A foaming agent for oil fields and its preparation method and application

Abstract

The present invention belongs to the field of oil and gas field development, and in particular to a foaming agent for oil fields and its preparation method and application. The preparation method is as follows: an autoclave adds 1,3-dibromo-2-propanol and sodium hydroxide, evacuates, stirs and heats up, passes into ethylene oxide, heats up, and cools the system to less than 40 ° C; adjust pH 3-4, add aminosulfonic acid powder in the above-mentioned autoclave, heat while stirring, and react in a warm state, cool to less than 40 ° C, and adjust pH 9-10; the above-mentioned mixed solution is transferred to a four-necked flask, ethanol is added, sodium methyltaurate is added, heated to reflux, and pH 7-8 is maintained; dodecylamine is added, heated to reflux 4-8h, while maintaining pH 7-8; chloroform extraction, vacuum distillation to obtain a product foaming agent. The foaming agent of the present invention has the advantages of strong foaming power, good stability, temperature resistance, and low interfacial tension.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas field development, and specifically relates to a foaming agent for oil fields and a preparation method and application thereof. Background Art

[0002] Foaming agents play a vital role in the development and production of oil fields. These chemical additives play an important role in improving crude oil recovery, optimizing production efficiency, protecting oil and gas resources, and improving the oil field operating environment through their unique physical and chemical properties.

[0003] Foaming agents can form stable foams in the formation. These foams have good fluidity and permeability and can effectively improve the fluidity of the oil-water phase. By injecting foaming agents into the formation, crude oil that is originally difficult to flow can be more easily extracted under the influence of foam, thereby improving the recovery rate of crude oil. This mechanism of action is particularly suitable for the extraction of low-permeability, high-viscosity or heavy crude oil, and can effectively solve the extraction problems faced by these oil fields.

[0004] During the oilfield exploitation process, changes in formation pressure have an important impact on the recovery rate of crude oil. Foaming agents can adjust the formation pressure distribution by forming foam in the formation, so that the low-pressure areas that were originally difficult to exploit can be effectively supplemented with pressure. This pressure adjustment effect helps maintain the stability of formation pressure and improve the production and recovery rate of oil wells.

[0005] CN102796498A discloses a foam drilling fluid, specifically a foam drilling fluid that can maintain the stability of the well wall, prevent the drill bit from being mud-packed, and keep drilling after water comes out of the formation during gas drilling. Specifically, a foam drilling fluid is provided, including the following components, each component is calculated by mass percentage: 0.5% to 2.0% of a foaming agent, 0.2% to 0.5% of a foam stabilizer, 2% to 10% of a shale inhibitor, 0.2% to 1.0% of a shale stabilizer, and the remainder is water; and the pH value of the foam drilling fluid is 8 to 10. The foam drilling fluid of the invention has excellent foaming properties, strong shale inhibition ability, and long-term shale inhibition performance, and can solve the problems of rock and water carrying, well wall instability, and adhesion and stuck drill in the well after water comes out of the formation during gas drilling, thereby achieving safe and rapid drilling. However, the foaming agent has a small foaming volume and a short half-life, and its prospects for promotion in oil fields are poor.

[0006] CN101798499B discloses a strong inhibition and anti-collapse foam liquid for drilling, characterized in that it is composed 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 reducer, and 94.51-93.29 parts of water. When gas drilling encounters complex situations such as formation water, the use of the invented foam liquid can effectively improve the rock and water carrying capacity, and at the same time protect the stability of the upper well wall. Laboratory studies have shown that the foam liquid has strong foaming ability, a foaming amount of ≥500%, a moderate half-life, is easy to control, and is conducive to drilling engineering construction. However, the temperature resistance of the system is general, and the foam liquid preparation and dissolution are slow due to the large amount of ultra-high molecular weight polymer, which will affect the efficiency of on-site construction. Summary of the invention

[0007] The present invention aims at the deficiencies of the prior art and provides a foaming agent for oil fields and a preparation method and application thereof. The foaming agent of the present invention has the advantages of strong foaming power, good stability, temperature resistance and low interfacial tension.

[0008] One of the purposes of the present invention is to disclose a method for preparing a foaming agent for oil fields, the specific steps of which are as follows:

[0009] (1) Add 1,3-dibromo-2-propanol and solid sodium hydroxide to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce ethylene oxide, raise the temperature to 150-170°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C;

[0010] (2) Adjust the pH to 3-4 with sulfuric acid, add aminosulfonic acid powder to the above autoclave, heat with stirring, keep the temperature at 140-150°C for 60-90 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution;

[0011] (3) Transfer the above mixed solution to a four-necked flask, add ethanol and sodium methyltaurine, heat and reflux for 1-2 hours, and maintain the pH at 7-8 with sodium hydroxide;

[0012] (4) Add dodecylamine and heat under reflux for 4-8 hours while maintaining pH 7-8 with sodium hydroxide;

[0013] (5) Extract with chloroform and distill under reduced pressure to obtain the foaming agent.

[0014] In the present invention, preferably, based on 1 mol part of 1,3-dibromo-2-propanol, the amounts of ethylene oxide, aminosulfonic acid, sodium methyl taurate and dodecylamine are 5-20 mol parts, 0.8-1.2 mol parts, 0.8-1.2 mol parts and 0.8-1.2 mol parts respectively.

[0015] In the present invention, preferably, the weight ratio of the sodium hydroxide solid to the 1,3-dibromo-2-propanol in step (1) is 0.1-0.2:1.

[0016] In the present invention, preferably, the weight ratio of ethanol to 1,3-dibromo-2-propanol in step (3) is 30-60:1.

[0017] The synthetic reaction equation of the oil field foaming agent of the present invention is as follows:

[0018]

[0019]

[0020]

[0021]

[0022] Another object of the present invention is to disclose a foaming agent for oil fields, wherein the molecular structure of the foaming agent is as follows:

[0023]

[0024] Among them, n=5-20.

[0025] The third object of the present invention is to disclose the application of the above foaming agent in the development of oil and gas fields.

[0026] The oil field foaming agent of the present invention is a composite surfactant, and its active groups include two anionic groups (one sulfonic acid group and one sulfate group) and one nonionic group (polyether). It is more active than conventional surfactants with a single active group, can greatly reduce surface tension, increase foaming volume and capacity, and has higher stability.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] (1) The foaming agent for oil fields of the present invention has good foaming performance. The foaming volume can reach 950 mL at room temperature. After rolling at 120 ° C for 16 h, the foaming volume is basically unchanged;

[0029] (2) The foaming agent for oil fields of the present invention has the characteristic of a long half-life, which can reach 4800s. After rolling at 120°C for 16 hours, the half-life remains basically unchanged;

[0030] (3) The oilfield foaming agent of the present invention has the characteristic of low interfacial tension. At a concentration of 0.1wt%, the interfacial tension can reach 0.07×10 -3 mN / m. DETAILED DESCRIPTION

[0031] 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.

[0032] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0033] Example 1

[0034] (1) Add 0.05 mol 1,3-dibromo-2-propanol and 1.1 g sodium hydroxide solid to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce 0.25 mol ethylene oxide, raise the temperature to 150°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C.

[0035] (2) Adjust the pH to 3-4 with 50wt% sulfuric acid, add 0.04mol aminosulfonic acid powder to the above autoclave, heat with stirring, keep the reaction at 140°C for 60 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution;

[0036] (3) The mixed solution was transferred to a four-necked flask, 327 g of ethanol and 0.045 mol of sodium methyl taurine were added, and the mixture was heated under reflux for 1 h while maintaining the pH at 7-8 with sodium hydroxide;

[0037] (4) Add 0.04 mol of dodecylamine and heat under reflux for 4 h while maintaining the pH at 7-8 with sodium hydroxide;

[0038] (5) Extract with chloroform and distill under reduced pressure to obtain the foaming agent.

[0039] Example 2

[0040] (1) Add 0.05 mol 1,3-dibromo-2-propanol and 1.3 g sodium hydroxide solid to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce 0.4 mol ethylene oxide, raise the temperature to 155°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C.

[0041] (2) Adjust the pH to 3-4 with 50wt% sulfuric acid, add 0.06mol aminosulfonic acid powder to the above autoclave, heat with stirring, keep the reaction at 142°C for 70 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution;

[0042] (3) The mixed solution was transferred to a four-necked flask, 368 g of ethanol and 0.04 mol of sodium methyl taurine were added, and the mixture was heated under reflux for 1.5 h while maintaining the pH at 7-8 with sodium hydroxide;

[0043] (4) Add 0.06 mol of dodecylamine and heat under reflux for 5 h while maintaining the pH at 7-8 with sodium hydroxide;

[0044] (5) Extract with chloroform and distill under reduced pressure to obtain the foaming agent.

[0045] Example 3

[0046] (1) Add 0.05 mol 1,3-dibromo-2-propanol and 1.6 g sodium hydroxide solid to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce 0.5 mol ethylene oxide, raise the temperature to 160°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C.

[0047] (2) Adjust the pH to 3-4 with 50wt% sulfuric acid, add 0.045mol aminosulfonic acid powder to the above autoclave, heat with stirring, keep the reaction at 145°C for 80 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution;

[0048] (3) The mixed solution was transferred to a four-necked flask, 415 g of ethanol and 0.06 mol of sodium methyl taurine were added, and the mixture was heated under reflux for 2 h while maintaining the pH at 7-8 with sodium hydroxide;

[0049] (4) Add 0.055 mol of dodecylamine and heat under reflux for 6 h while maintaining the pH at 7-8 with sodium hydroxide;

[0050] (5) Extract with chloroform and distill under reduced pressure to obtain the foaming agent.

[0051] Example 4

[0052] (1) Add 0.05 mol 1,3-dibromo-2-propanol and 1.8 g sodium hydroxide solid to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce 0.7 mol ethylene oxide, raise the temperature to 165°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C.

[0053] (2) Adjust the pH to 3-4 with 50wt% sulfuric acid, add 0.054mol aminosulfonic acid powder to the above autoclave, heat with stirring, keep the temperature at 150°C for 60 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution;

[0054] (3) Transfer the above mixed solution to a four-necked flask, add 500 g of ethanol and 0.052 mol of sodium methyl taurine, heat and reflux for 2 h, and maintain the pH at 7-8 with sodium hydroxide;

[0055] (4) Add 0.045 mol of dodecylamine and heat under reflux for 8 h while maintaining the pH at 7-8 with sodium hydroxide;

[0056] (5) Extract with chloroform and distill under reduced pressure to obtain the foaming agent.

[0057] Example 5

[0058] (1) Add 0.05 mol 1,3-dibromo-2-propanol and 2 g sodium hydroxide solid to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce 0.85 mol ethylene oxide, raise the temperature to 170°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C.

[0059] (2) Adjust the pH to 3-4 with 50wt% sulfuric acid, add 0.049mol aminosulfonic acid powder to the above autoclave, heat with stirring, keep the reaction at 142°C for 90 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution;

[0060] (3) The mixed solution was transferred to a four-necked flask, 586 g of ethanol and 0.048 mol of sodium methyl taurine were added, and the mixture was heated under reflux for 2 h while maintaining the pH at 7-8 with sodium hydroxide;

[0061] (4) Add 0.051 mol of dodecylamine and heat under reflux for 8 h while maintaining the pH at 7-8 with sodium hydroxide;

[0062] (5) Extract with chloroform and distill under reduced pressure to obtain the foaming agent.

[0063] Example 6

[0064] (1) Add 0.05 mol 1,3-dibromo-2-propanol and 2.1 g sodium hydroxide solid to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce 1 mol ethylene oxide, raise the temperature to 170°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C.

[0065] (2) Adjust the pH to 3-4 with 50wt% sulfuric acid, add 0.052mol aminosulfonic acid powder to the above autoclave, heat with stirring, keep the temperature at 150°C for 90 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution;

[0066] (3) The mixed solution was transferred to a four-necked flask, 653 g of ethanol and 0.05 mol of sodium methyl taurine were added, and the mixture was heated under reflux for 2 h while maintaining the pH at 7-8 with sodium hydroxide;

[0067] (4) Add 0.051 mol of dodecylamine and heat under reflux for 7 h while maintaining the pH at 7-8 with sodium hydroxide;

[0068] (5) Extract with chloroform and distill under reduced pressure to obtain the foaming agent.

[0069] Example 7 Foaming performance test

[0070] Test method: Refer to Q / SH1020 1873-2015 "General Technical Requirements for Foaming Agents for Drilling Fluids". Among them:

[0071] The foaming volume at room temperature was recorded as v1, mL;

[0072] The room temperature foam half-life, recorded as t1, s;

[0073] After tumbling at 120 °C / 16 h, record as v2, mL;

[0074] The foam half-life after tumbling at 120 °C / 16 h is recorded as t2, s.

[0075] The test results are shown in Table 1. A comparative experiment was also conducted using the high-density foaming agent produced by Henan Yuanchun Chemical Co., Ltd.

[0076] From Table 1 we can see that:

[0077] (1) The foaming agent for oil field use of the present invention (Examples 1-6) has good foaming performance. The foaming volume at room temperature is greater than 900 mL, and the highest is 950 mL (Example 5). After rolling at 120 ° C for 16 h, the foaming volume is basically unchanged. The foaming volume of the high-density foaming agent of Henan Yuanchun Chemical Co., Ltd. in the comparative example is 470 mL, which is significantly lower than that of the present invention. After rolling at 120 ° C for 16 h, the foaming volume is significantly reduced.

[0078] (2) The foaming agent for oil field use of the present invention (Examples 1-6) has the characteristic of a long half-life, which is greater than 4000 s, with the highest reaching 4800 s. After rolling at 120 °C for 16 h, the half-life is basically unchanged; while the half-life of the high-density foaming agent of the comparative example Henan Yuanchun Chemical Co., Ltd. is as short as 540 s. After rolling at 120 °C for 16 h, the half-life decreases.

[0079] Example 8 Test of interfacial tension

[0080] The interfacial tension γ was tested with reference to SY / T 5370-2018 "Measurement Method of Surface and Interfacial Tension", and the foaming agent of the present invention (Examples 1-6) was configured to a concentration of 0.1wt%. The oil phase was dehydrated crude oil from a joint station of Shengli Oilfield, with a viscosity of 630mPa•s.

[0081] The test results are shown in Table 1. A comparative experiment was also conducted using the high-density foaming agent produced by Henan Yuanchun Chemical Co., Ltd.

[0082] Table 1 Foaming performance and interfacial tension test results

[0083]

[0084] It can be seen from Table 1 that the interfacial tension of the oilfield foaming agent (Examples 1-6) of the present invention is lower than 0.25×10 -3 mN / m, the lowest is 0.07×10 -3 mN / m; while the interfacial tension of the high-density foaming agent of Henan Yuanchun Chemical Co., Ltd. in the comparative experiment is 75×10 -3 mN / m, which is significantly higher than that of the present invention.

[0085] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a foaming agent for oil fields, characterized in that: The specific steps of the preparation method are as follows: (1) Add 1,3-dibromo-2-propanol and solid sodium hydroxide to the autoclave, purge the pipeline and the autoclave with nitrogen, evacuate, stir and heat to 90°C, stop evacuating, introduce ethylene oxide, raise the temperature to 150-170°C, and gradually reduce the reaction pressure. When the pressure drops to 0, cool the system to below 40°C; (2) Adjust the pH to 3-4 with sulfuric acid, add aminosulfonic acid powder to the above autoclave, heat with stirring, keep the temperature at 140-150°C for 60-90 min, cool to below 40°C, and adjust the pH to 9-10 with sodium hydroxide solution; (3) Transfer the above mixed solution to a four-necked flask, add ethanol and sodium methyltaurine, heat and reflux for 1-2 hours, and maintain the pH at 7-8 with sodium hydroxide; (4) Add dodecylamine and heat under reflux for 4-8 hours while maintaining pH 7-8 with sodium hydroxide; (5) Extraction with chloroform and distillation under reduced pressure to obtain the product foaming agent; Based on 1 mol part of 1,3-dibromo-2-propanol, the amounts of ethylene oxide, aminosulfonic acid, sodium methyl taurate and dodecylamine are 5-20 mol parts, 0.8-1.2 mol parts, 0.8-1.2 mol parts and 0.8-1.2 mol parts respectively.

2. The method for preparing a foaming agent for oil fields as claimed in claim 1, characterized in that: The weight ratio of the sodium hydroxide solid to the 1,3-dibromo-2-propanol in step (1) is 0.1-0.2:

1.

3. The method for preparing a foaming agent for oil field according to claim 1, characterized in that: The weight ratio of ethanol to 1,3-dibromo-2-propanol in step (3) is 30-60:

1.

4. Use of the foaming agent prepared by the preparation method according to any one of claims 1 to 3 in oil and gas field development.

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