Organic composite pulverized coal treating agent and preparation method thereof

Abstract

The invention belongs to the technical field of oil and gas field chemical engineering, and discloses an organic composite pulverized coal treating agent and a preparation method thereof. The organic composite pulverized coal treating agent is prepared from alcohol amine components, alkyl quaternary ammonium ions [NRxH4-X] < + >, alkyl quaternary phosphorus ions [PRxH4-X] < + >, 1, 3-dialkyl substituted imidazole ions [R1R3Im] < + >, N-group substituted pyridine ions [Rpy] < + >, [Emim] BF4, sodium hydroxide, an initiator and water according to a specific compatibility ratio. The organic composite pulverized coal treating agent can effectively dissolve a pulverized coal mixture existing in the extraction process of a coal-bed gas well, the content of the pulverized coal mixture is remarkably reduced, the pulverized coal mixture is completely removed or reduced to an effective range, pulverized coal is prevented from entering a pump to cause pump blockage, and a small amount of superfine pulverized coal can be prevented from entering the pump through a screen pipe to cause pump blockage. And the device is of great significance to safety protection of pipelines and equipment and guarantee of safety of the equipment and operators.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field chemical industry and relates to an organic composite coal powder treating agent and a preparation method thereof. Background Art

[0002] In the process of coalbed methane well exploitation, the most commonly used system is the oil pumping system. Conventional whole-barrel pumps are mainly used for the production pumps. Since this type of pump has problems such as coal powder sticking in the pump and coal powder sticking in the fixed valve and floating valve during operation, it is necessary to check the pump and flush the oil pumping pipe many times during the production process, which leads to frequent operation of the system and seriously affects the production rate of coalbed methane.

[0003] Due to the particularity of coalbed methane mining, sand filter screens are usually used to prevent coal powder from entering the pump and causing the pump to get stuck. However, this method still inevitably results in a small amount of extremely fine coal powder entering the pump through the screen and depositing on the fixed valve and floating valve, causing the drainage pump to fail. In addition, excessive coal powder output will also cause a large amount of coarse coal powder to sink into the gas well pocket. In severe cases, the coal powder will bury the pipe column, making it difficult to pull out the pipe column.

[0004] After consulting the data, we learned that the organic composite coal powder treatment agent has an effect on the solubility, swelling and rheological properties of coal slurry. It has excellent solubility, no special irritating odor, good thermal stability, low toxicity, and fast action. It is widely used in oil field protection practice. The compounded organic composite coal powder treatment agent can not only remove the coal powder mixture brought out by the coalbed methane well, but also inhibit the blockage of equipment and pipelines by coal powder. Therefore, in order to more effectively remove the coal powder mixture in the coalbed methane production process and ensure production safety and personnel safety, it is necessary to develop an efficient coal powder treatment agent to solve the above-mentioned problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is that most coalbed methane wells contain coal powder mixtures to varying degrees. The presence of coal powder mixtures not only causes blockage of upstream equipment, pipelines, etc., but also blocks coalbed methane seepage channels and is harmful to downstream drainage and production. Furthermore, coal powder mixtures also pose a great safety hazard to workers during on-site operations.

[0006] Based on this demand, the inventor has developed an organic composite coal powder treatment agent, which is used to remove the coal powder mixture present in the process of fracturing and transformation of coalbed methane wells, thereby reducing the blockage of downhole pipe string tools by coal powder, ensuring the timeliness of the drainage process, and increasing the effective seepage channel of the coalbed methane well, thereby increasing the effective production of coalbed methane. In order to achieve this technical purpose, the present invention adopts the following technical solution.

[0007] The present invention first provides an organic composite coal powder treating agent, wherein the organic composite coal powder treating agent uses water as a solvent. Specifically, the organic composite coal powder treating agent comprises: by weight, 10 to 15 parts of an alcohol amine component, an alkyl quaternary ammonium ion [PRxH4-X] + 5-8 parts, alkyl quaternary phosphonium ion [PRxH4-X] + 3 to 6 parts of 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 3 to 5 parts, N-substituted pyridinium ion [Rpy] + 5-8 parts, sodium hydroxide 1-5 parts, initiator 1-3 parts, [Emim] BF4 10-12 parts, water 38-62 parts.

[0008] Furthermore, in the above organic composite coal powder treatment agent, the alcoholamine component is methyldiethanolamine.

[0009] Furthermore, in the above organic composite coal powder treating agent, the alkyl quaternary ammonium ion [NRxH4-X] + Selected from: one or more of tetrabutylammonium hydrogen sulfate, tetrabutylammonium bromide, and tetrabutylammonium hydroxide.

[0010] Furthermore, in the above organic composite coal powder treating agent, the alkyl quaternary phosphonium ion [PRxH4-X] + Selected from: one or more of 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, N-butylpyridinium hexafluorophosphate, methyltributylphosphine dimethyl sulfate, ethyltributylphosphine tetrafluoroborate, tetrabutylphosphine tetrafluoroborate, and hexyltributylphosphine hexafluorophosphate.

[0011] Furthermore, in the above organic composite coal powder treating agent, the 1,3 dialkyl substituted imidazolium ion [R1R3Im] + Selected from: one or more of methyl tributylphosphine dimethyl sulfate, ethyl tributylphosphine tetrafluoroborate, tetrabutylphosphine tetrafluoroborate, and hexyl tributylphosphine hexafluorophosphate.

[0012] Furthermore, in the above organic composite coal powder treating agent, the N-substituted pyridinium ion [Rpy] + Selected from: one or more of 1-butyl-4-methylpyridinium chloride, 1-hexyl-4-methylpyridinium chloride, and 1-octyl-4-methylpyridinium tetrafluoroborate.

[0013] Furthermore, in the above organic composite coal powder treatment agent, the initiator is thiourea.

[0014] On the other hand, the present invention also provides a method for preparing the above-mentioned organic composite coal powder treatment agent, which specifically comprises: according to the above-mentioned ratio, alkyl quaternary ammonium ion [NRxH4-X] +、Alkyl quaternary phosphonium ion [PRxH4-X] + 、1,3 dialkyl substituted imidazolium ion [R1R3Im] + , N-substituted pyridinium ion [Rpy] + and [Emim]BF4 are put into a stainless steel reactor with a bottom valve. The reactor is controlled to heat up at a heating rate of 1°C / min. When the reaction temperature reaches 20°C, the amine components are added and stirred evenly. Then, sodium hydroxide and initiator are slowly added and finally water is added and stirred evenly to obtain the product.

[0015] Finally, the present invention also seeks to protect the application of the above-mentioned organic composite coal powder treatment agent: the organic composite coal powder treatment agent is used to remove coal powder in coalbed methane wells.

[0016] Furthermore, in the above application, the organic composite coal powder treating agent is diluted 100 times and then pumped into the compound fracturing fluid for use.

[0017] The mechanism of action of the organic composite coal powder treatment agent is as follows: the organic composite coal powder treatment agent can strongly interact with the organic matter in the coal, utilizing the characteristics of the coal molecular structure that has both the ability to supply hydrogen and the ability to accept hydrogen, breaking the hydrogen bonds between the small molecule phase and the network structure under the action of nucleophilic or electrophilic solvents, breaking the weaker chemical bonds in the coal structure, reducing the cross-linking degree of the coal structure, and fully stretching the cross-linked network structure, thereby achieving the purpose of dissolving the coal powder.

[0018] Compared with the prior art, the present invention "an organic composite coal powder treatment agent and its preparation method" has the following beneficial effects:

[0019] The organic composite coal powder treating agent provided by the present invention can not only remove the coal powder mixture brought out from the coalbed methane well, but also inhibit the corrosion of the coal powder mixture to equipment and pipelines. The preparation method of the organic composite coal powder treating agent is simple, easy to operate and low in cost.

[0020] The alkyl quaternary ammonium ion [NRxH4-X] selected by the present invention + 、Alkyl quaternary phosphonium ion [PRxH4-X] + Etc., are easily soluble in water, and can use water as a carrier to quickly dissolve coal powder in coalbed methane, converting the water-insoluble organic macromolecules therein into water-soluble compound salts, which are then discharged through the drainage process. The dissolution reaction can be carried out at room temperature, and the product has stable performance, is not easy to decompose, and can be biodegraded and recycled.

[0021] The organic composite coal powder treatment agent provided by the present invention has good selectivity for coal powder mixtures in various media, has the characteristics of small dosage, fast action, and no corrosion to steel. In addition, the organic composite coal powder treatment agent has a high dissolution efficiency, which can reach 38.494%.

[0022] The organic composite coal powder treatment agent provided by the present invention has a wide range of applications and can be used in coalbed methane mining, gathering, transportation, storage and transportation, etc. The application of this organic composite coal powder treatment agent can completely remove or reduce the coal powder mixture to a safe range, which is very meaningful for equipment safety and personnel safety, can generate considerable economic benefits, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram of the compatibility test results.

[0024] Figure 2 This is the effect of organic composite coal powder treating agent 1# on the resistance reduction performance of variable viscosity fracturing fluid.

[0025] Figure 3 The figure shows the changes in rheological properties of variable viscosity fracturing fluid at different shear rates when the viscosity variable agent is added at a concentration of 0.4%.

[0026] Figure 4 The figure shows the changes in rheological properties of variable viscosity fracturing fluid at different shear rates when the amount of variable viscosity agent added is 1.0%.

[0027] Figure 5 In the range below 90℃, 170s -1 Viscosity change of the variable viscosity fracturing fluid system after shearing for 120 minutes.

[0028] Figure 6 These are the test results of the effect of organic composite coal powder treatment agent on the dispersibility of variable viscosity fracturing fluid. Figure 6 In the figure, from left to right are: clean water, 1% organic composite coal powder treatment agent + 0.4% viscosity changing agent.

[0029] Figure 7 It is a construction curve diagram for the actual application of organic composite coal powder treatment agent. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] This example provides the preparation of organic composite coal powder treating agent 1# and a test of its solubility in organic composite coal powder.

[0033] Referring to the Q / SY 126-2014 standard, 50.0g NaCl, 2.0g MgCl2·6H2O, 6.0g Na2SO4, and 4.0g anhydrous CaCl2 were weighed and dissolved in distilled water to prepare 950mL of solution. Then 0.4g NaHCO3 was weighed and dissolved in a small amount of distilled water. The mixture was mixed before use and the solution was diluted to 1L to simulate field water for solubility test.

[0034] 1. Preparation of organic composite coal powder treatment agent 1#

[0035] Formula components: 150kg methyldiethanolamine, alkyl quaternary ammonium ion [NRxH4-X] + 50kg, alkyl quaternary phosphonium ion [PRxH4-X] + 50kg, 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 30kg, N-substituted pyridinium ion [Rpy] + 50kg, sodium hydroxide is 2kg, thiourea (initiator) is 5kg,

[0036] [Emim] BF4 is 80kg, and solvent water is 410kg.

[0037] Preparation method: 50 kg of alkyl quaternary ammonium ion [NRxH4-X] prepared above + 、50kg alkyl quaternary phosphonium ion [PRxH4-X] + 、30kg 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 、50kg N-substituted pyridinium ion [Rpy] + and 80kg [Emim] BF4 are placed in a stainless steel reactor with a bottom valve. The reactor is controlled to heat up at a heating rate of 1°C / min. When the reaction temperature reaches 20°C, 150kg methyldiethanolamine is added and stirred evenly. Then 2kg sodium hydroxide and 5kg thiourea are slowly added and finally 410kg water is added. After stirring evenly, the material can be discharged.

[0038] 2. Dissolution rate test:

[0039] ①Prepare 100g coal powder, 100g coal block, and 20g organic composite coal powder treatment agent 1#.

[0040] ② Grind the coal powder to 50-100 mesh, place 100g of the coal powder in a drying oven at 100℃ and dry it for 4h; knock the coal blocks into 20-30mm, and place 100g of the coal blocks in a drying oven at 100℃ and dry them for 4h.

[0041] ③ Weigh 10g (accurate to 0.001) of 3 portions of dried coal powder and 10g (accurate to 0.001) of 3 portions of dried coal lumps, and record the initial mass data of coal powder or coal lumps.

[0042] ④ Use distilled water to prepare 2 portions of 1%, 2%, and 3% organic composite coal powder treatment agent 1# (200 mL) in a beaker, and add the dried coal powder or coal blocks into the 1%, 2%, and 3% organic composite coal powder treatment agent 1#, respectively.

[0043] ⑤ After placing each group of tests at room temperature (20℃) for 72h, weigh the mass of 6 filter papers (accurate to 0.001), then filter the mixed solution in ④ with filter paper, and wash the beaker with distilled water several times until there is no residual coal powder or coal block at the bottom of the beaker, then filter it twice with a suction filter, place the residue remaining on the filter paper in a drying oven at 100℃ for 6h, and weigh its 72h mass.

[0044] ⑥Calculate the dissolution rate: The dissolution rate test results of organic composite coal powder treatment agent 1# are shown in Table 1.

[0045] Table 1. Dissolution rate of organic composite coal powder treatment agent 1#

[0046]

[0047]

[0048] As shown in Table 1, the organic composite coal powder treating agent 1# prepared in this embodiment showed a dissolving effect on coal powder at a dosage of 1-3%. Among them, the coal powder dissolution rate corresponding to the 1% dosage was 38.494%, which was a significant effect.

[0049] Example 2

[0050] This example provides the preparation of organic composite coal powder treating agent 2# and a test of its solubility in organic composite coal powder.

[0051] 1. Preparation of organic composite coal powder treatment agent 2#

[0052] Formula components: 180kg methyldiethanolamine, alkyl quaternary ammonium ion [NRxH4-X] + 60kg, alkyl quaternary phosphonium ion [PRxH4-X] + 60kg, 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 40kg, N-substituted pyridinium ion [Rpy] + 60kg, sodium hydroxide is 2kg, thiourea (initiator) is 5kg,

[0053] [Emim] BF4 is 90kg, and solvent water is 380kg.

[0054] Preparation method: 60 kg of alkyl quaternary ammonium ion [NRxH4-X] prepared above + 、60kg alkyl quaternary phosphonium ion [PRxH4-X] + 、40kg 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 、60kg N-substituted pyridinium ion [Rpy] + and 90kg [Emim] BF4 are placed in a stainless steel reactor with a bottom valve. The reactor is controlled to heat up at a heating rate of 1°C / min. When the reaction temperature reaches 20°C, 180kg methyldiethanolamine is added and stirred evenly. Then 2kg sodium hydroxide and 5kg thiourea are slowly added and finally 380kg water is added. After stirring evenly, the material can be discharged.

[0055] 2. Dissolution efficiency test:

[0056] ① Prepare 100g coal powder, 100g coal block, and 20g organic composite coal powder treatment agent 2#.

[0057] ② Grind the coal powder to 50-100 mesh, place 100g of the coal powder in a drying oven at 100℃ and dry it for 4h; knock the coal blocks into 20-30mm, and place 100g of the coal blocks in a drying oven at 100℃ and dry them for 4h.

[0058] ③ Weigh 10g (accurate to 0.001) of 3 portions of dried coal powder and 10g (accurate to 0.001) of 3 portions of dried coal lumps, and record the initial mass data of coal powder or coal lumps.

[0059] ④ Use distilled water to prepare 2 portions of 1%, 2%, and 3% organic composite coal powder treatment agent 2# (200 mL) in a beaker, and add the dried coal powder or coal blocks into the 1%, 2%, and 3% organic composite coal powder treatment agent 2#, respectively.

[0060] ⑤ After placing each group of tests at room temperature (20℃) for 72h, weigh the mass of 6 filter papers (accurate to 0.001), then filter the mixed solution in ④ with filter paper, and wash the beaker with distilled water several times until there is no residue at the bottom of the beaker, then filter it twice with a vacuum filter, place the residue remaining on the filter paper in a drying oven at 100℃ for 6h, and weigh its 72h mass.

[0061] ⑥ Calculate the dissolution rate. The calculation method is the same as in Example 1. The dissolution rate test results of organic composite coal powder treatment agent 2# are shown in Table 2.

[0062] Table 2. Dissolution efficiency of organic composite coal powder treatment agent 2#

[0063] sample Dosage Initial mass (g) Mass after 72h (g) Dissolution rate (%) / No addition 10 10 0 Pulverized coal 1％ 10 9.1317 8.683％ Pulverized coal 2％ 10 9.3256 6.744％ Pulverized coal 3％ 10 9.4194 5.806％ Coal 1％ 10 9.6342 3.658％ Coal 2％ 10 9.5632 4.368％ Coal 3％ 10 9.3272 6.728％

[0064] As shown in Table 2, the organic composite coal powder treating agent 2# prepared in this embodiment showed the effect of dissolving coal powder under the condition of 1-3% dosage. Among them, the coal powder dissolution rate corresponding to 1% dosage was the highest, which was 8.683%, and the effect was good.

[0065] Example 3

[0066] This example provides the preparation of organic composite coal powder treating agent 3# and a test of its solubility in organic composite coal powder.

[0067] 1. Preparation of organic composite coal powder treatment agent 3#

[0068] Formula components: 160kg methyldiethanolamine, alkyl quaternary ammonium ion [NRxH4-X] + 40kg, alkyl quaternary phosphonium ion [PRxH4-X] + 40kg, 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 50kg, N-substituted pyridinium ion [Rpy] + 80kg, sodium hydroxide is 3kg, thiourea (initiator) is 5kg,

[0069] [Emim] BF4 is 70kg and solvent water is 400kg.

[0070] Preparation method: 40 kg of alkyl quaternary ammonium ion [NRxH4-X] prepared above + 、40kg alkyl quaternary phosphonium ion [PRxH4-X] + 、50kg 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 、80kg N-substituted pyridinium ion [Rpy] + and 70kg [Emim] BF4 are placed in a stainless steel reactor with a bottom valve. The reactor is controlled to heat up at a rate of 1°C / min. When the reaction temperature reaches 20°C, 160kg methyldiethanolamine is added and stirred evenly. Then 3kg sodium hydroxide and 5kg thiourea are slowly added and finally 400kg water is added. After stirring evenly, the material can be discharged.

[0071] 3. Dissolution efficiency test:

[0072] ① Prepare 100g coal powder, 100g coal block, and 20g organic composite coal powder treatment agent 3#.

[0073] ② Grind the coal powder to 50-100 mesh, place 100g of the coal powder in a drying oven at 100℃ and dry it for 4h; knock the coal blocks into 20-30mm, and place 100g of the coal blocks in a drying oven at 100℃ and dry them for 4h.

[0074] ③ Weigh 10g (accurate to 0.001) of 3 portions of dried coal powder and 10g (accurate to 0.001) of 3 portions of dried coal lumps, and record the initial mass data of coal powder or coal lumps.

[0075] ④ Use distilled water to prepare 2 portions of 1%, 2%, and 3% organic composite coal powder treatment agent 3# (200 mL) in a beaker, and add the dried coal powder or coal blocks into the 1%, 2%, and 3% organic composite coal powder treatment agent 3#, respectively.

[0076] ⑤ After placing each group of tests at room temperature (20℃) for 72h, weigh the mass of 6 filter papers (accurate to 0.001), then filter the mixed solution in ④ with filter paper, and wash the beaker with distilled water several times until there is no residue at the bottom of the beaker, then filter it twice with a vacuum filter, place the residue remaining on the filter paper in a drying oven at 100℃ for 6h, and weigh its 72h mass.

[0077] ⑥ Calculate the dissolution rate. The calculation method is the same as in Example 1. The dissolution rate test results of organic composite coal powder treatment agent 3# are shown in Table 3.

[0078] Table 3. Dissolution efficiency of organic composite coal powder treatment agent 3#

[0079] sample Dosage Initial coal powder mass (g) Mass after 72h (g) Dissolution rate (%) / No addition 10 10 0 Pulverized coal 1％ 10 9.0429 9.571％ Pulverized coal 2％ 10 8.8123 11.877％ Pulverized coal 3％ 10 8.6798 13.202％ Coal 1％ 10 9.1434 8.566％ Coal 2％ 10 8.9891 10.109％ Coal 3％ 10 8.8436 11.564％

[0080] As shown in Table 3, the organic composite coal powder treatment agent 3# prepared in this embodiment showed a dissolving effect on coal powder under the condition of 1-3% dosage. Among them, the coal powder dissolution rate corresponding to the 3% dosage was the highest, which was 13.202%, greater than 10%, and the effect was significant.

[0081] Based on Examples 1 to 3, the organic composite coal powder treatment agent can dissolve coal powder much better than coal blocks. The 1.0% coal powder composite dissolving agent can dissolve 38.494% of coal powder at room temperature. As the concentration increases, its ability to dissolve coal powder decreases. The optimal concentration is 1.0%.

[0082] Example 4

[0083] This example describes the compatibility of an organic composite coal powder treatment agent with formation water. Since coal seams usually contain a certain proportion of clay minerals, large-volume and large-displacement fracturing operations may cause clay minerals to swell and hydrate and disperse. Different amounts of thickening agents were added to prepare degelling liquids to analyze whether different working fluid media have an effect on the dissolution rate of coal powder. The produced water from the 8# coal seam in Lin County, Shanxi Province was used for the test.

[0084] 1. Preparation of organic composite coal powder treatment agent

[0085] The preparation method of the organic composite coal powder treating agent used in this example is the same as that in Example 1. Two commonly used additives, including KCl and viscosity-changing agents of different concentrations, were selected to compare whether the compatibility properties of the organic composite coal powder treating agent changed significantly before and after the addition of the additives.

[0086] 2. Compatibility Test

[0087] The prepared organic composite coal powder treatment agent 1# was subjected to a compatibility test. 1.0% organic composite coal powder treatment agent + 1.0% KCl + different concentrations of viscosity-changing agents were placed at 60°C for 72 hours. The test results are shown in Table 4.

[0088] Table 4. Compatibility test results of organic composite coal powder treatment agent and produced water

[0089] Serial number Treatment agent 1#% KCl% Thickening agent% Test results 1 1.0 1.0 0.2 No sedimentation and flocculation 2 1.0 1.0 0.4 No sedimentation and flocculation 3 1.0 1.0 0.6 No sedimentation and flocculation

[0090] As shown in Table 4, the organic composite coal powder treating agent 1# exhibits uniformity without precipitation and stratification when the amount of thickening agent and degelling liquid added is within the range of 0.2-0.6%. Figure 1 ), the result shows that the prepared organic composite coal powder treatment agent 1# has good compatibility.

[0091] Example 5

[0092] This example describes the compatibility of the organic composite coal powder treatment agent with formation water. The source of the coal seam produced water is the same as that of Example 4.

[0093] 1. Preparation of organic composite coal powder treatment agent

[0094] The preparation method of the organic composite coal powder treatment agent used in this embodiment is the same as that in Example 2.

[0095] 2. Compatibility Test

[0096] The prepared organic composite coal powder treatment agent 2# was subjected to a compatibility test. The test method was the same as that of Example 4. The test results are shown in Table 5.

[0097] Table 5. Compatibility test results of organic composite coal powder treatment agent 2# and produced water

[0098] Serial number Treatment agent 2#% KCl% Thickening agent% Test results 1 1 1 0.2 No sedimentation and flocculation 2 1 1 0.4 No sedimentation and flocculation 3 1 1 0.6 No sedimentation and flocculation

[0099] As shown in Table 5, the organic composite coal powder treatment agent 2# is uniform without precipitation and stratification when the addition amount of the thickening agent and the degelling liquid is in the range of 0.2-0.6%. This result shows that the prepared organic composite coal powder treatment agent 2# has good compatibility.

[0100] Example 6

[0101] This example describes the compatibility of the organic composite coal powder treatment agent with formation water. The source of the coal seam produced water is the same as that of Example 4.

[0102] 1. Preparation of organic composite coal powder treatment agent

[0103] The preparation method of the organic composite coal powder treatment agent used in this example is the same as that in Example 3.

[0104] 2. Compatibility Test

[0105] The prepared organic composite coal powder treatment agent 3# was subjected to a compatibility test. The test method was the same as that of Example 4. The test results are shown in Table 6.

[0106] Table 6. Compatibility test results of organic composite coal powder treatment agent 3# and produced water

[0107]

[0108]

[0109] It can be seen from Table 6 that the organic composite coal powder treatment agent 3# is uniform without precipitation and stratification when the addition amount of the thickening agent and the degelling liquid is in the range of 0.2-0.6%. This result shows that the prepared organic composite coal powder treatment agent 3# has good compatibility.

[0110] Example 7

[0111] This example describes the test of the effect of the organic composite coal powder treatment agent on the resistance reduction of the variable viscosity fracturing fluid. This example uses the organic composite coal powder treatment agent 1# for the test.

[0112] Test method: Referring to SY / T 5107-2016 "Water-based fracturing fluid performance evaluation method", a pipeline friction tester was used to evaluate the drag reduction performance of the variable viscosity fracturing fluid system. At room temperature, the pressure drop of the variable viscosity fracturing fluid system (clean water + 1.0% organic composite coal powder treatment agent 1# + 0.1% variable viscosity agent) in 10,000 salinity brine, 30,000 salinity brine, and 50,000 salinity brine in a Φ8.0mm straight pipe was measured, and compared with the pressure drop of clean water under the same conditions, to obtain the drag reduction rate of the variable viscosity fracturing fluid system under different pipeline diameters.

[0113] Test results: Figure 2 The effect of the organic composite coal powder treating agent 1# on the resistance reduction performance of the variable viscosity fracturing fluid is Figure 2 It can be seen that the organic composite coal powder treating agent 1# has no adverse effect on the drag reduction performance of the variable viscosity fracturing fluid, and the drag reduction rate is maintained above 60%.

[0114] Example 8

[0115] This example describes the test of the effect of the organic composite coal powder treating agent on the rheological properties of variable viscosity fracturing fluid. This example uses organic composite coal powder treating agent 1# for the test.

[0116] 1. Effect of the amount of thickener added on the viscosity of variable viscosity fracturing fluid

[0117] Test method: The viscosity of the variable viscosity fracturing fluid directly affects the drag reduction performance and sand carrying performance of the fracturing fluid. The organic composite coal powder treatment agent prepared by the present invention can be mixed online without affecting the viscosity of the fracturing fluid to meet the needs of on-site construction. This example measures the apparent viscosity of the variable viscosity fracturing fluid system (clean water + 1.0% organic composite coal powder treatment agent 1# + 0.4% or 1.0% variable viscosity agent) under different concentrations of variable viscosity agents.

[0118] Test results: Figure 3 and Figure 4 The results are shown in Table 2. The results are shown in Table 2. The results are shown in Table 2. The results are shown in Table 2. The results are shown in Table 2. -1 , 510s -1 , 850s -1 ) of the variable viscosity fracturing fluid system. Specifically, the shear rate is 170s -1 , 1800~3600s shear rate is 510s -1 , 3600~5400s shear rate is 850s -1 .Depend on Figure 3 and Figure 4 It can be seen that within the use range of 0.4-1.0% of the viscosity-changing agent, the organic composite coal powder treating agent has no adverse effect on the viscosity of the viscosity-changing fracturing fluid system.

[0119] 2. Effect of temperature on viscosity of variable viscosity fracturing fluid

[0120] Test method: The temperature and shear resistance of the variable viscosity fracturing fluid system was evaluated by referring to SY / T 5107-2016 "Performance Evaluation Method of Water-Based Fracturing Fluids". The rheological performance curve of the variable viscosity fracturing fluid system (clean water + 0.6% variable viscosity agent + 1.0% organic composite coal powder treatment agent 1#) at a reservoir temperature of 90°C was measured using a Hake rheometer.

[0121] Test results: Figure 5 In the range below 90℃, 170s -1 The viscosity change of the fracturing fluid system after shearing for 120 minutes. Figure 5 It can be seen that within the range below 90°C, the organic composite coal powder treating agent has no adverse effect on the viscosity of the variable viscosity fracturing fluid system.

[0122] Example 9

[0123] This example describes the test of the effect of the organic composite coal powder treatment agent on the dispersibility of the variable viscosity fracturing fluid. This example uses the organic composite coal powder treatment agent 1# for the test.

[0124] Since coal seams usually contain a certain proportion of clay minerals, large-volume and large-displacement fracturing operations may cause the clay minerals to expand and hydrate and disperse. Therefore, it is necessary to measure the dispersion properties of the organic composite coal powder treatment agent.

[0125] Test method:

[0126] ① Take 100g of coal core sample, grind it into powder, dry it, and pass it through 40-mesh and 70-mesh sieves respectively. Weigh 10g of coal powder less than 40 mesh and 10g of coal powder between 40 and 70 mesh respectively.

[0127] ②Mix coal powder smaller than 40 mesh and coal powder between 40 and 70 mesh respectively.

[0128] ③ Prepare variable viscosity fracturing fluid: 1.0% organic composite coal powder treatment agent + 0.4% variable viscosity agent 100mL, soak the mixed coal powder in the variable viscosity fracturing fluid, and observe the dispersibility of the coal powder. At the same time, replace the variable viscosity fracturing fluid with clean water, and the rest of the treatment steps are the same as the control.

[0129] Through multiple tests on coal powder with different particle sizes, the relationship between coal powder particles with different particle sizes and terminal settling velocity was established. After processing the test data, the data under this test situation were obtained, see Table 7.

[0130] Table 7. Experimental study on the effect of organic composite coal powder treatment agent 1# on the dispersibility of variable viscosity fracturing fluid

[0131]

[0132] As shown in Table 7, the organic composite coal powder treatment agent can effectively inhibit clay expansion and prevent coal powder migration. This is because the organic ions therein can enhance the bonding force between clay lattices, crystal layers and particles, prevent clay hydration expansion and dispersion, thereby enhancing the cementing strength of the oil and gas layer, achieving the effect of effectively inhibiting clay expansion and preventing coal powder migration for a long time (see Figure 6 ).

[0133] Example 10

[0134] This example describes the evaluation of the desorption performance of the organic composite coal powder treatment agent. This example uses organic composite coal powder treatment agent 1# for testing.

[0135] Test method: Surface tension, desorption recovery rate and contact angle were measured in accordance with the petroleum and natural gas industry standard SY / T 5107-2016 "Water-based fracturing fluid performance evaluation method". The lower the surface tension of the degelling fluid, the smaller the capillary resistance during the flowback process, the weaker the thermodynamic water lock effect, and the better the flowback effect of the fracturing fluid. The surface tension of the degelling fluid was measured using a K100 surface tension meter, and the contact angle measurement was performed using a contact angle meter. In this example, the desorption performance evaluation test was performed using organic composite coal powder treatment agent 1#.

[0136] Test results: See Table 8.

[0137] Table 8. Evaluation of desorption performance of organic composite coal powder treatment agent 1#

[0138]

[0139] It can be seen from Table 8 that the organic composite coal powder treating agent can reduce the surface tension of the degelling liquid, increase the contact angle of the liquid on the coal rock surface, and improve the desorption recovery rate, thereby improving the fracturing and production increase effect.

[0140] Embodiment 11

[0141] This example describes the actual application effect of the organic composite coal powder treatment agent in a coalbed methane well. This example uses organic composite coal powder treatment agent 1# for actual application testing.

[0142] The relevant parameters of the coalbed methane well are shown in Table 9.

[0143] Table 9. Coalbed methane well parameters

[0144]

[0145] 100m 3 Pre-liquid + 1.0% organic composite coal powder treatment agent was mixed to make viscous slippery water. After adding viscous slippery water, the viscosity was tested to be 2.4mPa·s. The results are shown in Figure 7 .Depend on Figure 7 It can be seen that the organic composite coal powder treating agent has no effect on the quality of the constructed fracturing fluid.

[0146] In summary, the organic composite coal powder treatment agent prepared by the present invention has good solubility, dispersibility and compatibility for organic composite coal powder, has no significant adverse effect on the rheology and drag reduction of variable viscosity fracturing fluid, can replace methane in coal rock without causing matrix expansion and thus improve the fracturing and production increase effect, and has excellent overall performance.

[0147] The embodiments described above are only some embodiments of the present invention, not all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. An organic composite coal powder treating agent, characterized in that: The organic composite coal powder treatment agent uses water as a solvent, and the components of the organic composite coal powder treatment agent are: by mass, 10 to 15 parts of alcohol amine components, alkyl quaternary ammonium ions [PRxH4-X] + 5-8 parts, alkyl quaternary phosphonium ion [PRxH4-X] + 3 to 6 parts of 1,3 dialkyl substituted imidazolium ion [R1R3Im] + 3 to 5 parts, N-substituted pyridinium ion [Rpy] + 5-8 parts, sodium hydroxide 1-5 parts, initiator 1-3 parts, [Emim] BF4 10-12 parts, water 38-62 parts.

2. The organic composite coal powder treating agent according to claim 1, characterized in that: The alcoholamine component is methyldiethanolamine.

3. The organic composite coal powder treating agent according to claim 1, characterized in that: The alkyl quaternary ammonium ion [NRxH4-X] + Selected from: one or more of tetrabutylammonium hydrogen sulfate, tetrabutylammonium bromide, and tetrabutylammonium hydroxide.

4. The organic composite coal powder treating agent according to claim 1, characterized in that: The alkyl quaternary phosphonium ion [PRxH4-X] + Selected from: one or more of 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, N-butylpyridinium hexafluorophosphate, methyltributylphosphine dimethyl sulfate, ethyltributylphosphine tetrafluoroborate, tetrabutylphosphine tetrafluoroborate, and hexyltributylphosphine hexafluorophosphate.

5. The organic composite coal powder treating agent according to claim 1, characterized in that: The 1,3 dialkyl substituted imidazolium ion [R1R3Im] + Selected from: one or more of methyl tributylphosphine dimethyl sulfate, ethyl tributylphosphine tetrafluoroborate, tetrabutylphosphine tetrafluoroborate, and hexyl tributylphosphine hexafluorophosphate.

6. The organic composite coal powder treating agent according to claim 1, characterized in that: The N-substituted pyridinium ion [Rpy] + Selected from: one or more of 1-butyl-4-methylpyridinium chloride, 1-hexyl-4-methylpyridinium chloride, and 1-octyl-4-methylpyridinium tetrafluoroborate.

7. The organic composite coal powder treating agent according to claim 1, characterized in that: The initiator is thiourea.

8. The method for preparing the organic composite coal powder treating agent according to claim 1, characterized in that: include: According to the ratio of claim 1, the alkyl quaternary ammonium ion [NRxH4-X] + 、Alkyl quaternary phosphonium ion [PRxH4-X] + 、1,3 dialkyl substituted imidazolium ion [R1R3Im] + , N-substituted pyridinium ion [Rpy] + and [Emim]BF4 are put into a stainless steel reactor with a bottom valve. The reactor is controlled to heat up at a heating rate of 1°C / min. When the reaction temperature reaches 20°C, the amine components are added and stirred evenly. Then, sodium hydroxide and initiator are slowly added and finally water is added and stirred evenly to obtain the product.

9. The use of the organic composite coal powder treating agent according to claim 1, characterized in that: The organic composite coal powder treating agent is used for removing coal powder in coalbed methane wells.

10. The use according to claim 9, characterized in that: The organic composite coal powder treating agent is diluted 100 times and then pumped into the compound fracturing fluid for use.

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