Condensate-oil-resistant and temperature-resistant foam scrubbing agent for deep coal bed gas exploitation and preparation method of condensate-oil-resistant and temperature-resistant foam scrubbing agent

Abstract

The invention relates to a condensate-oil-resistant and temperature-resistant foam scrubbing agent for deep coal bed gas exploitation and a preparation method of the condensate-oil-resistant and temperature-resistant foam scrubbing agent. The method comprises the following steps: (1) mixing 45-55 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 14-28 parts of lauryl sodium sulfate, dissolving in an aqueous solution containing a special additive, adding 70-110 parts of aliphatic tertiary amine, heating to dissolve the aliphatic tertiary amine, adding the mixed solution into a three-neck flask, adjusting the pH value, heating, adjusting the pH value once every 25-35 minutes, reacting at 70-90 DEG C for 6-8 hours, and cooling to obtain a reaction solution; obtaining a yellow viscous product, namely the long-chain fat hydroxypropyl sulfonated betaine; and (2) adding 5-10 parts of a mixture of polyacrylamide and cellulose and 1-8 parts of nanoparticles into 80-150 parts of a product obtained in the step (1) to obtain the condensate oil-resistant temperature-resistant foam scrubbing agent. The lowest surface tension of the foam scrubbing agent can reach 28.12 mN / m, the foam scrubbing agent is high in foaming capacity, the foam height in clear water can reach 980 mL, the half-life period in high condensate oil content can reach 350 s, the condensate oil content reaches 35%, the foam height can still reach 750 mL, and the liquid carrying rate can reach 83.2%.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, and relates to an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane extraction and a preparation method thereof. The agent is suitable for complex environments with high temperature and high condensate oil content, and can be applied to deep coalbed methane extraction. Background Art

[0002] Natural gas is a clean, high-quality fossil energy that plays a very important role in improving my country's energy structure, promoting low-carbon economic development, and reducing greenhouse gas emissions.

[0003] With the current development of the oil and gas industry, my country's demand for oil and natural gas resources has gradually increased. The advancement of bottom water and the operational measures in the acidification and fracturing stages will lead to the continuous accumulation of liquid in the wellbore, which will cause the pressure at the wellhead to drop, reduce the natural gas production in the wellbore, and even crush the gas well in severe cases. To solve this problem, the most commonly used method in the industry is foam drainage gas production. Foam drainage gas production refers to the process of adding a developed foaming agent and water in a certain proportion into the gas wellbore. Under the impact of the natural gas flow at the bottom of the well, the foaming agent will mix evenly with the accumulated liquid at the bottom of the well, forming a very fine foam flow, which is then carried to the surface by the vertical lifting force of the natural gas flow. Finally, the accumulated liquid at the bottom of the well is discharged and the production of the gas well is restored. In the foam drainage gas production process, the selection of the foaming agent is very important.

[0004] At present, with the exploration and development of gas wells, the number of gas wells with high condensate oil content has gradually increased. Among them, the condensate oil content of gas wells in Shenmu Gas Field, Yulin, Shaanxi Province is as high as 30%, with an average oil-gas ratio of 0.84m 3 , 2.3 times the volume of the entire gas field. Because condensate itself acts like a defoamer, conventional foaming agents are ineffective at bottomhole, let alone restoring gas well production. This requires foaming agents to exhibit a certain resistance to condensate. Domestically, there are few anti-condensate foaming agents available, which are not only expensive but also have poor oil resistance. Some foaming agents lose their foaming ability when condensate content reaches 20% or higher. Shenmu gas field wells not only have high condensate content but also complex bottomhole fluid composition, including methanol, TDS, and hydrocarbons. The bottomhole temperature is also relatively high, further complicating recovery efforts. This places even higher demands on foaming agents, requiring them to exhibit high foaming and liquid-carrying capacity under conditions of high temperature, high salinity, and high condensate content. Therefore, there is an urgent need to study the mechanisms by which condensate affects the foaming properties of foaming agents and the emulsification mechanism of foaming agents in the presence of condensate. The goal is to develop a foaming agent that is highly resistant to oil, temperature, and mineralization for this type of gas well to increase gas production. Summary of the Invention

[0005] In view of this, the present invention provides an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining and a preparation method thereof, which has low surface tension and critical gel concentration, and still has good foaming ability and liquid carrying performance in extreme environments of high temperature, high mineralization and high condensate oil content.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining, comprising the following steps:

[0007] (1) 45-55 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 14-28 parts of sodium lauryl sulfate are mixed and dissolved in an aqueous solution containing a special additive, 70-110 parts of a fatty tertiary amine are added, and the mixture is heated to 45-60°C to dissolve. The mixed solution is added to a three-necked flask, the pH is adjusted to 8-10, and the mixture is heated to 70-90°C. The pH is adjusted every 25-35 minutes, and the mixture is reacted at 70-90°C for 6-8 hours. The mixture is cooled to obtain a yellow viscous product, which is a long-chain fatty hydroxypropyl sulfonated betaine.

[0008] (2) 80-150 parts of the prepared long-chain fatty hydroxypropyl sulfonated betaine are added with 5-10 parts of a mixture of polyacrylamide and cellulose and 1-8 parts of nanoparticles to obtain an anti-condensate oil temperature-resistant foaming agent.

[0009] Furthermore, the special additive in step 1) is ethylene glycol or isopropyl alcohol or a mixture of the two.

[0010] Furthermore, in step 1), the fatty tertiary amine is octadecyl tertiary amine, behenyl tertiary amine, dodecyl tertiary amine, or tetradecyl tertiary amine.

[0011] Furthermore, the nanoparticles are silicon dioxide nanoparticles with a particle size of 20nm-500nm.

[0012] The anti-condensate oil temperature-resistant foaming agent prepared by the above preparation method.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1) The present invention uses sodium 3-chloro-2-hydroxypropanesulfonate, sodium lauryl sulfate and fatty tertiary amine as raw materials to prepare an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining through a two-step reaction, and the synthesis process is simple.

[0015] 2) The novel surfactant prepared by the present invention is a combination of amphoteric betaine and sodium lauryl sulfate, which not only has low tension, high surface activity, strong synergistic effect, etc., but also has the advantages of temperature resistance, salt tolerance, good compatibility, low toxicity, etc.

[0016] 3) The present invention first mixes sodium 3-chloro-2-hydroxypropanesulfonate and sodium lauryl sulfate, then dissolves them in an aqueous solution containing a special additive and then adds a fatty tertiary amine.

[0017] 4) The present invention uses a new type of surfactant as a foaming agent, and adds a polymer foam stabilizer and nanoparticles to prepare an environmentally friendly and efficient foaming agent. The foaming agent has a liquid separation half-life of up to 350s, and when the condensate oil content is more than 30%, the liquid carrying rate can still reach 83.2%. The minimum surface tension can reach 28.12mN / m, and the foaming ability is strong. The foam height in clear water can reach 980mL. It has good foaming ability and liquid carrying performance in extreme environments with high salt and high condensate oil content. It has both heat resistance, resistance to condensate oil, and resistance to mineralization, and can play an important role in the deep coalbed methane mining process.

[0018] 5) Based on the wellbore fluid characteristics of specific gas fields, the present invention is supplemented by targeted special additives to form a series of nanoparticle high-efficiency foaming agents suitable for different types of gas fields. The overall temperature resistance reaches 120°C, the mineralization degree is 250,000 mg / L, and the condensate content is more than 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a graph showing the relationship between foam half-life and temperature.

[0020] Figure 2 The graph shows the change of surface tension of different foaming agents with concentration. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] Example 1

[0023] A method for preparing an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining, comprising the following steps:

[0024] Step 1: Dissolve 50.3 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 26 parts of sodium lauryl sulfate in an aqueous solution containing isopropyl alcohol (the mass ratio of water to isopropyl alcohol is 3:1), add 80 parts of octadecyl tertiary amine and dodecyl tertiary amine, heat to 55°C, stir continuously to fully dissolve, add the mixed solution to a three-necked flask, adjust the pH to 9 with 10% NaOH solution, heat to 75°C, adjust the pH every 30 minutes, react at 75°C for 6 hours, cool to 30°C, and discharge to obtain a yellow viscous product which is long-chain fatty hydroxypropyl sulfonated betaine;

[0025] Step 2: 100 parts of the prepared long-chain fatty hydroxypropyl sulfonated betaine are added to 8.56 parts of a mixture of polyacrylamide and cellulose and 2 parts of nano-silica with a particle size of 200 nm to obtain an anti-condensate oil temperature-resistant foaming agent.

[0026] Example 2

[0027] A method for preparing an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining, comprising the following steps:

[0028] Step 1: Dissolve 52 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 18 parts of sodium lauryl sulfate in an aqueous solution containing isopropanol (the mass ratio of water to isopropanol is 3:1), add 95 parts of behenyl tertiary amine and dodecyl tertiary amine, heat to 60°C, stir continuously to fully dissolve, add the mixed solution to a three-necked flask, use triethanolamine solution to adjust the pH to 9, heat to 85°C, adjust the pH every 25 minutes, react at 85°C for 6.5 hours, cool to 35°C, and discharge to obtain a yellow viscous product, which is long-chain fatty hydroxypropyl sulfonated betaine;

[0029] Step 2: Take 120 parts of the prepared long-chain fatty hydroxypropyl sulfonated betaine, add 9.3 parts of a mixture of polyacrylamide and cellulose, and 5.6 parts of nano-silica with a particle size of 300 nm, and obtain an anti-condensate oil temperature-resistant foaming agent.

[0030] Example 3

[0031] A method for preparing an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining, comprising the following steps:

[0032] The first step is to dissolve 50.43 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 20.65 parts of sodium dodecyl sulfate in an aqueous solution containing ethylene glycol (the mass ratio of water to ethylene glycol is 3:1), add 96.5 parts of octadecyl tertiary amine and dodecyl tertiary amine, heat to 58 ° C, stir continuously to fully dissolve, add the mixed solution to a three-necked flask, use 10% KOH solution to adjust the pH to 10, heat to 90 ° C, adjust the pH every 30 minutes, react at 90 ° C for 7 hours, cool to 38 ° C, and discharge to obtain a yellow viscous product as long-chain fatty hydroxypropyl sulfonated betaine;

[0033] Step 2: 123.5 parts of the prepared long-chain fatty hydroxypropyl sulfonated betaine are added to 8.63 parts of a mixture of polyacrylamide and cellulose and 5.56 parts of nano-silica with a particle size of 400 nm to obtain an anti-condensate oil temperature-resistant foaming agent.

[0034] Example 4

[0035] A method for preparing an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining, comprising the following steps:

[0036] Step 1: Dissolve 47.8 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 16.45 parts of sodium lauryl sulfate in an aqueous solution containing isopropanol (the mass ratio of water to isopropanol is 3:1), add 86.5 parts of didecyl tertiary amine and tetradecyl tertiary amine, heat to 55°C, stir continuously to fully dissolve, add the mixed solution to a three-necked flask, use diethanolamine solution to adjust the pH to 8, heat to 70°C, adjust the pH every 30 minutes, react at 70°C for 6.5 hours, during which time the system pH is maintained at 8, cool to 34°C, and discharge to obtain a yellow viscous product, which is long-chain fatty hydroxypropyl sulfonated betaine.

[0037] Step 2: 101.45 parts of the prepared long-chain fatty hydroxypropyl sulfonated betaine are added to 7.69 parts of a mixture of polyacrylamide and cellulose and 6.3 parts of nano-silica with a particle size of 300 nm to obtain an anti-condensate oil temperature-resistant foaming agent.

[0038] Example 5

[0039] A method for preparing an anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining, comprising the following steps:

[0040] The first step is to dissolve 52.36 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 25.34 parts of sodium lauryl sulfate in an aqueous solution containing ethylene glycol (the mass ratio of water to ethylene glycol is 3:1), add 80 parts of octadecyl tertiary amine and tetradecyl tertiary amine, heat to 58 ° C, stir continuously to fully dissolve, add the mixed solution to a three-necked flask, use 10% NaOH solution to adjust the pH to 7, heat to 85 ° C, adjust the pH every 30 minutes, react at 85 ° C for 7.5 hours, maintain the system pH at 7 during this period, cool to 36 ° C, and discharge to obtain a yellow viscous product as long-chain fatty hydroxypropyl sulfonated betaine.

[0041] Step 2: 120.35 parts of the prepared long-chain fatty hydroxypropyl sulfonated betaine are added to 9.3 parts of a mixture of polyacrylamide and cellulose and 3.54 parts of nano-silica with a particle size of 500 nm to obtain an anti-condensate oil temperature-resistant foaming agent.

[0042] Performance test of the product of the present invention:

[0043] 1. Foaming agent liquid carrying rate test

[0044] Referring to SY / T6465-2000, "Evaluation Methods for Foam-Based Dewatering and Gas Recovery," a liquid carryover rate measurement device was assembled to measure the liquid carryover rates of the foaming agents used in Examples 1-5. Weigh 0.8 portions of the test sample and dissolve it in 200 mL of water. The solution was then aged in a constant-temperature water bath at (60±0.5)°C for 30 minutes, starting with the addition of water. During this aging period, a water pump was activated to circulate water through the graduated tube jacket, maintaining a stable temperature of (60±0.5)°C. The inner wall of the graduated tube was pre-soaked overnight in a chromic acid-sulfuric acid solution and then rinsed with distilled water until free of acid. During the test, first rinse the inner wall of the graduated tube with distilled water, then with the test solution. Rinse thoroughly, but leave no foam on the inner wall. Start the compressed air pump and adjust the flow rate to a fixed value (5 L / min) using the flow meter. Add the surfactant solution to the foaming tube. Start timing when the foam reaches the receiver. Measure the liquid carried by the foam within 15 minutes. Liquid carryover rate = liquid volume carried by the foam / initial volume of the foaming agent × 100%. Prepare 25,000 mg / L of mineralized water.

[0045] Table 1 Liquid carrying rate of foaming agent under different test conditions

[0046]

[0047]

[0048] 2. Half-life test

[0049] Determine the half-life of Examples 1-5 according to the method and steps in 6.1 of SY / T7494-2020. Place 200 mL of the foaming agent solution with a concentration of 0.4% (mass fraction) prepared with brine in 7.6 in a sealed oven at 65°C or the target formation temperature for 30 minutes, stir with a Wu Yin stirrer (speed 7000 r / min) for 1 minute, start the stopwatch, and immediately pour the foam in the mixing cup into a 200 mL measuring cylinder. Use a silicone scraper to transfer the residual foam on the cup wall to the measuring cylinder. The foam transfer process should be completed within 30 seconds. Seal with plastic wrap, read and record the foaming volume Vo of the foaming agent. Read and record the time required for the amount of liquid precipitated from the foam in the measuring cylinder to reach 100 mL, which is the half-life t of the foam. 1 / 2 .

[0050] Table 2 Foam half-life under different test conditions

[0051] Test conditions Example 1 Example 2 Example 3 Example 4 Example 5 25000mg / L mineralized water 372s 350s 386s 342s 377s 30% condensate 355s 342s 347s 361s 356s 15% methanol 321s 296s 298s 311s 306s

[0052] 3. Foam temperature resistance test

[0053] refer to Figure 1 The gas well foaming agent prepared in Example 2 was poured into the foam fluid sand carrying capacity evaluation device, the temperature was set, and the foam half-life at different temperatures was tested. The test results are shown in Table 3.

[0054] Table 3 Foam half-life determination at different temperatures

[0055] Experimental content 90℃ 100℃ 110℃ 120℃ 130℃ 140℃ Bubble half-life / s 386 372 364 336 310 302

[0056] As can be seen from Table 3, with the continuous increase of temperature, the foam half-life gradually decreases, but it is still greater than 5 minutes at 140°C, and the high temperature resistance is excellent. Figure 1 It can also be seen that the relationship between foam half-life and temperature.

[0057] Depend on Figure 2 It can be seen that as the concentration of the foaming agent increases, the surface tension of the corresponding aqueous solution decreases rapidly at first, and then tends to be stable after the concentration reaches a certain value. Through linear fitting of the surface tension, it can be seen that the CMC of the three kinds of foaming agents are 2.23×10 -4 , 9.34×10 -4 and 3.31×10 -3 mol / L, and the corresponding critical surface tension (γ cmc) are 29.67, 32.70 and 34.54 mN / m, respectively. By comparison, it can be seen that the critical micelle concentration and surface tension of the foaming agent prepared by the present invention are lower than those of the other two foaming agents. This is because the foaming agent of the present invention is composed of two parts: an amphoteric betaine surfactant and a sulfonate surfactant. The two types of surfactants work synergistically to make the lipophilic ends of the long-chain alkyl side chains more tightly arranged in the air, and the repulsion tendency between the hydrophilic groups is significantly weakened, thereby exhibiting a low surface tension and a low critical micelle concentration.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It should be pointed out that any improvements and modifications made by ordinary technicians in this technical field without departing from the principle of the present invention should be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a condensate-resistant, temperature-resistant foaming agent for deep coalbed methane mining, characterized in that: The steps are: (1) Mix 45-55 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 14-28 parts of sodium lauryl sulfate, dissolve them in an aqueous solution containing special additives, add 70-110 parts of fatty tertiary amine, heat to 45-60°C to dissolve them, add the mixed solution to a three-necked flask, adjust the pH to 8-10, heat to 70-90°C, adjust the pH every 25-35 minutes, react at 70-90°C for 6-8 hours, cool, and obtain a yellow viscous product which is long-chain fatty hydroxypropyl sulfonated betaine; (2) Take 80-150 parts of the prepared long-chain fatty hydroxypropyl sulfonated betaine, add 5-10 parts of a mixture of polyacrylamide and cellulose, and 1-8 parts of nanoparticles to obtain an anti-condensate oil temperature-resistant foaming agent.

2. The method for preparing a condensate-resistant, temperature-resistant foaming agent for deep coalbed methane mining according to claim 1 or 2, characterized in that: The special additive in step 1) is ethylene glycol or isopropyl alcohol or a mixture of the two.

3. The method for preparing the anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining according to claim 3, characterized in that: The fatty tertiary amine in step 1) is octadecyl tertiary amine, behenyl tertiary amine, dodecyl tertiary amine or tetradecyl tertiary amine.

4. The method for preparing the anti-condensate oil temperature-resistant foaming agent for deep coalbed methane mining according to claim 4, characterized in that: The nanoparticles are silicon dioxide nanoparticles with a particle size of 20nm-500nm.

5. The anti-condensate oil temperature-resistant foaming agent prepared by the preparation method according to claim 1.

Images