Degassing device and degassing method

Abstract

The present application relates to the field of oil and gas geochemical exploration, and particularly relates to a degassing device and a degassing method. The degassing device comprises a device main body and a piston arranged in the device main body, wherein the piston is movable up and down along the height direction of the device main body, and a sealed degassing cavity is arranged between the top of the piston and the inner wall of the device main body, the top of the device main body is respectively provided with a sample inlet tube and a gas collection tube, the sample inlet tube is in communication with the degassing cavity to inject the sample into the degassing cavity for degassing, and the gas collection tube is in communication with the degassing cavity to collect and measure the gas released by the sample. The degassing device has a compact structure, is simple to operate and convenient to carry, the position of the piston in the device main body can be adjusted up and down, the degassing of the sample and the collection of the released gas can be realized, the released gas can be immediately extracted for gas chromatography analysis, or can be saved in a sealed container for later testing, and the degassing device is suitable for field use on land or on a ship at sea.

Description

Technical Field

[0001] This invention relates to the field of oil and gas geochemical exploration, and particularly to a degassing device and degassing method. Background Technology

[0002] During their long vertical migration, hydrocarbons and other components in oil and gas reservoirs undergo a series of physicochemical reactions with the surrounding rocks, soil, and water, leaving behind traces. Therefore, dissolved hydrocarbon components in formation water and surface water have always been a crucial indicator of concern in oil and gas geochemical exploration. The detection techniques for dissolved hydrocarbons in water have been included in the national standard "Methods for Determination of Samples in Oil and Gas Geochemical Exploration (Standard No.: GB / T29173-2012)". In recent years, with the vigorous advancement of offshore oil and gas resource exploration in my country, especially the continuous rise in research on offshore natural gas hydrate exploration technology, geochemical exploration technology, with hydrocarbons and their alteration products as the main detection targets, has been recognized as one of the important means of offshore oil and gas exploration. Since natural gas hydrates are mainly composed of hydrocarbon gases, the concentration of dissolved hydrocarbons in seawater is undoubtedly the primary indicator for natural gas hydrate geochemical exploration.

[0003] Currently, the main method for removing dissolved hydrocarbons from seawater borrows from testing methods used in surface oil and gas geochemical exploration, specifically the vacuum degassing method in the national standard GB / T29173-2012. This method has several drawbacks: ① It is complex and cumbersome to operate, requiring specific experimental skills and experience; ② It primarily uses glass testing equipment connected by rubber tubing, which is prone to leakage, leading to a decrease in vacuum and degassing losses; ③ It requires a large number of reagents, materials, and auxiliary equipment, making it difficult to meet the needs of on-site testing. In addition, membrane degassing based on hollow fiber membrane technology is also frequently used for water degassing, such as the membrane degassing device described in patent CN110028132A. This method is mainly used for online degassing of industrial production water, requiring a large volume of water, and its biggest drawback is that the degassed gas is generally removed by the vacuum equipment and is difficult to collect.

[0004] Therefore, it is necessary to invent a seawater degassing device and method that is suitable for shipboard on-site operations and easy to operate, so as to obtain information on dissolved hydrocarbon indicators in seawater at the survey location in a timely manner, and to promote the greater role of geochemical technology in the exploration of marine oil and gas resources, especially natural gas hydrate resources. Summary of the Invention

[0005] The present invention provides a degassing device and a degassing method to solve at least one of the above-mentioned technical problems.

[0006] One aspect of the present invention provides a degassing device, comprising a device body and a piston disposed within the device body, wherein the piston is movable vertically along the height direction of the device body, and a sealed degassing chamber is provided between the top of the piston and the inner wall of the device body.

[0007] The top of the main body of the device is provided with a sample inlet tube and a gas collection tube. The sample inlet tube is connected to the degassing chamber to inject the sample into the degassing chamber for degassing. The gas collection tube is connected to the degassing chamber to collect and measure the gas degassed from the sample.

[0008] In one embodiment, a control lever is also included.

[0009] The bottom of the main body of the device is provided with a threaded hole, the operating rod is threaded into the threaded hole, and the upper end of the operating rod is connected to the bottom of the piston.

[0010] The piston can be moved up and down along the height direction of the main body of the device by rotating the operating lever.

[0011] In one embodiment, a bearing is provided at the bottom of the piston, and the upper end of the operating rod is connected to the bottom of the piston through the bearing, so that there is no relative rotation between the piston and the main body of the device.

[0012] In one embodiment, the gas collecting pipe is provided with a removable sealing cap, the sealing cap contains a sealing gasket, and the sealing cap has a gas intake port.

[0013] In one embodiment, the injection tube is provided with a removable sealing plug, and the bottom surface of the sealing plug is flush with the lower end surface of the injection tube.

[0014] In one embodiment, both the gas collecting tube and the device body are made of transparent material, and the outer wall of the gas collecting tube is marked with a first scale line, while the device body is marked with a second scale line.

[0015] Another aspect of the present invention provides a degassing method, which uses the above-described degassing device to degas a sample, comprising the following steps:

[0016] S1: After adjusting the piston to the first set scale, inject the sample through the injection tube until the sample fills the degassing chamber, gas collecting tube and injection tube. Then seal the gas collecting tube and injection tube with the sealing cap and sealing plug respectively.

[0017] S2: Adjust the piston downwards to the second set mark to degas the sample under negative pressure.

[0018] S3: After degassing is completed, drive the gas extracted from the sample into the gas collection tube until the internal pressure of the degassing device is balanced with the external pressure.

[0019] S4: After recording the volume of the gas released, extract the released gas from the gas collecting tube.

[0020] In one implementation, step S3 includes the following steps:

[0021] Insert the internally vented syringe into the air intake port on the sealed cap, and drive the vented gas into the gas collection tube by adjusting the position of the piston upwards until the syringe plunger is activated, and the internal pressure of the degassing device is balanced with the external pressure.

[0022] In another embodiment, step S3 includes the following steps:

[0023] Injecting the driving fluid through the air intake port on the sealed cover drives the extracted gas into the gas collection pipe until the internal pressure of the degassing device is balanced with the external pressure, at which point the injection of the driving fluid automatically stops.

[0024] In one embodiment, a step of performing a sealing check on the degassing device is included before step S1:

[0025] S01: After adjusting the piston to the top of the device body, seal the gas collecting tube and connect the vacuum gauge at the sample inlet tube;

[0026] S02: Adjust the position of the piston downwards until the vacuum gauge reading is the set vacuum level;

[0027] S03: Observe the reading of the vacuum gauge. If the reading of the vacuum gauge does not decrease within the set time, the airtightness of the degassing device is good.

[0028] Compared with existing technologies, the advantages of this invention are as follows: The degassing device of this invention has a compact structure, is simple to operate, and is easy to carry. The pressure within the sealed degassing chamber can be changed by adjusting the position of the piston. Specifically, when the piston moves downward, the volume of the degassing chamber expands, its internal pressure decreases, and the dissolved gas in the sample is released. After reaching gas-liquid equilibrium, the piston moves in the opposite direction, causing the liquid level in the degassing chamber to rise. The gas degassed from the sample is driven into the gas collecting tube, from which it can be directly analyzed or sealed for preservation. Using the degassing device and method of this invention, under uniform degassing conditions such as temperature and pressure, the hydrocarbon composition and concentration indicators in the degassed gas can serve as an important reference for natural gas hydrate exploration. Attached Figure Description

[0029] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of the degassing device in this invention;

[0031] Figure 2 This is a flowchart of the degassing method in this invention.

[0032] Figure label:

[0033] 1-Main body of the device; 2-Piston; 3-Sample inlet tube; 4-Gas collection tube; 5-Operating lever;

[0034] 6-Sealing cap; 7-Sealing plug; 8-Degassing chamber; 9-First graduation line; 10-Second graduation line;

[0035] 11-Fixed component; 12-Ventilation hole; 13-Handle. Detailed Implementation

[0036] The invention will now be further described with reference to the accompanying drawings.

[0037] like Figure 1 As shown, the present invention provides a degassing device, including a device body 1 and a piston 2 disposed within the device body 1. The piston 2 is movable up and down along the height direction of the device body 1, and a sealed degassing chamber 8 is provided between the top of the piston 2 and the inner wall of the device body 1. A sample inlet tube 3 and a gas collecting tube 4 are respectively disposed on the top of the device body 1. The sample inlet tube 3 is connected to the degassing chamber 8 to inject the sample into the degassing chamber 8 for degassing, and the gas collecting tube 4 is connected to the degassing chamber 8 to collect and measure the gas degassed from the sample.

[0038] The degassing device of this invention has a compact structure, is simple to operate, and is easy to carry. By adjusting the position of the piston 2, the pressure inside the sealed degassing chamber 8 can be changed. Specifically, when the piston 2 moves downward, the volume of the degassing chamber 8 expands, its internal pressure decreases, and the dissolved gas in the sample is released. After reaching gas-liquid equilibrium, the piston 2 moves in the opposite direction, causing the liquid level in the degassing chamber 8 to rise. The gas released from the sample is driven into the gas collecting tube 4, and can be extracted from the gas collecting tube 4 for direct analysis or sealed storage.

[0039] In addition, the extracted gas can be immediately analyzed by gas chromatography to obtain the composition and concentration of dissolved hydrocarbons. It can also be stored in a sealed container for later testing, making it suitable for use in land-based field or marine shipboard environments.

[0040] The degassing device and degassing method of this invention, under uniform degassing conditions such as temperature and pressure, can provide important reference for the hydrocarbon composition and concentration of the degassed gas, serving as an important reference for natural gas hydrate exploration.

[0041] It should be noted that the sample in this invention is a liquid sample, such as seawater.

[0042] Example 1

[0043] In this embodiment, the degassing device also includes an operating rod 5. A threaded hole is provided at the bottom of the device body 1, and the operating rod 5 is threaded into the threaded hole. The upper end of the operating rod 5 is connected to the bottom of the piston 2. Rotating the operating rod 5 can move the piston 2 up and down along the height direction of the device body 1.

[0044] In this embodiment, the piston 2 is slidably and sealed to the inner wall of the device body 1. The piston 2 can be moved up and down to a set scale by the operating rod 5. The power for the operating rod 5 to move up or down is provided by the operating rod 5 rotating in the threaded hole at the bottom of the device body 1.

[0045] Preferably, a bearing is provided at the bottom of the piston 2, and the upper end of the operating rod 5 is connected to the bottom of the piston 2 through the bearing, so that there is no relative rotation between the piston 2 and the main body 1 of the device. Thus, when the operating rod 5 rotates, the piston 2 does not rotate with it but only moves up and down.

[0046] Specifically, the main body 1 of the device is a cylindrical body with an open lower end, and a fixing member 11 is provided at its lower end. The fixing member 11 has a threaded hole as described above in its center for mounting the operating rod 5. Furthermore, the outer peripheral wall of the fixing member 11 is provided with external threads, and the lower end of the main body 1 of the device is provided with internal threads, so that the fixing member 11 is threadedly connected to the lower end of the main body 1 of the device. In addition, to prevent the pressure from the seal from affecting the device, a vent hole 12 can be provided in the fixing member 11 to ensure pressure balance.

[0047] Specifically, the lower end of the operating lever 5 is provided with a handle 13 or a hand crank to facilitate the rotation of the operating lever 5.

[0048] Example 2

[0049] This embodiment describes the differences from the above embodiments, while the similarities will not be repeated.

[0050] In this embodiment, the main body 1 of the device is cylindrical, with two branch pipes at its upper end, namely the sample inlet pipe 3 and the gas collecting pipe 4, which are respectively equipped with a sealing plug 7 and a sealing cap 6.

[0051] The gas collecting pipe 4 is equipped with a removable sealing cap 6, inside which is a sealing gasket. The sealing cap 6 also has a gas intake port. The sealing gasket seals the opening of the gas collecting pipe 4, and the gas intake port collects the gas expelled into the gas collecting pipe 4. Specifically, the sealing gasket is a rubber gasket, and the sealing cap 6 is threaded onto the opening of the gas collecting pipe 4.

[0052] The injection tube 3 is equipped with a removable sealing plug 7, and the bottom surface of the sealing plug 7 is flush with the lower end surface of the injection tube 3. In other words, the sealing plug 7 can fill the interior of the injection tube 3 and seal against the inner wall of the injection tube 3 to prevent gas from the sample from entering the injection tube 3. Specifically, the sealing plug 7 is threaded into the injection tube 3.

[0053] Example 3

[0054] This embodiment describes the differences from the above embodiments, while the similarities will not be repeated.

[0055] In this embodiment, both the gas collecting tube 4 and the device body 1 are made of transparent material, and the outer wall of the gas collecting tube 4 is marked with a first scale line 9, and the device body 1 is marked with a second scale line 10.

[0056] The gas collecting tube 4 is made of transparent material and marked with a first graduation line 9, which can be used to measure the volume of the degassed gas. The main body 1 of the device is made of transparent material and marked with a second graduation line 10, so that the sample volume and negative pressure vacuum can be adjusted based on the experiment to obtain the most satisfactory degassing effect.

[0057] Preferably, both the gas collecting pipe 4 and the main body 1 of the device are made of colorless and transparent materials, such as glass or plastic. In this way, the entire device has no metal parts and will not cause seawater corrosion.

[0058] It should be noted that the sample inlet tube 3 can also be made of transparent material. In addition, during manufacturing, the main body 1, the gas collecting tube 4, and the sample inlet tube 3 can be integrally molded.

[0059] like Figure 2 As shown, the present invention provides a degassing method, which uses the above-mentioned degassing device to degas a sample, including the following steps:

[0060] S1: After adjusting the piston 2 to the first set scale, inject the sample through the injection tube 3 until the sample fills the degassing chamber 8, the gas collecting tube 4 and the injection tube 3. Then seal the gas collecting tube 4 and the injection tube 3 through the sealing cap 6 and the sealing bolt 7 respectively.

[0061] S2: Adjust piston 2 downwards to the second set mark to degas the sample under negative pressure.

[0062] S3: After degassing is completed, drive the gas extracted from the sample into the gas collection tube 4 until the internal pressure of the degassing device is balanced with the external pressure.

[0063] S4: After recording the volume of the gas that has been released, extract the gas that has been released from the gas collecting pipe 4.

[0064] In the degassing method of this invention, the pressure inside the sealed degassing chamber 8 can be changed by adjusting the position of the piston 2 up and down. Specifically, when the piston 2 moves downward, the volume of the degassing chamber 8 expands, its internal pressure decreases, and the dissolved gas in the sample is released. After gas-liquid equilibrium is reached, the piston 2 moves in the opposite direction, causing the liquid level in the degassing chamber 8 to rise. The gas released from the sample is driven into the gas collecting tube 4, and can be extracted from the gas collecting tube 4 for direct analysis or sealed storage.

[0065] The extracted gas can be immediately analyzed by gas chromatography to obtain the composition and concentration of dissolved hydrocarbons. It can also be stored in a sealed container for later testing, making it suitable for use in land-based field or marine shipboard environments.

[0066] Under uniform degassing conditions such as temperature and pressure, the hydrocarbon composition and concentration in the degassing gas can serve as an important reference for natural gas hydrate exploration.

[0067] Preferably, since the device has a compact overall structure, when degassing the sample in step S2, the entire degassing device can be placed in a water bath for constant temperature heating to improve the degassing speed and efficiency.

[0068] Example 4

[0069] After degassing is complete, the degassed gas can be collected in two ways. Step 3 will be explained in detail below.

[0070] In one embodiment, step S3 includes the following steps: inserting an internally emptied syringe into the air intake port on the sealing cap 6, and driving the detached gas into the gas collection tube 4 by adjusting the position of the piston 2 upwards until the syringe plunger is activated, and the internal pressure of the degassing device is balanced with the external pressure.

[0071] Specifically, after inserting the internal evacuation syringe into the air intake port of the sealing cap 6, rotating the handle 13 causes the piston 2 to move upward, the liquid level in the degassing chamber 8 rises, the degassed gas is driven into the gas collecting tube 4, and the pressure rises until the syringe plunger is touched, at which point the internal pressure of the degassing device is balanced with the external pressure, and the rotation of the handle 13 stops.

[0072] In another embodiment, step S3 includes the following steps: injecting a driving liquid through the gas inlet on the sealing cover 6 to drive the extracted gas into the gas collecting pipe 4 until the internal pressure of the degassing device is balanced with the external pressure.

[0073] Specifically, saturated saline solution can be used as the driving fluid. The saturated saline solution is placed in a container and delivered via a rubber tube connected to an injection needle. After degassing, the needle is inserted into the gas extraction port, and the saturated saline solution is automatically injected. As the saturated saline solution is injected, the liquid level in the degassing chamber 8 rises, and the degassed gas is driven into the gas collecting pipe 4. Once the internal pressure of the degassing device balances with the external pressure, the injection of saturated saline solution automatically stops. The gas volume is recorded, and the transferred gas is extracted using a syringe.

[0074] Example 5

[0075] This embodiment describes the differences from the above embodiments, while the similarities will not be repeated.

[0076] The step of checking the sealing of the degassing device is included before step S1:

[0077] S01: After adjusting the piston 2 to the top of the main body 1 of the device, seal the gas collection port and connect the vacuum gauge at the sample inlet;

[0078] S02: Adjust the position of piston 2 downwards until the vacuum gauge reading is the set vacuum level;

[0079] S03: Observe the reading of the vacuum gauge. If the reading of the vacuum gauge does not decrease within the set time, the airtightness of the degassing device is good.

[0080] In this embodiment, when performing a sealing check on the degassing device, there is no need for an additional vacuum pump to evacuate it. Simply adjust the piston 2 to the top of the device body 1 to discharge all the gas in the degassing chamber 8. After sealing, adjust the piston 2 downwards to make the degassing chamber 8 a negative pressure state with a set vacuum degree. The operation is simple and convenient.

[0081] Example 6

[0082] The following is a detailed explanation of the steps for on-site degassing of dissolved hydrocarbons in seawater.

[0083] The first step is to clean all parts, let them air dry at room temperature, and then assemble them for later use.

[0084] The second step is to place piston 2 at the top, tighten the sealing cap 6 to seal the gas collecting tube 4, and connect the vacuum gauge at the sample inlet tube 3.

[0085] Third, rotate the operating lever 5 to make the piston 2 descend to a vacuum gauge reading close to -0.1 MPa, and maintain this position for 1 hour. If the vacuum gauge reading does not decrease during this period, it indicates that the degassing device is well-sealed, and the inspection is complete.

[0086] Fourth step, open the sample inlet tube 3 and the gas collecting tube 4, and move the piston 2 down to the set mark, then add water sample until the sample inlet tube 3 and the gas collecting tube 4 are full.

[0087] Fifth step: First, screw the sealing plug 7 into the sample inlet tube 3, then cover the gas collecting tube 4 with the sealing cap 6, and be careful to keep the inside free of air bubbles.

[0088] Step 6: Rotate the operating lever 5 to move the piston 2 down to another set mark, and degassing begins (if necessary, place the degassing device in a water bath at about 60°C to heat it, which can speed up the degassing speed and efficiency).

[0089] Step 7: After holding for 30 minutes, rotate the operating lever 5 in the opposite direction to make the piston 2 move upward until the internal and external pressures are balanced. As the piston 2 moves upward, the liquid level in the degassing chamber 8 rises, thereby driving the degassed gas into the gas collecting pipe 4.

[0090] Step 8: Read and record the gas volume in gas collection tube 4. Extract a portion for direct gas chromatography analysis; the remaining gas can be extracted and stored in a sealed container for later use, as needed.

[0091] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A degassing method, characterized in that, The degassing method includes the following steps: S1: After adjusting the piston to the first set scale, inject the sample through the injection tube until the sample fills the degassing chamber, gas collecting tube and injection tube. Then seal the gas collecting tube and injection tube with the sealing cap and sealing plug respectively. S2: Adjust the piston downwards to the second set mark to degas the sample under negative pressure. S3: After degassing is completed, drive the gas extracted from the sample into the gas collection tube until the internal pressure of the degassing device is balanced with the external pressure. S4: After recording the volume of the gas released, extract the released gas from the gas collecting tube; Step S3 includes the following steps: Insert the internally emptied syringe into the air intake port on the sealed cap, and drive the vented gas into the gas collection tube by adjusting the position of the piston upwards until the syringe plunger is activated and the internal pressure of the degassing device is balanced with the external pressure. The degassing method employs a degassing device to degas the sample. The degassing device includes a main body and a piston disposed within the main body. The piston is movable up and down along the height of the device body, and a sealed degassing chamber is provided between the top of the piston and the inner wall of the device body. The top of the main body of the device is provided with a sample inlet tube and a gas collection tube. The sample inlet tube is connected to the degassing chamber to inject the sample into the degassing chamber for degassing. The gas collection tube is connected to the degassing chamber to collect and measure the gas degassed from the sample. The sample inlet tube is equipped with a removable sealing plug, and the bottom surface of the sealing plug is flush with the lower end surface of the sample inlet tube; the gas collecting tube and the main body of the device are both made of transparent material, and the outer wall of the gas collecting tube is marked with a first scale line, and the main body of the device is marked with a second scale line. The device also includes an operating lever. A threaded hole is provided at the bottom of the main body of the device, and the operating lever is threaded into the threaded hole. The upper end of the operating lever is connected to the bottom of the piston. Rotating the operating lever allows the piston to move up and down along the height direction of the main body of the device. The main body of the device is a cylindrical body with an open bottom, and a fixing member is provided at its lower end. The threaded hole and a vent hole are provided in the center of the fixing member. A bearing is provided at the bottom of the piston, and the upper end of the operating lever is connected to the bottom of the piston through the bearing, so that there is no relative rotation between the piston and the main body of the device.

2. The degassing method according to claim 1, characterized in that, The gas collecting pipe is equipped with a removable sealing cap, a sealing gasket is provided inside the sealing cap, and a gas intake port is provided on the sealing cap.

3. The degassing method according to claim 1, characterized in that, Step S3 includes the following steps: Injecting the driving fluid through the air intake port on the sealed cover drives the extracted gas into the gas collection pipe until the internal pressure of the degassing device is balanced with the external pressure, at which point the injection of the driving fluid automatically stops.

4. A degassing method according to claim 1 or 3, characterized in that, The step of checking the sealing of the degassing device is included before step S1: S01: After adjusting the piston to the top of the device body, seal the gas collecting tube and connect the vacuum gauge at the sample inlet tube; S02: Adjust the position of the piston downwards until the vacuum gauge reading is the set vacuum level; S03: Observe the reading of the vacuum gauge. If the reading of the vacuum gauge does not decrease within the set time, the airtightness of the degassing device is good.

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