CN104614131A - Underground oil and gas storage cavern airtightness test method - Google Patents

Abstract

The invention discloses a method for testing the tightness of an underground oil and gas storage, which includes: cross-pressing tracer gas and air mixed with a set proportional pressure into the storage to be tested; A number of tracer gas qualitative leak detectors are placed at the joints of the rock mass for detection; qualitative analysis is carried out on the test results to determine the leak point of the storage; the leak point is sealed again, and the tracer gas qualitative leak detector is used for detection again , until the airtightness of the entire reservoir reaches the gas storage standard. Beneficial effects of the present invention: the method of the present invention adopts the combination of tracer gas and qualitative leak detector and the qualitative analysis technology of leak detector to achieve the purpose of detecting the airtightness of the storage, and at the same time, it can provide support for the construction of plugging leak points that may exist in the later stage. in accordance with.

Description

A method for testing the tightness of underground oil and gas storage

technical field

The method relates to a sealing test method, in particular to a method for testing the sealing of underground oil and gas storage.

Background technique

Large-scale underground oil and gas storage has become an important form of oil and gas storage because of its large storage capacity, strong emergency response capability, and long service life. The tightness test of the storage must be carried out before the official operation of the storage to prevent oil and gas volatilization due to poor sealing after storage of oil and gas, causing safety and environmental accidents. Due to the complicated underground geological conditions and many uncertain factors, there is still no good detection method at present.

The following methods are often used in traditional leak detection: 1. Ultrasonic detection method 2. Pressure water test 3. Compression air test.

These methods often have the following disadvantages:

① It is difficult to locate the drilling holes, and it is difficult to detect hidden dangers with unreasonable hole layout.

②The detection workload is heavy, the cost is high, and the cycle is long.

Contents of the invention

The object of the present invention is to solve the above-mentioned technical problems and provide a method for testing the leak tightness of underground oil and gas storage. The tightness of the warehouse can be accurately located, and the leak point can be accurately located to provide a basis for the corresponding post-construction.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for testing the tightness of underground oil and gas storage, comprising the following steps:

(1) Cross-pressing tracer gas and air mixed at a set proportional pressure into the storage to be detected;

(2) Place a number of tracer gas qualitative leak detectors at the junction of the artificial structure and the underground rock mass in the reservoir for detection;

(3) Qualitative analysis of the test results to determine the leak point of the storage;

(4) Carry out sealing construction on the leakage point again, and use the tracer gas qualitative leak detector to detect again until the sealing performance of the entire storage reaches the gas storage standard.

The tracer gas in the step (1) includes but not limited to SF ₆ , F ₆ , F ₁₂ .

The concrete method of described step (1) is:

First inject a certain quality of tracer gas into the storage to be detected, and then inject the same quality of air into the storage to check whether the gas pressure in the storage reaches the set air pressure standard, if it reaches, stop Gas injection; otherwise, re-inject the tracer gas and air according to the above method until the gas pressure in the reservoir reaches the set air pressure standard.

The qualitative analysis of the detection results is to determine the exact position and size of the leak point according to the alarm sound and light emitting mode of the tracer gas qualitative leak detector; the specific method is:

If the alarm of the tracer gas qualitative leak detector does not alarm, the tightness of the underground oil and gas storage has reached the standard for gas storage;

If the underground oil and gas storage is in a poorly sealed place, the leaked tracer gas is close to the tracer gas qualitative leak detector, the alarm will send out an alarm signal, and the speed and frequency of the alarm sound will increase with the increase of the leakage. The change of concentration changes the way of luminescence;

Use the tracer gas qualitative leak detector to locate the leak point, and determine that the point with the highest tracer gas concentration is the leak point.

Beneficial effects of the present invention:

The method of the invention adopts the combination of the tracer gas and the qualitative leak detector and the qualitative analysis technology of the leak detector, so as to achieve the purpose of detecting the airtightness of the storage warehouse, and at the same time, it can provide a basis for the construction of plugging the leakage point that may exist in the later stage.

The tracer gas selected by the method has the characteristics of low production cost, stable chemical properties, and little impact on the environment. The qualitative leak detector has the characteristics of simple operation, portability, high sensitivity and good stability.

This method can be used to collect real-time gas leakage at the junction of the artificial structure and the underground rock mass during the detection period. Through the detection and analysis of the leak detector, it can be known whether there is gas leakage in the storage, and at the same time, the size and location of the leakage point can be accurately determined. Carry out positioning to provide a basis for the corresponding later construction. Because the method can select the type of tracer gas and qualitative leak detector according to the specific conditions on site, it can be used under different detection conditions.

Description of drawings

Fig. 1 is this method schematic diagram;

Fig. 2 is a simulation diagram of the detection location of an underground oil and gas storage.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, a method for testing the tightness of underground oil and gas storage is divided into the following three steps:

1. After connecting the tracer gas storage cylinder to the air pump, press it into the storage to be tested, and then use the air pump to press in part of the air, and the two gases are pressed in sequentially. According to the chemical properties of the selected tracer gas, determine how much to use, so as to determine the pressure. The function of pressing in the air is to dilute the tracer gas, so that the tracer gas can evenly fill the reservoir, and stop inflating when the air pressure standard in the reservoir requires.

The specific method is: first inject a certain quality of tracer gas into the storage to be detected, then inject the same quality of air into the storage, and use a sensor to detect whether the gas pressure in the storage reaches the set air pressure Standard, generally take 2 atmospheres, if reached, stop the gas injection; otherwise, re-inject the tracer gas and air according to the above method, until the gas pressure in the storage reaches the set air pressure standard.

2. Place several tracer gas qualitative leak detectors at the junction of artificial structures and underground rock mass. Taking an underground oil and gas storage as an example, the detection parts are mostly concentrated in construction roadways, process shafts, ventilation shafts, etc. . Pay attention to keep the surface of the instrument clean and dry. Qualitative leak detection instrument test is qualitative analysis, the operator only needs to turn on the switch, the detector will be programmed, and the corresponding gas can be searched immediately.

3. If the alarm does not alarm, it means that the storage tank is well sealed and meets the gas storage standard. When the storage is in a poorly sealed place, the leaking tracer gas approaches the leak detector, and the alarm will send out an alarm signal. The speed and frequency of the alarm sound will increase with the increase of the leakage, and the luminescent tube will also change according to the change of the concentration. The way it shines. Use a leak detector to locate the leak point. The point with the highest concentration is the gas leak point. It is necessary to use a qualitative leak detector to determine the location with a higher concentration. Carry out sealing construction here again, and then use the leak detector to detect again until the alarm does not alarm, indicating that the entire storage is well sealed and meets the gas storage standard.

The concentration near the leak point is higher, and the concentration farther away from the leak point will decrease. Taking the XP-1A qualitative leak detector as an example, it defines 18 alarm levels, which can clearly indicate the relative size and intensity of the leak. The increased alarm level indicates that it is approaching the source of the leak (the highest concentration), and each level is indicated by LED. The LED displays one of the three colors of green, orange, and red. At the beginning, the display screen glows green from left to right, and then with the increase of the leaked gas concentration, the LED glows orange from left to right, replacing the green light each time. , and finally, the LED will glow red from left to right, replacing orange each time.

The tracer gas should have the following main characteristics: ①Stable chemical properties, no reaction with oil and gas, and no radioactivity. ②It does not burn in the air, does not support combustion, and the pure product is non-toxic. ③Low content in the atmosphere, less environmental pollution. According to the specific site conditions, select the corresponding tracer gas. For example, SF ₆ , F ₆ , F ₁₂ , etc., are non-toxic and harmless to the human body, are not radioactive, are inert gases with low content in the atmosphere, and are non-combustible and non-combustible.

The selection criteria for the tracer gas dose, concentration and storage internal pressure after gas storage can be determined according to the capacity of the underground storage, the detection sensitivity of the instrument, and the chemical properties of the selected gas.

The cross-pressing method used in the test is to use the airflow generated by the air pump to make the tracer gas evenly fill the storage under its action, so as to avoid excessive or low concentration of tracer gas in some parts of the storage Case.

The test and detection sites are mainly concentrated in the joints between artificial structures and underground rock mass, such as construction roadways, process shafts, ventilation shafts and other parts. The detection time should be adjusted accordingly according to the change of internal pressure of the storage.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (4)

1. A method for testing the tightness of underground oil and gas storage, characterized in that it comprises the following steps: (1) Cross-pressing tracer gas and air mixed at a set proportional pressure into the storage to be detected; (2) Place a number of tracer gas qualitative leak detectors at the junction of the artificial structure and the underground rock mass in the reservoir for detection; (3) Qualitative analysis of the test results to determine the leak point of the storage; (4) Carry out sealing construction on the leakage point again, and use the tracer gas qualitative leak detector to detect again until the sealing performance of the entire storage reaches the gas storage standard. 2 . The method for testing the tightness of underground oil and gas storage according to claim 1 , wherein the tracer gas in the step (1) includes but not limited to SF ₆ , F ₆ , and F ₁₂ . 3. A kind of method for testing the tightness of underground oil and gas storage as claimed in claim 1, is characterized in that, the concrete method of described step (1) is: First inject a certain quality of tracer gas into the storage to be detected, and then inject the same quality of air into the storage to check whether the gas pressure in the storage reaches the set air pressure standard, if it reaches, stop Gas injection; otherwise, re-inject the tracer gas and air according to the above method until the gas pressure in the reservoir reaches the set air pressure standard. 4. A kind of underground oil and gas storage storage sealing performance test method as claimed in claim 1, it is characterized in that, said qualitative analysis is carried out to the test result is to determine according to the alarm sound, luminous mode of tracer gas qualitative leak detector The exact location and size of the leakage point; the specific method is: If the alarm of the tracer gas qualitative leak detector does not alarm, the tightness of the underground oil and gas storage has reached the standard for gas storage; If the underground oil and gas storage is in a poorly sealed place, the leaked tracer gas is close to the tracer gas qualitative leak detector, the alarm will send out an alarm signal, and the speed and frequency of the alarm sound will increase with the increase of the leakage. The change of concentration changes the way of luminescence; Use the tracer gas qualitative leak detector to locate the leak point, and determine that the point with the highest tracer gas concentration is the leak point.