Graphene oxide and polymer composite filtrate reducer for water-based drilling fluid and preparation method of graphene oxide and polymer composite filtrate reducer

Abstract

The invention relates to the field of oilfield chemistry, and discloses a graphene oxide and polymer composite filtrate reducer for water-based drilling fluid and a preparation method of the graphene oxide and polymer composite filtrate reducer. The method specifically comprises the following steps: (1) adding graphene oxide powder into distilled water, stirring and performing ultrasonic treatment to obtain a graphene oxide aqueous solution for later use; (2) sequentially adding functional monomers, namely 2-acrylamide-2-methyl-1-propanesulfonic acid, 4-acryloylmorpholine and N, N-dimethylacrylamide into the graphene oxide aqueous solution for later use, and uniformly stirring; (3) adding ammonium persulfate and sodium hydrogen sulfite, heating in a water bath to a temperature required by reaction, and introducing nitrogen to wait for reaction; and (4) after the reaction is finished, washing with ethanol, drying, and crushing to obtain the graphene oxide and polymer composite filtrate reducer for the water-based drilling fluid. According to the invention, graphene oxide sheets are utilized to cover pores and polymer chains are utilized to connect bentonite particles, so that the water-based drilling fluid containing the filtrate reducer can resist the temperature of 220 DEG C, can resist salt by 15%, and can be applied to drilling of deep wells and ultra-deep wells.

Description

Technical Field

[0001] The invention relates to the field of oilfield chemistry, and in particular to a graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid and a preparation method thereof. Background Art

[0002] With the continuous development of society, the existing oil and gas resources are no longer sufficient to meet the growing demand. Therefore, the exploration and development of oil and gas resources needs to move towards deep and ultra-deep layers. In the complex environment of deep and ultra-deep layers, the drilling fluid used for drilling faces huge challenges of high temperature and high salt. Although the use of oil-based drilling fluid can withstand the complex situation of high temperature and high salt, its use is greatly restricted due to cost and environmental pollution. On the contrary, water-based drilling fluid has become the best choice for deep and ultra-deep drilling due to its low cost and low pollution.

[0003] At present, the fluid loss reducers used in water-based drilling fluids are mostly high molecular polymers, and the high molecular polymers commonly used in drilling sites have poor temperature resistance. When faced with high temperatures in deep layers, the polymer chains will break due to the high temperature, causing the bentonite particles to agglomerate and the fluid loss reduction effect to drop sharply. If high salt levels are encountered, the polymer chains will also curl due to salt invasion, causing the bentonite particles to agglomerate, resulting in poor fluid loss reduction effects.

[0004] Therefore, it is particularly important to develop a temperature-resistant and salt-resistant filtration reducer for water-based drilling fluids in deep and ultra-deep layers. Summary of the invention

[0005] In order to solve the problem that the existing water-based drilling fluid loss reducer cannot cope with the high temperature and high salt in deep and ultra-deep layers, the present invention provides a graphene oxide and polymer composite loss reducer for water-based drilling fluid and a preparation method thereof.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a method for preparing a graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid, and the specific preparation method comprises the following steps:

[0007] (1) adding graphene oxide powder to distilled water, stirring and ultrasonicating to obtain a graphene oxide aqueous solution for later use;

[0008] (2) adding functional monomers 2-acrylamide-2-methyl-1-propane sulfonic acid, 4-acryloylmorpholine, and N,N-dimethylacrylamide to the above-mentioned reserved graphene oxide aqueous solution in sequence, and stirring to form a mixed solution;

[0009] (3) adding initiators ammonium persulfate and sodium bisulfite to the mixed solution, heating the mixture in a water bath to the required reaction temperature, passing nitrogen gas and waiting for the reaction;

[0010] (4) After the reaction is completed, the product is washed with ethanol, dried, and crushed to obtain a composite fluid loss reducer of graphene oxide and polymer.

[0011] Preferably according to the present invention, the weight ratio of graphene oxide powder: distilled water is 0.2: (70-90).

[0012] Preferably according to the present invention, the weight ratio of graphene oxide aqueous solution: monomer 2-acrylamide-2-methyl-1-propane sulfonic acid: 4-acryloylmorpholine: N,N-dimethylacrylamide is 1: (12-14): (1-3): (4-6).

[0013] Preferably according to the present invention, the weight ratio of ammonium persulfate:sodium bisulfite is 0.72:0.24.

[0014] Preferably according to the present invention, the stirring rate is 800 rpm / / min, the stirring time is 10 min; the ultrasonic power is 1200 w, the ultrasonic time is 10 min; the reaction temperature is 50°C; the reaction time is 2 h; the washing is 3 times of ethanol washing; the drying temperature is 60°C; and the drying time is 24 h.

[0015] The second aspect of the present invention provides a graphene oxide and polymer composite fluid loss reducer prepared by the method described in the first aspect.

[0016] The third aspect of the present invention provides the use of the graphene oxide and polymer composite described in the second aspect as a fluid loss reducer in a water-based drilling fluid.

[0017] A fourth aspect of the present invention provides a water-based drilling fluid, which contains a bentonite-based slurry and the above-mentioned graphene oxide and polymer composite fluid loss reducer; preferably, every 400 mL of the bentonite-based slurry contains 12 parts by weight of the graphene oxide and polymer composite fluid loss reducer.

[0018] According to the present invention, the method for preparing bentonite-based slurry is already disclosed in the field of oilfield chemistry, and the specific method is as follows:

[0019] 400 mL of clean water, 16 parts by weight of bentonite, and 0.8 parts by weight of anhydrous sodium carbonate were weighed and uniformly stirred at a stirring rate of 1000 rpm / min, and sealed and cured at room temperature for 24 hours to obtain a bentonite-based slurry.

[0020] The technical features and beneficial effects of the present invention are as follows:

[0021] The present invention discloses a composite fluid loss reducer of graphene oxide and polymer for water-based drilling fluid. The composite fluid loss reducer of graphene oxide is based on graphene oxide. The primary free radicals generated by ammonium persulfate and sodium bisulfite as initiators take away the hydrogen atoms of hydroxyl and carboxyl groups on the graphene oxide, and the monomers 2-acrylamide-2-methyl-1-propane sulfonic acid, 4-acryloylmorpholine and N,N-dimethylacrylamide are linked into polymer chains by breaking the carbon-carbon double bonds, and the polymer chains are finally grafted onto the graphene oxide. The composite fluid loss reducer of graphene oxide and polymer combines the advantages of nanomaterials and polymers. On the one hand, the pores are adsorbed and attached by graphene oxide sheets to reduce the fluid loss; on the other hand, the amide groups, sulfonic acid groups, morpholine rings, methyl groups, etc. in the polymer chains increase the temperature resistance, salt resistance, hydrophilicity and other properties of the composite fluid loss reducer of graphene oxide and polymer for water-based drilling fluid. The synergistic effects in many aspects make the water-based drilling fluid containing the graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid still have good fluid loss reduction performance in the harsh environment of 220°C and 15% NaCl. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an infrared spectrum of the graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid prepared in Preparation Example 1;

[0023] Figure 2 This is a thermogravimetric analysis curve of the graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid prepared in Preparation Example 1;

[0024] Figure 3 The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid prepared in Example 1 1 H NMR spectrum; DETAILED DESCRIPTION

[0025] To further explain the present invention, the advantages of the present invention will be described below in conjunction with the preparation examples, implementation examples, and comparative examples of the present invention. It should be understood that the following preparation examples and embodiments are only a small part of the possible situations in the present invention and cannot cover the entire situation of the present invention. Therefore, all preparation examples and embodiments within the scope of the present invention should belong to the protection scope of the present invention.

[0026] The preparation example of the present invention is as follows:

[0027] Preparation Example 1

[0028] (1) Weighing 0.2 parts by weight of graphene oxide powder, adding it to a beaker containing 80 parts by weight of distilled water, stirring at a stirring rate of 800 rpm / min for 10 min, and then ultrasonicating at an ultrasonic power of 1200 w for 10 min to obtain a graphene oxide aqueous solution;

[0029] (2) mixing graphene oxide aqueous solution: monomer 2-acrylamide-2-methyl-1-propane sulfonic acid: 4-acryloylmorpholine: N,N-dimethylacrylamide in a weight ratio of 1:13:2:5 in a beaker, and stirring at a stirring rate of 800 rpm / min for 10 minutes to form a mixed solution;

[0030] (3) The mixed solution was transferred to a three-necked flask, and 0.72 parts by weight of ammonium persulfate and 0.24 parts by weight of sodium bisulfite as initiators were added. The mixture was heated to 50° C. in a water bath, nitrogen was introduced, and the reaction was allowed to proceed for 2 h.

[0031] (4) After the reaction is completed, the product is washed with anhydrous ethanol for three times and dried in an oven at 60° C. for 24 h. Finally, the dried product is crushed to obtain a graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid (denoted as G1).

[0032] Preparation Example 2

[0033] (1) Weighing 0.2 parts by weight of graphene oxide powder, adding it to a beaker containing 70 parts by weight of distilled water, stirring at a stirring rate of 800 rpm / min for 10 min, and then ultrasonicating at an ultrasonic power of 1200 w for 10 min to obtain a graphene oxide aqueous solution;

[0034] (2) mixing graphene oxide aqueous solution: monomer 2-acrylamide-2-methyl-1-propane sulfonic acid: 4-acryloylmorpholine: N,N-dimethylacrylamide in a weight ratio of 1:12:1:4 in a beaker, and stirring at a stirring rate of 800 rpm / min for 10 min to form a mixed solution;

[0035] (3) The mixed solution was transferred to a three-necked flask, and 0.72 parts by weight of ammonium persulfate and 0.24 parts by weight of sodium bisulfite as initiators were added. The mixture was heated to 50° C. in a water bath, nitrogen was introduced, and the reaction was allowed to proceed for 2 h.

[0036] (4) After the reaction is completed, the product is washed with anhydrous ethanol for three times and dried in an oven at 60° C. for 24 h. Finally, the dried product is crushed to obtain a graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid (denoted as G2).

[0037] Preparation Example 3

[0038] (1) Weighing 0.2 parts by weight of graphene oxide powder, adding it to a beaker containing 90 parts by weight of distilled water, stirring at a stirring rate of 800 rpm / min for 10 min, and then ultrasonicating at an ultrasonic power of 1200 w for 10 min to obtain a graphene oxide aqueous solution;

[0039] (2) mixing graphene oxide aqueous solution: monomer 2-acrylamide-2-methyl-1-propane sulfonic acid: 4-acryloylmorpholine: N,N-dimethylacrylamide in a weight ratio of 1:14:3:6 in a beaker, and stirring at a stirring rate of 800 rpm / min for 10 minutes to form a mixed solution;

[0040] (3) The mixed solution was transferred to a three-necked flask, and 0.72 parts by weight of ammonium persulfate and 0.24 parts by weight of sodium bisulfite as initiators were added. The mixture was heated to 50° C. in a water bath, nitrogen was introduced, and the reaction was allowed to proceed for 2 h.

[0041] (4) After the reaction is completed, the product is washed with anhydrous ethanol for three times and dried in an oven at 60° C. for 24 h. Finally, the dried product is crushed to obtain a graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid (denoted as G3).

[0042] The embodiments of the present invention are as follows:

[0043] Example 1

[0044] 12 parts by weight of the graphene oxide and polymer composite fluid loss reducer G1 for water-based drilling fluid was weighed and added to the 400 mL of bentonite-based slurry prepared in advance and stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as W1).

[0045] Example 2

[0046] 12 parts by weight of the graphene oxide and polymer composite fluid loss reducer G2 for water-based drilling fluid was weighed and added to the 400 mL of bentonite-based slurry prepared in advance and stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as W2).

[0047] Example 3

[0048] 12 parts by weight of the graphene oxide and polymer composite fluid loss reducer G3 for water-based drilling fluid was weighed and added to the 400 mL of bentonite-based slurry prepared in advance and stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as W3).

[0049] Example 4

[0050] 60 parts by weight of sodium chloride and 12 parts by weight of the graphene oxide and polymer composite fluid loss reducer G1 for water-based drilling fluid were weighed, and added to the 400 mL of bentonite-based slurry prepared in advance and stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as W4).

[0051] Example 5

[0052] 60 parts by weight of sodium chloride and 12 parts by weight of the graphene oxide and polymer composite fluid loss reducer G2 for water-based drilling fluid were weighed, and added to the 400 mL of bentonite-based slurry prepared in advance and stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as W5).

[0053] Example 6

[0054] 60 parts by weight of sodium chloride and 12 parts by weight of the graphene oxide and polymer composite fluid loss reducer G3 for water-based drilling fluid were weighed, and added to the 400 mL of bentonite-based slurry prepared in advance and stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as W6).

[0055] The comparative examples of the present invention are as follows:

[0056] Comparative Example 1

[0057] The 400 mL of the bentonite-based slurry prepared in advance was stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as D1).

[0058] Comparative Example 2

[0059] 60 parts by weight of sodium chloride was weighed and added to 400 mL of the bentonite-based slurry prepared in advance, and stirred at 6000 rpm / min for 10 min to obtain a water-based drilling fluid (denoted as D2).

[0060] In summary, the components of the embodiments and comparative examples are shown in Table 1:

[0061] Table 1

[0062]

[0063] The water-based drilling fluids (W1-W6) of Examples 1-6 and the water-based drilling fluids (D1, D2) of Comparative Examples 1-2 were tested for rheological properties and filtration properties after hot rolling at 220°C according to the test method of GB / T 16783.1-2014 (Petroleum and Natural Gas Industry, Field Testing of Drilling Fluids, Part 1: Water-Based Drilling Fluids). The rheological properties include: apparent viscosity (AV, mPa·s), plastic viscosity (PV, mPa·s), dynamic shear force (YP, Pa); the filtration properties include: low temperature and low pressure (FL API , mL) filtration test. The test results are shown in Table 2:

[0064] Table 2

[0065]

[0066] As can be seen from Table 2 above, the embodiments all reduce the filtration loss, confirming the effectiveness of the composite filtration reducer of graphene oxide and polymer; by comparing Examples W1 to W6, it can be obtained that the optimal ratio of graphene oxide and polymer composite filtration reducer for water-based drilling fluid is the ratio G1 in Example 1. From D2 and W4, it can be seen that the composite filtration reducer of graphene oxide and polymer for water-based drilling fluid can resist the pollution of 15% sodium chloride and the high temperature damage of 220°C. The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, the technical scheme 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 all belong to the protection scope of the present invention.

Claims

1. A graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid and a preparation method thereof, characterized in that: The method includes: (1) adding graphene oxide powder to distilled water, stirring and ultrasonicating to obtain a graphene oxide aqueous solution for later use; (2) adding functional monomers 2-acrylamide-2-methyl-1-propane sulfonic acid, 4-acryloylmorpholine, and N,N-dimethylacrylamide to the above-mentioned reserved graphene oxide aqueous solution in sequence, and stirring to form a mixed solution; (3) adding initiators ammonium persulfate and sodium bisulfite to the mixed solution, heating the mixture in a water bath to the required reaction temperature, passing nitrogen gas and waiting for the reaction; (4) After the reaction is completed, the product is washed with ethanol, dried, and crushed to obtain a composite fluid loss reducer of graphene oxide and polymer.

2. The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid according to claim 1, characterized in that: In step (1), the weight ratio of graphene oxide powder to distilled water is 0.2:(70-90).

3. The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid according to claim 1 and its preparation method, characterized in that: In step (2), the weight ratio of graphene oxide aqueous solution: monomer 2-acrylamide-2-methyl-1-propane sulfonic acid: 4-acryloylmorpholine: N,N-dimethylacrylamide is 1: (12-14): (1-3): (4-6).

4. The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid according to claim 1, characterized in that: In step (3), the weight ratio of ammonium persulfate:sodium bisulfite is 0.72:0.

24.

5. The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid according to claim 1, characterized in that: In step (1), the stirring rate is 800 rpm / min, and the stirring time is 10 min; the ultrasonic power is 1200 w, and the ultrasonic time is 10 min.

6. The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid according to claim 1 and the preparation method thereof, characterized in that: In step (2), the stirring rate is 800 rpm / min and the stirring time is 10 min.

7. The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid according to claim 1 and the preparation method thereof, characterized in that: In step (3), the water bath temperature required for the reaction is 50° C., and the waiting reaction time is 2 h.

8. The graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid according to claim 1 and the preparation method thereof, characterized in that: In step (4), the washing is performed by washing with ethanol for 3 times, the drying temperature is 60° C., and the drying time is 24 h.

9. A graphene oxide and polymer composite fluid loss reducer for water-based drilling fluid and a preparation method thereof, characterized in that: The antibody is prepared by the preparation method described in any one of claims 1 to 8.

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