Anti-shearing foam scrubbing composition, foam scrubbing agent and application thereof

Abstract

The invention relates to an anti-shearing foam scrubbing composition, a foam scrubbing agent and application thereof. The anti-shearing foam scrubbing composition consists of a main agent, a thickening agent and a stabilizing agent, the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 70-80% of the mass of the main agent; the dosage of the thickening agent is 0.2-0.4% of the mass of the main agent; the use amount of the stabilizer is 0.06-0.1% of the mass of the main agent; the first zwitterionic surfactant is cocamidopropyl betaine, and the second zwitterionic surfactant is cocamidopropyl betaine; and the second ionic surface active agent is dodecyl dimethyl amine oxide. The foam scrubbing agent provided by the invention does not contain a fluorocarbon surfactant, still has the performance advantages of strong foaming power, good stability and large liquid carrying capacity under the conditions of high temperature, high salinity, high gas condensate and methanol, is strong in adaptability, and is especially suitable for high-temperature deep well foam drainage gas recovery.

Description

Technical Field

[0001] The invention relates to an anti-shear foaming composition, a foaming agent and application thereof, and belongs to the technical field of gas field exploitation. Background Art

[0002] At present, there are dozens of foaming agents suitable for different reservoir conditions at home and abroad, and most of them have great performance changes due to temperature. They are generally suitable for temperatures below 90°C, salinity of 100,000 ppm, no H2S gas, and low condensate content. With the continuous development of natural gas, high-depth gas wells are becoming more and more important, and the gas reservoir temperature is higher, which leads to a significant reduction in the foaming performance and liquid carrying performance of conventional foaming agents. The foam produced by many foaming agents under the conditions of temperature greater than 120°C and salinity greater than 100,000 ppm will completely disappear within 1-2 minutes, or even no foam will be produced, which seriously restricts the application of foam drainage gas recovery in high-temperature gas wells.

[0003] The Chinese invention patent document with application publication number CN105086980A discloses "a foaming agent for deep gas well drainage and gas recovery and its preparation method", wherein, in terms of weight percentage, the composition of the foaming agent includes: zwitterionic surfactant A 15-35%, zwitterionic surfactant B 10-30%, anionic surfactant 10-20%, fluorocarbon surfactant 0.1-2%, solid foam stabilizer, and the balance is deionized water. The foaming agent has certain foaming, foam stabilization and liquid carrying properties under high temperature and high mineralization conditions, but from the experimental results in the examples, the liquid carrying volume is generally less than 180mL, and the calculated liquid carrying rate is less than 90%. At the same time, fluorocarbon surfactants are used in the foaming agent formula, but some fluorocarbon surfactants are restricted chemicals in oilfield chemicals, and it can be seen from the content description that the foaming agent has low toxicity characteristics. Importantly, the price of fluorocarbon surfactants is also relatively expensive, thus limiting the promotion and application of the technology.

[0004] The foaming agent described in the public document "Nano-particle foaming agent suitable for deep water-producing gas wells" also contains fluorocarbon surfactants, and also has the problem of restricted use and high prices that restrict promotion. The foaming agent described in the public document "A foaming agent suitable for high-temperature deep gas well drainage" uses SDS, BS, and PO as a compound, and is evaluated by a conventional Roche foam instrument, comparing the performance before and after aging at 120°C, but the adaptability to high temperature and high pressure conditions is not given, and the conditions of high mineralization and condensate oil are not evaluated, so the adaptability is unknown.

[0005] Therefore, providing a high temperature resistant, high mineralization resistant, simple and easily available foaming agent for high temperature gas well drainage and gas production, while also considering production costs, promotion and other issues, has become an urgent problem to be solved in this field. Summary of the invention

[0006] The first purpose of the present invention is to provide a shear-resistant foaming composition to solve the problem in the prior art that when draining water and producing gas from gas wells with high temperature, high mineralization and high condensate oil, the foaming agent usually contains fluorocarbon surfactants, which leads to complex composition of the foaming agent, high cost, certain biological toxicity, and is not conducive to large-scale promotion.

[0007] The second object of the present invention is to provide a shear-resistant foaming agent to solve the problem that the foaming agent without fluorocarbon surfactant has poor adaptability and low drainage efficiency when used in high-temperature deep condensate oil and gas wells in the prior art.

[0008] The third object of the present invention is to provide an anti-shear foaming composition or an anti-shear foaming agent for use in foam drainage and gas production in natural gas wells, so as to solve the problem that when the foaming agent is used in high-temperature deep condensate oil and gas wells in the prior art, the foaming agent usually contains fluorocarbon surfactants, which leads to complex composition of the foaming agent, high cost, certain biological toxicity, and is not conducive to large-scale promotion.

[0009] In order to achieve the above object, a technical solution of a shear-resistant foaming composition in the present invention is:

[0010] The invention discloses an anti-shear foaming composition, which is composed of a main agent, a thickener and a stabilizer; the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 70-80% of the mass of the main agent; the thickener is used in an amount of 0.2-0.4% of the mass of the main agent; the stabilizer is used in an amount of 0.06-0.1% of the mass of the main agent; the first zwitterionic surfactant is cocamidopropyl betaine; and the second ionic surfactant is dodecyl dimethyl amine oxide.

[0011] The beneficial effect of the above technical scheme is that: the present invention selects two zwitterionic surfactants, cocamidopropyl betaine and dodecyl dimethylamine oxide, as the main agent, and is matched with a thickener and a stabilizer to form an anti-shear foaming composition, which has the advantages of simple composition, easy availability and low cost. When facing high temperature, high mineralization, and high condensate oil gas well drainage and gas production, in the absence of fluorocarbon surfactants, it can also maintain high foaming and foam stabilization ability and excellent liquid carrying rate. Experiments have proved that the foaming agent prepared by the anti-shear foaming composition of the present invention has the advantages of strong foaming and liquid carrying ability, and at the same time has excellent cleanliness, good low temperature resistance and fluidity, meets the requirements of different filling processes, and is particularly suitable for high temperature deep gas well foam drainage and gas production.

[0012] Among them, cocamidopropyl betaine and dodecyl dimethylamine oxide have good foaming and foam stabilizing effects, and contain cationic groups and anionic groups at the same time. Their solubility is less restricted by the range of dielectric and solution pH values, and is less affected by high mineralization and condensate in the formation. The foam stabilizer composed of solid foam stabilizer and macromolecular foam stabilizer plays a synergistic role with the selected main agent, so that the molecules in the foaming agent are densely arranged, the strength and elasticity of the foam are enhanced, the discrete effect caused by the violent Brownian motion of molecules under high temperature in high-temperature deep gas wells is reduced, and the foam stabilizing ability of the foaming agent is further enhanced.

[0013] As a further improvement, the stabilizer is composed of lithium magnesium silicate and sodium gluconate; the mass ratio of the lithium magnesium silicate to sodium gluconate is 1:(1-1.1).

[0014] The beneficial effects of the above technical solution are: lithium magnesium silicate forms a certain spatial barrier network structure, increasing the rigidity of the bubbles; sodium gluconate interacts strongly with cocamidopropyl betaine and dodecyl dimethylamine oxide on the surface of the solution, increasing the surface viscosity and the volume exclusion effect between the two surfaces in the foam, thereby improving the stability of the foam. The two types of stabilizers can significantly improve the stability of the foaming agent foam, thereby increasing the liquid carrying capacity.

[0015] As a further improvement, the thickener is composed of polyethylene glycol 2000 and hydroxypropyl beta-cyclodextrin; the mass ratio of the polyethylene glycol 2000 to hydroxypropyl beta-cyclodextrin is 1:(1-1.1).

[0016] The beneficial effects of the above technical solution are: polyethylene glycol 2000 has good solubility, is stable to heat, acid and alkali, and has good hygroscopicity, lubricity and viscosity increasing properties, which can effectively improve the viscosity and shear resistance of the foaming agent, so as to improve the strength of the foam liquid film and further improve the stability of the foam; cyclodextrin has a thickening effect and also has strong stability. The two thickeners cooperate with each other, which can effectively improve the stability of the foaming agent and greatly reduce the production cost.

[0017] In order to achieve the above object, a technical solution of an anti-shear foaming agent in the present invention is:

[0018] An anti-shear foaming agent comprises an anti-shear foaming composition and water.

[0019] The beneficial effect of the above technical scheme is that: the present invention adopts cocamidopropyl betaine and dodecyl dimethylamine oxide, zwitterionic surfactants with suitable hydrophobic chain length, strong hydrophilic group hydration ability and high temperature resistance, to compound with stabilizer and thickener, give full play to synergistic effect and position adaptability, and obtain anti-shear foaming agent with good foaming and foam stability. It has been verified by experiments that the anti-shear foaming agent of the present invention has high foaming, foam stability and liquid carrying rate under the conditions of temperature of 130°C, mineralization of 200000ppm, condensate content of 20% (volume concentration of condensate in liquid), and methanol content of 20% (volume concentration of methanol in liquid). Under the conditions of pressure of 3MPa, 10MPa and temperature of 130°C, the liquid carrying rate reaches more than 95%.

[0020] As a further improvement, the weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition to the anti-shear foaming agent is 59-71%.

[0021] As a further improvement, the anti-shear foaming agent includes an antifreeze agent.

[0022] The beneficial effect of the above technical scheme is that the antifreeze agent is added to the foaming agent of the present invention, which does not affect the foaming and foam stabilizing ability of the foaming agent, and also makes the foaming agent have good antifreeze properties. After being frozen at -18°C for 24 hours, it is still a flowable liquid, which can adapt to the smooth filling of medicines in northern winter, and further expands the geographical scope of practical application of the foaming agent.

[0023] Preferably, the antifreeze agent is methanol.

[0024] As a further improvement, the amount of the antifreeze agent is 0-5% of the mass of the main agent.

[0025] In order to achieve the above-mentioned purpose, the technical scheme of the application of the anti-shear foaming composition or the anti-shear foaming agent in the foam drainage and gas production of natural gas wells is:

[0026] The invention discloses an application of a shear-resistant foaming composition or a shear-resistant foaming agent in foam drainage and gas production in natural gas wells.

[0027] The beneficial effect of the above technical solution is that the anti-shear foaming agent of the present invention can maintain high foaming and foam stabilization ability and excellent liquid carrying rate when facing high temperature, high mineralization, high condensate oil gas well drainage and gas production without containing fluorocarbon surfactant. At the same time, all components have good compatibility with the human body, low biological toxicity, easy biodegradation, and little impact on reservoirs and formations.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The anti-shear foaming agent of the present invention has the advantages of strong foaming and liquid carrying capabilities, and also has excellent cleanliness, good low temperature resistance and fluidity, meets the requirements of different filling processes, and is particularly suitable for high-temperature deep well foam drainage and gas production. Under the conditions of temperature of 130°C, salinity of 200000ppm, condensate content of 20% (volume concentration of condensate in liquid), and methanol content of 20% (volume concentration of methanol in liquid), it has high foaming, foam stability and liquid carrying rate. Under the conditions of pressure of 3MPa, 10MPa, and temperature of 130°C, the liquid carrying rate reaches more than 95%. The anti-shear foaming agent of the present invention has strong adaptability, and in high-temperature, high-salinity, high-condensate, methanol-containing formation water, even if it does not contain fluorocarbon surfactants, it still has the performance advantages of strong foaming power, good stability, and large liquid carrying capacity. After antifreeze is added to the anti-shear foaming agent, it does not affect the foaming and foam stabilizing ability of the foaming agent, but also has good antifreeze properties. After being frozen at -18°C for 24 hours, it is still a flowable liquid. It can adapt to the smooth filling of medicines in northern winter, further expanding the geographical scope of the practical application of the foaming agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart for preparing the shear-resistant and efficient foaming agent in Example 7 of the present invention (wherein, zwitterionic surfactant C and zwitterionic surfactant O represent the first and second zwitterionic surfactants, respectively; stabilizer 1 and stabilizer 2 represent lithium magnesium silicate and sodium gluconate, respectively; thickener 1 and thickener 2 represent polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin, respectively). DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with specific embodiments. It should be noted that, under the premise of no conflict, the embodiments or technical features described below can be arbitrarily combined to form new embodiments. The equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are all conventional methods in the art unless otherwise specified.

[0032] The first zwitterionic surfactant cocamidopropyl betaine and the second ionic surfactant dodecyl dimethyl amine oxide used in the following examples are both commercial products, wherein the cocamidopropyl betaine is CAB-35 and CAB-45, and the active matter content is 28% to 47%; the dodecyl dimethyl amine oxide is OB-2, and the active matter content is 30±2%.

[0033] Lithium magnesium silicate, CAS number: 37220-90-9.

[0034] 1. A specific embodiment of a shear-resistant foaming composition of the present invention is as follows:

[0035] Example 1

[0036] The anti-shear foaming composition of this embodiment is composed of a main agent, a thickener and a stabilizer; the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 70% of the mass of the main agent; the amount of the thickener is 0.4% of the mass of the main agent; the amount of the stabilizer is 0.1% of the mass of the main agent; the first zwitterionic surfactant is CAB-35; the second ionic surfactant is OB-2; the thickener is composed of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin, and the mass ratio of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin is 1:1; the stabilizer is composed of lithium magnesium silicate and sodium gluconate, and the mass ratio of lithium magnesium silicate and sodium gluconate is 1:1.

[0037] Example 2

[0038] The anti-shear foaming composition of this embodiment is composed of a main agent, a thickener and a stabilizer; the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 80% of the mass of the main agent; the amount of the thickener is 0.4% of the mass of the main agent; the amount of the stabilizer is 0.1% of the mass of the main agent; the first zwitterionic surfactant is CAB-35; the second ionic surfactant is OB-2; the thickener is composed of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin, and the mass ratio of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin is 1:1; the stabilizer is composed of lithium magnesium silicate and sodium gluconate, and the mass ratio of lithium magnesium silicate and sodium gluconate is 1:1.

[0039] Example 3

[0040] The anti-shear foaming composition of this embodiment is composed of a main agent, a thickener and a stabilizer; the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 80% of the mass of the main agent; the amount of the thickener is 0.2% of the mass of the main agent; the amount of the stabilizer is 0.1% of the mass of the main agent; the first zwitterionic surfactant is CAB-35; the second ionic surfactant is OB-2; the thickener is composed of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin, and the mass ratio of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin is 1:1; the stabilizer is composed of lithium magnesium silicate and sodium gluconate, and the mass ratio of lithium magnesium silicate and sodium gluconate is 1:1.

[0041] Example 4

[0042] The anti-shear foaming composition of this embodiment is composed of a main agent, a thickener and a stabilizer; the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 80% of the mass of the main agent; the amount of the thickener is 0.2% of the mass of the main agent; the amount of the stabilizer is 0.06% of the mass of the main agent; the first zwitterionic surfactant is CAB-35; the second ionic surfactant is OB-2; the thickener is composed of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin, and the mass ratio of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin is 1:1; the stabilizer is composed of lithium magnesium silicate and sodium gluconate, and the mass ratio of lithium magnesium silicate and sodium gluconate is 1:1.

[0043] Example 5

[0044] The anti-shear foaming composition of this embodiment is composed of a main agent, a thickener and a stabilizer; the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 80% of the mass of the main agent; the amount of the thickener is 0.4% of the mass of the main agent; the amount of the stabilizer is 0.06% of the mass of the main agent; the first zwitterionic surfactant is CAB-35; the second ionic surfactant is OB-2; the thickener is composed of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin, and the mass ratio of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin is 1:1; the stabilizer is composed of lithium magnesium silicate and sodium gluconate, and the mass ratio of lithium magnesium silicate and sodium gluconate is 1:1.

[0045] Example 6

[0046] The anti-shear foaming composition of this embodiment is composed of a main agent, a thickener and a stabilizer; the main agent is composed of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 80% of the mass of the main agent; the amount of the thickener is 0.4% of the mass of the main agent; the amount of the stabilizer is 0.1% of the mass of the main agent; the first zwitterionic surfactant is CAB-45; the second ionic surfactant is OB-2; the thickener is composed of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin, and the mass ratio of polyethylene glycol 2000 and hydroxypropyl β-cyclodextrin is 1:1; the stabilizer is composed of lithium magnesium silicate and sodium gluconate, and the mass ratio of lithium magnesium silicate and sodium gluconate is 1:1.

[0047] 2. A specific embodiment of an anti-shear foaming agent of the present invention is as follows:

[0048] Example 7

[0049] The anti-shear foaming agent of this embodiment is composed of the anti-shear foaming composition of embodiment 1, water and antifreeze agent; the weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition is 59.3% of the anti-shear foaming agent.

[0050] The specific formula composition is as follows:

[0051] 70 g of cocamidopropyl betaine (CAB-35), 30 g of dodecyl dimethyl amine oxide (OB-2), 0.2 g of polyethylene glycol 2000, 0.2 g of hydroxypropyl beta-cyclodextrin, 0.05 g of lithium magnesium silicate, 0.05 g of sodium gluconate, 5 g of methanol and 12.5 g of water.

[0052] Preparation process Figure 1 As shown, the specific preparation steps are as follows:

[0053] a. Take 70g of CAB-35 and 30g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A.

[0054] b. Take 0.2g of PEG2000 and 0.2g of carboxypropyl β-cyclodextrin solid powder, mix them evenly, and then slowly add them into 7.6g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 5h until they are completely dissolved to form 8g of solution B.

[0055] c. Take 0.05g of lithium magnesium silicate and 0.05g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.9g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0056] d. Directly mix the solutions A, B and C obtained in steps a, b and c and 5 g of methanol at 45° C. and stir for 2 h to obtain foaming agent 1.

[0057] Example 8

[0058] The anti-shear foaming agent of this embodiment is composed of the anti-shear foaming composition of embodiment 2, water and antifreeze agent; the weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition is 67.8% of the anti-shear foaming agent.

[0059] The specific formula composition is as follows:

[0060] 80g of cocamidopropyl betaine (CAB-35), 20g of dodecyl dimethyl amine oxide (OB-2), 0.2g of polyethylene glycol 2000, 0.2g of hydroxypropyl beta-cyclodextrin, 0.05g of lithium magnesium silicate, 0.05g of sodium gluconate, 5g of methanol and 12.5g of water.

[0061] The specific preparation steps are as follows:

[0062] a. Take 80g of CAB-35 and 20g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A.

[0063] b. Take 0.2g of PEG2000 and 0.2g of carboxypropyl β-cyclodextrin solid powder, mix them evenly, and then slowly add them into 7.6g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 5h until they are completely dissolved to form 8g of solution B.

[0064] c. Take 0.05g of lithium magnesium silicate and 0.05g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.9g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0065] d. Directly mix solution A, solution B, solution C obtained in steps a, b, and c and 5 g of methanol at 45° C. and stir for 2 h to obtain foaming agent 2.

[0066] Example 9

[0067] The anti-shear foaming agent of this embodiment is composed of the anti-shear foaming composition of embodiment 3, water and antifreeze agent; the weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition is 67.8% of the anti-shear foaming agent.

[0068] The specific formula composition is as follows:

[0069] 80 g of cocamidopropyl betaine (CAB-35), 20 g of dodecyl dimethyl amine oxide (OB-2), 0.1 g of polyethylene glycol 2000, 0.1 g of hydroxypropyl beta-cyclodextrin, 0.05 g of lithium magnesium silicate, 0.05 g of sodium gluconate, 5 g of methanol and 12.7 g of water.

[0070] The specific preparation steps are as follows:

[0071] a. Take 80g of CAB-35 and 20g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A.

[0072] b. Take 0.1g of PEG2000 and 0.1g of β-cyclodextrin solid powder, mix them evenly, and then slowly add them into 7.8g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 4h until they are completely dissolved to form 8g of solution B.

[0073] c. Take 0.05g of lithium magnesium silicate and 0.05g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.9g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0074] d. Directly mix the solution A, solution B, solution C obtained in steps a, b, and c and 5 g of methanol at 45° C. and stir for 2 h to obtain foaming agent 3.

[0075] Example 10

[0076] The anti-shear foaming agent of this embodiment is composed of the anti-shear foaming composition of embodiment 4, water and antifreeze agent; the weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition is 67.8% of the anti-shear foaming agent.

[0077] The specific formula composition is as follows:

[0078] 80 g of cocamidopropyl betaine (CAB-35), 20 g of dodecyl dimethyl amine oxide (OB-2), 0.1 g of polyethylene glycol 2000, 0.1 g of hydroxypropyl beta-cyclodextrin, 0.03 g of lithium magnesium silicate, 0.03 g of sodium gluconate, 5 g of methanol and 12.74 g of water.

[0079] The specific preparation steps are as follows:

[0080] a. Take 80g of CAB-35 and 20g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A.

[0081] b. Take 0.1g of PEG2000 and 0.1g of β-cyclodextrin solid powder, mix them evenly, and then slowly add them into 7.8g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 4h until they are completely dissolved to form 8g of solution B.

[0082] c. Take 0.03g of lithium magnesium silicate and 0.03g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.94g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0083] d. Directly mix the solutions A, B and C obtained in steps a, b and c and 5 g of methanol at 45° C. and stir for 2 h to obtain foaming agent 4.

[0084] Embodiment 11

[0085] The anti-shear foaming agent of this embodiment is composed of the anti-shear foaming composition of embodiment 5, water and antifreeze agent; the weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition is 67.8% of the anti-shear foaming agent.

[0086] The specific formula composition is as follows:

[0087] 80 g of cocamidopropyl betaine (CAB-35), 20 g of dodecyl dimethyl amine oxide (OB-2), 0.2 g of polyethylene glycol 2000, 0.2 g of hydroxypropyl beta-cyclodextrin, 0.03 g of lithium magnesium silicate, 0.03 g of sodium gluconate, 5 g of methanol and 12.54 g of water.

[0088] The specific preparation steps are as follows:

[0089] a. Take 80g of CAB-35 and 20g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A.

[0090] b. Take 0.2g of PEG2000 and 0.2g of β-cyclodextrin solid powder, mix them evenly, then slowly add them into 7.6g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 4h until they are completely dissolved to form 8g of solution B.

[0091] c. Take 0.03g of lithium magnesium silicate and 0.03g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.94g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0092] d. Directly mix the solutions A, B and C obtained in steps a, b and c and 5 g of methanol at 45° C. and stir for 2 h to obtain foaming agent 5.

[0093] Example 12

[0094] The anti-shear foaming agent of this embodiment is composed of the anti-shear foaming composition of embodiment 2 and water; the first zwitterionic surfactant in the anti-shear foaming composition accounts for 70.8% of the weight percentage of the anti-shear foaming agent.

[0095] The specific formula composition is as follows:

[0096] 80 g of cocamidopropyl betaine (CAB-35), 20 g of dodecyl dimethyl amine oxide (OB-2), 0.2 g of polyethylene glycol 2000, 0.2 g of hydroxypropyl beta-cyclodextrin, 0.05 g of lithium magnesium silicate, 0.05 g of sodium gluconate and 12.5 g of water.

[0097] The specific preparation steps are as follows:

[0098] a. Take 80g of CAB-35 and 20g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A.

[0099] b. Take 0.2g of PEG2000 and 0.2g of β-cyclodextrin solid powder, mix them evenly, then slowly add them into 7.6g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 4h until they are completely dissolved to form 8g of solution B.

[0100] c. Take 0.05g of lithium magnesium silicate and 0.05g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.9g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0101] d. Directly mix the solutions A, B and C obtained in steps a, b and c and 0 g of methanol at 45° C. and stir for 2 h to obtain foaming agent 6.

[0102] Embodiment 13

[0103] The anti-shear foaming agent of this embodiment is composed of the anti-shear foaming composition of embodiment 2, water and antifreeze agent; the weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition is 67.8% of the anti-shear foaming agent.

[0104] The specific formula composition is as follows:

[0105] 80g of cocamidopropyl betaine (CAB-45), 20g of dodecyl dimethyl amine oxide (OB-2), 0.2g of polyethylene glycol 2000, 0.2g of hydroxypropyl beta-cyclodextrin, 0.05g of lithium magnesium silicate, 0.05g of sodium gluconate, 5g of methanol and 12.5g of water.

[0106] The specific preparation steps are as follows:

[0107] a. Take 80g of CAB-45 and 20g of OB-2, mix them directly at 45°C and stir slowly for 1h to form 100g of solution A.

[0108] b. Take 0.2g of PEG2000 and 0.2g of carboxypropyl β-cyclodextrin solid powder, mix them evenly, and then slowly add them into 7.6g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 5h until they are completely dissolved to form 8g of solution B.

[0109] c. Take 0.05g of lithium magnesium silicate and 0.05g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.9g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0110] d. Directly mix the solutions A, B and C obtained in steps a, b and c and 5 g of methanol at 45° C. and stir for 2 h to obtain foaming agent 7.

[0111] 3. Comparison

[0112] Comparative Example 1

[0113] The difference between the foaming agent of this comparative example and the anti-shear foaming agent of Example 8 is that polyethylene glycol 2000 is replaced with detergent 6501. The specific formula composition is as follows:

[0114] 80g of cocamidopropyl betaine (CAB-35), 20g of dodecyl dimethyl amine oxide (OB-2), 10.2g of detergent 650, 0.2g of hydroxypropyl beta-cyclodextrin, 0.05g of lithium magnesium silicate, 0.05g of sodium gluconate, 5g of methanol and 12.5g of water.

[0115] The specific preparation steps are as follows:

[0116] a. Take 80g of CAB-35 and 20g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A;

[0117] b. Take 0.2g of detergent 6501 and 0.2g of carboxypropyl β-cyclodextrin solid powder, mix them evenly, then slowly add them to 7.6g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 5h until they are completely dissolved to form 8g of solution B.

[0118] c. Take 0.05g of lithium magnesium silicate and 0.05g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.9g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0119] d. Directly mix the solutions A, B and C obtained in steps a, b and c and 5 g of methanol at 45° C. and stir for 2 h to obtain the foaming agent 1-1.

[0120] Comparative Example 2

[0121] The difference between the foaming agent of this comparative example and the anti-shear foaming agent of Example 8 is that lithium magnesium silicate is replaced with silicon dioxide (particle size less than 100 nm), and the specific formula composition is as follows:

[0122] 80g of cocamidopropyl betaine (CAB-35), 20g of dodecyl dimethyl amine oxide (OB-2), 0.2g of polyethylene glycol 2000, 0.2g of hydroxypropyl beta-cyclodextrin, 0.05g of silicon dioxide, 0.05g of sodium gluconate, 5g of methanol and 12.5g of water.

[0123] The specific preparation steps are as follows:

[0124] a. Take 80g of CAB-35 and 20g of OB-2 and mix them directly at 45°C and stir slowly for 1h to form 100g of solution A;

[0125] b. Take 0.2g of PEG2000 and 0.2g of carboxypropyl β-cyclodextrin solid powder, mix them evenly, and then slowly add them into 7.6g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 5h until they are completely dissolved to form 8g of solution B.

[0126] c. Take 0.05g of silicon dioxide and 0.05g of sodium gluconate solid powder, mix them evenly, then slowly add them to 4.9g of deionized water at 80°C while stirring continuously. Continue stirring for 8h until they are completely dissolved to form 5g of solution C.

[0127] d. Directly mix the solutions A, B and C obtained in steps a, b and c and 5 g of methanol at 45° C. and stir for 2 h to obtain the foaming agent 1-2.

[0128] Comparative Example 3

[0129] The difference between the foaming agent of this comparative example and the anti-shear foaming agent of Example 8 is that cocamidopropyl betaine is replaced with sodium α-olefin sulfonate, and polyethylene glycol 2000 is replaced with sodium lauryl sulfate. The specific formula composition is as follows:

[0130] 6 g of sodium α-olefin sulfonate, 20 g of dodecyl dimethyl amine oxide (OB-2), 0.2 g of sodium lauryl sulfate, 0.2 g of hydroxypropyl β-cyclodextrin, 0.05 g of silicon dioxide, 0.05 g of sodium gluconate, 5 g of methanol and 26.5 g of water.

[0131] The specific preparation steps are as follows:

[0132] a. Dissolve 6 g of sodium α-olefin sulfonate in 14 g of water and stir slowly for 1 h to form 20 g of aqueous solution A;

[0133] b. Take 80g of CAB-35 and 20g of solution A and mix them directly at 45°C and stir slowly for 1h to form 100g of solution B;

[0134] c. Take 0.2 g of sodium dodecyl sulfate and 0.2 g of carboxypropyl β-cyclodextrin solid powder, mix them evenly, then slowly add them to 7.6 g of deionized water at 60°C while stirring continuously. After adding, continue stirring for 5 hours until they are completely dissolved to form 8 g of solution C.

[0135] d. Take 0.05 g of lithium magnesium silicate and 0.05 g of sodium gluconate solid powder, mix them evenly, and slowly add them to 4.9 g of deionized water at 80°C while stirring continuously. Continue stirring for 8 h until they are completely dissolved to form 5 g of solution D.

[0136] e. Directly mix the solution B, solution C, solution D obtained in steps b, c, and d and 5 g of methanol at 45° C. and stir for 2 h to obtain the foaming agent 1-3.

[0137] IV. Experimental Example Application of Shear-Resistant Foaming Composition or Shear-Resistant Foaming Agent in Foam Water Drainage and Gas Production in Natural Gas Wells

[0138] Experimental Example 1

[0139] In this experimental example, the foaming performance and foam carrying performance of the foaming agents 1 to 7 prepared in Examples 7 to 13 and the foaming agents 1-1 to 1-3 prepared in Comparative Examples 1 to 3 were evaluated.

[0140] (1) Using a Ross-Miles instrument, 50000 mg / L and 200000 mg / L standard solutions (composed of sodium chloride, calcium chloride and magnesium chloride, where the mass ratio of NaCl: CaCl2: MgCl2·6H2O is 7: 0.6: 0.4) were used to carry out foaming performance and liquid carrying performance experiments at 80°C. The performance test results of foaming agents 1 to 6 and foaming agents 1-1 to 1-3 are shown in Tables 1 and 2. Among them, the foaming power and foam stabilization power were determined according to the Ross-Miles method in GB / T13173-2021 Test Method for Surfactant Detergents, and the liquid carrying performance was tested according to the liquid carrying capacity determination method in the standard QSH CG0.135-2021 Technical Requirements for Foaming Agents.

[0141] Table 1 Foaming performance and liquid carrying performance test results at 80℃ and 50000mg / L standard solution

[0142] Foaming force(mm) Foam stability(mm) Liquid carrying rate (%) Foaming agent 1 178 178 98.5 Foaming agent 2 182 182 99.3 Foaming agent 3 175 175 97.6 Foaming agent 4 173 173 97.3 Foaming agent 5 177 177 98.3 Foaming agent 6 179 179 98.6 Foaming agent 7 185 185 99.8 Foaming agent 1-1 167 159 99.3 Foaming agent 1-2 169 164 87.5 Foaming agent 1-3 161 152 85.3

[0143] Table 2 Foaming performance and liquid carrying performance test results at 80℃ and 200000mg / L standard solution

[0144]

[0145]

[0146] (2) Using a high-temperature and high-pressure reactor, the foaming agent was aged for 24 hours at 2MPa (pressurized to 2MPa with nitrogen to keep the liquid in a liquid phase at 130°C to avoid evaporation of the solution) and 130°C, and then a Ross-Miles instrument was used to carry out foaming performance and liquid carrying performance experiments at 80°C using 50000mg / L and 200000mg / L standard solutions (composed of sodium chloride, calcium chloride and magnesium chloride, where the mass ratio of NaCl:CaCl2:MgCl2·6H2O is 7:0.6:0.4). The performance test results of foaming agents 1 to 6 and foaming agents 1-1 to 1-3 are shown in Tables 3 and 4. Among them, the foaming power and foam stabilization power were determined according to the Ross-Miles method in GB / T13173-2021 Test Methods for Surfactant Detergents, and the liquid carrying performance was tested according to the liquid carrying capacity determination method in the standard QSH CG0.135-2021 Technical Requirements for Foaming Agents.

[0147] Table 3 Foaming performance and liquid carrying performance test results at 80℃ and 50000mg / L standard solution after aging

[0148] Foaming force(mm) Foam stability(mm) Liquid carrying rate (%) Foaming agent 1 177 177 97.2 Foaming agent 2 180 180 98.8 Foaming agent 3 173 173 96.8 Foaming agent 4 172 172 97.1 Foaming agent 5 176 176 98.1 Foaming agent 6 178 178 98.6 Foaming agent 7 185 185 99.7 Foaming agent 1-1 163 150 90.2 Foaming agent 1-2 166 150 86.0 Foaming agent 1-3 157 150 82.6

[0149] Table 4 Foaming performance and liquid carrying performance test results at 80℃ and 200000mg / L standard solution after aging

[0150]

[0151]

[0152] (3) Using a high-temperature and high-pressure foam performance evaluation device, 50,000 mg / L and 200,000 mg / L standard solutions (composed of sodium chloride, calcium chloride and magnesium chloride, with a mass ratio of NaCl:CaCl2:MgCl2·6H2O of 7:0.6:0.4) were stirred at 130°C and 10 MPa (pressurized to 10 MPa with nitrogen) at a speed of 3200 r / min to carry out high-temperature and high-pressure foaming performance and liquid carrying performance experiments. Among them, the liquid carrying performance test was carried out according to the liquid carrying capacity determination method in the standard QSH CG0.135-2021 foaming agent technical requirements. The specific operation of the foaming performance test is:

[0153] Transfer 250mL of foaming agent solution (the concentration of the foaming agent is about 3% (volume ratio): prepare 1000mL of standard solution, then add 3mL of foaming agent solution, mix evenly and set aside; during the experiment, take out 250mlL from the 1003mL mixed solution to carry out relevant foaming agent performance evaluation experiments, where the standard solution is composed of sodium chloride, calcium chloride and magnesium chloride, and the mass ratio of NaCl:CaCl2:MgCl2·6H2O is 7:0.6:0.4) into a high-temperature and high-pressure visual reactor with a high-speed stirring device, and pressurize it to 10MPa with nitrogen, heat it to 130℃ with oil bath circulation, turn on the stirring motor after the pressure and temperature reach the experimental conditions, set the stirring speed to 3200r / min, stop stirring after stirring for 3min, and read the initial foam height (foaming power) and the foam height (stable foam power) after 5min through the visual window.

[0154] The performance test results of foaming agents 1 to 6 and foaming agents 1-1 to 1-3 are shown in Tables 5 and 6.

[0155] Table 5 Experimental results of high temperature and high pressure foaming performance and liquid carrying performance 1

[0156]

[0157]

[0158] Table 6 Experimental results of high temperature and high pressure foaming performance and liquid carrying performance 2

[0159] Foaming force(mm) Foam stability(mm) Liquid carrying rate (%) Foaming agent 1 190 190 98.5 Foaming agent 2 193 193 98.9 Foaming agent 3 187 187 98.9 Foaming agent 4 186 186 98.1 Foaming agent 5 191 191 98.8 Foaming agent 6 194 194 99.0 Foaming agent 7 198 198 99.6 Foaming agent 1-1 171 171 93.0 Foaming agent 1-2 170 170 86.8 Foaming agent 1-3 162 162 82.7

[0160] (4) Freeze resistance test

[0161] After being frozen at -18°C for 24 hours, foaming agents 1 to 5, 7 and 1-1 to 1-3 were still flowable liquids, showing good antifreeze properties. However, foaming agent 6 lost its fluidity after being frozen at -18°C for 1 hour, indicating that it had no antifreeze properties.

[0162] Experimental Example 2

[0163] This experimental example is the field application effect of the foaming agent of the present invention. The experimental site is a high-temperature gas well in the Ordos Basin. The reservoir temperature at the bottom of the well is 132°C. The foaming agent is added to a high-temperature gas well in the Ordos Basin for drainage and gas production using an automatic wellhead dosing device. The gas well was previously produced using a conventional foaming agent (model: SPR-01, manufacturer: Dongying Shipurui Petroleum Engineering Technology Co., Ltd.). The conventional foaming agent solution was added twice a day at 11:00 and 20:00 through the automatic wellhead dosing device, 37.5 liters of each, a total of 75 liters of agent solution (the foaming agent and water were prepared in a ratio of 1:4), and the daily production of gas was 6506 cubic meters and the daily production of liquid was 1.6 cubic meters. The foaming agent solution in the filling device was replaced with the foaming agent of Example 9 of the present invention. The same system was adopted, and 37.5 liters of the foaming agent solution of the present invention were added twice a day at 11:00 and 20:00, for a total of 75 liters of agent solution (the foaming agent and water were prepared in a ratio of 1:4). The daily gas production was 7792 cubic meters and the daily liquid production was 2.0 cubic meters. Through the comparison of production effects, the foaming agent of the present invention has a good effect of increasing liquid production.

[0164] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A shear-resistant foaming composition, characterized in that: The anti-shear foaming composition consists of a main agent, a thickener and a stabilizer; the main agent consists of a first zwitterionic surfactant and a second ionic surfactant; the first zwitterionic surfactant accounts for 70-80% of the mass of the main agent; the thickener is used in an amount of 0.2-0.4% of the mass of the main agent; the stabilizer is used in an amount of 0.06-0.1% of the mass of the main agent; the first zwitterionic surfactant is cocamidopropyl betaine; and the second ionic surfactant is dodecyl dimethyl amine oxide.

2. The shear-resistant foaming composition according to claim 1, characterized in that: The stabilizer consists of lithium magnesium silicate and sodium gluconate; the mass ratio of the lithium magnesium silicate to the sodium gluconate is 1:(1-1.1).

3. The shear-resistant foaming composition according to claim 1, characterized in that: The thickener consists of polyethylene glycol 2000 and hydroxypropyl beta-cyclodextrin; the mass ratio of the polyethylene glycol 2000 to hydroxypropyl beta-cyclodextrin is 1:(1-1.1).

4. An anti-shear foaming agent, characterized in that: The invention comprises the anti-shear foaming composition according to any one of claims 1 to 3 and water.

5. The anti-shear foaming agent according to claim 4, characterized in that: The weight percentage of the first zwitterionic surfactant in the anti-shear foaming composition to the anti-shear foaming agent is 59-71%.

6. The anti-shear foaming agent according to claim 4 or 5, characterized in that: The anti-shear foaming agent includes an antifreeze agent.

7. The anti-shear foaming agent according to claim 6, characterized in that: The amount of the antifreeze agent is 0-5% of the mass of the main agent.

8. Use of the anti-shear foaming composition according to any one of claims 1 to 3 or the anti-shear foaming agent according to any one of claims 4 to 7 in foam drainage and gas production in natural gas wells.

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