A foaming agent for nitrogen foam cementing and preparation method thereof

Abstract

The present invention belongs to the technical field of petroleum extraction, and specifically relates to a nitrogen foam cementing foaming agent and a preparation method thereof. The preparation method is as follows: add tris(hydroxymethyl)aminomethane, ethanol, and dodecyl halide to a reactor, stir evenly, heat and insulate to react, and adjust the pH; add benzyl halide to the reactor, stir evenly, heat and insulate to react, and adjust the pH; vacuum distill to obtain a viscous liquid, add toluene to dissolve and transfer to a high-pressure reactor, add a catalyst, close the reactor, stir and heat, evacuate, introduce ethylene oxide, after the introduction is completed, heat, stop heating when the pressure no longer drops, and cool the system; adjust the pH, add aminosulfonic acid powder, heat and insulate while stirring to react, and cool; filter, vacuum distill to obtain a viscous solid, that is, a cementing foaming agent product. The cementing foaming agent of the present invention has the advantages of large foaming volume and long half-life.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum exploitation, and in particular relates to a foaming agent for nitrogen foam cementing and a preparation method thereof. Background Art

[0002] Foam fluid is widely used in oilfield exploitation due to its low density, high viscosity and unique rheological properties, such as foam drilling, foam cementing, foam acidizing, foam fracturing, foam sand flushing, foam profile control, foam oil recovery, etc.

[0003] Among them, foam cementing technology is an advanced technology widely used in oil and gas well development. Its core lies in injecting foaming agents, foam stabilizers and nitrogen into cement slurry to form foam cement slurry with stable density and uniform mixing. This technology not only improves the displacement capacity of cement slurry, but also avoids the damage caused by shear stress of cement shell caused by temperature and pressure, thereby effectively improving the cementing quality.

[0004] The main function of the foaming agent is to form a stable and uniform foam structure in the cement slurry, which can significantly reduce the density of the cement slurry and improve the fluidity and displacement capacity of the cement slurry. At the same time, the foaming agent can also enhance the thermal insulation capacity of the foam cement slurry, effectively maintain the temperature of the gas and liquid during the oil and gas production process, reduce the salt precipitation rate, and improve the production efficiency of oil and gas wells.

[0005] As a key component in foam cementing technology, the performance of foaming agent directly affects the stability and performance of foam cement slurry. Therefore, the development of new, efficient, stable and environmentally friendly foaming agent is of great significance to promote the development of foam cementing technology.

[0006] CN1046150A discloses a cement foaming agent for oil and gas well cementing and its preparation method. The cement foaming agent is composed of metal aluminum powder, non-polar organic compound encapsulant and auxiliary agent, can be stored for a long time in the temperature range of -20℃ to 40℃, has good compatibility with other cement additives for cementing, and basically does not react when the temperature is lower than 40℃ when directly mixed with slurry. After entering the predetermined well section, the encapsulant gradually melts away, so that the aluminum powder reacts with the cement slurry to produce uniform bubbles, thereby compensating for the decrease in static liquid column pressure during the solidification process of the cement slurry. Preventing the occurrence of annular air leakage. Its preparation method adopts a melt-mixed solvent-free encapsulation process, and the required equipment is simple. However, the main component of the gas produced by the foaming agent is hydrogen, the cementing effect is not good, and there are safety hazards, so it cannot be promoted in actual production.

[0007] CN104312563B discloses a cationic micro-bubble surfactant for drilling fluid and a preparation method thereof, which is obtained by mixing a vinyl cationic monomer and a vinyl amide compound in a mass ratio of 10:1-10, adding a relative molecular mass regulator, and performing free radical copolymerization, and the average relative molecular mass is between 1000 and 4000. However, the foaming performance and foam stabilization performance are poor, and the effect in actual application is difficult to meet the on-site requirements. Summary of the invention

[0008] The present invention aims at the above-mentioned deficiencies of the prior art and provides a nitrogen foam cementing foaming agent and a preparation method thereof. The cementing foaming agent of the present invention has the advantages of large foaming volume and long half-life.

[0009] One of the purposes of the present invention is to disclose a method for preparing a nitrogen foam cementing foaming agent, wherein the specific steps of the preparation method are as follows:

[0010] (1) Add tris(hydroxymethyl)aminomethane, ethanol and dodecyl halide into the reactor, stir evenly, heat and keep warm for reaction, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0011] (2) Add benzyl halide to the above reactor, stir evenly, heat and keep warm for reaction, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0012] (3) Vacuum distillation to obtain a viscous liquid, add toluene to dissolve and transfer to a high-pressure reactor, add a catalyst, purge the reactor and pipelines with nitrogen for 2-3 minutes, close the reactor, stir and heat to 70-80°C, evacuate, and introduce ethylene oxide. After the introduction is completed, the temperature is raised to 150-180°C, and the reaction pressure gradually decreases. When the pressure no longer decreases, stop heating and use circulating cooling water to cool the system to below 50°C;

[0013] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add sulfamic acid powder into the above autoclave, heat and keep the reaction while stirring, and cool to below 40° C.

[0014] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0015] Preferably, based on 1 mol part of tris(hydroxymethyl)aminomethane, the amounts of dodecyl halide, benzyl halide, ethylene oxide and aminosulfonic acid are 0.8-1.2 mol parts, 0.8-1.2 mol parts, 15-60 mol parts and 1-3.6 mol parts respectively.

[0016] More preferably, based on 1 mol part of tris(hydroxymethyl)aminomethane, the amounts of dodecyl halide, benzyl halide, ethylene oxide and aminosulfonic acid are 0.9-1.1 mol parts, 0.9-1.1 mol parts, 30-60 mol parts and 1.5-3.3 mol parts respectively.

[0017] Preferably, the dodecyl halide is dodecyl chloride or dodecyl bromide, and the benzyl halide is benzyl chloride or benzyl bromide.

[0018] More preferably, the dodecyl halide is dodecyl bromide, and the benzyl halide is benzyl bromide.

[0019] Preferably, the mass ratio of ethanol, toluene and tris(hydroxymethyl)aminomethane is 20-40:2-3:1.

[0020] Preferably, the temperature of the heating and heat preservation reaction in step (1) is 40-60° C. and the time is 30-60 min.

[0021] Preferably, the temperature of the heating and heat preservation reaction in step (2) is 50-70° C. and the time is 30-60 min.

[0022] Preferably, the temperature of the heating and heat preservation reaction in step (4) is 120-140° C. and the time is 60-120 min.

[0023] Preferably, the catalyst in step (3) is one of sodium hydroxide, calcium hydroxide and potassium hydroxide, and the mass ratio of the catalyst to tris(hydroxymethyl)aminomethane is 0.2-0.6:1.

[0024] The synthetic reaction equation of the foaming agent for cementing of the present invention is as follows:

[0025] or or Wherein, X is Cl or Br.

[0026] Another object of the present invention is to disclose a foaming agent for nitrogen foam cementing, wherein the molecular structure of the foaming agent is as follows:

[0027] , and One or more of the following, where n=5-20.

[0028] The foaming agent for cementing of the present invention is a composite surfactant. The lipophilic groups are classic dodecyl and benzyl, and the hydrophilic groups are nonionic polyoxyethylene ether and anionic sulfate groups. When the solution containing the present invention is stirred or bubbled, air will enter the solution to form bubbles. The adsorption of the present invention on the gas-liquid interface reduces the surface tension between the gas and the liquid, which makes the formation of bubbles easier and improves the stability of the bubbles. The present invention is more active than conventional single-active group surfactants, can greatly reduce surface tension, increase foaming volume and capacity, and has higher stability. The molecules are multilinear molecules, have strong flexibility, and cover a large area. When the foam liquid film becomes thinner, it can quickly attract other parts of the liquid film laterally to supplement and enhance the stability of the foam.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] (1) The foaming agent for cementing of the present invention has the characteristic of large foaming volume, which can reach 780 ml or more at room temperature, and the foaming volume can reach 770 ml or more after rolling at 120 ° C / 16 h;

[0031] (2) The foaming agent for cementing of the present invention has the characteristic of a long half-life, which reaches 1020 seconds or more at room temperature, and the half-life reaches more than 1000 seconds after rolling at 120°C / 16 h. DETAILED DESCRIPTION

[0032] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0033] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0034] Example 1

[0035] (1) Add 0.05 mol tris(hydroxymethyl)aminomethane, 121 g ethanol, and 0.04 mol dodecyl chloride into the reactor, stir evenly, heat to 50°C, keep warm for 30 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0036] (2) Add 0.04 mol of benzyl chloride to the above reactor, stir evenly, heat to 60°C, keep warm for 40 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0037] (3) Vacuum distillation to obtain a viscous liquid, add 12.1 g of toluene to dissolve and transfer to a high-pressure reactor, add 1.21 g of sodium hydroxide, purge the reactor and pipelines with nitrogen for 2-3 minutes, close the reactor, stir and heat to 70°C, evacuate, and introduce 0.75 mol of ethylene oxide. After the introduction is complete, the temperature is raised to 150°C, and the reaction pressure gradually decreases. When the pressure no longer decreases, stop heating and use circulating cooling water to cool the system to below 50°C;

[0038] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add 0.05 mol of aminosulfonic acid powder into the above autoclave, heat to 120° C. while stirring, keep the temperature for 90 min, and cool to below 40° C.;

[0039] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0040] Example 2

[0041] (1) Add 0.05 mol tris(hydroxymethyl)aminomethane, 242 g ethanol, and 0.06 mol dodecyl chloride into the reactor, stir evenly, heat to 60°C, keep warm for 30 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0042] (2) Add 0.045 mol of benzyl chloride to the above reactor, stir evenly, heat to 50°C, keep warm for 60 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0043] (3) Vacuum distillation to obtain a viscous liquid, add 18.15 g of toluene to dissolve and transfer to a high-pressure reactor, add 1.87 g of sodium hydroxide, purge the reactor and pipelines with nitrogen for 2-3 minutes, close the reactor, stir and heat to 78°C, evacuate, and introduce 1.2 mol of ethylene oxide. After the introduction is complete, the temperature is raised to 160°C, and the reaction pressure gradually decreases. When the pressure no longer decreases, stop heating and use circulating cooling water to cool the system to below 50°C;

[0044] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add 0.08 mol of aminosulfonic acid powder into the above autoclave, heat to 120° C. while stirring, keep the temperature for 90 min, and cool to below 40° C.;

[0045] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0046] Example 3

[0047] (1) Add 0.05 mol tris(hydroxymethyl)aminomethane, 165 g ethanol, and 0.045 mol dodecyl chloride into the reactor, stir evenly, heat to 40°C, keep warm for 60 min, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0048] (2) Add 0.06 mol of benzyl chloride to the above reactor, stir evenly, heat to 70°C, keep warm for 30 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0049] (3) A viscous liquid was obtained by vacuum distillation, 14.7 g of toluene was added to dissolve the liquid and transferred to a high-pressure reactor, 2.14 g of sodium hydroxide was added, the reactor and pipeline were purged with nitrogen for 2-3 min, the reactor was closed, stirred and heated to 72°C, vacuumed, 1.5 mol of ethylene oxide was introduced, and after the introduction was completed, the temperature was raised to 160°C, and the reaction pressure gradually decreased. When the pressure no longer decreased, the heating was stopped and the system was cooled to below 50°C using circulating cooling water;

[0050] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add 0.1 mol of aminosulfonic acid powder into the above autoclave, heat to 130° C. while stirring, keep the temperature for 60 min, and cool to below 40° C.;

[0051] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0052] Example 4

[0053] (1) Add 0.05 mol tris(hydroxymethyl)aminomethane, 221 g ethanol, and 0.055 mol dodecyl chloride into the reactor, stir evenly, heat to 50°C, keep warm for 40 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0054] (2) Add 0.045 mol of benzyl chloride to the above reactor, stir evenly, heat to 65°C, keep warm for 40 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0055] (3) Vacuum distillation to obtain a viscous liquid, add 16.1 g of toluene to dissolve and transfer to a high-pressure reactor, add 2.91 g of calcium hydroxide, purge the reactor and pipelines with nitrogen for 2-3 minutes, close the reactor, stir and heat to 80°C, evacuate, and introduce 1.8 mol of ethylene oxide. After the introduction is complete, the temperature is raised to 170°C, and the reaction pressure gradually decreases. When the pressure no longer decreases, stop heating and use circulating cooling water to cool the system to below 50°C;

[0056] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add 0.18 mol of aminosulfonic acid powder into the above autoclave, heat to 130° C. while stirring, keep the temperature for 70 min, and cool to below 40° C.

[0057] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0058] Example 5

[0059] (1) Add 0.05 mol tris(hydroxymethyl)aminomethane, 188 g ethanol, and 0.047 mol dodecyl chloride into the reactor, stir evenly, heat to 55°C, keep warm for 35 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0060] (2) Add 0.055 mol of benzyl chloride to the above reactor, stir evenly, heat to 60°C, keep warm for 40 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0061] (3) Vacuum distillation to obtain a viscous liquid, add 15 g of toluene to dissolve it and transfer it to a high-pressure reactor, add 3.02 g of calcium hydroxide, purge the reactor and pipelines with nitrogen for 2-3 minutes, close the reactor, stir and heat it to 70°C, evacuate, and introduce 2.2 mol of ethylene oxide. After the introduction is complete, the temperature is raised to 170°C, and the reaction pressure gradually decreases. When the pressure no longer decreases, stop heating and use circulating cooling water to cool the system to below 50°C;

[0062] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add 0.13 mol of aminosulfonic acid powder into the above autoclave, heat to 135° C. while stirring, keep the temperature for 100 min, and cool to below 40° C.

[0063] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0064] Example 6

[0065] (1) Add 0.05 mol tris(hydroxymethyl)aminomethane, 191 g ethanol, and 0.052 mol dodecyl bromide into the reactor, stir evenly, heat to 45°C, keep warm for 30 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0066] (2) Add 0.05 mol of benzyl bromide to the above reactor, stir evenly, heat to 55°C, keep warm for 60 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0067] (3) A viscous liquid was obtained by vacuum distillation, 14 g of toluene was added to dissolve the liquid and the liquid was transferred to a high-pressure reactor, 3.41 g of potassium hydroxide was added, the reactor and pipeline were purged with nitrogen for 2-3 min, the reactor was closed, the reaction mixture was stirred and the temperature was raised to 75°C, vacuumed, and 2.5 mol of ethylene oxide was introduced. After the introduction was completed, the temperature was raised to 180°C, and the reaction pressure gradually decreased. When the pressure no longer decreased, the heating was stopped, and the system was cooled to below 50°C using circulating cooling water;

[0068] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add 0.165 mol of aminosulfonic acid powder into the above autoclave, heat to 140° C. while stirring, keep the temperature for 120 min, and cool to below 40° C.;

[0069] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0070] Example 7

[0071] (1) Add 0.05 mol tris(hydroxymethyl)aminomethane, 214 g ethanol, and 0.05 mol dodecyl bromide into the reactor, stir evenly, heat to 50°C, keep warm for 40 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0072] (2) Add 0.052 mol of benzyl bromide to the above reactor, stir evenly, heat to 60°C, keep warm for 50 minutes, and adjust and maintain the pH at 8-9 with sodium hydroxide;

[0073] (3) A viscous liquid was obtained by vacuum distillation, 15 g of toluene was added to dissolve the liquid and the liquid was transferred to a high-pressure reactor, 3.63 g of potassium hydroxide was added, the reactor and pipeline were purged with nitrogen for 2-3 min, the reactor was closed, the reaction mixture was stirred and the temperature was raised to 70°C, vacuumed, and 3 mol of ethylene oxide was introduced. After the introduction was completed, the temperature was raised to 180°C, and the reaction pressure gradually decreased. When the pressure no longer decreased, the heating was stopped, and the system was cooled to below 50°C using circulating cooling water;

[0074] (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add 0.155 mol of aminosulfonic acid powder into the above autoclave, heat to 125° C. while stirring, keep the temperature for 100 min, and cool to below 40° C.

[0075] (5) Filter and distill under reduced pressure to obtain a viscous solid, which is the foaming agent product for cementing.

[0076] Example 8 Foaming agent performance test

[0077] The foaming agent for cementing of the present invention (Examples 1-7) was configured to a concentration of 0.1 wt %, and the room temperature foaming volume, room temperature foam half-life, foaming volume after rolling at 120 ° C / 16 h, and foam half-life after rolling at 120 ° C / 16 h were tested with reference to the method of Q / SH10201873-2015 "General Technical Conditions for Foaming Agents for Drilling Fluids". The test results are shown in Table 1.

[0078] At the same time, Guangzhou Zhonghai Oilfield cementing high-efficiency foaming agent 01 oilfield foaming agent was used for comparative experiments.

[0079] Table 1 Foaming performance test results

[0080]

[0081] From Table 1 we can see that:

[0082] (1) The nitrogen foam cementing foaming agent of the present invention has the characteristic of large foaming volume. When the concentration is 0.1wt% and the foaming volume is 780ml or more at room temperature, the maximum is 880ml (Examples 6 and 7), while the foaming volume of the comparative example is 425ml; after rolling at 120℃ / 16h, the foaming volume is 770ml or more, the maximum is 875ml (Example 6), while the foaming volume of the comparative example after rolling at 120℃ / 16h is 410ml, which is significantly lower than that of the present invention.

[0083] (2) The nitrogen foam cementing frother of the present invention has the characteristic of a long half-life. When the concentration is 0.1wt% and the half-life is at room temperature, it reaches 1020s or more, and the maximum is 1240s (Example 6), while the half-life of the comparative example is 520s. After rolling at 120℃ / 16h, it reaches more than 1000s, and the maximum is 1210s (Example 6), while the half-life of the comparative example after rolling at 120℃ / 16h is 496s, which is significantly lower than that of the present invention.

[0084] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0085] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0086] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a foaming agent for nitrogen foam cementing, characterized in that: The specific steps of the preparation method are as follows: (1) Add tris(hydroxymethyl)aminomethane, ethanol and dodecyl halide into the reactor, stir evenly, heat and keep warm for reaction, and adjust and maintain the pH at 8-9 with sodium hydroxide; (2) Add benzyl halide to the above reactor, stir evenly, heat and keep warm for reaction, and adjust and maintain the pH at 8-9 with sodium hydroxide; (3) Vacuum distillation to obtain a viscous liquid, add toluene to dissolve and transfer to a high-pressure reactor, add a catalyst, purge the reactor and pipelines with nitrogen for 2-3 minutes, close the reactor, stir and heat to 70-80°C, evacuate, and introduce ethylene oxide. After the introduction is completed, the temperature is raised to 150-180°C, and the reaction pressure gradually decreases. When the pressure no longer decreases, stop heating and use circulating cooling water to cool the system to below 50°C; (4) Adjust the pH to 2-3 with 50 wt % sulfuric acid, add sulfamic acid powder into the above autoclave, heat and keep the reaction while stirring, and cool to below 40° C. (5) filtering and distilling under reduced pressure to obtain a viscous solid, i.e., a foaming agent product for cementing; Based on 1 mol part of tris(hydroxymethyl)aminomethane, the amounts of dodecyl halide, benzyl halide, ethylene oxide and aminosulfonic acid used are 0.8-1.2 mol parts, 0.8-1.2 mol parts, 15-60 mol parts and 1-3.6 mol parts respectively.

2. The method for preparing a nitrogen foam cementing foaming agent according to claim 1, characterized in that: Based on 1 mol part of tris(hydroxymethyl)aminomethane, the amounts of dodecyl halide, benzyl halide, ethylene oxide and aminosulfonic acid used are 0.9-1.1 mol parts, 0.9-1.1 mol parts, 30-60 mol parts and 1.5-3.3 mol parts respectively.

3. The method for preparing a nitrogen foam cementing foaming agent according to claim 1, characterized in that: The dodecyl halide is dodecyl chloride or dodecyl bromide, and the benzyl halide is benzyl chloride or benzyl bromide.

4. The method for preparing a nitrogen foam cementing foaming agent according to claim 3, characterized in that: The dodecyl halide is dodecyl bromide, and the benzyl halide is benzyl bromide.

5. The method for preparing a nitrogen foam cementing foaming agent according to claim 1, characterized in that: The mass ratio of the ethanol, toluene and tris(hydroxymethyl)aminomethane is 20-40:2-3:

1.

6. The method for preparing a nitrogen foam cementing foaming agent according to claim 1, characterized in that: The temperature of the heating and heat preservation reaction in step (1) is 40-60°C and the time is 30-60 minutes.

7. The method for preparing a nitrogen foam cementing foaming agent according to claim 1, characterized in that: The temperature of the heating and heat preservation reaction in step (2) is 50-70°C and the time is 30-60 minutes.

8. The method for preparing a nitrogen foam cementing foaming agent according to claim 1, characterized in that: The catalyst in step (3) is one of sodium hydroxide, calcium hydroxide and potassium hydroxide, and the mass ratio of the catalyst to tris(hydroxymethyl)aminomethane is 0.2-0.6:

1.

9. The method for preparing a nitrogen foam cementing foaming agent according to claim 1, characterized in that: The temperature of the heating and heat preservation reaction in step (4) is 120-140°C and the time is 60-120 minutes.

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