Salt-tolerant mining foaming agent and preparation method thereof

Abstract

The application provides a salt-tolerant mining foaming agent and a preparation method thereof, and relates to the technical field of oil and gas field development and oil and gas field application chemical materials. According to the mass percentage, the raw material of the salt-tolerant mining foaming agent comprises 60%-80% of foaming surfactant, 5%-10% of auxiliary surfactant, 0.05%-1.0% of foam stabilizer, and the rest is water. The salt-tolerant mining foaming agent prepared by the application has stable properties, excellent salt-resistant foaming and liquid carrying capacity, and can reach the new standard V technical index in 150g / L super-high-salt-content mineralized water.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development and the application of chemical materials in oil and gas fields, and more specifically to a salt-resistant foaming agent for drainage and its preparation method. Background Technology

[0002] During natural gas extraction, water production from the reservoir reduces the efficiency of gas wells, necessitating timely and effective drainage of the bottom fluid. Foam drainage gas production technology is highly favored in the domestic and international drainage gas production field due to its low cost, rapid effectiveness, simple equipment, and convenient construction. With the continuous development of oil and gas extraction, formations generally exhibit high temperature and high salinity characteristics, rendering conventional foaming agents unable to meet increasingly demanding formation conditions. Especially near the wellhead, high salinity and high water content severely affect the performance of drainage gas production foaming agents, requiring solutions to address the impact of high salinity on foaming performance to improve their fluid-carrying capacity.

[0003] The patent document CN115521767A introduces hydrophobic nano-silica, which can achieve a foaming volume of 180 mL and a liquid carrying capacity of 82% in mineralized water with a concentration of over 20 g / L. In the literature, Zhang Tailiang et al. developed a temperature- and salt-resistant polyether sulfosuccinate salt foaming agent (see: Zhang Tailiang, Liu Wanqin, Dai Shanshan, et al. Research and development of temperature- and salt-resistant polyether sulfosuccinate salt foaming agent [J]. Natural Gas Industry, 2014, 34(10):103-107.), which can achieve a foaming volume of 600 mL in mineralized water with a concentration of 38 g / L. However, the preparation process is complicated, requiring high-temperature esterification and sulfonation reactions, and the alkylphenol polyoxyethylene ether in the composition has strong emulsifying properties, which brings many inconveniences to the later treatment of produced fluid. In both of the above cases, the salinity of the mineralized water used in the salt-resistant foaming agent was less than 50 g / L. The former did not specify the measurement standard, while the latter referred to SY / T 6465-2000 "Evaluation Method of Foaming Agent for Foam Drainage and Gas Extraction" and the foaming volume was determined according to GB / T 13173-2008 "Test Method of Surfactants and Detergents".

[0004] Patent document CN109054797A describes the preparation of a foaming agent for gas production that is antifreeze, anti-condensate, and anti-calcium and magnesium ion. The foaming volume in 100 g / L mineralized water is 165 mL, and the testing standard used is SY / T 5761-1995 "Foaming Agent for Gas Production through Drainage" (CT5-2). In the literature, Yang Yijun et al. developed a low-pressure salt-resistant foaming agent (see: Yang Yijun, Liu Hui, Wang Jinchang, et al. Application and evaluation of low-pressure salt-resistant foaming agent in Daniudi gas field [J]. Petrochemical Application, 2020, 39(05): 13-20.), which can withstand 149 g of salt and has a foaming volume of 220 mL. The test was conducted according to Q / SH 400603-2014 "Operational Specification for Foam Drainage Gas Production Process in Daniudi Gas Field". The two cases above showed improved salt tolerance, but the applicable standards were different, indicating that the industry requirements for drainage foaming agents also vary.

[0005] The current petroleum industry standard is Q / SY 17815-2021 "Technical Specification for Foaming Agents for Drainage and Gas Production," while the evaluation of foaming agents refers to SY / T 7494-2020 "Experimental Evaluation Methods for Foaming Agents Used in Oil and Gas Fields." The new standard has higher requirements, and given the need for formations with higher salinity, there is an urgent need to develop a salt-resistant foaming agent suitable for the new standard. Summary of the Invention

[0006] To overcome the defects and shortcomings of the existing technology, this invention provides a salt-resistant drainage foaming agent and its preparation method. The purpose of this invention is to solve the problem of foaming and liquid carrying difficulties of foaming agents in high-salt water during natural gas drainage and gas production. This invention provides a salt-resistant drainage foaming agent and its preparation method. The salt-resistant drainage foaming agent prepared by this invention is stable in properties and possesses excellent salt resistance foaming and liquid carrying capacity. In mineralized water with an ultra-high salt content of 150 g / L, it can meet the Class V technical indicators of the new standard.

[0007] To address the problems existing in the prior art, the present invention is implemented through the following technical solution.

[0008] The first aspect of this invention provides a salt-tolerant frothing agent for drainage, comprising, by weight percentage, a 60%-80% foaming surfactant; 5%-10% auxiliary surfactant; 0.05%-1.0% foam stabilizer; The rest is water.

[0009] More preferably, the foaming surfactant is any one or a mixture of two of lauryl betaine, lauramide propyl betaine, cocamidopropyl betaine, dodecyl sulfobetaine, and hexadecyl sulfobetaine.

[0010] More preferably, the foaming surfactant is a mixture of lauramidopropyl betaine and dodecyl sulfobetaine.

[0011] More preferably, the ratio of lauramidopropyl betaine to dodecyl sulfobetaine in the foaming surfactant is 1:0.5-2.0.

[0012] More preferably, the ratio of lauramidopropyl betaine to dodecyl sulfobetaine in the foaming surfactant is 1:1-2.

[0013] More preferably, the foaming surfactant is a mixture of lauramidopropyl betaine and hexadecyl sulfobetaine.

[0014] More preferably, the ratio of lauramidopropyl betaine to hexadecyl sulfobetaine in the foaming surfactant is 1:0.5-2.0.

[0015] More preferably, the ratio of lauramidopropyl betaine to hexadecyl sulfobetaine in the foaming surfactant is 1:1-2.0.

[0016] More preferably, the auxiliary surfactant is any one or a combination of two of the following: sodium perfluorononenoxybenzenesulfonate, sodium dodecyl sulfate, potassium ferrocyanide, disodium ethylenediaminetetraacetate, dodecylbenzenesulfonic acid, and p-methylbenzenesulfonic acid.

[0017] More preferably, the auxiliary surfactant is a mixture of sodium perfluorononenoxybenzenesulfonate and dodecylbenzenesulfonic acid.

[0018] More preferably, the ratio of sodium perfluorononenoxybenzenesulfonate to dodecylbenzenesulfonic acid in the auxiliary surfactant is 1:4-20.

[0019] More preferably, the ratio of sodium perfluorononenoxybenzenesulfonate to dodecylbenzenesulfonic acid in the auxiliary surfactant is 1:8-18.

[0020] More preferably, the auxiliary surfactant is a mixture of sodium perfluorononenoxybenzenesulfonate and p-toluenesulfonic acid.

[0021] More preferably, in the auxiliary surfactant, the ratio of sodium perfluorononenoxybenzenesulfonate to p-toluenesulfonic acid is 1:4-20.

[0022] More preferably, the ratio of sodium perfluorononenoxybenzenesulfonate to p-toluenesulfonic acid in the auxiliary surfactant is 1:8-18.

[0023] More preferably, the foam stabilizer is polyvinyl alcohol, sodium carboxymethyl cellulose, carrageenan, guar gum, or polyacrylamide.

[0024] More preferably, the amount of the foam stabilizer is 0.1%-0.5%.

[0025] More preferably, the foam stabilizer is carrageenan or guar gum.

[0026] The second aspect of the present invention provides a method for preparing a salt-tolerant drainage foaming agent. The preparation method specifically involves dissolving an auxiliary surfactant in a certain amount of water, then adding a foaming surfactant and a foam stabilizer, and stirring until a uniform orange-yellow transparent viscous liquid is obtained, which is the salt-tolerant drainage foaming agent.

[0027] In a further preferred embodiment, 1.0 g of sodium perfluorononenoxybenzenesulfonate and 9.0 g of p-toluenesulfonic acid are added to the reactor, followed by 9.5 g of water and stirred until homogeneous. Then, 40.0 g of lauramidopropyl betaine, 40.0 g of hexadecyl sulfobetaine and 0.5 g of carrageenan are added, stirred and dispersed until the system becomes transparent and clear. The resulting orange-yellow transparent viscous liquid is the salt-resistant foaming agent.

[0028] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1. The salt-resistant foaming agent prepared by this invention has excellent salt resistance and can exhibit good foaming performance even at high salt content of 150 g / L. Under test conditions of 65℃, the foaming volume reaches 560 mL, the liquid carrying capacity reaches 95.3%, and the foam half-life is as long as 285 s. The foaming effect can meet the Class V technical indicators of the new standard (foaming volume ≥ 500 mL, liquid carrying capacity ≥ 80%, half-life ≥ 70 s), which can significantly improve the gas well drainage and gas production efficiency.

[0029] 2. This invention, through careful selection of foaming surfactants, auxiliary surfactants, and foam stabilizers, and by optimizing the formulation, enhances the salt resistance and foaming performance of the foaming agent. The raw materials used in this invention are already industrially produced, readily available, and low-cost. Furthermore, the reaction process is simple, mild, and safe, facilitating preparation and saving both production costs and time, while also improving efficiency and safety.

[0030] 3. The foaming agent prepared by this invention is stable and can be stored for a long time at room temperature and pressure, making it convenient to store and use. It also has good compatibility with other water-based systems and can be used directly.

[0031] 4. The salt-resistant foaming agent prepared by this invention has unique salt resistance properties and can be used in high salt content conditions of 150 g / L.

[0032] 5. This invention represents a significant improvement over existing technologies. The performance indicators of existing foaming agents are all based on old standards, with foaming volumes below 200 mL and a maximum liquid carrying capacity of 93.2%. The salt-tolerant drainage foaming agent prepared by this invention achieves a foaming volume of 560 mL and a liquid carrying capacity of 95.3%, significantly improving the performance of foaming agents in high-salt environments.

[0033] 6. The key improvement of this invention compared to existing technologies lies in the enhanced stability of the foaming agent in high-salt environments. Existing technologies have a foam half-life of less than 200 s. The salt-resistant drainage foaming agent prepared by this invention has a foam half-life as long as 285 s, improving foam stability and durability.

[0034] 7. The salt-resistant foaming agent prepared by this invention has excellent performance and can be used in the process of drainage and gas production of gas wells with high water and high salt content. The foaming effect can reach the Class V technical indicators of the new standard, which can significantly improve the drainage and gas production efficiency of gas wells. Detailed Implementation

[0035] The technical solution of the present invention will be further supplemented and explained in detail below with reference to specific embodiments.

[0036] Example 1 As a preferred embodiment of the present invention, this embodiment discloses a method for preparing a salt-tolerant drainage foaming agent. Specifically, an auxiliary surfactant is dissolved in a certain amount of water, followed by the addition of a foaming surfactant and a foam stabilizer. The resulting orange-yellow, transparent, viscous liquid is the salt-tolerant drainage foaming agent. In this embodiment, various salt-tolerant drainage foaming agents are obtained according to the components shown in Table 1 below.

[0037] Table 1 lists salt-tolerant frothing agents composed of different component combinations. Example 2 As another preferred embodiment of the present invention, this embodiment provides a salt-tolerant drainage foaming agent, which is prepared as follows: 1.0 g of sodium perfluorononenoxybenzenesulfonate and 4.0 g of dodecylbenzenesulfonic acid are added to a reactor, followed by the addition of 34.5 g of water and stirring. After the mixture is homogeneous, 30.0 g of lauramidopropyl betaine, 30.0 g of dodecyl sulfobetaine and 0.5 g of guar gum are added. After stirring and dispersing, the system is allowed to become transparent and clear. The resulting orange-yellow transparent viscous liquid is the salt-tolerant drainage foaming agent.

[0038] Example 3 The preparation method is the same as described in Example 2, except that the dodecylbenzenesulfonic acid is replaced with p-methylbenzenesulfonic acid.

[0039] Example 4 The preparation method described in Example 3 differs in that the amount of p-toluenesulfonic acid is increased from 4.0 g to 9.0 g, and the amount of water is decreased from 34.5 g to 29.5 g.

[0040] Example 5 The preparation method is the same as described in Example 4, except that the dodecyl sulfobetaine is replaced with hexadecyl sulfobetaine.

[0041] Example 6 The preparation method described in Example 5 differs in that the amount of lauramidopropyl betaine is increased from 30.0 g to 40.0 g, and the amount of water is reduced to 19.5 g.

[0042] Example 7 The preparation method is the same as described in Example 6, except that the amount of hexadecyl sulfobetaine is increased from 30.0 g to 40.0 g, and the amount of water is reduced to 9.5 g.

[0043] Example 8 The preparation method is the same as described in Example 6, except that the guar gum is replaced with carrageenan.

[0044] Example 9 As another preferred embodiment of the present invention, this embodiment provides a salt-tolerant drainage foaming agent, which is prepared as follows: 0.5 g of sodium perfluorononenoxybenzenesulfonate and 9.5 g of p-methylbenzenesulfonic acid are added to a reactor, followed by 29.7 g of water and stirred until mixed evenly. Then, 20.0 g of lauramidopropyl betaine, 40.0 g of dodecyl sulfobetaine and 0.3 g of guar gum are added and stirred until dispersed. After the system becomes transparent and clear, the resulting orange-yellow transparent viscous liquid is the salt-tolerant drainage foaming agent.

[0045] Comparative Example 1 A low-pressure, salt-resistant foaming agent CP-01 is used in the Daniudi gas field. Reference: Yang Yijun, Liu Hui, Wang Jinchang, et al. Application and evaluation of low-pressure, salt-resistant foaming agent in Daniudi gas field [J]. Petrochemical Application, 2020, 39(05): 13-20. Comparative Example 2 The foaming agent prepared in Example 1 of patent document CN 115521767 A.

[0046] Comparative Example 3 The foaming agent prepared in Example 1 of patent document CN 109054797 A.

[0047] Experiment Example 1: Foaming Agent Performance Experiment The performance of the foaming agent was evaluated in accordance with Q / SY 17815-2021 "Technical Specification for Foaming Agents for Drainage and Gas Production" and the foaming agent evaluation criteria were based on SY / T7494-2020 "Experimental Evaluation Method for Foaming Agents for Oil and Gas Fields". The experimental results are shown in Table 1.

[0048] Table 2 shows the performance of different foaming agents. Note: The data in Comparative Examples 1-3 are derived from the original records in the relevant literature, or converted from the original data.

[0049] As shown in Table 2, the salt-tolerant foaming agent prepared by this invention meets the Class V indicators (foaming volume ≥ 500 mL, liquid carrying rate ≥ 80%, half-life ≥ 70 s) in the implementation standard within the experimental range.

[0050] Comparing Examples 2 and 3, changing the type of sulfonic acid in the auxiliary surfactant resulted in improved performance across all indicators of the prepared product, with a significant increase in foam volume. Comparing Examples 3 and 4, increasing the content of p-dimethylbenzenesulfonic acid in the auxiliary surfactant further improved the foam volume of the prepared product. This indicates that the auxiliary surfactant can provide excellent salt resistance.

[0051] Compared with Examples 4 and 5, increasing the alkyl length of some molecules in the foaming surfactant resulted in improved performance across all indicators of the prepared product, with a significant increase in liquid carrying capacity. Combining Examples 6 and 7, continuously increasing the foaming surfactant content led to substantial increases in both the liquid carrying capacity and half-life of the prepared product. This demonstrates that the foaming surfactant plays a crucial role in the liquid carrying capacity and stability of the product.

[0052] Comparing Examples 7 and 8, where the type of foam stabilizer was changed, the most significant change in the half-life of the prepared product was observed. This indicates that carrageenan exhibits the best performance among the screened foam stabilizers.

[0053] Example 9 involves random preparation within the range of material types and proportions selected in the invention, and the performance of the prepared product meets the Class V performance index in the new standard.

[0054] The standards used in this invention are more recent than those in existing literature, therefore the foaming volume measurement is not comparable. However, the foaming agent's salt resistance, liquid carrying capacity, and foam half-life are all superior to those of Comparative Examples 1-3. Therefore, the salt-resistant drainage foaming agent prepared in this invention has better salt resistance and foaming performance.

[0055] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or thresholds should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A salt-tolerant foaming agent for drainage, characterized in that: This salt-tolerant frothing agent comprises the following raw materials by weight percentage: 60%-80% foaming surfactant; the foaming surfactant is any one or a mixture of two of lauryl betaine, lauramide propyl betaine, cocamidopropyl betaine, dodecyl sulfobetaine, and hexadecyl sulfobetaine; 5%-10% auxiliary surfactant; the auxiliary surfactant is a mixture of sodium perfluorononenoxybenzenesulfonate and p-toluenesulfonic acid; the ratio of sodium perfluorononenoxybenzenesulfonate to p-toluenesulfonic acid in the auxiliary surfactant is 1:4-20; 0.05%-1.0% foam stabilizer; The rest is water.

2. The salt-tolerant frothing agent for drainage as described in claim 1, characterized in that: The foaming surfactant is a mixture of lauramidopropyl betaine and dodecyl sulfobetaine.

3. The salt-tolerant frothing agent for drainage as described in claim 2, characterized in that: In the foaming surfactant, the ratio of lauramidopropyl betaine to dodecyl sulfobetaine is 1:0.5-2.

0.

4. The salt-tolerant frothing agent for drainage as described in claim 2, characterized in that: The foaming surfactant contains lauramidopropyl betaine and dodecyl sulfobetaine in a ratio of 1:1-2.

5. The salt-tolerant foaming agent for drainage as described in claim 1, characterized in that: The foaming surfactant is a mixture of lauramidopropyl betaine and hexadecyl sulfobetaine.

6. The salt-tolerant frothing agent for drainage as described in claim 5, characterized in that: The ratio of lauramidopropyl betaine to hexadecyl sulfobetaine in the foaming surfactant is 1:0.5-2.

0.

7. The salt-tolerant frothing agent for drainage as described in claim 5, characterized in that: The ratio of lauramidopropyl betaine to hexadecyl sulfobetaine in the foaming surfactant is 1:1-2.

0.

8. A salt-tolerant frothing agent for drainage as described in any one of claims 1-7, characterized in that: In the auxiliary surfactant, the ratio of sodium perfluorononenoxybenzenesulfonate to p-toluenesulfonic acid is 1:8-18.

9. A salt-tolerant frothing agent for drainage as described in any one of claims 1-7, characterized in that: The foam stabilizer is polyvinyl alcohol, sodium carboxymethyl cellulose, carrageenan, guar gum, or polyacrylamide.

10. A salt-tolerant frothing agent for drainage as described in any one of claims 1-7, characterized in that: The amount of the foam stabilizer used is 0.1%-0.5%.

11. The salt-tolerant frothing agent for drainage as described in claim 10, characterized in that: The foam stabilizer is carrageenan or guar gum.

12. A method for preparing a salt-tolerant frothing agent for drainage as described in any one of claims 1-11, characterized in that: Dissolve the auxiliary surfactant in a certain amount of water, then add the foaming surfactant and foam stabilizer, and stir until the resulting orange-yellow transparent viscous liquid is the salt-tolerant drainage foaming agent.

13. A method for preparing a salt-tolerant frothing agent for drainage as described in any one of claims 1-11, characterized in that: In a reactor, 1.0 g of sodium perfluorononenoxybenzenesulfonate and 9.0 g of p-toluenesulfonic acid were added, followed by 9.5 g of water and stirred until homogeneous. Then, 40.0 g of lauramidopropyl betaine, 40.0 g of hexadecyl sulfobetaine and 0.5 g of carrageenan were added and stirred until the system was clear and transparent. The resulting orange-yellow transparent viscous liquid is the salt-resistant foaming agent.

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