowchart of the salt cavern creation method for recycling deep saline water provided in Embodiment 1 of the present invention;

[0027] Figure 2 This is a flowchart of the salt cavern creation method for recycling deep saline water provided in Embodiment 2 of the present invention;

[0028] Figure 3 This is a schematic diagram of a salt cavern creation device for recycling deep saline water provided in an embodiment of the present invention.

[0029] In the picture:

[0030] 100. Deep saline aquifer; 200. Target salt layer;

[0031] 1. First water injection pipe string; 2. First water pumping pipe string; 3. Second water injection pipe string; 4. Second water pumping pipe string; 5. Bidirectional pipeline; 6. First water treatment station; 7. Second water treatment station. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0033] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0036] Example 1:

[0037] Embodiment 1 of the present invention provides a method for creating salt caverns by recycling deep saline water, such as... Figure 1 and Figure 3 As shown, it includes the following steps:

[0038] S0, drill a cavity well above the target salt layer 200, and drill a water well above the deep saline layer 100;

[0039] S1, through a well, draws saline water from a deep saline layer of 100, filters the saline water to remove impurities, and uses it to create a salt cavern for water.

[0040] S2, through the cavity-making well, water for creating cavities in the salt cavern is injected into the target salt layer 200 to dissolve salt and create cavities, generating cavity-making brine;

[0041] S3, after extracting the brine from the cavity and filtering out impurities, it is reinjected into the deep saline layer 100.

[0042] S4. Repeat steps S1-S3 to recycle the saline water from the deep saline layer 100 for salt dissolution and cavity creation until the cavity creation is completed.

[0043] The salt cavern cavity-building method for recycling deep saline water provided in this embodiment of the invention involves extracting saline water from a deep saline water layer 100 and injecting it into a target salt layer 200 to create a cavity. The cavity-creating brine is then reinjected into the deep saline water layer 100, thus recycling the saline water from the deep saline water layer 100 to construct a salt cavern gas storage facility. This significantly increases the cavity-dissolving speed, is not constrained by the brine digestion capacity of salt chemical enterprises, and thereby improves the construction speed of the salt cavern gas storage facility.

[0044] like Figure 3 As shown, in order to better realize the bidirectional circulation of saline water and cavity-forming brine, the deep saline water layer 100 includes a first saline water layer and a second saline water layer at different depths. The saline water is extracted from the first saline water layer for salt dissolution and cavity formation, and the cavity-forming brine is injected into the second saline water layer; or, the saline water is extracted from the second saline water layer for salt dissolution and cavity formation, and the cavity-forming brine is injected into the first saline water layer; that is, using two different saline water layers helps to ensure the concentration of saline water used for cavity formation and ensure the cavity formation effect.

[0045] In some embodiments, the impurity filtration process employs membrane filtration. Membrane filtration is simple and easy to implement, and the brine and cavitation brine in these embodiments only require simple impurity filtration, making membrane filtration a low-cost method.

[0046] Example 2:

[0047] Embodiment 2 of the present invention provides a method for creating salt caverns by recycling deep saline water, such as... Figure 2 and Figure 3 As shown, it includes the following steps:

[0048] S0, drill a cavity well above the target salt layer 200, and drill a water well above the deep saline layer 100;

[0049] S1, inject fresh water into the target salt layer 200 to dissolve salt and build a tank. During the process of dissolving salt and building a tank, the fresh water generates cavity-forming brine. The cavity-forming brine is extracted and injected into the deep saline layer 100.

[0050] S2, salt water is extracted from the deep saline layer 100 and filtered to remove impurities, forming water for salt cavern creation.

[0051] It should be noted that when the cavity-forming brine in step S1 is injected into the first saline water layer, step S2 extracts saline water from the second saline water layer for cavity formation; conversely, when the cavity-forming brine in step S1 is injected into the second saline water layer, step S2 extracts saline water from the first saline water layer for cavity formation.

[0052] S3, inject water into the target salt layer 200 to dissolve salt and create a cavity, generating cavity-creating brine;

[0053] S4, after extracting the brine from the cavity and filtering out impurities, it is reinjected into the deep saline layer 100.

[0054] The cavity-forming brine in this step is injected into the same deep saline layer 100 as the cavity-forming brine in step S1.

[0055] S5. Repeat steps S2-S4 to recycle the saline water from the deep saline layer 100 for salt dissolution and cavity creation until the cavity creation is completed.

[0056] In this embodiment, considering the influence of salt concentration on the salt rock dissolution rate and cavity shape, fresh water is injected into the target salt layer 200 in the early stage of cavity construction to quickly dissolve the salt rock and complete the trench construction. During the trench construction process, the fresh water gradually forms low-concentration brine, i.e. cavity-building brine, in the target salt layer 200. The cavity-building brine is extracted and injected into the deep saline layer 100 without the need for digestion treatment by salt chemical enterprises, thereby greatly improving the cavity construction speed.

[0057] In this embodiment, by first injecting fresh water to quickly dissolve salt and build a trench, and then recycling the saline water to create a cavity, the geological conditions near the target salt layer 200 are fully utilized. The saline water in the deep saline water layer 100 is utilized and then reinjected, which can greatly improve the cavity creation speed without wasting salt rock resources.

[0058] To achieve the salt cavern creation method for recycling deep saline water provided in Embodiments 1 and 2 above, combined with... Figure 3This invention also provides a salt cavern creation device for recycling deep saline water, comprising a first bidirectional tubing string disposed in a cavity-creating well, a second bidirectional tubing string disposed in a water well, and a bidirectional pipeline 5 connecting the first and second bidirectional tubing strings. The cavity-creating well is drilled above the target salt layer 200, and a water well is drilled above the deep saline water layer 100. The first bidirectional tubing string includes a first injection tubing string 1 and a first pumping tubing string 2; the second bidirectional tubing string includes a second injection tubing string 3 and a second pumping tubing string 4; the bidirectional pipeline 5 includes a first pipeline and a second pipeline disposed on the ground, with the two ends of the first pipeline connected to the first pumping tubing string 2 and the second injection tubing string 3, and the two ends of the second pipeline connected to the second pumping tubing string 4 and the first injection tubing string 1, respectively. The saline water in the water well sequentially enters the cavity-creating well through the second pumping tubing string 4, the second pipeline, and the first injection tubing string 1; the cavity-creating brine in the cavity-creating well sequentially enters the water well through the first pumping tubing string 2, the first pipeline, and the second injection tubing string 3, achieving bidirectional circulation.

[0059] The salt cavern creation device for recycling deep saline water provided by this invention achieves bidirectional circulation of saline water from the deep saline water layer 100 and brine formed during cavity creation by drilling a cavity-creating well and a water well. A first bidirectional tubing string is installed in the cavity-creating well, and a second bidirectional tubing string is installed in the water well. A bidirectional pipeline 5 connects the first and second bidirectional tubing strings, enabling bidirectional circulation of saline water from the deep saline water layer 100 and the brine formed during cavity creation. This allows for the recycling of saline water from the deep saline water layer 100 to construct salt cavern gas storage facilities, significantly increasing the cavity-creating speed and overcoming the limitations of brine digestion capacity in salt chemical enterprises, thereby accelerating the construction speed of salt cavern gas storage facilities. It should be noted that the second water injection tubing 3 and the second water extraction tubing 4 have different depths; that is, the bottom ends of the second water injection tubing 3 and the second water extraction tubing 4 are located at different depths in the first and second saline water layers, respectively, to ensure that the brine injection area and the saline water extraction area are located in different saline water layers.

[0060] In some embodiments, the salt cavern creation device for recycling deep saline water further includes a first water treatment station 6 and a second water treatment station 7 located on the ground. The first water treatment station 6 is configured to extract brine from the creation well and filter it for impurities before injecting it into the water well. The second water treatment station 7 is configured to extract saline water from the water well and filter it for impurities before injecting it into the creation well.

[0061] like Figure 3 As shown, both the first water treatment station 6 and the second water treatment station 7 are surface treatment stations, used for power control of water pumping and injection, and for simple filtration of brackish water or brine at ground level. They also allow for the storage or dilution of brackish water or brine to achieve better brine formation and improve efficiency. The first water treatment station 6 enables the injection of fresh water into the target salt layer 200 or the deep brackish water layer 100, and the transfer of a portion of the brine to a salt chemical enterprise for digestion.

[0062] Specifically, the first water treatment station 6 is equipped with a first pump connected to the pumping end of the first bidirectional tubing string to extract the cavity-forming brine; the second water treatment station 7 is equipped with a second pump located at the pumping end of the second bidirectional tubing string to extract saline water. The first pump is connected to the ground end of the first pumping tubing string 2 to extract the cavity-forming brine and reinject it into the second injection tubing string 3 via a first pipeline; the second pump is connected to the ground end of the second pumping tubing string 4 to extract saline water from the well and reinject it into the first injection tubing string 1 via a second pipeline. Thus, only two pumps are needed to achieve bidirectional circulation drive, saving equipment costs.

[0063] In some embodiments, both the first water treatment station 6 and the second water treatment station 7 are equipped with membrane filtration devices, which are located at both ends of the bidirectional pipeline 5. Specifically, the membrane filtration devices are arranged between the first pumping column 2 and the first pipeline, and between the second pumping column 4 and the second pipeline, or between the first pipeline and the second water injection pipeline, and between the second pipeline and the first water injection pipeline, for filtering impurities from the pumped saline water or brine.

[0064] According to research, deep saline aquifers are widely distributed in my country. A deep saline aquifer 100 was screened near the site of a salt cavern gas storage facility to serve as the water source for cavity construction. Deep saline water is extracted through drilling wells, and the brine from the cavity construction is reinjected into the deep saline aquifer 100, achieving rapid brine utilization. This significantly increases the cavity construction speed without wasting salt rock resources. Given the widespread development and enormous reserves of deep saline aquifers in my country, and considering the current large-scale construction of salt cavern gas storage facilities, this invention has broad application prospects in salt cavern gas storage construction.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for creating salt caverns by recycling deep saline water, characterized in that, Includes the following steps: S0, drill a cavity well above the target salt layer (200) and a water well above the deep saline layer (100); S1, salt water is drawn from the deep saline layer (100) through the well, and the salt water is filtered to remove impurities to form water for salt cavern creation; S2, the water used for creating the salt cavern is injected into the target salt layer (200) through the cavity-creating well to dissolve salt and create a cavity, generating cavity-creating brine; S3, the cavity-forming brine is extracted and filtered for impurities before being reinjected into the deep saline layer (100); S4. Repeat steps S1-S3 to recycle the saline water in the deep saline water layer (100) for salt dissolution and cavity creation until the cavity creation is completed.

2. The method for creating salt caverns by recycling deep saline water according to claim 1, characterized in that, The impurity filtration process employs a membrane filtration method.

3. The method for creating salt caverns by recycling deep saline water according to claim 1, characterized in that, In step S1, fresh water is first injected into the target salt layer (200) to dissolve salt and build a tank. During the process of dissolving salt and building the tank, the fresh water generates cavity-forming brine. The cavity-forming brine is extracted and injected into the deep saline layer (100). Then, the saline water is extracted from the deep saline layer (100).

4. The method for creating salt caverns by recycling deep saline water according to claim 3, characterized in that, The deep saline water layer (100) includes a first saline water layer and a second saline water layer at different depths. One of the first saline water layer and the second saline water layer is used to extract the saline water, and the other is used to inject the cavity brine.

5. A salt cavern creation device for recycling deep saline water, characterized in that, include: The first bidirectional tubing string includes a first water injection tubing string (1) and a first water pumping tubing string (2) located in the cavity well and connected to the target salt layer (200); The second bidirectional tubing string includes a second injection tubing string (3) and a second pumping tubing string (4) installed in the well and connected to the deep saline aquifer (100); The bidirectional pipeline (5) includes a first pipeline and a second pipeline installed on the ground. The two ends of the first pipeline are connected to the first pumping pipe (2) and the second injection pipe (3), respectively. The two ends of the second pipeline are connected to the second pumping pipe (4) and the first injection pipe (1), respectively. The saline water in the well enters the cavity-forming well in sequence through the second pumping pipe (4), the second pipeline and the first injection pipe (1). The cavity-forming brine in the cavity-forming well enters the well in sequence through the first pumping pipe (2), the first pipeline and the second injection pipe (3), realizing bidirectional circulation.

6. The salt cavern creation device for recycling deep saline water according to claim 5, characterized in that, It also includes a first water treatment station (6) and a second water treatment station (7) located on the ground. The first water treatment station (6) is configured to extract the cavity-forming brine from the cavity-forming well and filter out impurities before injecting it into the well. The second water treatment station (7) is configured to extract the saline water from the well and filter out impurities before injecting it into the cavity-forming well.

7. The salt cavern creation device for recycling deep saline water according to claim 6, characterized in that, The first water treatment station (6) is equipped with a first water pump, which is connected to the pumping end of the first bidirectional tubing to extract the cavity brine; the second water treatment station (7) is equipped with a second water pump, which is located at the pumping end of the second bidirectional tubing to extract the saline water.

8. The salt cavern creation device for recycling deep saline water according to claim 6, characterized in that, Both the first water treatment station (6) and the second water treatment station (7) are equipped with membrane filtration devices, which are located at both ends of the bidirectional pipeline (5).

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