A foaming agent for microbubble drilling fluid and a preparation method thereof

Abstract

The application provides a preparation method of a foaming agent for microbubble drilling fluid, and comprises the following steps: carrying out a first reaction on a fluorine-containing compound, an acid binding agent, an organic solvent and an amine-based compound to obtain a first reactant; carrying out a second reaction on sodium bisulfite, water and epichlorohydrin to obtain a second reactant; and carrying out a third reaction on the first reactant and the second reactant to obtain the foaming agent for microbubble drilling fluid. The foaming agent for microbubble drilling fluid prepared by the application has good anti-pollution performance and can be used for preparing high-salt-resistant and oil-pollution-resistant microbubble drilling fluid.

Description

Technical Field

[0001] This invention belongs to the field of oilfield chemical additives technology, and particularly relates to a foaming agent for microbubble drilling fluid and its preparation method. Background Technology

[0002] With the continuous exploration and development of the domestic oil industry, the formation pressure coefficient of oil and gas reservoirs has been decreasing year by year, with some reservoirs even having a formation pressure coefficient below 1.0. In drilling in these low-pressure formations, the use of conventional drilling fluids easily leads to fluid loss, necessitating the use of low-density drilling fluids to reduce the probability of fluid loss. To address these issues, existing microbubble drilling fluids offer advantages such as low density, no need for on-site gas injection equipment, effective prevention of fluid loss in low-pressure fractured, high-permeability sandstone, and fractured formations, protection of oil and gas reservoirs, and reduction of overall drilling costs. The core technology of microbubble drilling fluids lies in the foaming agent that forms the microbubbles. In microbubble drilling fluids, the foaming agents used are combinations of commonly used surfactants. While these have strong foaming performance under freshwater conditions, under salt and crude oil contamination conditions (such as the presence of salt layers or oil production in the formation), the commonly used surfactants are insufficient in their salt and oil resistance, making it difficult to form stable foams and ensuring the stable performance of the microbubble drilling fluid. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a foaming agent for microbubble drilling fluid and its preparation method. The foaming agent provided by this invention has good resistance to salt and oil pollution, and still has strong foaming performance and foam stability under salt and oil pollution conditions.

[0004] This invention provides a method for preparing a foaming agent for microbubble drilling fluid, comprising:

[0005] A fluorinated compound, an acid-binding agent, an organic solvent, and an amine compound are subjected to a first reaction to obtain a first reactant.

[0006] Sodium bisulfite, water, and epichlorohydrin are subjected to a second reaction to obtain a second reactant.

[0007] The first reactant and the second reactant are subjected to a third reaction to obtain a foaming agent for microbubble drilling fluid.

[0008] Preferably, the fluorinated compound is selected from one or more of hexafluoropropylene dimer and hexafluoropropylene trimer.

[0009] Preferably, the acid-binding agent is selected from one or more of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and triethylamine.

[0010] Preferably, the organic solvent is selected from one or more of diethyl ether, dichloromethane, and ethyl acetate.

[0011] Preferably, the amino compound is selected from one or more of N,N-dimethylethylenediamine, N,N-dimethylpropylenediamine, N,N-dimethylbutanediamine, N,N-diethylethylenediamine, N,N-diethylpropylenediamine, and N,N-diethylbutanediamine.

[0012] Preferably, the ratio of the fluorinated compound, acid-binding agent, organic solvent, and amine compound is 1 mol : (0.5-1.5) mol : (100-500) mL : (0.8-1.5) mol;

[0013] The ratio of sodium bisulfite, water, and epichlorohydrin used is (0.8–1.5) mol: (200–1000) mL: (0.8–1.5) mol;

[0014] The molar ratio of the fluorine-containing compound to sodium bisulfite is 1:(0.8-1.5).

[0015] Preferably, the temperature of the first reaction is 0–60°C and the time is 2–12 h.

[0016] Preferably, the temperature of the second reaction is 50–90°C and the time is 1–8 hours.

[0017] Preferably, the temperature of the third reaction is 60–100°C and the time is 2–12 hours.

[0018] This invention provides a foaming agent for microbubble drilling fluid, comprising the structure of Formula I:

[0019]

[0020] In formula I, R1 = C6F 11 Or C9F 17 R2 = CH3 or C2H5, where n is an integer from 2 to 4.

[0021] The foaming agent for microbubble drilling fluid prepared by this invention has good anti-pollution properties and can be used to formulate microbubble drilling fluids with high resistance to salt and oil pollution. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides a foaming agent for microbubble drilling fluid, comprising the structure of Formula I:

[0024]

[0025] In formula I, R1 = C6F 11 Or C9F 17 R2 = CH3 or C2H5, where n is an integer from 2 to 4.

[0026] This invention provides a method for preparing the foaming agent for microbubble drilling fluid described in the above technical solution, comprising:

[0027] A fluorinated compound, an acid-binding agent, an organic solvent, and an amine compound are subjected to a first reaction to obtain a first reactant.

[0028] Sodium bisulfite, water, and epichlorohydrin are subjected to a second reaction to obtain a second reactant.

[0029] The first reactant and the second reactant are subjected to a third reaction to obtain a foaming agent for microbubble drilling fluid.

[0030] In this invention, the fluorinated compound is preferably selected from one or more of hexafluoropropylene dimer and hexafluoropropylene trimer.

[0031] In this invention, the acid-binding agent is preferably selected from one or more of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and triethylamine.

[0032] In this invention, the organic solvent is preferably selected from one or more of diethyl ether, dichloromethane, and ethyl acetate.

[0033] In this invention, the amino compound is preferably selected from one or more of N,N-dimethylethylenediamine, N,N-dimethylpropylenediamine, N,N-dimethylbutanediamine, N,N-diethylethylenediamine, N,N-diethylpropylenediamine, and N,N-diethylbutanediamine.

[0034] In this invention, the preferred ratio of the fluorinated compound, acid-binding agent, organic solvent and amine compound is 1 mol: (0.5-1.5) mol: (100-500) mL: (0.8-1.5) mol, more preferably 1 mol: (0.8-1.2) mol: (200-400) mL: (1.0-1.3) mol, and most preferably 1 mol: 1 mol: 300 mL: 1.2 mol.

[0035] In this invention, the temperature of the first reaction is preferably 0-60°C, more preferably 10-50°C, even more preferably 20-40°C, and most preferably 30°C; the time of the first reaction is preferably 2-12 hours, more preferably 4-10 hours, and most preferably 6-8 hours.

[0036] In this invention, after the first reaction is completed, it is preferable to further include:

[0037] The obtained product was filtered and then distilled to obtain the first reactant.

[0038] In this invention, the filtration preferably yields a filtrate; the distillation is preferably vacuum distillation; the temperature of the vacuum distillation is preferably 50-100°C, more preferably 60-90°C, and most preferably 70-80°C.

[0039] In this invention, the water is preferably deionized water.

[0040] In this invention, the preferred ratio of sodium bisulfite, water, and epichlorohydrin is (0.8–1.5) mol: (200–1000) mL: (0.8–1.5) mol, more preferably (1.0–1.3) mol: (400–800) mL: (1.0–1.3) mol, and most preferably 1.2 mol: 600 mL: 1.2 mol.

[0041] In this invention, the temperature of the second reaction is preferably 50-90°C, more preferably 60-80°C, and most preferably 70°C; the time of the second reaction is preferably 1-8 hours, more preferably 2-6 hours, and most preferably 3-5 hours.

[0042] In this invention, the molar ratio of the fluorine-containing compound to sodium bisulfite is preferably 1:(0.8-1.5), more preferably 1:(1.0-1.3), and most preferably 1:1.2.

[0043] In this invention, the temperature of the third reaction is preferably 60-100°C, more preferably 70-90°C, and most preferably 80°C; the time of the third reaction is preferably 2-12 hours, more preferably 4-10 hours, and most preferably 6-8 hours.

[0044] In this invention, the preferred method for preparing the foaming agent for the microbubble drilling fluid includes:

[0045] 1 mol of a fluorine-containing compound, 0.5–1.5 mol of an acid-binding agent, and 100–500 mL of organic solvent are added to a reactor and stirred until homogeneous. Then, 0.8–1.5 mol of an amino compound is added to the reactor, and the reaction is carried out at 0–60 °C for 2–12 h. After the reaction is complete, the mixture is filtered, and the filtrate is distilled under reduced pressure at 50–100 °C to obtain reactant I, which is then set aside for use. 0.8–1.5 mol of sodium bisulfite and 200–1000 mL of deionized water are added to a reactor and mixed until homogeneous. Then, 0.8–1.5 mol of epichlorohydrin is added, and the reaction is carried out at 50–90 °C for 1–8 h. Then, reactant I is added to the reactor, and the reaction is carried out at 60–100 °C for 2–12 h to obtain a foaming agent for microbubble drilling fluid.

[0046] The foaming agent for microbubble drilling fluid prepared by this invention has good anti-pollution properties and can be used to formulate microbubble drilling fluids with high resistance to salt and oil pollution.

[0047] Example 1

[0048] 1 mol of hexafluoropropylene dimer, 1.2 mol of potassium carbonate, and 100 mL of dichloromethane were added to a reactor and stirred until homogeneous. Then, 1.5 mol of N,N-dimethylethylenediamine was added to the reactor, and the reaction was carried out at 0 °C for 10 h. After the reaction was completed, the mixture was filtered, and the filtrate was distilled under reduced pressure at 80 °C to obtain reactant I, which was set aside for later use. 1.1 mol of sodium bisulfite and 400 mL of deionized water were added to a reactor, mixed thoroughly, and then 0.8 mol of epichlorohydrin was added. The reaction was carried out at 60 °C for 5 h. Then, reactant I was added to the reactor, and the reaction was carried out at 100 °C for 2 h to obtain a foaming agent for microbubble drilling fluid.

[0049] Example 2

[0050] 1 mol of hexafluoropropylene trimer, 0.5 mol of sodium hydroxide, and 200 mL of ethyl acetate were added to a reactor and stirred until homogeneous. Then, 1.3 mol of N,N-dimethylpropylenediamine was added to the reactor, and the reaction was carried out at 20 °C for 12 h. After the reaction was completed, the mixture was filtered, and the filtrate was distilled under reduced pressure at 100 °C to obtain reactant I, which was set aside for later use. 0.8 mol of sodium bisulfite and 1000 mL of deionized water were added to a reactor, mixed thoroughly, and then 1.0 mol of epichlorohydrin was added. The reaction was carried out at 90 °C for 1 h. Then, reactant I was added to the reactor, and the reaction was carried out at 60 °C for 12 h to obtain a foaming agent for microbubble drilling fluid.

[0051] Example 3

[0052] 1 mol of hexafluoropropylene trimer, 1.5 mol of triethylamine, and 500 mL of diethyl ether were added to a reactor and stirred until homogeneous. Then, 0.8 mol of N,N-diethylpropylenediamine was added to the reactor, and the reaction was carried out at 60 °C for 2 h. After the reaction was completed, the mixture was filtered, and the filtrate was distilled under reduced pressure at 50 °C to obtain reactant I, which was set aside for later use. 1.5 mol of sodium bisulfite and 200 mL of deionized water were added to a reactor, mixed thoroughly, and then 1.5 mol of epichlorohydrin was added. The reaction was carried out at 50 °C for 8 h. Then, reactant I was added to the reactor, and the reaction was carried out at 80 °C for 8 h to obtain a foaming agent for microbubble drilling fluid.

[0053] Examples 4-6

[0054] The foaming agent for microbubble drilling fluid was prepared according to the method of Example 1, the difference being that the reactants and amounts in the table below were used:

[0055]

[0056] Comparative Example 1

[0057] 70g of sodium dodecyl sulfate and 30g of sodium dodecylbenzene sulfonate solids were mixed evenly to obtain a foaming agent.

[0058] Performance testing

[0059] 1. Performance evaluation of foaming agents

[0060] The foaming agents prepared in Examples 1-6 and Comparative Example 1 were evaluated for performance.

[0061] (1) Salt resistance

[0062] The foaming agent was thoroughly dissolved in 100 mL of water, then 36 g of NaCl was added and dissolved completely. The solution was then stirred at 10000 rpm for 1 minute using a high-speed mixer. The resulting foam slurry was poured into a graduated cylinder, and the foam volume and the time required for 50 mL of foaming base solution to separate were recorded as the foam half-life. The results are as follows:

[0063] Surfactant type foaming volume / mL half-life / min Example 1 420 5.4 Example 2 600 8.1 Example 3 550 7.2 Example 4 480 6.0 Example 5 580 7.5 Example 6 440 5.7 Comparative Example 1 180 0.4

[0064] (2) Oil resistance

[0065] The foaming agent was thoroughly dissolved in 100 mL of water and heated to 50 °C. Then, 10 g of white oil (3#) was added, and the mixture was stirred at 10000 r / min for 1 min using a high-speed mixer. The resulting foam slurry was then poured into a graduated cylinder, and the foam volume and the time it took for 50 mL of foaming base liquid to separate were recorded as the foam half-life. The results are as follows:

[0066] Surfactant type foaming volume / mL half-life / min Example 1 350 4.8 Example 2 560 7.0 Example 3 520 6.5 Example 4 390 5.1 Example 5 550 6.7 Example 6 360 4.8 Comparative Example 1 120 /

[0067] As can be seen from the two tables above, the foaming agent prepared in Comparative Example 1 under the same conditions has poor resistance to salt and oil pollution and is difficult to form stable foam; while the foaming agent prepared in the embodiments of the present invention has good resistance to salt and oil pollution and still has good foaming performance and foam stability under high salt and oil pollution conditions.

[0068] The foaming agent for microbubble drilling fluid prepared by this invention has good anti-pollution properties and can be used to formulate microbubble drilling fluids with high resistance to salt and oil pollution.

[0069] While the invention has been described and illustrated with reference to specific embodiments thereof, such description and illustration are not intended to limit the invention. It will be readily understood by those skilled in the art that various changes may be made to suit particular circumstances, materials, compositions, substances, methods, or processes to the objectives, spirit, and scope of this application without departing from the true spirit and scope of the invention as defined by the appended claims. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a particular order, it should be understood that these operations may be combined, subdivided, or reordered to form equivalent methods without departing from the teachings of the invention. Therefore, unless specifically indicated herein, the order and grouping of operations are not a limitation of this application.

Claims

1. A method for preparing a foaming agent for microbubble drilling fluid, comprising: A fluorinated compound, an acid-binding agent, an organic solvent, and an amine compound are subjected to a first reaction to obtain a first reactant. The fluorinated compound is selected from one or more of hexafluoropropylene dimer and hexafluoropropylene trimer; the amine compound is selected from one or more of N,N-dimethylethylenediamine, N,N-dimethylpropylenediamine, N,N-dimethylbutanediamine, N,N-diethylethylenediamine, N,N-diethylpropylenediamine, and N,N-diethylbutanediamine; the temperature of the first reaction is 0~60℃, and the time is 2~12h; Sodium bisulfite, water, and epichlorohydrin are subjected to a second reaction to obtain a second reactant; the temperature of the second reaction is 50~90℃ and the time is 1~8h. The first reactant and the second reactant are subjected to a third reaction to obtain a foaming agent for microbubble drilling fluid with formula I; the temperature of the third reaction is 60~100℃ and the time is 2~12h. Formula I; In Equation I, R1 = C6F 11 Or C9F 17 R2 = CH3 or C2H5, where n is an integer from 2 to 4.

2. The method according to claim 1, characterized in that, The acid-binding agent is selected from one or more of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and triethylamine.

3. The method according to claim 1, characterized in that, The organic solvent is selected from one or more of diethyl ether, dichloromethane, and ethyl acetate.

4. The method according to claim 1, characterized in that, The ratio of the fluorinated compound, acid-binding agent, organic solvent, and amine compound is 1 mol : (0.5~1.5) mol : (100~500) mL : (0.8~1.5) mol; The ratio of sodium bisulfite, water, and epichlorohydrin used is (0.8~1.5) mol : (200~1000) mL : (0.8~1.5) mol; The molar ratio of the fluorine-containing compound to sodium bisulfite is 1:(0.8~1.5).

Images