Temperature-resistant and salt-resistant foaming agent for drilling and synthesis method thereof

Abstract

The application belongs to the technical field of oil and gas field development, and particularly relates to a temperature-resistant and salt-resistant foaming agent for drilling and a synthesis method thereof. The synthesis method is as follows: diphenylamine-4-sodium sulfonate, isopropyl alcohol and 1,3-dibromopropane are added into a four-necked flask, stirred, heated and refluxed to obtain a mixed solution; 90-95wt% of isopropyl alcohol in the mixed solution is distilled off under reduced pressure, distilled water is added, and the whole is transferred into a separatory funnel, fully shaken, separated, and a small amount of oil phase is discarded; the pH is adjusted to 2-3, a precipitate is separated out, suction filtration is performed, and an intermediate is obtained; the intermediate is transferred into a four-necked flask with isopropyl alcohol, sodium bromoethyl sulfonate is added, the pH is adjusted to 7-8, and the product solution is obtained by heating and refluxing; the product is obtained by vacuum distillation, recrystallization and drying. The foaming agent for drilling has the advantages of good temperature resistance, salt resistance and salinity resistance.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, and particularly relates to the field of drilling technology, specifically to a temperature- and salt-resistant drilling foaming agent and its synthesis method. Background Technology

[0002] During drilling, well leakage occurs when the formation pressure is lower than the fluid column pressure, causing a large amount of drilling fluid to leak into the formation. Well leakage can lead to downhole accidents or complex situations, resulting in serious waste of resources and huge economic losses.

[0003] Currently, domestic oilfields often use foam drilling fluid to reduce drilling fluid density and ensure drilling safety during low-pressure or underbalanced drilling. Foam drilling technology is one of the most effective methods for protecting low-pressure oil and gas reservoirs. Foam fluid has a lower density than conventional mud drilling fluid and a smaller bottomhole pressure holding effect. It can not only effectively control drilling fluid circulation loss and improve mechanical drilling rate, but also reduce reservoir damage and protect low-pressure oil and gas reservoirs.

[0004] Formation fluids are often highly salinized and hard formation water, and their temperature is relatively high. Foaming agents used in foam drilling should have strong foaming capabilities in the encountered formation fluids, produce stable foams, and exhibit resistance to temperature, salinity, and hardness.

[0005] CN104312563B discloses a cationic microbubble drilling fluid surfactant and its preparation method. The surfactant is obtained by mixing vinyl cationic monomer A and vinyl amide compound B in a mass ratio of 10:1 to 10, adding a relative molecular mass regulator, and then copolymerizing via free radicals. The average relative molecular mass is between 1000 and 4000. This invention is simple and feasible. Using the surfactant obtained by this invention in microbubble drilling fluid results in foam with good stability and strong compression resistance, ensuring a low circulation density of the microbubble drilling fluid under high pressure at the bottom of the well, which helps reduce downhole complexity. However, its foaming and foam stabilization properties are poor, and its effectiveness in practical applications is difficult to meet field requirements.

[0006] CN101798499B discloses a strong anti-collapse foam fluid for drilling, characterized by its composition of the following components and their weight parts: 0.09-0.11 parts of foam stabilizer, 0.36-0.44 parts of foaming agent, 2.34-2.86 parts of anti-collapse agent, 2.7-3.3 parts of filtration loss reducer, and 94.51-93.29 parts of water. When encountering complex situations such as formation water inflow during gas drilling, the foam fluid of this invention can effectively improve rock and water carrying capacity while simultaneously protecting the stability of the upper wellbore. Laboratory studies have demonstrated that this foam fluid has strong foaming ability, with a foaming amount ≥500%, a moderate half-life, and is easy to control, which is beneficial for drilling engineering construction. However, this system has limitations in terms of temperature resistance, and the large amount of ultra-high molecular weight polymer used results in slow foam fluid preparation and dissolution, affecting on-site construction efficiency. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies by providing a temperature- and salt-resistant drilling foaming agent and its synthesis method. This drilling foaming agent has the advantages of temperature resistance, mineralization resistance, and hardness resistance.

[0008] One objective of this invention is to disclose a temperature- and salt-resistant foaming agent for drilling, the molecular structural formula of which is as follows:

[0009]

[0010] Another objective of this invention is to disclose a method for synthesizing the above-mentioned drilling foaming agent, the specific steps of which are as follows:

[0011] (1) Add sodium diphenylamine-4-sulfonate, isopropanol and 1,3-dibromopropane to a four-necked flask, stir and heat under reflux to obtain a mixture. During the reaction, adjust the pH to 7-8 with 2 mol / L sodium hydroxide.

[0012] (2) Distill off 90-95 wt% of isopropanol from the above mixture under reduced pressure, add distilled water, transfer all of it to a separatory funnel, shake thoroughly, separate the liquid and discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1 mol / L hydrochloric acid, precipitate out, filter, and obtain the intermediate.

[0013] (3) Transfer the above intermediate to a four-necked flask with isopropanol, add sodium bromoethylsulfonate, adjust the pH to 7-8 with 2 mol / L sodium hydroxide, and heat under reflux to obtain the product solution.

[0014] (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 80-85℃ overnight to obtain the product, a foaming agent for drilling.

[0015] Preferably, based on 1 mole of sodium diphenylamine-4-sulfonate, the amounts of 1,3-dibromopropane and sodium bromoethylsulfonate are 0.45-0.6 moles and 0.8-1 moles, respectively; more preferably, based on 1 mole of sodium diphenylamine-4-sulfonate, the amounts of 1,3-dibromopropane and sodium bromoethylsulfonate are 0.5-0.55 moles and 0.85-0.95 moles, respectively.

[0016] Preferably, in step (1), the weight ratio of isopropanol to sodium diphenylamine-4-sulfonate is 20-30:1.

[0017] Preferably, in step (1), the reflux reaction time is 6-12 hours; more preferably, the reflux reaction time is 7-10 hours.

[0018] Preferably, in step (2), the weight ratio of distilled water to sodium diphenylamine-4-sulfonate is 40-50:1.

[0019] Preferably, in step (3), the weight ratio of isopropanol to sodium diphenylamine-4-sulfonate is 40-50:1.

[0020] Preferably, in step (3), the reflux reaction time is 24-48h; more preferably, the reflux reaction time is 28-36h.

[0021] The reaction equation for synthesizing the drilling foaming agent of the present invention is as follows:

[0022]

[0023] The third objective of this invention is to disclose the application of the above-mentioned drilling foaming agent in reservoir drilling.

[0024] The drilling foaming agent of this invention belongs to the bicational cationic and tetraanionic zwitterionic surfactant category. Its active groups include four sulfonic acid groups and two quaternary ammonium salts, resulting in higher surface activity and a lower critical micelle concentration than conventional surfactants with single active groups, thus requiring a lower dosage. The benzene ring structure is rigid, exhibiting stable physicochemical properties and strong overall temperature resistance. The active groups in the molecule are quaternary ammonium salts and sulfonates, providing high tolerance to salinity and hardness.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] (1) The drilling foaming agent of the present invention has good foaming performance, with a foaming volume of more than 900 ml at room temperature and a foam half-life of more than 4800 s;

[0027] (2) The drilling foaming agent of the present invention has the advantages of good temperature resistance, salt resistance and mineralization resistance. In simulated water containing 5wt% sodium chloride and 0.1wt% calcium chloride, after rolling at 120℃ / 16h, the foaming performance is good.

[0028] (3) The drilling foaming agent of the present invention has the characteristics of low surface and interfacial tension. At a concentration of 300 mg / L, the surface tension is less than 30 mN / m and the interfacial tension reaches 0.02 mN / m.

[0029] (4) The drilling foaming agent of the present invention has the characteristic of low critical micelle concentration, which is less than 80 mg / L. Detailed Implementation

[0030] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] Example 1:

[0032] (1) Add 20 mmol (5.42 g) sodium diphenylamine-4-sulfonate, 108.4 g isopropanol and 9 mmol 1,3-dibromopropane to a four-necked flask, stir, and heat under reflux for 6 h to obtain a mixed solution. During the reaction, the pH is adjusted to 7-8 with 2 mol / L sodium hydroxide.

[0033] (2) Distill off 90wt% isopropanol from the above mixture under reduced pressure, add 216.8g of distilled water, transfer all to a separatory funnel, shake thoroughly, separate the liquid and discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1mol / L hydrochloric acid, precipitate out, filter, and obtain the intermediate.

[0034] (3) Transfer the intermediate to a four-necked flask with 216.8 g of isopropanol, add 16 mmol of sodium bromoethylsulfonate, adjust the pH to 7-8 with 2 mol / L sodium hydroxide, and heat under reflux for 24 h to obtain the product solution.

[0035] (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 80°C overnight to obtain product drilling foaming agent A.

[0036] Example 2:

[0037] (1) Add 20 mmol of sodium diphenylamine-4-sulfonate, 162.6 g of isopropanol and 12 mmol of 1,3-dibromopropane to a four-necked flask, stir, heat under reflux for 12 h, and adjust the pH to 7-8 with 2 mol / L sodium hydroxide during the reaction.

[0038] (2) Distill off 92wt% isopropanol from the above mixture under reduced pressure, add 271g of distilled water, transfer all of it to a separatory funnel, shake thoroughly, separate the liquid and discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1mol / L hydrochloric acid, precipitate out, filter, and obtain the intermediate.

[0039] (3) Transfer the intermediate to a four-necked flask with 271g of isopropanol, add 20mmol of sodium bromoethylsulfonate, adjust the pH to 7-8 with 2mol / L sodium hydroxide, and heat under reflux for 48h to obtain the product solution.

[0040] (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 85°C overnight to obtain product drilling foaming agent B.

[0041] Example 3:

[0042] (1) Add 20 mmol of sodium diphenylamine-4-sulfonate, 118.3 g of isopropanol and 9.5 mmol of 1,3-dibromopropane to a four-necked flask, stir, heat under reflux for 8 h, and adjust the pH to 7-8 with 2 mol / L sodium hydroxide during the reaction.

[0043] (2) Distill off 95wt% isopropanol from the above mixture under reduced pressure, add 235g of distilled water, transfer all of it to a separatory funnel, shake thoroughly, separate the liquid and discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1mol / L hydrochloric acid, precipitate out, filter, and obtain the intermediate.

[0044] (3) Transfer the intermediate to a four-necked flask with 230.6 g of isopropanol, add 18.1 mmol of sodium bromoethylsulfonate, adjust the pH to 7-8 with 2 mol / L sodium hydroxide, and heat under reflux for 30 h to obtain the product solution.

[0045] (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 82°C overnight to obtain the product drilling foaming agent C.

[0046] Example 4:

[0047] (1) Add 20 mmol of sodium diphenylamine-4-sulfonate, 151.5 g of isopropanol and 11.2 mmol of 1,3-dibromopropane to a four-necked flask, stir, heat under reflux for 11 h, and adjust the pH to 7-8 with 2 mol / L sodium hydroxide during the reaction.

[0048] (2) Distill off 93wt% isopropanol from the above mixture under reduced pressure, add 264.3g of distilled water, transfer all to a separatory funnel, shake thoroughly, separate the liquid and discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1mol / L hydrochloric acid, precipitate out, filter, and obtain the intermediate.

[0049] (3) Transfer the intermediate to a four-necked flask with 259.3g of isopropanol, add 19.2mmol of sodium bromoethylsulfonate, adjust the pH to 7-8 with 2mol / L sodium hydroxide, and heat under reflux for 40h to obtain the product solution.

[0050] (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 83°C overnight to obtain the product, drilling foaming agent D.

[0051] Example 5:

[0052] (1) Add 20 mmol of sodium diphenylamine-4-sulfonate, 125 g of isopropanol and 10.2 mmol of 1,3-dibromopropane to a four-necked flask, stir, heat under reflux for 7 h, and adjust the pH to 7-8 with 2 mol / L sodium hydroxide during the reaction.

[0053] (2) Distill off 92wt% isopropanol from the above mixture under reduced pressure, add 242.3g of distilled water, transfer all to a separatory funnel, shake thoroughly, separate the liquid and discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1mol / L hydrochloric acid, precipitate out, filter, and obtain the intermediate.

[0054] (3) Transfer the intermediate to a four-necked flask with 247.3g of isopropanol, add 18.4mmol of sodium bromoethylsulfonate, adjust the pH to 7-8 with 2mol / L sodium hydroxide, and heat under reflux for 38h to obtain the product solution.

[0055] (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 84°C overnight to obtain the product, drilling foaming agent E.

[0056] Example 6:

[0057] (1) Add 20 mmol of sodium diphenylamine-4-sulfonate, 140 g of isopropanol and 10.5 mmol of 1,3-dibromopropane to a four-necked flask, stir, heat under reflux for 9 h, and adjust the pH to 7-8 with 2 mol / L sodium hydroxide during the reaction.

[0058] (2) Distill off 90wt% isopropanol from the above mixture under reduced pressure, add 251.3g of distilled water, transfer all to a separatory funnel, shake thoroughly, separate the liquid and discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1mol / L hydrochloric acid, precipitate out, filter, and obtain the intermediate.

[0059] (3) Transfer the intermediate to a four-necked flask with 253g isopropanol, add 18.8mmol sodium bromoethylsulfonate, adjust the pH to 7-8 with 2mol / L sodium hydroxide, and heat under reflux for 40h to obtain the product solution.

[0060] (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 80°C overnight to obtain the product drilling foaming agent F.

[0061] Example 7: Evaluation of foaming performance

[0062] Evaluation method reference: Q / SH10201873—2015 "General Technical Conditions for Foaming Agents for Drilling Fluids".

[0063] The volume of foaming at room temperature is recorded as v1, mL;

[0064] The half-life of the room temperature foam is recorded as t1, s;

[0065] After rolling at 120℃ for 16 hours, the result was recorded as v2, mL;

[0066] After rolling at 120℃ for 16 hours, the result is recorded as t2, s.

[0067] The test results are shown in Table 1.

[0068] As can be seen from Table 1:

[0069] (1) At room temperature, the foaming agents A, B, C, D, E and F of the present invention have good foaming properties and foaming volumes greater than 940 ml, namely 945 mL, 948 mL, 948 mL, 948 mL, 950 mL and 950 mL, respectively, while the foaming volume of sodium dodecyl sulfonate is 486 ml, which is significantly lower than that of the present invention; the foam half-life is greater than 4700 s, namely 4740 s, 4800 s, 4800 s, 4800 s, 4860 s and 4860 s, respectively, while the half-life of sodium dodecyl sulfonate is 510 s, which is significantly lower than that of the present invention.

[0070] (2) At high temperatures, the foaming agents A, B, C, D, E, and F of this invention have good foaming properties and foaming volumes greater than 940 ml, namely 943 mL, 943 mL, 945 mL, 945 mL, 948 mL, and 950 mL, respectively, while the foaming volume of sodium dodecyl sulfonate is 420 ml, which is significantly lower than that of this invention; the foam half-life is greater than 4600 s, namely 4680 s, 4740 s, 4740 s, 4800 s, 4800 s, and 4860 s, respectively, while the half-life of sodium dodecyl sulfonate is 480 s, which is significantly lower than that of this invention.

[0071] Example 8: Evaluation of mineralization resistance and hardness resistance

[0072] The evaluation method references Q / SH10201873—2015 "General Technical Conditions for Foaming Agents for Drilling Fluids". Distilled water is replaced with simulated water, and the composition of simulated water is: 1g calcium chloride + 50g sodium chloride + 1000ml distilled water.

[0073] After rolling at 120℃ for 16 hours, the volume was recorded as v3, mL;

[0074] After rolling at 120℃ for 16 hours, the result is recorded as t3, s.

[0075] The test results are shown in Table 1.

[0076] Table 1 Evaluation of foaming performance

[0077]

[0078]

[0079] As can be seen from 1:

[0080] The drilling foaming agents A, B, C, D, E, and F of this invention exhibit good temperature, salt, and mineralization resistance. In simulated water containing 5 wt% sodium chloride and 0.1 wt% calcium chloride, after rolling at 120℃ for 16 hours, the foaming volumes are greater than 800 ml, specifically 880 mL, 885 mL, 890 mL, 895 mL, 895 mL, and 900 mL; the half-lives are greater than 4300 s, specifically 4380 s, 4440 s, 4440 s, 4500 s, 4560 s, and 4560 s, demonstrating good temperature, salt, and mineralization resistance. In contrast, sodium dodecyl sulfonate has a foaming volume of 400 ml, a half-life greater than 420 s, and only moderate temperature, salt, and mineralization resistance.

[0081] Example 9: Testing of Surface Tension and Interfacial Tension

[0082] Surface tension and interfacial tension were determined according to the method in SY / T 5370-2018 "Methods for Determination of Surface and Interfacial Tension". The test samples were prepared as 300 mg / L aqueous solutions. The results are shown in Table 2.

[0083] As can be seen from Table 2:

[0084] (1) The surface tension test values ​​of the drilling foaming agents A, B, C, D, E and F of the present invention are all 27.4 mN / m, which is lower than 30 mN / m; while the surface tension test value of sodium dodecyl sulfonate is 34.3 mN / m, which is significantly higher than that of the present invention.

[0085] (2) The interfacial tension test values ​​of the drilling foaming agents A, B, C, D, E, and F of this invention are all 0.02 mN / m. However, the interfacial tension test value of sodium dodecyl sulfonate is 1400 mN / m, which is significantly higher than that of this invention.

[0086] Example 10: Test of Critical Micelle Concentration

[0087] The critical micelle concentration was determined according to the method in GB / T 11276-2007 "Determination of Critical Micelle Concentration of Surfactants", and the results are shown in Table 2.

[0088] Table 2. Test results of surface tension, interfacial tension, and critical micelle concentration.

[0089]

[0090] As can be seen from Table 2, the critical micelle concentrations of the drilling foaming agents A, B, C, D, E, and F of this invention are 73 mg / L, 73 mg / L, 72 mg / L, 72 mg / L, 70 mg / L, and 70 mg / L, respectively, all below 80 mg / L; while the critical micelle concentration of sodium dodecyl sulfonate is 730 mg / L, which is significantly higher than that of the foaming agents of this invention.

[0091] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for synthesizing a temperature- and salt-resistant drilling foaming agent, characterized in that, The synthesis method is as follows: (1) Add sodium diphenylamine-4-sulfonate, isopropanol and 1,3-dibromopropane to a four-necked flask, stir and heat under reflux to obtain a mixture. During the reaction, the pH is adjusted to 7-8 with 2 mol / L sodium hydroxide. The weight ratio of isopropanol to sodium diphenylamine-4-sulfonate is 20-30:

1. (2) Distill off 90-95 wt% of isopropanol from the above mixture under reduced pressure, add distilled water, transfer the entire mixture to a separatory funnel, shake thoroughly, separate the liquids, discard a small amount of oil phase, adjust the pH of the aqueous phase to 2-3 with 1 mol / L hydrochloric acid, precipitate the precipitate, filter, and obtain the intermediate. The weight ratio of distilled water to sodium diphenylamine-4-sulfonate is 40-50:

1. (3) The above intermediate was transferred to a four-necked flask with isopropanol, sodium bromoethylsulfonate was added, the pH was adjusted to 7-8 with 2 mol / L sodium hydroxide, and the solution was heated under reflux to obtain the product solution. Based on 1 mole of sodium diphenylamine-4-sulfonate, the amounts of 1,3-dibromopropane and sodium bromoethylsulfonate were 0.45-0.6 moles and 0.8-1 moles, respectively, and the weight ratio of isopropanol to sodium diphenylamine-4-sulfonate was 40-50:

1. (4) The product solution was distilled under reduced pressure using a rotary evaporator to obtain a semi-solid, which was then recrystallized with ethyl acetate to obtain pale yellow crystals. The crystals were dried at 80-85℃ overnight to obtain the drilling foaming agent. The molecular structural formula of the main component of the drilling foaming agent is as follows: 。 2. The synthesis method according to claim 1, characterized in that, Based on 1 mole of sodium diphenylamine-4-sulfonate, the amounts of 1,3-dibromopropane and sodium bromoethylsulfonate are 0.5-0.55 moles and 0.85-0.95 moles, respectively.

3. The synthesis method according to claim 1, characterized in that, In step (1), the reflux reaction time is 6-12 hours.

4. The synthesis method according to claim 1, characterized in that, In step (3), the reflux reaction time is 24-48h.

5. The drilling foaming agent prepared by the synthesis method according to claim 1.

6. The application of the drilling foaming agent according to claim 5, characterized in that, The application described is in oil reservoir drilling.

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