Corrosion collapse method for thick interlayer of layered salt-rock salt-cavern gas storage

Abstract

The invention relates to the technical field of salt cavern gas storage construction engineering, and discloses a layered salt rock salt cavern gas storage thick interlayer corrosion collapse method which comprises the steps that a drilling well penetrating through an upper salt rock layer (106) and a thick interlayer (107) and extending to a lower salt rock layer (110) is formed in a stratum; building a lower design salt cavity (109) in the lower salt rock formation (110) using a lower cavity building apparatus; building an upper design salt cavity (206) in the upper salt rock layer (106) using an upper cavity building apparatus; and hydraulic jetting equipment is used for carrying out hydraulic jetting in the thick interlayer (107), so that the thick interlayer (107) between the upper designed salt cavity (206) and the lower designed salt cavity (109) collapses, and the salt cavern gas storage is formed. By means of the technical scheme, vibration and collapse of the thick interlayer are achieved in a hydraulic jetting mode, the damage risk of the pipe column can be reduced, and good reliability and practicability are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of salt cavern gas storage construction engineering, and in particular to a method for dissolution and collapse of thick interlayers in layered salt rock salt cavern gas storage. Background Art

[0002] Salt cavern gas storage is one of the main types of underground gas storage. In foreign countries, salt cavern gas storage is built in salt dome type, while in China, it is basically layered salt rock. Effective collapse control of multiple interlayers is the technical key to the success of water-soluble cavity making and the reduction of cavity making string accidents. For thick and difficult to dissolve interlayers, due to the lack of effective technical methods, the thick interlayers often cannot be effectively collapsed, affecting the stability of the cavity and forming irregular salt cavities. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem that the prior art lacks a method for breaking the thick interlayer.

[0004] In order to achieve the above-mentioned object, the present invention provides a method for dissolution and collapse of thick interlayers in a layered salt rock cavern gas storage, wherein the dissolution and collapse method comprises:

[0005] S1. forming a well in the formation through an upper salt rock layer, a thick interlayer and extending to a lower salt rock layer;

[0006] S2. constructing a lower designed salt cavity in the lower salt rock layer using a lower cavity making device;

[0007] S3, constructing an upper designed salt cavity in the upper salt rock layer using an upper cavity making device;

[0008] S4. Use hydraulic jetting equipment to perform hydraulic jetting in the thick interlayer, so that the thick interlayer between the upper designed salt cavity and the lower designed salt cavity collapses to form a salt cavern gas storage.

[0009] In some embodiments, in S2, a protective fluid is first injected into the lower salt rock layer through the lower cavity making device, and then a dissolving liquid is injected into the lower salt rock layer, and the dissolving products are discharged.

[0010] In some embodiments, the lower cavity making device comprises a lower casing, a lower cavity making outer tube, and a lower cavity making inner tube which are sequentially sleeved from the outside to the inside, and a protective fluid is injected through the annulus between the lower casing and the lower cavity making outer tube.

[0011] Among them, the dissolving liquid is injected through the annulus between the lower cavity making outer tube and the lower cavity making inner tube, and the dissolving products in the lower salt rock layer are discharged through the lower cavity making inner tube; or, the dissolving liquid is injected through the lower cavity making inner tube, and the dissolving products in the lower salt rock layer are discharged through the annulus between the lower cavity making outer tube and the lower cavity making inner tube.

[0012] In some embodiments, the lower end of the lower sleeve is located in the thick interlayer, the lower end of the lower outer luminal tube extends to the lower side of the thick interlayer, and the lower end of the lower inner luminal tube extends to the outside of the lower outer luminal tube.

[0013] In some embodiments, in S3, a protective fluid is first injected into the upper salt rock layer through the upper cavity making device, and then a dissolving liquid is injected into the upper salt rock layer, and the dissolving products are discharged.

[0014] In some embodiments, the upper cavity making equipment includes an upper casing, an upper cavity making outer tube, and an upper cavity making inner tube which are sequentially arranged from the outside to the inside, a protective fluid is injected through the annulus between the upper casing and the upper cavity making outer tube, a dissolving fluid is injected through the annulus between the upper cavity making outer tube and the upper cavity making inner tube, and the dissolution products in the upper salt rock layer are discharged through the upper cavity making inner tube.

[0015] In some embodiments, the lower end of the upper casing is located in the upper salt rock layer, the lower end of the upper cavity-forming outer tube extends to the outside of the upper casing, and the lower end of the upper cavity-forming inner tube extends to the outside of the upper cavity-forming outer tube.

[0016] In some embodiments, in S4, the protective fluid is first injected through the hydraulic jetting equipment, and then the thick interlayer around the wellbore is hydraulically jetted.

[0017] In some embodiments, the hydraulic jet equipment includes a hydraulic jet casing, a hydraulic jet outer pipe, a hydraulic jet inner pipe, a hydraulic jet gun arranged at the lower part of the hydraulic jet inner pipe, and a wire plug arranged at the lower end of the hydraulic jet inner pipe, which are sequentially arranged from the outside to the inside, wherein a protective fluid is injected through the annulus between the hydraulic jet casing and the hydraulic jet outer pipe, the thick interlayer is sprayed through the hydraulic jet gun, and the fluid is discharged through the annulus between the hydraulic jet outer pipe and the hydraulic jet inner pipe.

[0018] In some embodiments, the lower end of the hydraulic jet casing extends into the upper salt rock layer, the lower end of the hydraulic jet outer pipe extends to the outside of the hydraulic jet casing, the lower end of the hydraulic jet inner pipe extends to the outside of the hydraulic jet outer pipe, and the hydraulic jet gun is located in the thick interlayer.

[0019] Through the above technical solution, the vibration and collapse of the thick interlayer can be achieved by hydraulic jetting, which can reduce the risk of pipe column damage and has good reliability and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the lower cavity making device in operation according to the implementation mode of this scheme;

[0021] Figure 2 It is a schematic diagram of the structure of the upper cavity-making device in operation according to the implementation scheme of the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of the hydraulic jetting equipment during operation described in the implementation mode of this scheme.

[0023] Description of Reference Numerals

[0024] 101-upper casing, 102-upper cavity outer tube, 103-upper cavity inner tube, 104-casing shoe, 105-lower protective fluid layer, 106-upper salt rock layer, 107-thick interlayer, 108-lower salt-making cavity, 109-lower designed salt cavity, 110-lower salt rock layer, 201-upper casing, 202-upper cavity outer tube, 203-upper cavity inner tube, 204-upper fluid protective layer, 205-upper salt-making cavity, 206-upper designed salt cavity, 301-hydraulic jet casing, 302-hydraulic jet outer tube, 303-hydraulic jet inner tube, 304-hydraulic jet gun, 305-thread plug. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0026] This solution provides a method for dissolution and collapse of thick interlayers in a layered salt rock cavern gas storage, wherein the dissolution and collapse method comprises:

[0027] S1. forming a well in the formation, passing through the upper salt rock layer 106, the thick interlayer 107 and extending to the lower salt rock layer 110;

[0028] S2, using a lower cavity making device to construct a lower designed salt cavity 109 in the lower salt rock layer 110;

[0029] S3, using an upper cavity making device to construct an upper designed salt cavity 206 in the upper salt rock layer 106;

[0030] S4. Use hydraulic jetting equipment to perform hydraulic jetting in the thick interlayer 107, so that the thick interlayer 107 between the upper designed salt cavity 206 and the lower designed salt cavity 109 collapses to form a salt cavern gas storage.

[0031] The present solution aims to construct a salt cavern gas storage in a stratum having a salt rock layer, wherein there is a thick interlayer 107 in the stratum, which divides the salt rock layer into an upper salt rock layer 106 and a lower salt rock layer 110 .

[0032] When constructing a salt cavern gas storage, a well can be first drilled in the target stratum by means of a drilling device, so that the well extends from the upper salt rock layer 106 to the lower salt rock layer 110; then a lower cavity-making device is installed in the well to construct a lower designed salt cavity 109 in the lower salt rock layer 110; then an upper cavity-making device is installed in the well to construct an upper designed salt cavity 206 in the upper salt rock layer 106; finally, a hydraulic jetting device is installed in the well to perform hydraulic jetting in the thick interlayer 107 so that the portion of the thick interlayer 107 between the upper designed salt cavity 206 and the lower designed salt cavity 109 collapses to form a salt cavern gas storage.

[0033] In this scheme, the vibration and collapse of thick interlayers are achieved by hydraulic jetting, which can reduce the risk of pipe column damage and has good reliability and practicality.

[0034] Among them, in S2, the protective fluid is first injected into the lower salt rock layer 110 through the lower cavity making device, and then the dissolving liquid is injected into the lower salt rock layer 110, and the dissolving product is discharged. The protective fluid is a gas or liquid with a density less than the dissolving liquid, which can float on the surface of the dissolving liquid, and can prevent the dissolving liquid from dissolving upward, thereby protecting the formation structure above the target position. The protective fluid can be a fluid that cannot dissolve the salt rock layer, such as oil or inert gas. The dissolving liquid can be a liquid that can dissolve salt rock, such as water, which can make the salt rock form a salt solution.

[0035] Further, the lower cavity making equipment comprises a lower casing 101, a lower cavity making outer pipe 102, and a lower cavity making inner pipe 103, which are sequentially sleeved from the outside to the inside, and a protective fluid is injected through the annulus between the lower casing 101 and the lower cavity making outer pipe 102 to form a lower protective fluid layer 105, wherein a dissolving liquid is injected through the annulus between the lower cavity making outer pipe 102 and the lower cavity making inner pipe 103, and the dissolving products in the lower salt rock layer 110 are discharged through the lower cavity making inner pipe 103; or, a dissolving liquid is injected through the lower cavity making inner pipe 103, and the dissolving products in the lower salt rock layer 110 are discharged through the annulus between the lower cavity making outer pipe 102 and the lower cavity making inner pipe 103. The lower casing 101 of the lower cavity making equipment can be the casing of the drilling equipment. Reference Figure 1As shown, the lower casing 101 is anchored in the formation by the casing shoe 104; a protective fluid can be injected into the wellbore of the lower salt rock layer 110 through the annulus between the lower casing 101 and the lower cavity-making outer pipe 102, and the protective fluid can float at the junction of the lower salt rock layer 110 and the thick interlayer 107; when cavitating the lower salt rock layer 110, positive circulation and reverse circulation can be performed alternately, that is, a dissolving liquid is injected into the lower salt-making cavity 108 through the lower cavity-making inner pipe 103, and the dissolving products are discharged through the annulus between the lower cavity-making inner pipe 103 and the lower cavity-making outer pipe 102 (positive circulation), and a dissolving liquid is injected into the lower salt-making cavity 108 through the annulus between the lower cavity-making inner pipe 103 and the lower cavity-making outer pipe 102, and the dissolving products are discharged through the lower cavity-making inner pipe 103.

[0036] The lower end of the lower casing 101 is located in the thick interlayer 107, the lower end of the lower cavity-making outer pipe 102 extends to the lower side of the thick interlayer 107, and the lower end of the lower cavity-making inner pipe 103 extends to the outside of the lower cavity-making outer pipe 102. The lower casing 101 extends into the thick interlayer 107, and in particular, its lower end is flush with the lower interface of the thick interlayer 107, which can prevent the fluid below the thick interlayer 107 from being injected upward into the upper salt rock layer 106; the lower cavity-making outer pipe 102 extends from the lower casing 101 to inject the protective fluid into the lower salt rock layer 110, and the protective fluid is located at the lower interface of the thick interlayer 107; the lower cavity-making inner pipe 103 extends from the lower cavity-making outer pipe 102, and its lower end is at a large distance from the lower end of the annulus of the lower cavity-making inner pipe 103 and the lower cavity-making outer pipe 102, so as to prevent the injection and discharge of the fluid from affecting each other.

[0037] Specifically, the upper salt rock layer 106 is first injected with a protective fluid through the upper cavity making device, and then a dissolving liquid is injected into the upper salt rock layer 106, and the dissolving product is discharged. The protective fluid is a gas or liquid with a density less than that of the dissolving liquid, which can float on the surface of the dissolving liquid, and can prevent the dissolving liquid from dissolving upward, and protect the stratum structure above the target position, especially the upper part of the upper salt rock layer 106 needs to be retained and cannot be dissolved. The protective fluid can be a fluid that cannot dissolve the salt rock layer, such as oil or inert gas. The dissolving liquid can be a liquid that can dissolve salt rock, such as water, which can make the salt rock form a salt solution.

[0038] The upper cavity making equipment includes an upper casing 201, an upper cavity making outer pipe 102, and an upper cavity making inner pipe 203, which are sequentially sleeved from the outside to the inside. A protective fluid is injected through the annulus between the upper casing 201 and the upper cavity making outer pipe 202, a dissolving liquid is injected through the annulus between the upper cavity making outer pipe 202 and the upper cavity making inner pipe 203, and the dissolving products in the upper salt rock layer 106 are discharged through the upper cavity making inner pipe 203. The structure of the upper cavity making equipment is similar to that of the lower cavity making equipment, and the same equipment can be used, which will not be repeated here. The cavity making process only needs to be reversed, that is, the dissolving liquid is injected through the annulus of the upper cavity making outer pipe 202 and the upper cavity making inner pipe 203, and the dissolving liquid is discharged through the upper cavity making inner pipe 203.

[0039] Specifically, the lower end of the upper casing 201 is located in the upper salt rock layer 106, the lower end of the upper cavity-making outer tube 202 extends to the outside of the upper casing 201, and the lower end of the upper cavity-making inner tube 203 extends to the outside of the upper cavity-making outer tube 202. The lower end of the upper casing 201 corresponds to the top surface of the upper designed salt cavity 206, and the protective fluid injected through the upper casing 201 and the upper cavity-making outer tube 202 is located at the top surface of the upper salt-making cavity 205, forming an upper protective fluid layer 204; the upper cavity-making inner tube 203 extends from the upper cavity-making outer tube 202 and extends to the upper interface of the thick interlayer 107, so as to discharge the corrosion products from the upper salt-making cavity 205.

[0040] Among them, in S4, the protective fluid is first injected through the hydraulic jetting equipment, and then the thick interlayer 107 around the wellbore is hydraulically jetted. The protective fluid can float to the top of the upper designed salt cavity 206 to protect the top of the upper salt cavity 206 and prevent its top from being dissolved; through hydraulic jetting, the thick interlayer 107 around the wellbore can be impacted by the water flow and vibrated and collapsed, and finally the thick interlayer 107 between the upper designed salt cavity 206 and the lower designed salt cavity 109 is broken to form a complete salt cavern gas storage.

[0041] Among them, reference Figure 3As shown, the hydraulic jet equipment includes a hydraulic jet casing 301, a hydraulic jet outer pipe 302, a hydraulic jet inner pipe 303, a hydraulic jet gun 304 arranged at the lower part of the hydraulic jet inner pipe 303, and a wire plug 305 arranged at the lower end of the hydraulic jet inner pipe 303, wherein a protective fluid is injected through the annulus between the hydraulic jet casing 301 and the hydraulic jet outer pipe 302, the thick interlayer 107 is sprayed through the hydraulic jet gun 304, and the fluid is discharged through the annulus between the hydraulic jet outer pipe 302 and the hydraulic jet inner pipe 303. The hydraulic jet gun 304 can spray high-speed water flow to the surroundings to impact the surrounding thick interlayer 107; the protective fluid can be injected through the annulus between the hydraulic jet casing 301 and the hydraulic jet outer tube 302; the annulus between the hydraulic jet outer tube 302 and the hydraulic jet inner tube 303 can be used as a channel for discharging solid particles (together with water) after the thick interlayer 107 is crushed; the wire plug 305 is used to seal the lower end of the hydraulic jet inner tube 303.

[0042] The lower end of the hydraulic jet casing 301 extends into the upper salt rock layer 106, the lower end of the hydraulic jet outer pipe 302 extends to the outside of the hydraulic jet casing 301, the lower end of the hydraulic jet inner pipe 303 extends to the outside of the hydraulic jet outer pipe 302, and the hydraulic jet gun 304 is located in the thick interlayer 107. The lower end of the hydraulic jet casing 301 is located on the upper side of the thick interlayer 107, so that the protective fluid introduced into the annulus between the hydraulic jet casing 301 and the hydraulic jet outer pipe 302 can easily float to the top of the upper designed salt cavity 206; the lower end of the hydraulic jet inner pipe 303 extends to the lower interface of the thick interlayer 107, and can be located below the lower interface of the thick interlayer 107; the hydraulic jet gun 304 is located at the thick interlayer 107 to spray water flow to the surrounding thick interlayer 107.

[0043] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various specific technical features in any suitable manner. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for dissolution and collapse of thick interlayers in layered salt rock and salt cavern gas storage, characterized in that: The dissolution collapse method comprises: S1. forming a well in the formation, passing through an upper salt rock layer (106), a thick interlayer (107) and extending to a lower salt rock layer (110); S2. constructing a lower designed salt cavity (109) in the lower salt rock layer (110) using a lower cavity making device; S3, using an upper cavity making device to construct an upper designed salt cavity (206) in the upper salt rock layer (106); S4. Use hydraulic jetting equipment to perform hydraulic jetting in the thick interlayer (107), so that the thick interlayer (107) between the upper designed salt cavity (206) and the lower designed salt cavity (109) collapses to form a salt cavern gas storage.

2. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 1, characterized in that: In S2, a protective fluid is firstly injected into the lower salt rock layer (110) through the lower cavity making device, and then a dissolving liquid is injected into the lower salt rock layer (110), and the dissolving products are discharged.

3. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 2, characterized in that: The lower cavity making device comprises a lower casing (101), a lower cavity making outer tube (102), and a lower cavity making inner tube (103) which are sequentially sleeved from the outside to the inside, and a protective fluid is injected into the annulus between the lower casing (101) and the lower cavity making outer tube (102). wherein, a dissolving liquid is injected through the annulus between the lower cavity-forming outer tube (102) and the lower cavity-forming inner tube (103), and the dissolving products in the lower salt rock layer (110) are discharged through the lower cavity-forming inner tube (103); or, a dissolving liquid is injected through the lower cavity-forming inner tube (103), and the dissolving products in the lower salt rock layer (110) are discharged through the annulus between the lower cavity-forming outer tube (102) and the lower cavity-forming inner tube (103).

4. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 2, characterized in that: The lower end of the lower sleeve (101) is located in the thick interlayer (107), the lower end of the lower extracavitary tube (102) extends to the lower side of the thick interlayer (107), and the lower end of the lower intracavitary tube (103) extends to the outside of the lower extracavitary tube (102).

5. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 1, characterized in that: In S3, a protective fluid is firstly injected into the upper salt rock layer (106) through the upper cavity making device, and then a dissolving liquid is injected into the upper salt rock layer (106), and the dissolving products are discharged.

6. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 5, characterized in that: The upper cavity making equipment comprises an upper casing (201), an upper cavity making outer pipe (102), and an upper cavity making inner pipe (203) which are sequentially sleeved from the outside to the inside; a protective fluid is injected through the annulus between the upper casing (201) and the upper cavity making outer pipe (202); a dissolving fluid is injected through the annulus between the upper cavity making outer pipe (202) and the upper cavity making inner pipe (203); and the dissolving products in the upper salt rock layer (106) are discharged through the upper cavity making inner pipe (203).

7. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 5, characterized in that: The lower end of the upper casing (201) is located in the upper salt rock layer (106), the lower end of the upper cavity-making outer tube (202) extends to the outside of the upper casing (201), and the lower end of the upper cavity-making inner tube (203) extends to the outside of the upper cavity-making outer tube (202).

8. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 1, characterized in that: In S4, the protective fluid is first injected through the hydraulic jetting equipment, and then the thick interlayer (107) around the wellbore is hydraulically jetted.

9. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 8, characterized in that: The hydraulic jet equipment comprises a hydraulic jet casing (301), a hydraulic jet outer pipe (302), a hydraulic jet inner pipe (303), a hydraulic jet gun (304) arranged at the lower part of the hydraulic jet inner pipe (303), and a wire plug (305) arranged at the lower end of the hydraulic jet inner pipe (303), wherein a protective fluid is injected through the annulus between the hydraulic jet casing (301) and the hydraulic jet outer pipe (302), the thick interlayer (107) is sprayed through the hydraulic jet gun (304), and the fluid is discharged through the annulus between the hydraulic jet outer pipe (302) and the hydraulic jet inner pipe (303).

10. The method for dissolution and collapse of thick interlayers in layered salt rock cavern gas storage according to claim 9, characterized in that: The lower end of the hydraulic jet casing (301) extends into the upper salt rock layer (106), the lower end of the hydraulic jet outer tube (302) extends to the outside of the hydraulic jet casing (301), the lower end of the hydraulic jet inner tube (303) extends to the outside of the hydraulic jet outer tube (302), and the hydraulic jet gun (304) is located in the thick interlayer (107).

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