Solid non-acid blocking remover as well as preparation method and application thereof

Abstract

The invention provides a solid non-acid blocking remover as well as a preparation method and application thereof, and the solid non-acid blocking remover comprises the following components in percentage by mass: 60-75% of a main agent, 25-35% of an alkali activator and 1-5% of a metal ion stabilizer, the preparation method comprises the following steps: (1) mixing a main agent and an alkali activator, and carrying out alkali activation treatment to obtain an alkali activated main agent; and (2) compounding the mixed alkali activation main agent and the metal ion stabilizer to obtain the solid non-acid blocking remover. The solid non-acid blocking remover provided by the invention effectively removes blockages in a shaft and an electric pump, prevents formation and accumulation of sediments, relieves corrosion of chemicals to pipeline equipment, reduces the frequency of well repair and pump inspection, realizes cost reduction and efficiency improvement, effectively recovers and improves the oil well yield, and is beneficial to large-scale popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of blocking agents, and relates to a solid non-acid blocking agent, and in particular to a solid non-acid blocking agent and a preparation method and application thereof. Background Art

[0002] During the development and production of oil fields, due to the complex nature of formation fluids, some wells have problems with electric submersible pumps being stuck or wellbore being blocked during production, which prevents normal production and reduces production capacity. Nearly 10% of wells fail to produce normally due to mechanical failures during the lifting process of electric submersible pumps, of which about 90% are caused by pump sticking or wellbore blockage, which leads to a significant drop in the well opening rate and seriously affects oil well production.

[0003] In recent years, the blockage of oil wellbore and electric pump has been increasing year by year, which has brought great impact on oil field production. In particular, oil production projects mainly based on ESP electric pump production have different degrees of scaling and blockage problems. In severe cases, it leads to pump blockage, which directly affects ESP pump efficiency and oil well production. Therefore, efficiently removing the blockage of wellbore and electric pump is a difficult problem that needs to be solved in the process of oil field development.

[0004] At present, the main types of plugging removers used in various oil fields are acid systems, such as hydrochloric acid systems, soil acid systems, and organic weak acid systems. The acid system has a fast unblocking rate, but it is highly corrosive to pipelines and pump bodies, and secondary precipitation is serious; at the same time, due to the organic sludge wrapping the blockage, the acid system cannot effectively penetrate the wrapping layer to remove the inorganic scale. With the increasing requirements for environmental protection, the large amount of residual acid discharged after conventional acid unblocking is difficult to handle later, and acid neutralization treatment must be carried out on site. At the same time, the unblocking return fluid cannot enter the production process, which increases the requirements for emission treatment. Conventional acid systems are all liquids, and are generally acid-corrosive hazardous chemicals, which adds unsafe factors to transportation and use. Although solid-type unblocking agents have also been reported, most of them are solid organic acids, which cannot fundamentally eliminate the secondary damage caused by the corrosion of pipeline equipment by the agent.

[0005] It can be seen that how to provide a plugging remover and a preparation method thereof to effectively remove blockages in wellbores and electric pumps, prevent sediment formation and accumulation, and at the same time alleviate the corrosion of the agent to pipeline equipment, reduce the frequency of well repair and pump inspection, achieve cost reduction and efficiency improvement, and effectively restore and increase oil well production has become a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a solid non-acid plugging remover and a preparation method and application thereof. The solid non-acid plugging remover effectively removes blockages in the wellbore and electric pump, prevents the formation and accumulation of sediments, and at the same time alleviates the corrosion of the agent to the pipeline equipment, reduces the frequency of well repair and pump inspection, achieves cost reduction and efficiency improvement, effectively restores and increases the production of oil wells, and is conducive to large-scale promotion and application.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a solid non-acid plugging remover, which comprises the following components in terms of mass percentage:

[0009] Main agent 60-75%;

[0010] Alkali activator 25-35%;

[0011] Metal ion stabilizer 1-5%.

[0012] Among them, the mass percentage of the main agent is 60-75%, for example, it can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74% or 75%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] The mass percentage of the alkali activator is 25-35%, for example, it can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34% or 35%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] The mass percentage of the metal ion stabilizer is 1-5%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] The present invention prepares the main agent, the alkali activator and the metal ion stabilizer according to specific mass percentages to obtain a solid non-acid plugging remover that is easy to transport and safe to use. Compared with conventional acid plugging removers, the solid non-acid plugging remover has a carbonate and corrosion product scale dissolution rate of ≥80%, a silicate sediment dissolution rate of ≥20%, and a corrosion rate of ≤1 g / cm2 for N80 steel. 2h, and has good compatibility with other commonly used organic and inorganic plugging-removing materials, no precipitation after compounding, effectively improving the dissolution efficiency of various inorganic and organic scales and polymers, meeting the conditions of non-acidic, fixed pipe operation, low-cost maintenance measures and no banned chemical materials, etc. The solid non-acid plugging-removing agent is injected into the wellbore regularly after being mixed with other materials to form a solution, which can clear the blockage in the wellbore and the electric pump in advance, prevent the formation and accumulation of sediments, and the return fluid after unblocking is neutral, reducing the frequency of unblocking return fluid treatment procedures and well repair and pump inspection, achieving cost reduction and efficiency improvement, effectively restoring and improving oil well production, and facilitating large-scale promotion and application.

[0016] Preferably, the main agent includes any one of sodium persulfate, sodium sulfate, sodium citrate, sodium sulfite or sodium bisulfate, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of sodium persulfate and sodium sulfate, a combination of sodium sulfate and sodium citrate, a combination of sodium citrate and sodium sulfite, a combination of sodium sulfite and sodium bisulfate, a combination of sodium persulfate, sodium sulfate and sodium citrate, a combination of sodium sulfate, sodium citrate and sodium sulfite, or a combination of sodium citrate, sodium sulfite and sodium bisulfate.

[0017] In the present invention, the alkali-activated sodium sulfate salt has a high degradation and dispersion effect on oil well blockages, especially oil well polymers and organic-inorganic composite blockages. After being compounded with a metal ion stabilizer, it can effectively prevent the damage of secondary precipitation after unblocking.

[0018] Preferably, the alkali activator comprises any one of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate or sodium bicarbonate, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of sodium hydroxide and potassium hydroxide, a combination of potassium hydroxide and calcium hydroxide, a combination of calcium hydroxide and sodium carbonate, a combination of sodium carbonate and sodium bicarbonate, a combination of sodium hydroxide, potassium hydroxide and calcium hydroxide, a combination of potassium hydroxide, calcium hydroxide and sodium carbonate, or a combination of calcium hydroxide, sodium carbonate and sodium bicarbonate.

[0019] Preferably, the metal ion stabilizer includes any one or a combination of at least two of disodium ethylenediaminetetraacetate, nitrilotriacetic acid, citric acid, tetrasodium glutamate diacetate, hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, 2-hydroxyphosphonoacetic acid or hexamethylenediaminetetramethylenephosphonic acid. Typical but non-limiting combinations include a combination of disodium ethylenediaminetetraacetate and nitrilotriacetic acid, a combination of nitrilotriacetic acid and citric acid, a combination of citric acid and tetrasodium glutamate diacetate, a combination of tetrasodium glutamate diacetate and hydroxyethylidene diphosphonic acid, a combination of hydroxyethylidene diphosphonic acid and aminotrimethylenephosphonic acid, a combination of aminotrimethylenephosphonic acid and ethylenediaminetetramethylenephosphonic acid, a combination of ethylenediaminetetramethylenephosphonic acid and 2-hydroxyphosphonoacetic acid, or a combination of 2-hydroxyphosphonoacetic acid and hexamethylenediaminetetramethylenephosphonic acid.

[0020] In a second aspect, the present invention provides a method for preparing the solid non-acid plugging remover as described in the first aspect, the preparation method comprising the following steps:

[0021] (1) mixing a main agent and an alkali activator for alkali activation treatment to obtain an alkali-activated main agent;

[0022] (2) The alkali-activated main agent and the metal ion stabilizer are mixed and compounded to obtain a solid non-acid plugging remover.

[0023] Preferably, the alkali activation treatment in step (1) is carried out in a reactor, and the reactor and pipelines are purged with nitrogen.

[0024] Preferably, the alkali activation treatment in step (1) comprises: starting the stirrer and heating to a first temperature, starting vacuuming and continuing to heat to a second temperature, stopping vacuuming, continuing stirring for a certain period of time, cooling and discharging.

[0025] Preferably, the first temperature is 80-90°C, for example, it can be 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the second temperature is 140-145°C, for example, it can be 140°C, 140.5°C, 141°C, 141.5°C, 142°C, 142.5°C, 143°C, 143.5°C, 144°C, 144.5°C or 145°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the pressure in the reactor during vacuum extraction is ≤0.1 MPa, for example, it may be 0.01 MPa, 0.02 MPa, 0.03 MPa, 0.04 MPa, 0.05 MPa, 0.06 MPa, 0.07 MPa, 0.08 MPa, 0.09 MPa or 0.1 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the certain time period is 4-6 hours, for example, it can be 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h or 6h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the compounding treatment in step (2) is carried out in a stirrer until the alkali-activated main agent and the metal ion stabilizer are mixed evenly.

[0030] Preferably, the temperature of the compounding treatment in step (2) is 20-40°C, for example, it can be 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, 38°C or 40°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the pressure of the compounding treatment in step (2) is 0.8-1.2 bar, for example, it can be 0.8 bar, 0.85 bar, 0.9 bar, 0.95 bar, 1 bar, 1.05 bar, 1.1 bar, 1.15 bar or 1.2 bar, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] As a preferred technical solution of the second aspect of the present invention, the preparation method comprises the following steps:

[0033] (1) adding the main agent and the alkali activator to a reactor for alkali activation treatment, purging the reactor and pipelines with nitrogen, turning on the stirrer and heating to 80-90° C., starting to evacuate until the pressure in the reactor is ≤0.1 MPa, continuing to heat to 140-145° C., stopping evacuation, continuing to stir for 4-6 hours, cooling and discharging, and obtaining the alkali-activated main agent;

[0034] (2) Add the alkali-activated main agent and the metal ion stabilizer into a stirrer for compounding, and stir at 20-40° C. and 0.8-1.2 bar until the alkali-activated main agent and the metal ion stabilizer are evenly mixed to obtain a solid non-acid plugging remover.

[0035] In a third aspect, the present invention provides a use of the solid non-acid plugging remover as described in the first aspect, wherein the solid non-acid plugging remover is used to remove blockages in oil well bores and / or electric pumps.

[0036] Preferably, the application comprises: preparing the solid non-acid plugging remover into a solution and then injecting the solution into the wellbore regularly.

[0037] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention prepares the main agent, the alkali activator and the metal ion stabilizer according to specific mass percentages to obtain a solid non-acid plugging remover that is easy to transport and safe to use. Compared with conventional acid plugging removers, the solid non-acid plugging remover has a carbonate and corrosion product scale dissolution rate of ≥80%, a silicate sediment dissolution rate of ≥20%, and a corrosion rate of ≤1 g / cm2 for N80 steel. 2 h, and has good compatibility with other commonly used organic and inorganic plugging-removing materials, no precipitation after compounding, effectively improving the dissolution efficiency of various inorganic and organic scales and polymers, meeting the conditions of non-acidic, fixed pipe operation, low-cost maintenance measures and no banned chemical materials, etc. The solid non-acid plugging-removing agent is injected into the wellbore regularly after being mixed with other materials to form a solution, which can clear the blockage in the wellbore and the electric pump in advance, prevent the formation and accumulation of sediments, and the return fluid after unblocking is neutral, reducing the frequency of unblocking return fluid treatment procedures and well repair and pump inspection, achieving cost reduction and efficiency improvement, effectively restoring and improving oil well production, and facilitating large-scale promotion and application. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0041] Example 1

[0042] This embodiment provides a solid non-acid plugging remover and a preparation method thereof, the preparation method comprising the following steps:

[0043] (1) According to the percentage by mass, 20% sodium persulfate and 45% sodium citrate are used as the main agent, 10% sodium hydroxide and 20% sodium carbonate are used as the alkali activator, and the main agent and the alkali activator are added into a reactor for alkali activation treatment, the reactor and pipeline are purged with nitrogen, the stirrer is turned on and the temperature is raised to 85° C., vacuuming is started until the pressure in the reactor is 0.08 MPa, the temperature is continued to be raised to 142° C., vacuuming is stopped, stirring is continued for 5 hours, cooling and discharging are performed to obtain the alkali-activated main agent;

[0044] (2) According to the percentage by mass, the alkali-activated main agent and 5% disodium ethylenediaminetetraacetate were added into a stirrer for compounding, and stirred at 30° C. and 1 bar until the mixture was uniformly mixed to obtain a solid non-acid plugging remover BRS1.

[0045] Example 2

[0046] This embodiment provides a solid non-acid plugging remover and a preparation method thereof, the preparation method comprising the following steps:

[0047] (1) According to the percentage by mass, 60% of sodium persulfate is used as a main agent, 20% of sodium hydroxide and 15% of sodium bicarbonate are used as alkali activators, and the main agent and the alkali activator are added to a reactor for alkali activation treatment, the reactor and pipeline are purged with nitrogen, the stirrer is turned on and the temperature is raised to 80° C., vacuuming is started until the pressure in the reactor is 0.06 MPa, the temperature is continued to be raised to 140° C., vacuuming is stopped, stirring is continued for 6 hours, cooling and discharging, and the alkali-activated main agent is obtained;

[0048] (2) According to the percentage by mass, the alkali-activated main agent, 2% disodium ethylenediaminetetraacetate and 3% tetrasodium glutamate diacetate were added into a blender for compounding, and stirred at 20° C. and 0.8 bar until the mixture was uniformly mixed to obtain a solid non-acid plugging remover BRS2.

[0049] Example 3

[0050] This embodiment provides a solid non-acid plugging remover and a preparation method thereof, the preparation method comprising the following steps:

[0051] (1) According to the percentage by mass, 40% sodium persulfate and 30% sodium sulfate are used as the main agent, and 25% sodium hydroxide is used as the alkali activator, and the main agent and the alkali activator are added to the reactor for alkali activation treatment, the reactor and pipeline are purged with nitrogen, the stirrer is turned on and the temperature is raised to 90° C., vacuuming is started until the pressure in the reactor is 0.1 MPa, the temperature is continued to be raised to 145° C., vacuuming is stopped, stirring is continued for 4 hours, cooling and discharging, and the alkali-activated main agent is obtained;

[0052] (2) According to the mass percentage, the alkali-activated main agent, 2% disodium ethylenediaminetetraacetate and 3% tetrasodium glutamate diacetate were added into a blender for compounding, and stirred at 40° C. and 1.2 bar until the mixture was uniformly mixed to obtain a solid non-acid plugging remover BRS3.

[0053] Example 4

[0054] This embodiment provides a solid non-acid plugging remover and a preparation method thereof. Except that the final temperature of the alkali activation treatment in step (1) is changed to 130° C., the remaining steps and conditions are the same as those in Example 1 and are not described in detail here.

[0055] In this example, the solid non-acid plugging remover BRS4 was finally obtained.

[0056] Example 5

[0057] This embodiment provides a solid non-acid plugging remover and a preparation method thereof. Except that the pressure in the reactor during vacuuming in step (1) is changed to 0.2 MPa, the remaining steps and conditions are the same as those in Example 1 and are not described in detail here.

[0058] In this example, the solid non-acid plugging remover BRS5 was finally obtained.

[0059] Comparative Example 1

[0060] This comparative example provides a solid non-acid plugging remover and a preparation method thereof. Except that the main agent in step (1) is changed to 50% sodium citrate and the alkali activator is changed to 45% sodium carbonate, the remaining steps and conditions are the same as those in Example 1 and are not described in detail here.

[0061] This comparative example finally obtained the solid non-acid plugging remover BRS6.

[0062] Comparative Example 2

[0063] This comparative example provides a solid non-acid plugging remover and a preparation method thereof. Except that the main agent in step (1) is changed to 75% sodium citrate and the alkali activator is changed to 20% sodium carbonate, the remaining steps and conditions are the same as those in Example 1 and are not described in detail here.

[0064] This comparative example finally obtained the solid non-acid plugging remover BRS7.

[0065] Performance Testing

[0066] The solid non-acid plugging remover obtained in Examples 1-5 and Comparative Examples 1-2 was prepared into a plugging remover solution with a pH value of ≥6 and a concentration of 10 wt% using deionized water. The dissolution rate of the plugging material and the corrosion rate of the N80 steel were tested at 90°C for 4 h. The relevant results are shown in Table 1 below.

[0067] Table 1

[0068]

[0069]

[0070] It can be seen from Table 1 that the solid non-acid plugging remover prepared in Examples 1-5 has a carbonate and corrosion product scale dissolution rate of ≥80%, a silicate sediment dissolution rate of ≥20%, and can ensure that the corrosion rate of N80 steel is ≤1g / cm 2 ·h, it can be seen that the solid non-acid plugging remover prepared by the present invention can effectively remove the blockages in the wellbore and the electric pump, while effectively avoiding and alleviating the corrosion of pipeline equipment, reducing the frequency of well repair and pump inspection, and achieving cost reduction and efficiency improvement.

[0071] It can be seen that the present invention mixes the main agent, the alkali activator and the metal ion stabilizer according to specific mass percentages to obtain a solid non-acid plugging remover that is easy to transport and safe to use. Compared with conventional acid plugging removers, the solid non-acid plugging remover has a carbonate and corrosion product scale dissolution rate of ≥80%, a silicate sediment dissolution rate of ≥20%, and a corrosion rate of ≤1 g / cm2 for N80 steel. 2 h, and has good compatibility with other commonly used organic and inorganic plugging-removing materials, no precipitation after compounding, effectively improving the dissolution efficiency of various inorganic and organic scales and polymers, meeting the conditions of non-acidic, fixed pipe operation, low-cost maintenance measures and no banned chemical materials, etc. The solid non-acid plugging-removing agent is injected into the wellbore regularly after being mixed with other materials to form a solution, which can clear the blockage in the wellbore and the electric pump in advance, prevent the formation and accumulation of sediments, and the return fluid after unblocking is neutral, reducing the frequency of unblocking return fluid treatment procedures and well repair and pump inspection, achieving cost reduction and efficiency improvement, effectively restoring and improving oil well production, and facilitating large-scale promotion and application.

[0072] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A solid non-acid plugging remover, characterized in that: The solid non-acid plugging remover comprises the following components in terms of mass percentage: Main agent 60-75%; Alkali activator 25-35%; Metal ion stabilizer 1-5%.

2. The solid non-acid plugging remover according to claim 1, characterized in that: The main agent includes any one of sodium persulfate, sodium sulfate, sodium citrate, sodium sulfite or sodium bisulfate, or a combination of at least two thereof.

3. The solid non-acid plugging remover according to claim 1 or 2, characterized in that: The alkali activator includes any one of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate or sodium bicarbonate, or a combination of at least two thereof.

4. The solid non-acid plugging remover according to any one of claims 1 to 3, characterized in that: The metal ion stabilizer includes any one or a combination of at least two of disodium ethylenediaminetetraacetate, nitrilotriacetic acid, citric acid, tetrasodium glutamate diacetate, hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, 2-hydroxyphosphonoacetic acid or hexamethylenediaminetetramethylenephosphonic acid.

5. A method for preparing the solid non-acid plugging remover according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) mixing a main agent and an alkali activator for alkali activation treatment to obtain an alkali-activated main agent; (2) The alkali-activated main agent and the metal ion stabilizer are mixed and compounded to obtain a solid non-acid plugging remover.

6. The preparation method according to claim 5, characterized in that: The alkali activation treatment in step (1) is carried out in a reactor, and the reactor and pipelines are purged with nitrogen; Preferably, the alkali activation treatment in step (1) comprises: starting the stirrer and heating the mixture to a first temperature, starting vacuuming and continuing to heat the mixture to a second temperature, stopping vacuuming, continuing to stir the mixture for a certain period of time, cooling the mixture and discharging the mixture; Preferably, the first temperature is 80-90°C; Preferably, the second temperature is 140-145°C; Preferably, the pressure in the reactor during vacuuming is ≤0.1 MPa; Preferably, the certain period of time is 4-6 hours.

7. The preparation method according to claim 5 or 6, characterized in that: The compounding treatment in step (2) is carried out in a stirrer until the alkali-activated main agent and the metal ion stabilizer are evenly mixed; Preferably, the temperature of the compounding treatment in step (2) is 20-40°C; Preferably, the pressure of the compounding treatment in step (2) is 0.8-1.2 bar.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The preparation method comprises the following steps: (1) adding the main agent and the alkali activator to a reactor for alkali activation treatment, purging the reactor and pipelines with nitrogen, turning on the stirrer and heating to 80-90° C., starting to evacuate until the pressure in the reactor is ≤0.1 MPa, continuing to heat to 140-145° C., stopping evacuation, continuing to stir for 4-6 hours, cooling and discharging, and obtaining the alkali-activated main agent; (2) Add the alkali-activated main agent and the metal ion stabilizer into a stirrer for compounding, and stir at 20-40° C. and 0.8-1.2 bar until the alkali-activated main agent and the metal ion stabilizer are evenly mixed to obtain a solid non-acid plugging remover.

9. An application of the solid non-acid plugging remover according to any one of claims 1 to 4, characterized in that: The solid non-acid plugging remover is used for clearing blockages in oil well bores and / or electric pumps.

10. The use according to claim 9, characterized in that: The application comprises: preparing the solid non-acid plugging remover into a solution and then injecting the solution into the wellbore regularly.

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