Sand scouring composition and sand scouring liquid

Abstract

The present invention relates to a sand washing composition and a sand washing liquid, and belongs to the technical field of oil and gas field chemistry. The sand washing composition of the present invention is composed of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil; the mass ratio of the alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil is (24-29): (8-13): (4-6): (2-3.5). The sand washing composition of the present invention is composed of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and polyacrylamide, wherein the alkylphenol polyoxyethylene ether is used as a foaming agent, the fatty alcohol polyoxyethylene ether is used as a foam stabilizer, and the polyacrylamide is used as a thickener. When the sand washing composition of the present invention is used for sand washing operations, it has the advantages of simple preparation process, strong sand carrying capacity and short recovery period after operation.

Description

Technical Field

[0001] The invention relates to a sand flushing composition and sand flushing liquid, belonging to the technical field of oil and gas field chemistry. Background Art

[0002] In the middle and late stages of oil and gas field development, some wells will experience varying degrees of sand production. Once sand is produced, it will seriously affect production capacity and even cause the oil and gas wells to stop production. In order to restore production capacity, it is necessary to perform sand flushing operations on the oil and gas wells that produce sand. Sand flushing operations use sand flushing fluid to disperse the sand plug at the bottom of the well, and use the carrying capacity of the liquid circulation to bring the dispersed sand out of the ground, remove the sand in the wellbore, and restore the reservoir production capacity of the sand buried section of the oil and gas well.

[0003] The existing sand flushing fluids include six types: clean water, clean water + clay stabilizer + active treatment agent, clean water + polymer + clay stabilizer + active treatment agent, clean water + polymer + solid phase particles + active treatment agent, clean water + polymer + cross-linking agent + active treatment agent, clean water + foaming agent + polymer + cross-linking agent + active treatment agent. The advantage of clean water is low cost, and the disadvantage is large leakage, severe reservoir damage, poor sand carrying capacity, and slow production capacity recovery. The advantage of clean water + clay stabilizer + active treatment agent is less damage than clean water, and the disadvantage is poor plugging and sand carrying capacity, and a long recovery period after operation. The advantages of clean water + polymer + clay stabilizer + active treatment agent are strong sand carrying capacity and good reservoir compatibility, and the disadvantage is poor plugging performance and difficult recovery after operation. The advantages of clean water + polymer + solid phase particles + active treatment agent are strong sand carrying capacity, good plugging performance, and good reservoir compatibility, and the disadvantage is poor reservoir permeability recovery. The advantages of clean water + polymer + cross-linking agent + active treatment agent are good plugging and sand carrying capacity and good reservoir compatibility, while the disadvantages are difficulty in breaking gel and poor reservoir permeability recovery. The advantages of clean water + foaming agent + polymer + cross-linking agent + active treatment agent are good plugging performance, strong sand carrying capacity, good reservoir compatibility and good reservoir permeability recovery, while the disadvantages are high cost, many materials and complicated preparation process. Based on the problems existing in the current sand flushing fluid, it is urgent to develop a sand flushing fluid with a simple preparation process, strong sand carrying capacity and short recovery period after operation. Summary of the invention

[0004] The purpose of the present invention is to provide a sand flushing composition, which is used to solve the problems of complex preparation process, poor sand carrying capacity and long recovery period after operation of the current sand flushing fluid.

[0005] Another object of the present invention is to provide a sand flushing liquid.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the sand scouring composition of the present invention is:

[0007] A sand blasting composition is composed of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil; the mass ratio of the alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil is (24-29):(8-13):(4-6):(2-3.5).

[0008] The sand washing composition of the present invention is composed of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil, wherein the alkylphenol polyoxyethylene ether is used as a foaming agent and an emulsifier, the fatty alcohol polyoxyethylene ether is used as a foam stabilizer and an emulsifier, the polyacrylamide is used as a thickener, and the white oil is an oil phase solvent. When the sand washing composition of the present invention is used for sand washing operations, it has the advantages of simple preparation process, strong sand carrying capacity, and short recovery period after operation.

[0009] Preferably, the mass ratio of the alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil is 28.6:12.3:6:3.1.

[0010] Preferably, the alkylphenol polyoxyethylene ether is C 17 -C 51 Alkylphenol polyoxyethylene ether. Preferably, the viscosity average molecular weight of the alkylphenol polyoxyethylene ether is 300 to 1000. For example, the viscosity average molecular weight of the alkylphenol polyoxyethylene ether is 900. As a foaming agent, the alkylphenol polyoxyethylene ether has the advantages of large foaming volume and long half-life.

[0011] Preferably, the alkylphenol polyoxyethylene ether is nonylphenol polyoxyethylene ether.

[0012] Preferably, the fatty alcohol polyoxyethylene ether is C 19 -C 32 Fatty alcohol polyoxyethylene ether. Preferably, the viscosity average molecular weight of the fatty alcohol polyoxyethylene ether is 300 to 700. For example, the viscosity average molecular weight of the fatty alcohol polyoxyethylene ether is 500. Fatty alcohol polyoxyethylene ether, as a foam stabilizer, has the advantage of extending the half-life of the foam.

[0013] Preferably, the fatty alcohol polyoxyethylene ether is stearyl alcohol polyoxyethylene ether. Alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether are non-ionic surfactants, with ether groups that do not dissociate in aqueous solution as the main hydrophilic groups, and have high surface activity, good solubilization, washing, antistatic, calcium soap dispersion and other properties, low irritation, and excellent wetting and washing functions, and a pH range wider than that of general ionic surfactants. When the sand washing composition of the present invention is used for sand washing operations, the hydrophilic groups in the alkylphenol polyoxyethylene ether and the fatty alcohol polyoxyethylene ether are inserted into the water phase, and the lipophilic groups are inserted into the oil phase or stand upright in the air, forming a directional arrangement on the interface layer or surface, thereby reducing the interfacial tension or surface tension.

[0014] Preferably, the viscosity average molecular weight of the polyacrylamide is 20000 to 200000. For example, the viscosity average molecular weight of the polyacrylamide is 100000. As a thickener, polyacrylamide has the advantages of good dispersibility, low cost and fast viscosity increase.

[0015] The technical solution adopted by the sand washing fluid of the present invention is:

[0016] A sand flushing liquid mainly consists of water and the above-mentioned sand flushing composition; the mass fraction of the sand flushing composition in the sand flushing liquid is 0.4-1.5%.

[0017] The sand flushing fluid of the present invention has the advantages of simple preparation process, strong sand carrying capacity and short recovery period after operation.

[0018] Preferably, the sand flushing liquid is mainly composed of water and the sand flushing composition; the mass fraction of the sand flushing composition in the sand flushing liquid is 0.4-0.5%.

[0019] Preferably, the sand washing liquid is a mixture of water, an alkylphenol polyoxyethylene ether aqueous solution, a fatty alcohol polyoxyethylene ether aqueous solution and a polyacrylamide emulsion; the polyacrylamide emulsion is composed of nonylphenol polyoxyethylene ether, stearyl alcohol polyoxyethylene ether, polyacrylamide and white oil.

[0020] Preferably, the mass fraction of the alkylphenol polyoxyethylene ether aqueous solution is 20%; the mass fraction of the fatty alcohol polyoxyethylene ether aqueous solution is 20%; the mass fraction of polyacrylamide in the polyacrylamide emulsion is 60%, the mass fraction of white oil is 31%, the mass fraction of nonylphenol polyoxyethylene ether is 6%, and the mass fraction of stearyl alcohol polyoxyethylene ether is 3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a relationship diagram between the foaming volume of the foam liquid prepared by the sand washing liquid of the comparative example 1-5 in the experimental example and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution;

[0022] Figure 2 The graph is a relationship between the half-life of the foam liquid prepared by the sand washing liquid of the comparative example 1-5 in the experimental example and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution;

[0023] Figure 3 It is a relationship diagram between the foaming volume of the foam liquid prepared by the sand washing liquid of the comparative example 6-10 in the experimental example and the mass fraction of the stearyl alcohol polyoxyethylene ether aqueous solution;

[0024] Figure 4 The graph is a relationship between the half-life of the foam liquid prepared by the sand washing liquid of the comparative example 6-10 in the experimental example and the mass fraction of the stearyl alcohol polyoxyethylene ether aqueous solution;

[0025] Figure 5 The graph is a relationship between the foaming volume of the water-based foam liquid prepared by the sand-washing liquid of the comparative examples 1-10 in the experimental examples and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution;

[0026] Figure 6 The graph is a relationship between the half-life of the water-based foam liquid prepared by the sand washing liquid of the comparative examples 1-10 in the experimental examples and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution;

[0027] Figure 7 The graph is a relationship between the foaming volume of the backflow liquid-based foam liquid prepared by the sand flushing liquid of the comparative example 1-10 in the experimental example and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution;

[0028] Figure 8 This is a relationship diagram between the half-life of the flowback liquid-based foam liquid prepared by using the sand flushing liquid of Comparative Examples 1-10 in the experimental examples and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0030] The viscosity average molecular weight of the nonylphenol polyoxyethylene ether used in the embodiment of the present invention, the comparative example and the polyacrylamide emulsion is 900, the viscosity average molecular weight of stearyl alcohol polyoxyethylene ether is 500, and the viscosity average molecular weight of polyacrylamide is 100000. The mass fractions of the nonylphenol polyoxyethylene ether aqueous solution and the stearyl alcohol polyoxyethylene ether aqueous solution are both 20%. The polyacrylamide emulsion is composed of nonylphenol polyoxyethylene ether, stearyl alcohol polyoxyethylene ether, polyacrylamide and white oil, wherein the mass fraction of polyacrylamide in the polyacrylamide emulsion is 60%, the mass fraction of white oil is 31%, the mass fraction of nonylphenol polyoxyethylene ether is 6%, and the mass fraction of stearyl alcohol polyoxyethylene ether is 3%.

[0031] 1. The specific embodiments of the sand washing composition of the present invention are as follows:

[0032] Example 1

[0033] The sand blasting composition of the present embodiment is composed of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil; the mass ratio of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil is 24.6:12.3:6:3.1. In the present embodiment, the alkylphenol polyoxyethylene ether is nonylphenol polyoxyethylene ether, and the fatty alcohol polyoxyethylene ether is stearyl alcohol polyoxyethylene ether.

[0034] Example 2

[0035] The sand scouring composition of this embodiment is different from the sand scouring composition of Embodiment 1 only in that the mass ratio of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil is 28.6:12.3:6:3.1.

[0036] Example 3

[0037] The sand scouring composition of this embodiment is different from the sand scouring composition of Embodiment 1 only in that the mass ratio of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil is 24.6:8.3:6:3.1.

[0038] Example 4

[0039] The sand scouring composition of this embodiment is different from the sand scouring composition of Embodiment 1 only in that the mass ratio of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyacrylamide and white oil is 24.48:12.24:4.8:2.48.

[0040] Second, the specific embodiments of the sand washing liquid of the present invention are as follows:

[0041] Example 5

[0042] The sand washing liquid of this embodiment is composed of water and the sand washing composition of embodiment 1. The mass fraction of the sand washing composition of embodiment 1 in the sand washing liquid is 0.46%.

[0043] The sand washing liquid of this embodiment is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98.1:1.2:0.6:0.1.

[0044] Example 6

[0045] The sand washing liquid of this embodiment is composed of water and the sand washing composition of embodiment 2. The mass fraction of the sand washing composition of embodiment 2 in the sand washing liquid is 0.5%.

[0046] The sand washing liquid of this embodiment is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 97.9:1.4:0.6:0.1.

[0047] Example 7

[0048] The sand washing liquid of this embodiment is composed of water and the sand washing composition of embodiment 3. The mass fraction of the sand washing composition of embodiment 3 in the sand washing liquid is 0.42%.

[0049] The sand washing liquid of this embodiment is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98.3:1.2:0.4:0.1.

[0050] Example 8

[0051] The sand washing liquid of this embodiment is composed of water and the sand washing composition of embodiment 4. The mass fraction of the sand washing composition of embodiment 4 in the sand washing liquid is 0.44%.

[0052] The sand washing liquid of this embodiment is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98.12:1.2:0.6:0.08.

[0053] Comparative Example 1

[0054] The sand washing liquid of this comparative example is composed of water and nonylphenol polyoxyethylene ether, and the mass fraction of nonylphenol polyoxyethylene ether in the sand washing liquid is 0.04%; the sand washing liquid of this comparative example is obtained by mixing water and nonylphenol polyoxyethylene ether aqueous solution.

[0055] Comparative Example 2

[0056] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 1 is that the mass fraction of nonylphenol polyoxyethylene ether in the sand washing liquid is 0.08%.

[0057] Comparative Example 3

[0058] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 1 is that the mass fraction of nonylphenol polyoxyethylene ether in the sand washing liquid is 0.12%.

[0059] Comparative Example 4

[0060] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 1 is that the mass fraction of nonylphenol polyoxyethylene ether in the sand washing liquid is 0.16%.

[0061] Comparative Example 5

[0062] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 1 is that the mass fraction of nonylphenol polyoxyethylene ether in the sand washing liquid is 0.2%.

[0063] Comparative Example 6

[0064] The sand washing liquid of this comparative example is composed of water and stearyl alcohol polyoxyethylene ether, and the mass fraction of stearyl alcohol polyoxyethylene ether in the sand washing liquid is 0.04%; the sand washing liquid of this comparative example is obtained by mixing water and stearyl alcohol polyoxyethylene ether aqueous solution.

[0065] Comparative Example 7

[0066] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 6 is that the mass fraction of stearyl alcohol polyoxyethylene ether in the sand washing liquid is 0.08%.

[0067] Comparative Example 8

[0068] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 6 is that the mass fraction of stearyl alcohol polyoxyethylene ether in the sand washing liquid is 0.12%.

[0069] Comparative Example 9

[0070] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 6 is that the mass fraction of stearyl alcohol polyoxyethylene ether in the sand washing liquid is 0.16%.

[0071] Comparative Example 10

[0072] The difference between the sand washing liquid of this comparative example and the sand washing liquid of comparative example 6 is that the mass fraction of stearyl alcohol polyoxyethylene ether in the sand washing liquid is 0.2%.

[0073] Comparative Example 11

[0074] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution and stearyl alcohol polyoxyethylene ether aqueous solution in a mass ratio of 98.2:1.2:0.6.

[0075] Comparative Example 12

[0076] The sand washing liquid of this comparative example is obtained by mixing water, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 99.3:0.6:0.1.

[0077] Comparative Example 13

[0078] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98.7:1.2:0.1.

[0079] Comparative Example 14

[0080] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 97.7:1.6:0.6:0.1.

[0081] Comparative Example 15

[0082] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 97.9:1.2:0.8:0.1.

[0083] Comparative Example 16

[0084] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98:1.2:0.6:0.2.

[0085] Comparative Example 17

[0086] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98.3:1.0:0.6:0.1.

[0087] Comparative Example 18

[0088] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98.5:1.2:0.2:0.1.

[0089] Comparative Example 19

[0090] The sand washing liquid of this comparative example is obtained by mixing water, nonylphenol polyoxyethylene ether aqueous solution, stearyl alcohol polyoxyethylene ether aqueous solution and polyacrylamide emulsion in a mass ratio of 98.14:1.2:0.6:0.06.

[0091] Experimental Example 1

[0092] In order to investigate the influence of clean water and flowback fluid on the performance of the prepared sand flushing fluid, clean water was first used to prepare the corresponding clean water-based foam liquid according to the formula and preparation method of the sand flushing fluid of Example 2 and Comparative Examples 1-10, and then the reservoir flowback fluid was used to replace the water to prepare the corresponding flowback liquid-based foam liquid according to the formula and preparation method of the sand flushing fluid of Example 2 and Comparative Examples 1-10, and then 150 mL of clean water-based foam liquid or flowback liquid-based foam liquid was taken respectively, and then the foam liquid was stirred for 60 seconds at a speed of 5000 r / min and a temperature of 20°C, and the foaming volume was observed and the half-life was recorded. The experimental results are shown in Table 1.

[0093] Table 1 Foaming volume and half-life of clean water, clean water-based foam liquid and backflow liquid-based foam liquid prepared according to the formula and preparation method of Example 2 and Comparative Examples 1-10

[0094]

[0095]

[0096] Taking the nonylphenol polyoxyethylene ether aqueous solution and stearyl alcohol polyoxyethylene ether aqueous solution with a mass fraction of 20% as the benchmark:

[0097] When 100 parts by mass of foam liquid (clear water-based foam liquid or backflow liquid-based foam liquid) are prepared using clear water, the parts by mass of the nonylphenol polyoxyethylene ether aqueous solution and the stearyl alcohol polyoxyethylene ether aqueous solution used are both 0 parts.

[0098] The mass fractions of 20% nonylphenol polyoxyethylene ether aqueous solution used to prepare 100 mass parts of the water-based foam liquid or backflow liquid-based foam liquid corresponding to the sand flushing liquid of comparative examples 1-5 are 0.2, 0.4, 0.6, 0.8 and 1 part respectively.

[0099] The mass fractions of 20% stearyl alcohol polyoxyethylene ether aqueous solution used to prepare 100 mass parts of the clear water-based foam liquid or backflow liquid-based foam liquid corresponding to the sand flushing liquid of comparative examples 6-10 are 0.2, 0.4, 0.6, 0.8 and 1 part respectively.

[0100] In order to more intuitively compare the effects of the mass fractions of nonylphenol polyoxyethylene ether and stearyl alcohol polyoxyethylene ether in the sand washing liquid (clear water-based foam liquid or backflow liquid-based foam liquid) on the foaming volume and half-life of the sand washing liquid, the mass fractions of 20% nonylphenol polyoxyethylene ether aqueous solution or stearyl alcohol polyoxyethylene ether aqueous solution used to prepare 100 mass parts of the clear water-based foam liquid or backflow liquid-based foam liquid corresponding to the sand washing liquid of the formula of Comparative Examples 1-10 are used as the abscissa, and the foaming volume and half-life of the foam liquid are used as the ordinate for plotting. The results are shown in FIG. Figure 1-8 shown.

[0101] Figure 1 The relationship between the foaming volume of the foam liquid prepared by the sand washing liquid of the comparative example 1-5 and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution is shown in FIG. Figure 2 The relationship between the half-life of the foam liquid prepared by the sand washing liquid of the comparative example 1-5 and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution is shown in FIG. Figure 3 The relationship between the foaming volume of the foam liquid prepared by the sand washing liquid of the comparative example 6-10 and the mass fraction of the stearyl alcohol polyoxyethylene ether aqueous solution is shown in FIG. Figure 4 The relationship between the half-life of the foam liquid prepared by the sand washing liquid of the comparative example 6-10 and the mass fraction of the stearyl alcohol polyoxyethylene ether aqueous solution is shown in FIG. Figure 5 The relationship between the foaming volume of the water-based foam liquid prepared by using the sand washing liquid of the comparative examples 1-10 and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution is shown in FIG. Figure 6 The graph is a relationship between the half-life of the water-based foam liquid prepared by using the sand washing liquid of Comparative Examples 1-10 and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution, Figure 7The relationship between the foaming volume of the backflow liquid-based foam liquid prepared by using the sand flushing liquid of the formula of Comparative Examples 1-10 and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution is shown in FIG. Figure 8 The graph is a relationship between the half-life of the flowback liquid-based foam liquid prepared by using the sand flushing liquid of the formula of Comparative Examples 1-10 and the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution.

[0102] From Table 1 and Figure 1-8 It can be seen that the foaming volume and half-life of the foam liquid prepared by the sand washing liquid of the comparative example 1-10 cannot meet the requirements; when the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution used to prepare 100 mass parts of the foam liquid is less than 0.8 parts, the performance of the water-based foam liquid prepared by using the same mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution is almost the same; when the mass fraction of the nonylphenol polyoxyethylene ether aqueous solution or the stearyl alcohol polyoxyethylene ether aqueous solution used to prepare 100 mass parts of the foam liquid is greater than 0.8 parts, the performance of the water-based foam liquid prepared by using the nonylphenol polyoxyethylene ether aqueous solution is better than the performance of the water-based foam liquid prepared by using the same mass fraction of the stearyl alcohol polyoxyethylene ether aqueous solution.

[0103] Experimental Example 2

[0104] The surface tension and sand settling rate of the sand washing liquids of Examples 5-8 and Comparative Examples 11-19 at 20°C were tested using a SIGMA700 surface tension tester and a measuring cylinder method, and 150 mL of the sand washing liquids of Examples 5-8 and Comparative Examples 11-19 were taken, respectively, and stirred for 60 seconds at a speed of 5000 r / min and a temperature of 20°C, and the foaming volume was observed and the half-life was recorded. The experimental results are shown in Table 2.

[0105] Table 2 Surface tension and sand settling rate of sand washing solution at 20°C of Examples 5-8 and Comparative Examples 11-19

[0106]

[0107]

[0108] Experimental Example 3

[0109] The sand flushing fluids of Examples 5-8 and Comparative Examples 11-19 were used to perform sand flushing operations (the oil wells used for the sand flushing operations were similar, and each sand flushing fluid was used to complete the sand flushing operations for 3 wells). The amount of sand flushing fluid used was 100m 3 , record the average amount of sand cleaned out, calculate the average sand ratio (the ratio of the average amount of sand cleaned out to the amount of sand flushing fluid used), and then record the average production recovery period. The experimental results are shown in Table 3.

[0110] Table 3 Average amount of sand removed, average sand ratio and average production recovery period when sand flushing operation is performed using the sand flushing fluids of Examples 5-8 and Comparative Examples 11-19

[0111] Sand washing fluid <![CDATA[Average amount of sand cleared (m 3 )]]> Average sand ratio (%) Average production recovery cycle (days) Example 5 5.8 5.8 1 Example 6 5.1 6.6 0.5 Example 7 5.7 5.8 0.8 Example 8 5.0 5.9 0.9 Comparative Example 11 7.2 6.2 1.3 Comparative Example 12 5.1 4.2 1.5 Comparative Example 13 6.6 5.9 1.3 Comparative Example 14 5.4 4.6 1.2 Comparative Example 15 4.3 5.2 1.4 Comparative Example 16 7.1 5.5 0.8 Comparative Example 17 6.3 5.1 1.1 Comparative Example 18 5.2 4.9 1.4 Comparative Example 19 5.4 3.8 1.4

[0112] The results show that although the sand washing fluid of Comparative Example 16 has better performance, the cost of the sand washing fluid of Comparative Example 16 is also high because the mass of the added polyacrylamide emulsion is large and the cost of the polyacrylamide emulsion is high. When the sand washing fluids of Examples 5-8 are used for sand washing operations, the average amount of sand cleaned out is 5.8m 3 、5.1m 3 、5.7m 3 and 5.0m 3 , the average sand ratio reached 5.8%, 6.6%, 5.8% and 5.9% respectively, protecting the reservoir, and the average production recovery period was 1 day, 0.5 day, 0.8 day and 0.9 day respectively. It shows that the sand flushing fluid of the present invention has low liquid column pressure in the wellbore, which reduces the loss of the reservoir; due to the low surface tension, the capillary resistance of the sand flushing fluid of the present invention in the reservoir is small, which is convenient for backflow; the friction resistance is low, which reduces the power load; and the sand flushing fluid of the present invention has good compatibility with the reservoir, which increases the single well production.

Claims

1. A sand washing composition, characterized in that: The invention is composed of nonylphenol polyoxyethylene ether, stearyl alcohol polyoxyethylene ether, polyacrylamide and white oil; the mass ratio of the nonylphenol polyoxyethylene ether, stearyl alcohol polyoxyethylene ether, polyacrylamide and white oil is (24-29):(8-13):(4-6):(2-3.5); the viscosity average molecular weight of the nonylphenol polyoxyethylene ether is 300-1000; the viscosity average molecular weight of the stearyl alcohol polyoxyethylene ether is 300-700; and the viscosity average molecular weight of the polyacrylamide is 20000-200000.

2. The sand blasting composition according to claim 1, characterized in that The mass ratio of the nonylphenol polyoxyethylene ether, stearyl alcohol polyoxyethylene ether, polyacrylamide and white oil is 28.6:12.3:6:3.

1.

3. A sand washing liquid, characterized in that: The sand washing liquid mainly consists of water and the sand washing composition according to claim 1 or 2; the mass fraction of the sand washing composition in the sand washing liquid is 0.4-1.5%.

4. The sand washing liquid according to claim 3, characterized in that: The invention is prepared by mixing water, a nonylphenol polyoxyethylene ether aqueous solution, a stearyl alcohol polyoxyethylene ether aqueous solution and a polyacrylamide emulsion; the polyacrylamide emulsion is composed of nonylphenol polyoxyethylene ether, stearyl alcohol polyoxyethylene ether, polyacrylamide and white oil.

5. The sand washing liquid according to claim 4, characterized in that: The mass fraction of the nonylphenol polyoxyethylene ether aqueous solution is 20%; the mass fraction of the stearyl alcohol polyoxyethylene ether aqueous solution is 20%; the mass fraction of polyacrylamide in the polyacrylamide emulsion is 60%, the mass fraction of white oil is 31%, the mass fraction of nonylphenol polyoxyethylene ether is 6%, and the mass fraction of stearyl alcohol polyoxyethylene ether is 3%.

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