Salt cavern gas storage roof collapse test method and test device
By simulating the working conditions of a salt cavern gas storage facility in a pressure chamber and observing the spalling of the core samples from the roof, the problem of assessing the stability of the roof of a salt cavern gas storage facility was solved, achieving accurate prediction and assessment. It also has the capability of multi-field coupled loading, expanding its application scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA ENERGY CONSTRUCTION DEEP EARTH TECHNOLOGY (HUBEI) CO LTD
- Filing Date
- 2026-01-13
- Publication Date
- 2026-05-08
AI Technical Summary
Existing technologies make it difficult to accurately predict and assess the stability of the roof of salt cavern gas storage facilities, which could lead to catastrophic consequences such as the collapse of downhole tubing, gas leakage, and surface subsidence if the roof collapses.
A method and apparatus for testing the collapse of the roof of a salt cavern gas storage facility are provided. By fixing the roof core sample in a pressure chamber, the actual working conditions of the salt cavern gas storage facility are simulated. Test liquid or high-pressure test gas is injected, and the spalling of the roof core sample is observed. The stability of the roof is estimated by combining multi-field coupled loading (brine dissolution, gas permeation, temperature change, etc.).
It enables accurate simulation and prediction of roof spalling in salt cavern gas storage facilities, provides stability assessment support during the construction and operation of salt cavern gas storage facilities, has visualization and quantifiable analysis capabilities, and expands application scenarios to simulate a variety of complex working conditions.
Smart Images
Figure CN121995032A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of salt cavern gas storage technology, and in particular to a test method and test apparatus for the collapse of the roof of a salt cavern gas storage facility. Background Technology
[0002] Underground salt cavern gas storage facilities have become key facilities for strategic energy reserves and natural gas peak shaving due to their enormous storage capacity, excellent peak-shaving capabilities, and high operational safety. Their working principle involves utilizing underground salt rock layers to create huge underground cavities through water dissolution, which are then used for gas and energy storage.
[0003] Throughout its lifecycle, a salt cavern gas storage facility undergoes several operational phases, including "filling with brine," "gas injection and brine discharge," and long-term "circulating gas injection and production." During these phases, the pressure, temperature, and stress environment of the surrounding rock within the salt cavern gas storage facility experience drastic and periodic changes, posing a severe challenge to the stability of the roof. Roof collapse and spalling not only significantly reduce the effective volume of the gas storage facility and decrease peak-shaving capacity, but can also trigger a series of catastrophic consequences, such as downhole tubing failure, gas leakage, and even surface subsidence. Therefore, accurate prediction and assessment of roof stability are crucial before the construction and during the operation of a salt cavern gas storage facility. Summary of the Invention
[0004] The purpose of this invention is to provide a test method and apparatus for the collapse of the roof of a salt cavern gas storage facility, so as to solve the problems existing in the prior art, and to simulate the actual working conditions of the salt cavern gas storage facility and predict the spalling of the roof of the salt cavern gas storage facility.
[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a method for testing the collapse of the roof of a salt cavern gas storage facility, comprising the following steps: Step 1: Fix the top plate core sample inside the pressure chamber, so that the top plate core sample and the pressure chamber form a closed simulated cavity. Step 2: Fill the simulated cavity with test liquid, place the bottom of the top plate core sample in the test liquid, and at the same time expel the air from the simulated cavity to observe the peeling of the top plate core sample.
[0006] Preferably, the method also includes step three: continuing to inject test fluid into the simulated cavity to increase the pressure of the test fluid in the simulated cavity to the target pressure, and observing the spalling of the top plate core sample.
[0007] Preferably, in step three, the test liquid in the simulated cavity is heated to raise the temperature of the test liquid in the simulated cavity to the target temperature, and the spalling of the top plate core sample is observed.
[0008] Preferably, after injecting the test liquid into the simulated cavity, the test liquid is discharged from the bottom of the simulated cavity, and high-pressure test gas is injected into the simulated cavity from the top, and the spalling of the top plate core sample is observed.
[0009] Preferably, after the bottom of the top plate core sample is separated from the test liquid, the discharge of test liquid from the bottom of the simulated cavity is stopped, and the injection of high-pressure test gas from the top of the simulated cavity is stopped, and the peeling of the top plate core sample is observed.
[0010] Preferably, after filling the simulated cavity with high-pressure test gas, the simulated cavity is circulated to discharge and inject high-pressure test gas, and the spalling of the top plate core sample is observed.
[0011] Preferably, the pressure-resistant chamber is a transparent chamber; a high-frequency high-definition camera is installed outside the pressure-resistant chamber.
[0012] Preferably, the sidewalls of the top plate core sample are sealed and isolated before proceeding to step one.
[0013] The present invention also provides a test apparatus for the test method of roof collapse of salt cavern gas storage as described above, including a roof core sample and a pressure-resistant chamber, wherein the roof core sample is fixedly placed in the pressure-resistant chamber, and the roof core sample and the pressure-resistant chamber form a closed simulated cavity.
[0014] Preferably, the system further includes a pressure block, a telescopic slip, and a telescopic double-layer sealing sleeve. The telescopic slip is fixedly connected to the top of the pressure chamber and is fitted over the top plate core sample. The telescopic slip can hold and lock the top of the top plate core sample tightly. The telescopic double-layer sealing sleeve is placed below the telescopic slip and is fitted over the top plate core sample. The telescopic double-layer sealing sleeve is in sealing contact or connection with the outer side wall of the top plate core sample and the inner side wall of the pressure chamber. The pressure block is placed on the top end face of the top plate core sample. The cross-sectional area is larger than that of the top plate core sample; the bottom of the side wall of the pressure chamber is provided with a water inlet and a water outlet, and the middle of the side wall of the pressure chamber is provided with a heater and a temperature sensor. The heater can heat the test liquid in the simulated cavity, and the temperature sensor can detect the temperature of the test liquid in the simulated cavity. The upper part of the side wall of the pressure chamber is provided with an air inlet and an air outlet. The air inlet and the air outlet are both located below the telescopic double-layer sealing rubber tube. The side wall of the pressure chamber is provided with a pressure sensor, which can detect the pressure of the test liquid or high-pressure test gas in the simulated cavity.
[0015] The present invention achieves the following technical effects compared to the prior art: The present invention provides a method and apparatus for testing the collapse of the roof of a salt cavern gas storage facility. A core sample of the roof is fixed inside a pressure chamber, forming a closed simulated cavity. This cavity simulates the salt cavern gas storage facility, and the core sample simulates the roof. The cavity is filled with test liquid to simulate the roof being in a "brine-filled" environment. By observing the spalling of the core sample, the spalling of the roof during the "brine-filled" stage can be predicted. This provides crucial support for accurately predicting and assessing the stability of the roof before and during the operation of salt cavern gas storage facilities. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 A schematic diagram of the experimental apparatus provided by the present invention; In the figure: 1-Pressure chamber; 2-Top plate core sample; 3-Sealant; 4-Pressure block; 5-Telescopic slip; 6-Telescopic double-layer sealing tube; 7-Air inlet; 8-Air outlet; 9-Pressure sensor; 10-Heater; 11-Temperature sensor; 12-Water inlet; 13-Water outlet; 14-Simulated cavity. Detailed Implementation
[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] The purpose of this invention is to provide a test method and apparatus for the collapse of the roof of a salt cavern gas storage facility, so as to solve the problems existing in the prior art, and to simulate the actual working conditions of the salt cavern gas storage facility and predict the spalling of the roof of the salt cavern gas storage facility.
[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0021] Example 1 like Figure 1 As shown in the figure, this embodiment provides a method for testing the collapse of the roof of a salt cavern gas storage facility, including the following steps: Step 1: Fix the top plate rock core sample 2 inside the pressure chamber 1, so that the top plate rock core sample 2 and the pressure chamber 1 form a closed simulated cavity 14. Step 2: Fill the simulated cavity 14 with test liquid, place the bottom end of the top plate core sample 2 in the test liquid, and at the same time expel the air from the simulated cavity 14 to observe the peeling of the top plate core sample 2.
[0022] The method for testing the collapse of the roof of a salt cavern gas storage facility provided in this embodiment involves fixing the roof core sample 2 inside the pressure chamber 1 in step one, so that the roof core sample 2 and the pressure chamber 1 form a closed simulated cavity 14. The simulated cavity 14 simulates the salt cavern gas storage facility, and the roof core sample 2 simulates the roof of the salt cavern gas storage facility. In step two, the simulated cavity 14 is filled with test liquid to simulate the roof of the salt cavern gas storage facility being in a "brine-filled" environment. By observing the spalling of the roof core sample 2, the spalling of the roof of the salt cavern gas storage facility in the "brine-filled" stage can be estimated, providing important support for accurately predicting and evaluating the stability of the roof before the construction and during the operation of the salt cavern gas storage facility.
[0023] The top plate core sample 2 is a core sample taken from the well. The same core sample as the top plate of the salt cavern gas storage is selected. In this embodiment, the dimensions of the top plate core sample 2 are 100 mm in diameter and 200 mm in height.
[0024] As a preferred embodiment of this invention, the method for testing the collapse of the roof of a salt cavern gas storage facility provided in this embodiment further includes step three: continuing to inject test liquid into the simulated cavity 14 to raise the pressure of the test liquid in the simulated cavity 14 to the target pressure, and observing the spalling of the roof core sample 2, thereby predicting the spalling of the roof of the salt cavern gas storage facility under a high-pressure environment filled with saturated brine, providing important support for accurately predicting and evaluating the stability of the roof before and during the construction and operation of the salt cavern gas storage facility.
[0025] As a preferred embodiment of this example, in step three, the test liquid in the simulated cavity 14 is heated to raise the temperature of the test liquid in the simulated cavity 14 to the target temperature, and the spalling of the top plate core sample 2 is observed. This allows for the prediction of the spalling of the top plate of the salt cavern gas storage under conditions of being filled with saturated brine, high pressure, and high temperature, providing important support for accurately predicting and evaluating the stability of the top plate before and during the construction and operation of the salt cavern gas storage.
[0026] As a preferred embodiment of this invention, after injecting the test liquid into the simulated cavity 14, the test liquid is discharged from the bottom of the simulated cavity 14, and high-pressure test gas is injected into the simulated cavity 14 from the top. The high-pressure test gas simulates high-pressure storage gas, and the spalling of the roof core sample 2 is observed. This allows for the prediction of the spalling of the roof of the salt cavern gas storage under the "gas injection and brine discharge" condition, providing important support for accurately predicting and evaluating the stability of the roof before and during the construction and operation of the salt cavern gas storage.
[0027] As a preferred embodiment of this example, after the bottom of the top plate core sample 2 is removed from the test liquid, the discharge of test liquid from the bottom of the simulated cavity 14 is stopped, and the injection of high-pressure test gas into the simulated cavity 14 from the top is stopped. The peeling of the top plate core sample 2 is observed, thereby predicting the peeling of the top plate of the salt cavern gas storage tank under the condition of direct contact with high-pressure storage gas.
[0028] As a preferred embodiment of this example, after the simulated cavity 14 is filled with high-pressure test gas, the simulated cavity 14 is circulated to discharge and inject high-pressure test gas, and the spalling of the top plate core sample 2 is observed, thereby predicting the spalling of the top plate of the salt cavern gas storage under the "circulating gas injection and gas extraction" conditions of the salt cavern gas storage.
[0029] As a preferred embodiment of this invention, the pressure chamber 1 is a transparent chamber to facilitate the visual analysis of the collapse and spalling of the roof of the salt cavern gas storage facility; a high-frequency high-definition camera is installed outside the pressure chamber 1 to directly record the entire process of the collapse and spalling of the roof core sample 2.
[0030] As a preferred embodiment of this example, before performing step one, the sidewall of the top plate core sample 2 is sealed and isolated using sealant 3 to restore the actual working conditions of the salt cavern gas storage top plate; as a preferred embodiment of this example, the weight of the top plate core sample 2 after sealing and isolation is obtained.
[0031] In this embodiment, the pressure-bearing capacity of the pressure chamber 1 is set to be no less than 18 MPa, and the temperature resistance is set to be no less than 80℃; the observation time for the spalling of the roof core sample 2 is set to 48 hours (which can be adjusted according to the test results); during the test, the failure mode, spalling degree and rate of the roof core sample 2 are observed; after the test, the roof core sample 2 is taken out, and the spalling amount and the accumulation morphology of the spalling material of the roof core sample 2 under different environments are recorded for subsequent test analysis; the test process can be carried out in stages according to the schemes of the above preferred embodiments, or it can be carried out continuously in sequence, so as to meet a variety of test requirements.
[0032] The salt cavern gas storage roof collapse test method provided in this embodiment can simulate the real working conditions of salt cavern gas storage, comprehensively consider multi-field coupling effects, and integrate "multi-field coupling loading" (the dissolving and softening effect of brine on the roof, the permeation effect of gas in the roof, and the temperature change effect). It can simulate "progressive roof collapse of salt cavern gas storage under multiple working conditions" and can realistically and comprehensively simulate the actual damage and collapse process of the salt cavern gas storage roof in real time, so as to make up for the shortcomings of the existing technology and provide a more scientific and direct theoretical and experimental basis for the long-term safe operation of salt cavern gas storage.
[0033] The salt cavern gas storage roof collapse test method provided in this embodiment directly records the entire process of roof core sample 2 collapse and spalling through the combination of a transparent pressure chamber 1 and a high-frequency high-definition camera. After the test, the damage condition and mechanism of the roof core sample 2 can be quantitatively analyzed, realizing the "visualization" and "quantification" of the entire failure process of the salt cavern gas storage roof. It can capture the dynamic evolution sequence of internal cracks in the salt cavern gas storage roof in real time and in situ, which cannot be observed by traditional methods, and obtain continuous and quantitative data of the failure process, rather than static data "after the fact". As a result, it possesses extensive operational simulation capabilities and a wide range of applications. It can simulate not only the collapse of the roof of a salt cavern gas storage facility filled with brine, but also actual operational conditions such as "gas injection and brine discharge" and "circulating gas injection and extraction." At the same time, it can also simulate extreme operational conditions (such as a sharp drop in pressure or abnormal pressure fluctuations caused by rapid gas extraction) by adjusting the loading method, which can be used to assess the risk boundary of gas storage facility operation. Pressure, temperature, and medium can all be independently and precisely controlled, making it possible to simulate a variety of complex and non-standard operational conditions, greatly expanding the application scenarios.
[0034] Example 2 like Figure 1 As shown, this embodiment provides a test device for the test method of roof collapse of salt cavern gas storage in Embodiment 1. It includes a roof core sample 2 and a pressure chamber 1. The roof core sample 2 is fixedly placed in the pressure chamber 1, and the roof core sample 2 and the pressure chamber 1 form a closed simulated cavity 14.
[0035] The test apparatus provided in this embodiment fixes the top plate rock core sample 2 inside the pressure chamber 1, so that the top plate rock core sample 2 and the pressure chamber 1 form a closed simulated cavity 14. The simulated cavity 14 simulates a salt cavern gas storage tank, and the top plate rock core sample 2 simulates the top plate of the salt cavern gas storage tank, thus simulating the real working conditions of the salt cavern gas storage tank.
[0036] As a preferred embodiment of this invention, the test apparatus provided in this embodiment further includes a pressure block 4, a telescopic slip 5, and a telescopic double-layer sealing tube 6. The telescopic slip 5 is fixedly connected to the top of the pressure chamber 1 and is fitted over the top plate core sample 2, capable of tightly locking the top of the top plate core sample 2. The telescopic double-layer sealing tube 6 is placed below the telescopic slip 5 and is fitted over the top plate core sample 2, sealingly contacting or connecting with the outer side wall of the top plate core sample 2 and the inner side wall of the pressure chamber 1. The pressure block 4 is placed on the top end face of the top plate core sample 2, and the cross-sectional area of the pressure block 4 is larger than that of the top plate core sample 2. The bottom of the side wall of the pressure chamber 1 is provided with an inlet 12 and an outlet 13, and a heater 10 and a temperature sensor 11 are provided in the middle of the side wall of the pressure chamber 1. The device 10 can heat the test liquid in the simulated cavity 14. The temperature sensor 11 can detect the temperature of the test liquid in the simulated cavity 14. The upper part of the side wall of the pressure chamber 1 is provided with an air inlet 7 and an air outlet 8. Both the air inlet 7 and the air outlet 8 are located below the telescopic double-layer sealing rubber tube 6. The side wall of the pressure chamber 1 is provided with a pressure sensor 9. The pressure sensor 9 can detect the pressure of the test liquid or high-pressure test gas in the simulated cavity 14. Before the test begins, the pressure chamber 1 with the top plate rock core sample 2 is placed on the press. The pressure of the press is transmitted to the top plate rock core sample 2 through the pressure block 4 to keep the top plate rock core sample 2 from moving upward during the test. The telescopic clamp 5 fixes the top plate rock core sample 2 to keep the top plate rock core sample 2 from moving laterally during the test. The telescopic double-layer sealing rubber tube 6 is seated to keep the outer wall of the top plate rock core sample 2 sealed during the test.
[0037] In this embodiment, valves are provided on the water inlet 12, water outlet 13, air inlet 7 and air outlet 8; the telescopic slip 5 and the telescopic double-layer sealing rubber sleeve 6 can both adopt existing technologies.
[0038] The experimental apparatus provided in this embodiment comprehensively considers the multi-field coupling effect and integrates "multi-field coupling loading" (the dissolving and softening effect of brine on the roof, the permeation effect of gas in the roof, and the temperature change effect). It can simulate "progressive roof collapse under multiple working conditions of salt cavern gas storage" and can realistically and comprehensively simulate the actual damage and collapse process of the roof of the salt cavern gas storage in real time. This can make up for the shortcomings of the existing technology and provide a more scientific and direct theoretical and experimental basis for the long-term safe operation of salt cavern gas storage.
[0039] The experimental apparatus provided in this embodiment, through the cooperation of a transparent pressure chamber 1 and a high-frequency high-definition camera, directly records the entire process of the collapse and spalling of the roof core sample 2. After the test, the damage situation and mechanism analysis of the roof core sample 2 can be quantitatively analyzed, realizing the "visualization" and "quantification" of the entire process of the failure of the roof of the salt cavern gas storage. It can capture the dynamic evolution sequence of internal cracks in the roof of the salt cavern gas storage in real time and in situ, which cannot be observed by traditional methods, and obtain continuous and quantitative data of the failure process, rather than static results "after the fact". It has a wide range of working condition simulation capabilities and a wide range of applications. It can not only simulate the collapse of the roof of the "brine-filled" salt cavern gas storage, but also simulate actual working conditions such as "gas injection and brine discharge" and "circular gas injection and gas extraction". At the same time, it can also simulate extreme working conditions (such as rapid pressure drop and abnormal pressure fluctuation caused by rapid gas extraction) by adjusting the loading method, which can be used to assess the risk boundary of gas storage operation. Pressure, temperature and medium can be independently and accurately controlled, making it possible to simulate a variety of complex and non-standard operating conditions, greatly expanding the application scenarios.
[0040] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.
Claims
1. A method for testing the collapse of the roof of a salt cavern gas storage facility, characterized in that: Includes the following steps: Step 1: Fix the top plate core sample inside the pressure chamber, so that the top plate core sample and the pressure chamber form a closed simulated cavity. Step 2: Fill the simulated cavity with test liquid, place the bottom of the top plate core sample in the test liquid, and at the same time expel the air from the simulated cavity to observe the peeling of the top plate core sample.
2. The test method for roof collapse of a salt cavern gas storage facility according to claim 1, characterized in that: It also includes step three: continue to inject test fluid into the simulated cavity to increase the pressure of the test fluid in the simulated cavity to the target pressure, and observe the spalling of the top plate core sample.
3. The test method for roof collapse of a salt cavern gas storage facility according to claim 2, characterized in that: In step three, the test liquid inside the simulated cavity is heated to raise its temperature to the target temperature, and the spalling of the top plate core sample is observed.
4. The test method for roof collapse of a salt cavern gas storage facility according to claim 1, 2, or 3, characterized in that: After injecting the test liquid into the simulated cavity, the test liquid is discharged from the bottom of the simulated cavity, while high-pressure test gas is injected into the simulated cavity from the top, and the spalling of the top plate core sample is observed.
5. The test method for roof collapse of a salt cavern gas storage facility according to claim 4, characterized in that: After the test liquid is removed from the bottom of the top plate core sample, stop draining the test liquid from the bottom of the simulated cavity and stop injecting high-pressure test gas into the simulated cavity from the top. Observe the spalling of the top plate core sample.
6. The test method for roof collapse of a salt cavern gas storage facility according to claim 4, characterized in that: After filling the simulated cavity with high-pressure test gas, the simulated cavity is circulated to discharge and inject high-pressure test gas, and the spalling of the top plate core sample is observed.
7. The test method for roof collapse of a salt cavern gas storage facility according to claim 1, characterized in that: The pressure chamber used is a transparent chamber; a high-frequency high-definition camera is installed outside the pressure chamber.
8. The test method for roof collapse of a salt cavern gas storage facility according to claim 1, characterized in that: Before proceeding to step one, the sidewalls of the top plate core sample are sealed and isolated.
9. A test apparatus, applied to the test method for roof collapse of a salt cavern gas storage facility as described in any one of claims 1 to 8, characterized in that: It includes a top plate rock core sample and a pressure chamber. The top plate rock core sample is fixedly placed inside the pressure chamber, and the top plate rock core sample and the pressure chamber form a closed simulated cavity.
10. The test apparatus according to claim 9, characterized in that: It also includes a pressure block, telescopic slips, and a telescopic double-layer sealing sleeve. The telescopic slips are fixedly connected to the top of the pressure chamber and are fitted over the top plate core sample. The telescopic slips can tightly lock the top of the top plate core sample. The telescopic double-layer sealing sleeve is placed below the telescopic slips and is fitted over the top plate core sample. The telescopic double-layer sealing sleeve is in sealing contact or connection with the outer side wall of the top plate core sample and the inner side wall of the pressure chamber. The pressure block is placed on the top end face of the top plate core sample, and the cross-section of the pressure block... The area is larger than the cross-sectional area of the top plate core sample; the bottom of the side wall of the pressure chamber is provided with a water inlet and a water outlet, the middle of the side wall of the pressure chamber is provided with a heater and a temperature sensor, the heater can heat the test liquid in the simulated cavity, the temperature sensor can detect the temperature of the test liquid in the simulated cavity, the upper part of the side wall of the pressure chamber is provided with an air inlet and an air outlet, both of which are located below the telescopic double-layer sealing rubber tube, and a pressure sensor is provided on the side wall of the pressure chamber, the pressure sensor can detect the pressure of the test liquid or high-pressure test gas in the simulated cavity.