A slow-release foam-displacing agent, a preparation method and application thereof

Abstract

The application discloses a slow-release foam displacement agent and a preparation method and application thereof. The slow-release foam displacement agent comprises a metal slow-release film and a foam displacement agent wrapped inside the metal slow-release film. The slow-release foam displacement agent has a slow-release time of greater than 3 days under the conditions of a temperature of 30-80 DEG C and a pH of 3-6 of a gas well. According to the foam performance test of the slow-release foam displacement agent according to the enterprise standard QSHCG0135-2021 'Technical requirements for foam displacement agents' of China Petroleum and Chemical Corporation, the slow-release foam displacement agent reaches the peak value of foaming capacity, foam stability and liquid carrying capacity of a solution when being slow-released for 2-5 days. When the peak value is reached, the liquid carrying capacity is greater than or equal to 120 mL, the foaming capacity is greater than or equal to 140 mm, and the foam stability is greater than or equal to 120 mm, and the slow-release foam displacement agent has good foaming performance, foam stability and liquid carrying capacity.

Description

Technical Field

[0001] This invention relates to the field of foam drainage and gas extraction technology, specifically to a slow-release foam drainage agent, its preparation method, and its application. Background Technology

[0002] Currently, with the continuous exploitation of gas fields, formation pressure decreases, and gas production gradually declines. When the gas volume is insufficient to carry out the accompanying liquid, the liquid accumulates in the wellbore, forming a liquid seal, further reducing gas production until the well shuts down. Liquid removal has become a key issue restricting the normal production of gas wells. Foam drainage gas production involves injecting a foaming agent into the well through the annulus of the tubing or casing. Under the agitation of the gas flow, foam with a certain degree of stability is generated. The liquid phase that has slid and deposited in the tubing transforms into foam, changing the relative density of the fluid in the lower part of the tubing. The continuously produced gas phase displaces the foam and flows out of the wellbore, thereby removing the accumulated liquid and achieving the purpose of drainage gas production.

[0003] Conventional foaming agents are injected as solids or in aqueous solutions. They dissolve rapidly at the bottom of the well, quickly forming foam that is carried out, resulting in a short-lasting foaming effect. Most gas wells with accumulated liquid require daily injection of foaming agents. For gas wells with packers between the tubing and casing, adding foaming agents requires shutting down the well, depressurizing, adding the agent, and then reopening the well. Frequent well opening and closing significantly impacts production and increases operational risks, especially for gas wells containing high levels of hydrogen sulfide, such as Puguang and Yuanba wells, greatly increasing labor costs and operational risks. Summary of the Invention

[0004] To address the problems of short duration, frequent injections, and high operational risks associated with foam drainage agents in gas wells containing hydrogen sulfide and carbon dioxide acidic gases in existing technologies, this invention provides a slow-release foam drainage agent, its preparation method, and its application. This invention employs a method of coating the foam drainage agent with a metal slow-release membrane, achieving a slow-release time of over 3 days, effectively solving this problem and making it applicable to the drainage and gas production process in high-temperature gas wells.

[0005] One of the objectives of this invention is to provide a sustained-release foaming agent comprising a metal sustained-release membrane and a foaming agent encapsulated within the metal sustained-release membrane.

[0006] In a preferred embodiment of the present invention,

[0007] The material of the metal slow-release membrane is a metal alloy material, including aluminum, magnesium, and optionally zinc and manganese.

[0008] In a preferred embodiment of the present invention,

[0009] Based on the total weight of the metal slow-release membrane as 100%, the aluminum content is 7-10%, the manganese content is 0-0.6%, the zinc content is 0-1%, and the balance is magnesium.

[0010] In a preferred embodiment of the present invention,

[0011] The metal slow-release membrane may be a single layer or multiple layers.

[0012] In a preferred embodiment of the present invention,

[0013] The thickness of the single layer of the metal slow-release membrane is 10 to 100 micrometers, preferably 20 to 70 micrometers.

[0014] In a preferred embodiment of the present invention,

[0015] The multilayer metal slow-release membrane may be filled with at least one of polyester, polyglycolic acid, polylactic acid, polyethylene wax, and paraffin wax between its layers.

[0016] In a preferred embodiment of the present invention,

[0017] The polyester is at least one of polybutylene terephthalate, polyethylene terephthalate, polybutylene succinate, polybutylene succinate / terephthalate, and polybutylene adipate / terephthalate.

[0018] In a preferred embodiment of the present invention,

[0019] The foaming agent is at least one of anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

[0020] In a preferred embodiment of the present invention,

[0021] The anionic surfactant is at least one selected from α-olefin sulfonate, alkylbenzene sulfonate, alkyl sulfonate, and alkyl sulfate; and / or,

[0022] The cationic surfactant is at least one of alkylammonium chloride and imidazoline; and / or,

[0023] The nonionic surfactant is at least one selected from alkyl polyoxyethylene ether, amine oxide, and alkyl glycoside; the alkyl polyoxyethylene ether is preferably an alkylamine polyoxyethylene ether; and / or...

[0024] The zwitterionic surfactant is at least one of alkylamide betaine, alkyl betaine, alkyl sulfobetaine, amphoteric propionate, and amino acid.

[0025] The slow-release foaming agent of this invention, in order to be well applied to gas well drainage and gas production, has a cross-sectional diameter smaller than the diameter of the well tubing, preferably one-half to two-thirds of the diameter of the well tubing; in the actual gas well drainage and gas production operation environment, the diameter of the slow-release foaming agent is more preferably 35-52mm; in order to avoid bridging and accumulation in the wellbore, the length of the slow-release foaming agent is preferably greater than or equal to its diameter and less than or equal to 600mm.

[0026] The film thickness of the sustained-release foaming agent described in this invention is on the micrometer level, so it can be considered that the size of the foaming agent inside the sustained-release foaming agent is equal to or slightly smaller than the size of the sustained-release foaming agent.

[0027] A second objective of this invention is to provide a method for preparing a sustained-release foaming agent, which is one of the objectives of this invention, comprising:

[0028] The slow-release foaming agent is obtained by covering and sealing it with a metal slow-release film.

[0029] In a preferred embodiment of the present invention,

[0030] The coating can be done using conventional coating processes in the prior art. In this invention, it is preferred to make the metal slow-release membrane into a sleeve with one end open, and then fill the foaming agent into the metal slow-release membrane sleeve and seal it to obtain the slow-release foaming agent.

[0031] The sleeve can be prepared using conventional manufacturing processes in the prior art, as long as the sleeve required by the present invention can be obtained. In the present invention, it is preferred to use a precision rolling method to prepare a metal alloy material of the required thickness according to the stated amounts of each metal component, and then use conventional processes in the prior art to make a sleeve with a metal slow-release film open at one end.

[0032] In a preferred embodiment of the present invention,

[0033] The size of the metal slow-release membrane after the sleeve is sealed is the size of the slow-release foaming agent.

[0034] In a preferred embodiment of the present invention,

[0035] When the foaming agent is in solid form, it is preferable to press the foaming agent into shape, then put the pressed foaming agent into a metal slow-release membrane sleeve and seal it to obtain the slow-release foaming agent.

[0036] In a preferred embodiment of the present invention,

[0037] The pressing pressure is 10-30 MPa, and the pressing time is 0.5-15 min.

[0038] In a preferred embodiment of the present invention,

[0039] The compressed foaming agent is cylindrical. To avoid bridging and accumulation inside the wellbore, the cross-sectional diameter of the cylindrical foaming agent is preferably 2-5 mm smaller than the diameter of the sleeve.

[0040] In a preferred embodiment of the present invention,

[0041] After the compressed foaming agent is loaded into the slow-release membrane sleeve, the air in the sleeve is expelled before sealing.

[0042] The sealing can employ conventional sealing processes found in existing technologies. In this invention, sealing processes such as knotting, tying, and adhesive bonding are preferred. Tying is the preferred sealing method for the slow-release membrane sleeve.

[0043] Other commonly used additives in the art, such as inorganic salts, urea, and corrosion inhibitors, can also be added to the foaming agent of the present invention. The dosage is also the conventional dosage, and those skilled in the art can add them according to the actual situation.

[0044] A third objective of this invention is to provide a slow-release foaming agent, either as described in one objective of this invention or prepared by the method described in another objective of this invention, for use in foam drainage gas production in acidic gas wells.

[0045] Specific applications include injecting at least one of the slow-release foaming agents described in this invention into the tubing of a gas well, where it is slowly released and generates foam with a certain degree of stability under the action of acidic gas in the gas well, thereby draining the accumulated liquid in the well and achieving the purpose of draining the liquid and producing gas; the slow-release foaming agents of this invention injected may be the same or different.

[0046] The beneficial effects of this invention are:

[0047] The slow-release foaming agent provided by this invention relies on the corrosion and perforation of the metal slow-release membrane, thereby releasing the foaming agent encapsulated inside the metal slow-release membrane to achieve the purpose of slow release. Therefore, it can effectively solve the problems of short onset time, multiple injections, waste of process costs, and high operational risks of existing foaming drainage agents in gas well development. Furthermore, when applied to gas well drainage and gas production containing acidic gases such as hydrogen sulfide and carbon dioxide, it can improve the dissolution time of the foaming agent and extend its shelf life.

[0048] The slow-release foaming agent of this invention has a slow-release time of more than 3 days under gas well conditions of 30-80℃ and pH 3-6. According to the enterprise standard QSH CG0135-2021 "Technical Requirements for Foaming Agents" of China Petroleum & Chemical Corporation, the foaming performance of the slow-release foaming agent of this invention is tested. The foaming power, foam stability and liquid carrying capacity of the solution reach the peak after 2-5 days of slow release. At the peak, the liquid carrying capacity is ≥120mL, the foaming power is ≥140mm and the foam stability is ≥120mm, which shows good foaming performance, foam stability and liquid carrying capacity. Detailed Implementation

[0049] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0050] All raw materials used in the examples are conventional commercially available raw materials.

[0051] Example 1

[0052] 60g sodium dodecyl sulfate (Sinopharm Group), 30g sodium dodecylbenzenesulfonate (Sinopharm Group), 20g oleylamine polyoxyethylene ether (Jiangsu Haian Chemical AC1803), 90g solid cocoamide betaine (Evonik, model TEGO Betain CKD), and 30g dodecyl sulfobetaine (Aladdin) were mixed in a kneader for 15 minutes until homogeneous. The mixture was then pressed in a hydraulic press for 10 minutes at a pressure of 20MPa. Finally, the mixture was extruded at a speed of 30cm / min into foaming rods with a diameter of 5cm and a length of 10.5cm.

[0053] Take 50g of the above-mentioned compressed foaming rod (the cross-sectional diameter of the 50g foaming rod is still 5cm) and put it into a metal sleeve A with a film thickness of 30μm (the metal alloy of metal sleeve A contains 10% aluminum and 90% magnesium). The sleeve diameter is 5.2cm. Keep one end open, evacuate the opening to expel air, and seal it tightly to form a slow-release foaming agent F1-A.

[0054] Example 2

[0055] Take 50g of the foaming rods pressed in Example 1 (the cross-sectional diameter of the 50g foaming rods taken out is still 5cm) and put them into a metal sleeve B with a film thickness of 30μm (the metal alloy of the metal sleeve B contains 7% aluminum and 93% magnesium). The sleeve diameter is 5.2cm. Keep one end open, evacuate the opening to expel air, and seal it to form a slow-release foaming agent F1-B.

[0056] Example 3

[0057] Take 50g of the foaming rods pressed in Example 1 (the cross-sectional diameter of the 50g foaming rods taken out is still 5cm) and put them into a metal sleeve C with a film thickness of 30μm (the metal alloy of the metal sleeve C contains 8.5% aluminum and 91.5% magnesium). The sleeve diameter is 5.2cm. Keep one end open, evacuate the opening to expel air, tie it to seal, and form a slow-release foaming agent F1-C.

[0058] Prepare 500g of saline solution with a mineralization of 50000mg / L according to the QSH CG0135-2021 "Technical Requirements for Foaming Agents" standard. Saturate the saline solution with 1MPa CO2 and determine the pH to be 4.5. Seal the slow-release foaming agents F1-A, F1-B, and F1-C and add them to the above saline solution respectively. Aging is carried out in ovens at 30℃ and 80℃. Take out 500g of liquid every 24 hours, and then add 500g of fresh water saturated with CO2 and a mineralization of 50000mg / L. Repeat this process for five consecutive days. Dilute the taken-out solution 5 times with the corresponding mineralized water to 2500g. Refer to the QSH CG0135-2021 "Technical Requirements for Foaming Agents" standard to determine the foaming power, foam stabilizing power, and liquid carrying capacity of the slow-release foaming agents. The results are shown in Table 1 (30℃ aging) and Table 2 (80℃ aging).

[0059] Table 1. Foaming power, foam stability, and liquid carrying capacity of the sustained-release foaming agents in Examples 1-3 after aging at 30°C.

[0060]

[0061]

[0062] Table 2 shows the foaming power, foam stability, and liquid carrying capacity of the sustained-release foaming agents in Examples 1-3 after aging at 80°C.

[0063]

[0064] As shown in Tables 1 and 2, the higher the aluminum content in the metal sustained-release membrane, the better the sustained-release performance of the foaming agent. However, if the aluminum content is too high, the sustained-release time will be too long, and the foaming agent will not be released smoothly. Therefore, in this invention, the aluminum content in the metal sustained-release membrane is preferably 7-10%.

[0065] Example 4

[0066] The foam release rods were pressed using the same method as in Example 1 (the composition of the foam release rods was the same as in Example 1). 50g of the pressed foam release rods (the cross-sectional diameter of the 50g foam release rods was still 5cm) were placed into a 30μm thick metal sleeve A (the metal alloy of sleeve A contained 10% aluminum and 90% magnesium). The sleeve diameter was 5.2cm, with one end open. A vacuum was drawn to expel air from the opening, and the opening was sealed tightly. Another metal sleeve A of the same thickness was then placed over this sleeve. 10g of molten polyglycolic acid was added between the two layers (forming a thickness of approximately 1mm), and the opening was sealed tightly to form the slow-release foam release agent F2-A.

[0067] Example 5

[0068] The foam release rods were pressed using the same method as in Example 1 (the composition of the foam release rods was the same as in Example 1). 50g of the pressed foam release rods (the cross-sectional diameter of the 50g foam release rods was still 5cm) were placed into a metal sleeve A with a film thickness of 30μm (the metal alloy of sleeve A contained 10% aluminum and 90% magnesium). The sleeve diameter was 5.2cm, with one end open. A vacuum was drawn to expel air from the opening, and the opening was sealed tightly. Another metal sleeve A of the same thickness was then placed over this sleeve. 10g of molten polyethylene wax was added between the two layers (forming a thickness of approximately 1mm), and the opening was sealed tightly to form the slow-release foam release agent F2-B.

[0069] Example 6

[0070] The foam release rods were pressed using the same method as in Example 1 (the composition of the foam release rods was the same as in Example 1). 50g of the pressed foam release rods (the cross-sectional diameter of the 50g foam release rods taken out was still 5cm) were placed into two stacked metal sleeves A with a film thickness of 30μm (the metal alloy of metal sleeve A contains 10% aluminum and 90% magnesium). The sleeves had a diameter of 5.2cm. One end was kept open, and the opening was evacuated to expel air. The opening was then sealed tightly to form the slow-release foam release agent F2-C.

[0071] Example 7

[0072] The foam release rods were pressed using the same method as in Example 1 (the composition of the foam release rods was the same as in Example 1). 50g of the pressed foam release rods (the cross-sectional diameter of the 50g foam release rods taken out was still 5cm) were placed into a metal sleeve D with a film thickness of 60μm (the composition was the same as that of metal sleeve A: 10% aluminum content and 90% magnesium content). The sleeve diameter was 5.2cm. The opening was evacuated to remove air, and the opening was sealed tightly to form a slow-release foam release agent F2-D.

[0073] Prepare 500g of saline solution with a mineralization of 50000mg / L according to the QSH CG0135-2021 "Technical Requirements for Foaming Agents" standard. Saturate the saline solution with 1MPa CO2 and determine the pH to be 4.5. Seal the slow-release foaming agents F2-A, F2-B, F2-C, and F2-D and add them to the above saline solution respectively. Aging is carried out in ovens at 30℃ and 80℃. Take out 500g of liquid every 24 hours, and then add 500g of fresh water saturated with CO2 and a mineralization of 50000mg / L. Repeat this process for five consecutive days. Dilute the taken-out solution 5 times with the corresponding mineralized water to 2500g. Refer to the QSH CG0135-2021 "Technical Requirements for Foaming Agents" standard to determine the foaming power, foam stabilizing power, and liquid carrying capacity of the slow-release foaming agents. The results are shown in Table 3 (30℃ aging) and Table 4 (80℃ aging).

[0074] Table 3 shows the foaming power, foam stability, and liquid carrying capacity of the sustained-release foaming agents in Examples 4-7 after aging at 30°C.

[0075]

[0076] Table 4 shows the foaming power, foam stability, and liquid carrying capacity of the sustained-release foaming agents in Examples 4-7 after aging at 80°C.

[0077]

[0078] The results in Tables 1-4 above show that the thickness and number of layers of the sustained-release membrane both affect the sustained-release performance. Increasing the thickness and the number of layers, especially when an organic phase is used as a separator between membranes, can prolong the sustained-release performance.

[0079] Comparative Example 1

[0080] Take 50g of the same compressed foaming agent as in Example 1 (the diameter of the 50g foaming rod taken out is still 5cm), without adding a slow-release membrane, and use the saline solution from Example 1. Prepare the solution according to the method in the corresponding example, and place it in an 80℃ oven for aging. Take out 500g of the solution every 24 hours, and then add 500g of fresh saline solution, for five consecutive days. Dilute the taken-out solution 5 times with the corresponding mineralized water to 2500g. According to the QSH CG0135-2021 "Technical Requirements for Foaming Agents" standard, determine the foaming power, foam stabilizing power, and liquid carrying capacity of the foaming agent. The results are shown in Table 5.

[0081] Table 5 shows the foaming properties of the foaming agent in Comparative Example 1 after aging at 80℃.

[0082]

[0083] As can be seen from the examples and comparative examples, the slow-release foaming agent of the present invention has a slow-release time of more than 3 days under gas well conditions of temperature 30-80℃ and pH 4.5. According to the QSH CG0135-2021 "Technical Requirements for Foaming Agents" standard, the foaming power, foam stabilizing power and liquid carrying capacity of the slow-release foaming agent were measured. The slow-release foaming agent of the present invention reaches its peak value in terms of foaming power, foam stabilizing power and liquid carrying capacity after 2-5 days of slow release. At the peak value, the liquid carrying capacity is ≥120mL, the foaming power is ≥140mm, and the foam stabilizing power is ≥120mm, which shows good foaming performance, foam stability and liquid carrying capacity.

Claims

1. A sustained-release foaming agent, comprising a metal sustained-release membrane and a foaming agent encapsulated within the metal sustained-release membrane; wherein the metal sustained-release membrane is made of a metal alloy material, comprising aluminum, magnesium, and optionally zinc and manganese; and, based on the total weight of the metal sustained-release membrane as 100%, wherein... The aluminum content is 7-10%, the manganese content is 0-0.6%, the zinc content is 0-1%, and the balance is magnesium; the foaming agent is at least one of anionic surfactant, cationic surfactant, nonionic surfactant, and amphoteric surfactant.

2. The sustained-release foaming agent as described in claim 1, characterized in that: The metal slow-release membrane may be a single layer or multiple layers.

3. The sustained-release foaming agent as described in claim 2, characterized in that: The thickness of the single layer of the metal slow-release membrane is 10. 100 micrometers.

4. The sustained-release foaming agent as described in claim 3, characterized in that: The thickness of the single layer of the metal slow-release membrane is 20-70 micrometers.

5. The sustained-release foaming agent as described in claim 2, characterized in that: The multilayer metal slow-release membrane may be filled with at least one of polyester, polyglycolic acid, polylactic acid, polyethylene wax, and paraffin wax between its layers.

6. The sustained-release foaming agent as described in claim 5, characterized in that: The polyester is at least one of polybutylene terephthalate, polyethylene terephthalate, polybutylene succinate, polybutylene succinate / terephthalate, and polyadipate / butylene terephthalate.

7. The sustained-release foaming agent as described in claim 1, characterized in that: The anionic surfactant is at least one selected from α-olefin sulfonate, alkylbenzene sulfonate, alkyl sulfonate, and alkyl sulfate; and / or, The cationic surfactant is at least one of alkylammonium chloride and imidazoline; and / or, The nonionic surfactant is at least one of alkyl polyoxyethylene ether, amine oxide, and alkyl glycoside; and / or, The zwitterionic surfactant is at least one of alkylamide betaine, alkyl betaine, alkyl sulfobetaine, amphoteric propionate, and amino acid.

8. A method for preparing a sustained-release foaming agent as described in any one of claims 1-7, comprising: The slow-release foaming agent is obtained by covering and sealing it with a metal slow-release film.

9. The preparation method according to claim 8, characterized in that: The metal sustained-release membrane is made into a sleeve with one end open, and then the foaming agent is put into the metal sustained-release membrane sleeve and then sealed to obtain the sustained-release foaming agent.

10. The preparation method according to claim 9, characterized in that: When the foaming agent is in solid form, it is placed into a metal slow-release membrane sleeve and then sealed to obtain the slow-release foaming agent.

11. The preparation method according to claim 10, characterized in that: When the foaming agent is in solid form, it is pressed into shape, and then the pressed foaming agent is put into a metal slow-release membrane sleeve and sealed to obtain the slow-release foaming agent.

12. The application of a slow-release foaming agent as described in any one of claims 1-7 or a slow-release foaming agent prepared by the method described in any one of claims 8-11 in foam drainage gas production in acidic gas wells.

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