Neutral blocking remover for removing blockage of water injection well of low-permeability oil and gas field and preparation method of neutral blocking remover

Abstract

The invention provides a neutral chelating blocking remover composition for removing blockage of a water injection well of a low-permeability oil and gas field and a preparation method and a use method of the neutral chelating blocking remover composition. The neutral chelating blocking remover composition comprises ethylenediaminetetraacetic acid and diethylenetriamine pentaacetic acid which serve as chelating agents, sodium hydroxide serving as a dissolution promoter, sulfamic acid serving as a pH regulator, sodium hydroxide serving as a pH regulator and water. Dodecylbenzene sulfonate as an anionic surfactant, potassium chloride as an anti-swelling agent, and low-molecular sodium polyacrylate as an anti-blocking agent. The blocking remover is a solid product, is high in content of effective substances, simple in production process, convenient to store and transport and low in corrosivity, and can efficiently remove calcium carbonate composite scale blocking substances in near-wellbore areas of oil and gas field water injection pipelines and water injection wells, so that the water injection pressure is reduced, and the oil and gas well yield is improved.

Description

Technical Field

[0001] The invention relates to the field of oilfield chemistry, and in particular to a neutral plugging remover for removing plugging of water injection wells in low-permeability oil and gas fields and a preparation method thereof. Background Art

[0002] During the flow of formation fluid from the reservoir to the ground, due to changes in flow velocity and flow pressure, complex scale such as paraffin, asphalt, calcium carbonate, barium strontium sulfate, and microorganisms will appear in the near-well area and at the bottom of the oil pipe (scale deposition), which directly leads to a decrease in reservoir permeability and an increase in flow resistance in the oil and gas pipes and ground pipelines, seriously affecting the recovery rate of oil field development and the economic benefits of the mining process.

[0003] The basic characteristics of low permeability reservoirs are: low reservoir porosity, low permeability, low maturity of sedimentary minerals, large differences in reservoir matrix permeability and fracture permeability, which make it difficult to inject displacement fluids and difficult to develop residual oil in the matrix. The average recovery rate of low permeability reservoirs at home and abroad is only 20%-30%, and most of the crude oil is retained in the oil layer matrix and has not been mined. Improving the recovery rate of low permeability reservoir matrix is ​​currently the main means of stabilizing oil field production. It is urgent to remove the blockage of organic scale, microbial scale, inorganic scale and other composite scales in the water injection pipelines and near-wellbore areas of oil and gas fields.

[0004] Chinese patent CN201410489268.6 proposes a low permeability oilfield unblocking agent composition with polyepoxysuccinic acid, sodium gluconate, ethylenediaminetetraacetic acid, polyethylene glycol, triethanolamine, ethyl acetate, lipase, sodium acetate, sodium hydroxyacetate, sorbitan fatty acid ester, diethylene glycol laurate, etc. as main components, and the temperature is adjusted from room temperature to 160°C. However, this type of unblocking agent needs to be hydrolyzed at the bottom hole temperature to generate a certain concentration of organic acid. The unblocking time is about 7 hours, which is a long time, and it is liquid and not convenient for transportation.

[0005] Chinese patent CN201911396382.3 is composed of ethylene oxide condensate, fast penetrant T, poly(AA-AMPS-HPA) terpolymer, ammonium bifluoride and water, and its corrosion rate is 0.15g / ㎡*h. However, ethylene oxide has strong oxidizing properties, and acidification is mainly used for unblocking. Acidification is easy to produce scale and secondary precipitation, resulting in secondary blockage of oil wells and oil pumps. There are also factors such as corrosion inhibitor failure, uneven emulsification of corrosion inhibitors or improper operation during the acidification process that cause corrosion to oil production equipment.

[0006] Chinese patent CN201410489269.0 proposes to use 10-14 parts of polyepoxysuccinic acid amine, 35-40 parts of diethylenetriamine pentaacetic acid amine, 33-37 parts of hydroxysuccinic acid amine, 20-25 parts of polyacrylamide, 7-10 parts of sodium polyaspartate, 10-14 parts of sodium gluconate, and 10-15 parts of activated clay as the main components of the unblocking agent. Chinese patent CN201410489225.8 uses 16-20 parts of polyepoxysuccinic acid, 7-12 parts of sodium hydroxyethylene diphosphate, 21-25 parts of diethylenetriamine pentaacetic acid ammonium, 20-25 parts of hydroxy ammonium acetate, and 7-8 parts of activated attapulgite as the main components of the unblocking agent. However, both patent applications are based on scale inhibitors, which can play a role in scale prevention, but have limited ability to dissolve and block scale substances. In addition, both patent applications are doped with vanadium pentoxide as catalyst adsorption powder, which is not only relatively expensive, but also a highly toxic chemical that is extremely harmful to the human body. Moreover, the active bentonite and active attapulgite added in these two patent applications to prepare solid plugging agents will cause secondary blockage of the reservoir by solid clay particles.

[0007] Therefore, it is necessary to provide a solid neutral plugging remover that is convenient to store and transport, has a high cost performance, and can effectively remove calcium carbonate composite scale blockages. Summary of the invention

[0008] The inventors have found that a solid unblocking agent is obtained by using ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid as chelating agents, sodium hydroxide as a dissolution promoter, aminosulfonic acid as a pH regulator, dodecylbenzenesulfonate as an anionic surfactant, potassium chloride as an anti-swelling agent, and small-molecule sodium polyacrylate as an anti-caking agent. The solid unblocking agent is convenient to store and transport, and can be prepared into a solution on site in an oil field when used. The calcium carbonate composite scale blockage can be efficiently unblocked, thereby achieving the purpose of increasing the output of oil and gas wells and improving the recovery rate, thereby completing the present invention.

[0009] The object of the present invention is to provide a neutral plugging remover for removing plugging of water injection wells in low permeability oil and gas fields, comprising the following components in weight ratio:

[0010]

[0011] Preferably, the neutral plugging remover for removing blockages in water injection wells in low permeability oil and gas fields comprises the following components in weight ratio:

[0012]

[0013] More preferably, the neutral plugging remover for removing plugging of water injection wells in low permeability oil and gas fields comprises the following components in weight ratio:

[0014]

[0015]

[0016] In the present invention, the raw materials used, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, sodium hydroxide, dodecylbenzenesulfonate, potassium chloride, aminosulfonic acid and small molecular sodium polyacrylate, are all used in solid form.

[0017] In the present invention, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid are used as complexing agents. When combined, they have a strong complexing effect on calcium and magnesium ions, and also have a certain chelating ability for barium and strontium ions. The combination of their gradient complexing ability for ions and the sustained release and decomposition properties of aminosulfonic acid can avoid the formation of secondary blockage and avoid / reduce corrosion to the pipeline as much as possible.

[0018] In the present invention, the raw material sodium hydroxide is used as a solubilizing agent, and the heat of dissolution in water enables ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, which have poor solubility at low temperatures, to dissolve quickly and fully in water, ensuring that no insoluble flocs that block the reservoir are generated. Moreover, compared with potassium hydroxide, sodium hydroxide has a higher cost-effectiveness and significantly reduces costs.

[0019] In the present invention, the raw material aminosulfonic acid is used as a pH regulator to ensure / adjust the reaction environment to be weakly acidic to neutral, and the metal salts of aminosulfonic acid are all soluble in water, and no secondary blockage will occur. Moreover, aminosulfonic acid is a medium-strength acid, in which the amino group has a certain corrosion inhibition effect on steel. Therefore, the neutral unblocking agent used for calcium carbonate composite scale unblocking in the present application does not need to be additionally added with a corrosion inhibitor, and can also minimize the corrosion of metal pipes.

[0020] During operation, aminosulfonic acid solution is easily decomposed to produce sulfuric acid at above 60°C. In order to avoid the precipitation of calcium sulfate (gypsum) and cause secondary blockage of the reservoir, diethylenetriaminepentaacetic acid chelating agent is used to preferentially chelate calcium and magnesium ions to form fine loose gypsum particles, which are convenient for discharge back into the wellbore after unblocking.

[0021] In a preferred embodiment, sodium dodecylbenzenesulfonate is used as the dodecylbenzenesulfonate.

[0022] In the present invention, sodium dodecylbenzene sulfonate is used as a wetting synergist to reduce the surface tension of the liquid during use and improve the wetting effect.

[0023] In the present invention, potassium chloride is used as an anti-swelling aid to inhibit the reduction of formation permeability or wellbore blockage caused by clay expansion, and can effectively prevent secondary blockage caused by the use of the unblocking agent.

[0024] In the present invention, as low molecular weight sodium polyacrylate, sodium polyacrylate with a molecular weight of 5000-100000 Dalton is preferably used. Because small molecular weight sodium polyacrylate has a very fast water absorption speed, it is added to the solid blocking agent as an anti-caking agent to prevent the solid blocking agent of the present invention from deteriorating during storage due to caking or water absorption even in a humid environment. In addition, sodium polyacrylate also has a certain complexing ability for calcium and magnesium ions, so it has a certain auxiliary dissolution-promoting effect on the scale dissolving ability of the blocking agent.

[0025] The invention selects and uses ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, sodium hydroxide as a cosolvent, aminosulfonic acid, dodecylbenzenesulfonate, potassium chloride, and low-molecular sodium polyacrylate in combination. In particular, under the above dosage ratio, the obtained plugging remover has a good effect of removing calcium carbonate composite scale blockages, can synergistically and efficiently remove calcium carbonate composite scale blockages in the water injection pipeline of the oil and gas field and the near-well area of ​​the water injection well, thereby reducing the water injection pressure and increasing the oil and gas well production.

[0026] The present invention also provides a method for preparing the neutral plugging remover for removing plugging of water injection wells in low permeability oil and gas fields, the method comprising:

[0027] (1) mixing ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid uniformly by dry mixing, and grinding the mixture to a fineness of 40-100 mesh to obtain a composite chelating agent powder;

[0028] (2) mixing sodium hydroxide and aminosulfonic acid evenly and grinding them to a fineness of 40-100 mesh to obtain a pH regulator powder;

[0029] (3) mixing dodecylbenzene sulfonate and potassium chloride uniformly, and grinding the mixture to a fineness of 40-100 mesh to obtain a conditioning agent powder;

[0030] (4) The composite chelating agent powder, the pH adjusting agent powder, the conditioning agent powder and the low molecular weight sodium polyacrylate anti-caking powder are mixed together and mixed evenly to obtain a solid neutral plugging remover for removing blockages in low permeability oil and gas field water injection wells.

[0031] The solid plugging remover provided by the present invention is convenient for transportation and storage. When removing plugs on site in oil and gas fields, it is prepared as an aqueous solution for use, and the solid plugging remover product is quickly and fully dissolved into a transparent solution by dissolving sodium hydroxide in water to release heat.

[0032] The present invention has the following beneficial effects:

[0033] (1) The blocking agent provided by the present invention, as a solid product, has a high content of effective substances compared to liquid products, is convenient to produce, store, transport, and use, and has a relatively higher cost-effectiveness;

[0034] (2) Even in a humid environment, the solid plugging remover of the present invention will not deteriorate due to agglomeration or moisture absorption during storage;

[0035] (3) The heat of dissolution of sodium hydroxide in water allows ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, which have poor solubility at low temperatures, to dissolve quickly and fully in water, ensuring that no insoluble flocs that block the reservoir are generated;

[0036] (4) No need to add corrosion inhibitor, which can minimize the corrosion of metal pipes;

[0037] (5) It can efficiently remove calcium carbonate composite scale without causing secondary blockage of the reservoir;

[0038] (6) It can be used for dissolution and declogging of calcium carbonate composite scale blockages in neutral environments of deep wells. DETAILED DESCRIPTION

[0039] It is worth noting that the raw materials used in the present invention are all common commercial products, and their sources are not specifically limited. The technical solution of the present invention is described below through specific examples.

[0040] Example 1

[0041] 15g of ethylenediaminetetraacetic acid solid particles and 5g of diethylenetriaminepentaacetic acid solid particles were mixed evenly and crushed to 100 mesh; 20g of solid sodium hydroxide and 30g of solid aminosulfonic acid were mixed evenly and crushed to 100 mesh; 2g of solid sodium dodecylbenzenesulfonate and 2g of solid potassium chloride were mixed evenly and crushed to 100 mesh; finally, the above three pretreated composite powders were mixed together with 5g of low molecular weight sodium polyacrylate (small molecular weight sodium polyacrylate CUP purchased from Hubei Tianyi Chemical Co., Ltd., with a molecular weight of 5000-50000 Daltons) powder, added into a dry mixer for even mixing, and 79g of unblocking agent solid sample A1 was obtained.

[0042] The unblocking agent A1 was dissolved in 160g of water to prepare a uniform unblocking agent solution (unblocking agent concentration 33%, solution pH = 3), and 11.36g of calcium carbonate was added; the prepared unblocking agent liquid was placed in a beaker, left to react at room temperature for 3h, and the solubility of calcium carbonate was measured.

[0043] The unblocking agent A1 was dissolved in 160g of water to prepare a uniform unblocking agent solution (unblocking agent concentration 33%, solution pH = 3), and 11.36g of calcium carbonate was added; the prepared unblocking agent liquid was placed in a beaker, left to react at room temperature for 48h, and the solubility of calcium carbonate was measured.

[0044] Example 2

[0045] The unblocking agent sample A1 prepared according to Example 1 was dissolved in 160g of water to prepare a uniform unblocking agent solution (unblocking agent concentration 33%, solution pH = 3), and 11.45g of calcium carbonate was added; the prepared unblocking agent liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a water bath at 40°C for reaction for 3h or 48h, and the dissolution rate of calcium carbonate was measured respectively.

[0046] Example 3

[0047] The unblocking agent sample A1 prepared according to Example 1 was dissolved in 160g of water to prepare a uniform unblocking agent solution (unblocking agent concentration 33%, solution pH = 3), 10.00g of calcium carbonate and 1.16g of barium sulfate (baryte) were added; the prepared unblocking agent liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a water bath at 60°C for reaction for 3h or 48h, and the dissolution rate of calcium carbonate was measured respectively.

[0048] Example 4

[0049] The unblocking agent sample A1 prepared according to Example 1 was dissolved in 160g of water to prepare a uniform unblocking agent (unblocking agent concentration 33%, solution pH = 3), 10.00g of calcium carbonate and 1.68g of calcium sulfate (gypsum) were added; the prepared unblocking agent liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a water bath at 80°C for reaction for 3h or 48h, and the dissolution rate of calcium carbonate was measured respectively.

[0050] Example 5

[0051] The hydrochloric acid was diluted to pH=3, and 160 g of dilute hydrochloric acid with pH=3 was prepared as comparative sample B1.

[0052] 11.36 g of calcium carbonate was added to comparative sample B1; the prepared liquid was placed in a beaker and reacted at room temperature for 3 hours, and the solubility of calcium carbonate was measured.

[0053] Example 6

[0054] 11.45 g of calcium carbonate was added to the comparative sample B1 prepared according to Example 5; the prepared liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a water bath at 40° C. for reaction for 3 hours, and the solubility of calcium carbonate was measured.

[0055] Example 7

[0056] 11.60 g of calcium carbonate was added to the comparative sample B1 prepared according to Example 5; the prepared liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a water bath at 60° C. for reaction for 3 hours, and the solubility of calcium carbonate was measured.

[0057] Example 8

[0058] 11.68 g of calcium carbonate was added to the comparative sample B1 prepared according to Example 5; the prepared liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a water bath at 80° C. for reaction for 3 hours, and the solubility of calcium carbonate was measured.

[0059] Example 9

[0060] 5g of ethylenediaminetetraacetic acid solid particles and 15g of diethylenetriaminepentaacetic acid solid particles were mixed evenly and crushed to 100 mesh; 15g of solid sodium hydroxide, 5g of solid potassium hydroxide, and 30g of solid aminosulfonic acid were mixed evenly and crushed to 100 mesh; 4g of solid potassium chloride was crushed to 100 mesh; finally, the above three pretreated composite powders were mixed together with 5g of low molecular weight sodium polyacrylate (small molecular weight sodium polyacrylate CUP purchased from Hubei Tianyi Chemical Co., Ltd., with a molecular weight of 10000-50000 Daltons) powder, added to a dry mixer for uniform mixing, and 79g of neutral calcium carbonate composite scale chelating plugging agent solid sample A2 was obtained.

[0061] The above sample A2 was dissolved in 160g of water to prepare a uniform neutral calcium carbonate composite scale chelating plugging agent solution (plugging agent concentration 33%, solution pH = 3), and 10.00g of calcium carbonate and 1.36g of barium sulfate were added; the prepared plugging agent liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a water bath at 40°C for reaction for 48h, and the dissolution rate of calcium carbonate was measured.

[0062] Example 10

[0063] 20 g of diethyltriaminepentaacetic acid solid particles were crushed to 100 mesh, 20 g of solid sodium hydroxide was crushed to 100 mesh, 2 g of solid sodium dodecylbenzenesulfonate was crushed to 100 mesh, 5 g of solid potassium chloride was crushed to 100 mesh, and 30 g of solid aminosulfonic acid was crushed to 100 mesh. All the pretreated materials were added into a dry mixer and evenly mixed to obtain 79 g of neutral calcium carbonate composite scale chelating and plugging agent solid sample A3.

[0064] The above sample A3 was dissolved in 160g of water to prepare a uniform neutral calcium carbonate composite scale chelating plugging agent solution (plugging agent concentration 33%, solution pH = 3), and 11.36g of calcium carbonate was added; the prepared plugging agent liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a 40°C water bath for 48h to react, and the dissolution rate of calcium carbonate was measured.

[0065] Embodiment 11

[0066] 10 g of ethylenediaminetetraacetic acid solid particles were crushed to 100 mesh, 10 g of diethylenetriaminepentaacetic acid solid particles were crushed to 100 mesh, 20 g of solid potassium hydroxide was crushed to 100 mesh, 2 g of solid sodium dodecylbenzenesulfonate was crushed to 100 mesh, 5 g of solid potassium chloride was crushed to 100 mesh, 25 g of solid aminosulfonic acid was crushed to 100 mesh, 5 parts of small molecule sodium polyacrylate (small molecule sodium polyacrylate CUP purchased from Hubei Tianyi Chemical Co., Ltd., with a molecular weight of 5000-50000 Daltons) did not need to be crushed, and all the pretreated materials were added to a universal dry mixer for uniform mixing to obtain 79 g of neutral calcium carbonate composite scale chelating plugging agent solid sample A4.

[0067] The above sample A4 was dissolved in 160g of water to prepare a uniform neutral calcium carbonate composite scale chelating plugging agent solution (plugging agent concentration 33%, solution pH = 3), and 11.36g of calcium carbonate was added; the prepared plugging agent liquid was placed in a round-bottom flask, and the round-bottom flask was placed in a 40°C water bath for 48h to react, and the dissolution rate of calcium carbonate was measured.

[0068] Scaling rate evaluation test method:

[0069] Implementation method for evaluation of calcium carbonate / composite scale dissolution rate

[0070] 1. Main instruments and equipment

[0071] a) Constant temperature water bath: temperature control range 1~100℃;

[0072] b) Circulating water multi-purpose vacuum pump;

[0073] c) Electric constant temperature drying oven: temperature control range 1 ~ 200 ℃, temperature control sensitivity is ± 2 ℃;

[0074] d) Rapid quantitative filter paper: diameter 15 cm;

[0075] 2. Main reagents and materials

[0076] a) Calcium carbonate: analytical grade calcium carbonate;

[0077] b) Deionized water: laboratory deionized water that complies with GB / T 6682-2008 standard;

[0078] 3. Calcium carbonate dissolution rate test method

[0079] a) According to the method of Examples 1 to 11, the blocking agent solution is placed in a water bath for reaction, and the mass of the calcium carbonate scale sample added is recorded as m 1 ;

[0080] b) After the dissolution reaction is completed, take out the round-bottom flask from the water bath, pour the liquid into a beaker, and cool to room temperature;

[0081] c) Place the quantitative filter paper in a 75°C oven and dry it to constant weight (its mass is recorded as m 2 );

[0082] d) Use quantitative filter paper and vacuum pump to filter the unblocking agent liquid after the dissolution reaction to filter out the undissolved calcium carbonate residue;

[0083] e) Place the residue together with the filter paper in a 75°C oven and dry until constant weight (the mass is recorded as m 3 );

[0084] f) Calculation of calcium carbonate dissolution rate

[0085] 4. Determination of solubility results

[0086] The solubility of calcium carbonate is calculated according to the following formula (1):

[0087]

[0088] Where:

[0089] CS—calcium carbonate dissolution rate, %;

[0090] m 1 —Mass of scale sample before test, g;

[0091] m 2 —Quantitative filter paper mass, g;

[0092] m 3 —After dissolution reaction, the mass of (filter paper + remaining scale sample), g.

[0093] Table 1 Calcium carbonate / composite scale dissolution rate determination results

[0094]

[0095]

[0096] Table 1 shows the dissolution rates of calcium carbonate by different neutral calcium carbonate composite scale chelating deblocking agents at different temperatures and reaction times in Examples 1 to 11.

[0097] From the comparison of Examples 1 to 8, it can be seen that the removal rate of calcium carbonate by the present invention is much higher than the dissolution rate of calcium carbonate by conventional dilute hydrochloric acid (under the same pH conditions).

[0098] Examples 9 and 10 show that the removal rate of calcium carbonate by using the composite chelating agent of ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid as the main component of the neutral chelating plugging remover is much higher than that by using diethylenetriaminepentaacetic acid alone as the main component of the neutral chelating plugging remover.

[0099] Examples 9-11 show that using sodium hydroxide and potassium hydroxide as pH regulators has little effect on the overall calcium carbonate removal rate, but considering the cost issue, the present invention uses sodium hydroxide as the pH regulator.

[0100] The present invention can achieve a high scale removal rate at room temperature, and the manufacturing cost of the neutral calcium carbonate composite scale chelating and plugging remover of the present invention is low. Compared with other similar technologies, the present invention has a huge cost advantage.

[0101] The present invention has been described in detail above in conjunction with preferred embodiments and exemplary examples. However, it should be noted that these specific embodiments and examples are only illustrative explanations of the present invention and do not constitute any limitation on the protection scope of the present invention. Without exceeding the spirit and protection scope of the present invention, various improvements, equivalent substitutions or modifications may be made to the technical content of the present invention and its implementation methods, all of which fall within the protection scope of the present invention. The protection scope of the present invention shall be subject to the attached claims.

Claims

1. A neutral plugging remover for removing blockages in water injection wells in low permeability oil and gas fields, comprising: Ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid as chelating agents, sodium hydroxide as a solubilizing agent, aminosulfonic acid as a pH adjuster, dodecylbenzenesulfonate as an anionic surfactant, potassium chloride as an anti-swelling agent, and low molecular weight sodium polyacrylate as an anti-caking agent.

2. The blocking agent as claimed in claim 1, comprising the following components in weight ratio:

3. The blocking agent as claimed in claim 1, comprising the following components in weight ratio:

4. The blocking agent as claimed in claim 1, comprising the following components in weight ratio: The blocking remover according to claim 1 , wherein the dodecylbenzene sulfonate is sodium dodecylbenzene sulfonate.

6. The blocking agent as claimed in claim 1, wherein the low molecular weight sodium polyacrylate is sodium polyacrylate with a molecular weight of 5000-100000.

7. A method for preparing the blocking agent according to any one of claims 1 to 6, comprising: (1) mixing ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid uniformly by dry mixing, and grinding the mixture to a fineness of 40-100 mesh to obtain a composite chelating agent powder; (2) mixing sodium hydroxide and aminosulfonic acid evenly and grinding them to a fineness of 40-100 mesh to obtain a pH regulator powder; (3) mixing dodecylbenzene sulfonate and potassium chloride uniformly, and grinding the mixture to a fineness of 40-100 mesh to obtain a conditioning agent powder; (4) The composite chelating agent powder, the pH adjusting agent powder, the conditioning agent powder and the low molecular weight sodium polyacrylate anti-caking powder are mixed together and mixed evenly to obtain a neutral plugging remover for removing blockages in low permeability oil and gas field water injection wells.

8. The method for using the blocking remover as claimed in claim 1, wherein the blocking remover is added with water to prepare an aqueous solution for use.

9. The method of use according to claim 8, wherein: The aqueous solution of the plugging remover is prepared according to the mass ratio of water: plugging remover = 2:1.

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