A blocking agent, preparation method, use method and purpose

Abstract

In order to solve the technical problems that the prior art requires that the constituent reagents of the unblocking agent be added separately, resulting in cumbersome construction process and the unblocking agent cannot be mixed uniformly in the wellbore according to the designed ratio, the embodiment of the present invention provides a unblocking agent, a preparation method, a use method and purpose. The unblocking agent is made into a uniform solid reagent from the following components: amine, paraformaldehyde, phosphorus pentachloride, an exothermic agent for reacting with water, a dissolution inhibitor for accelerating the dissolution of hydrates and inhibiting the secondary formation of hydrates, and a water-soluble adhesive; the embodiment of the present invention dissolves dense hydrate blockages and viscous organic blockages such as wax and asphalt in the wellbore to achieve unblocking; the embodiment of the present invention makes the unblocking agent a uniform solid reagent, thereby avoiding the cumbersome process of alternately injecting oxidants, reductants and catalysts in existing chemical reaction heat-generating agents and the problem of uneven distribution of various agents in the wellbore.

Description

Technical Field

[0001] The invention relates to a plugging remover, a preparation method, a use method and application, and belongs to the field of oil and gas well exploitation chemistry. Background Art

[0002] In the process of oil and gas field development, hydrate blockage, wax and asphalt and other viscous organic blockage often occur. This type of wellbore hydrate blockage is extremely dense and the length is difficult to determine. For high-pressure sour natural gas wells, hydrates are more likely to form, usually at the downhole throttle valve.

[0003] For this type of wellbore hydrate blockage, the existing technology usually uses the following methods to remove the blockage.

[0004] 1. Injection of liquid hydrate inhibitors (methanol, ethylene glycol) and hot water, etc., due to the fact that the wellbore is completely blocked and cannot be injected, conventional operations such as liquid hydrate inhibitors and hot water injection are difficult to implement.

[0005] 2. Drilling with pressure or running oil down to the blockage location to pump liquid hydrate inhibitors or hot water. This method has extremely high safety risks: such as toxicity and explosion risks caused by sulfur-containing gas leakage; the risk of releasing high-pressure trap pressure instantly when unblocking the blockage; in addition, the construction cost of drilling with pressure or running oil down to the blockage location to pump liquid hydrate inhibitors or hot water is relatively high.

[0006] 3. Injection of plugging remover. The blockage of viscous organic matter such as wax and asphalt in the wellbore is also an important factor restricting the production of oil and gas fields. Conventional plugging removers have poor solubility and dispersion and need to be heated to dissolve and disperse. Summary of the invention

[0007] The inventors have found that in the prior art, the temperature is lowered due to the throttling effect during the unblocking process using unblocking agents, which poses a risk of secondary hydrate formation. Some unblocking agents with solid self-heating technology require the separate addition of multiple agents, which require acid for catalysis, making the construction process cumbersome. In addition, there is a problem that multiple agents cannot be mixed evenly in the wellbore according to the designed proportions.

[0008] In order to solve the technical problems in the prior art that the component reagents of the plugging remover need to be added separately, resulting in cumbersome construction process and the plugging remover cannot be mixed evenly in the wellbore according to the designed proportion, the embodiments of the present invention provide a plugging remover, a preparation method, a use method and purpose.

[0009] The embodiment of the present invention is achieved through the following technical solutions:

[0010] In a first aspect, an embodiment of the present invention provides a plugging remover, which is made into a uniform solid reagent from the following components: amine, paraformaldehyde, phosphorus pentachloride, an exothermic agent for reacting with water, a dissolution inhibitor for accelerating the dissolution of hydrates and inhibiting the secondary formation of hydrates, and a water-soluble adhesive.

[0011] Furthermore, the exothermic agent for reacting with water consists of nitrite and ammonium salt.

[0012] Furthermore, the dissolution inhibitor for accelerating the dissolution of hydrates and inhibiting the secondary formation of hydrates consists of ionic liquids and ice-melting salts.

[0013] Furthermore, the water-soluble adhesive is a water-soluble fatty acid metal salt.

[0014] Furthermore, the blocking agent is a spherical or rod-shaped solid.

[0015] In a second aspect, an embodiment of the present invention provides a plugging remover, which is made into a uniform solid reagent by the following components in mass percentage: 20%-30% nitrite; 10%-15% ammonium salt; 10%-15% amine; 1%-2% paraformaldehyde; 1%-2% phosphorus pentachloride; 5%-8% ionic liquid; 5%-8% de-icing salt and the remainder adhesive.

[0016] Furthermore, the nitrite is at least one of sodium nitrite, potassium nitrite, and calcium nitrite; the ammonium salt is at least one of ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, and ammonium sulfate; and the amine is at least one of urea and acetamide.

[0017] Further, the ionic liquid is at least one of 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butylpyridinium bromide, 1-butylpyridinium chloride, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium bromide, 1-butyl-3-methylpyridinium chloride, 1-butyl-4-methylpyridinium chloride, 1-ethylpyridinium bromide, and 1-butyl-3-methylpyridinium hexafluorophosphate.

[0018] Furthermore, the ice-melting salt is at least one of magnesium chloride, sodium chloride, magnesium nitrate and sodium nitrate.

[0019] Furthermore, the water-soluble adhesive is a water-soluble fatty acid metal salt; the water-soluble fatty acid metal salt is a water-soluble fatty acid metal salt with a carbon atom number of C10-C18; the water-soluble fatty acid metal salt is at least one of sodium fatty acid and potassium fatty acid.

[0020] In a third aspect, an embodiment of the present invention provides a method for preparing a blocking agent, comprising:

[0021] Evenly mixing nitrite, paraformaldehyde, ionic liquid and ice-melting salt, and vacuum drying to obtain a first mixture;

[0022] adding ammonium salt, amine and binder to the first mixture, mixing evenly, and vacuum drying to obtain a second mixture;

[0023] Phosphorus pentachloride is added to the second mixture, mixed evenly, and vacuum dried to obtain a blocking remover.

[0024] Furthermore, the method also includes: pressing and molding the blocking agent into a spherical or rod-shaped solid blocking agent, and storing the agent in a vacuum-packed plastic bag.

[0025] In a fourth aspect, an embodiment of the present invention provides a method for using a blocking agent, comprising:

[0026] S1. Open and depressurize the blocked well;

[0027] S2. Use a pump to inject a certain amount of water into the wellbore;

[0028] S3. Close the wellhead;

[0029] S4. Install the plugging agent filling cylinder on the top of the gas tree;

[0030] S5. Adding the blocking agent to the blocking agent filling cylinder;

[0031] S6. Close the valve on the plugging remover filling cylinder;

[0032] S7. Open the connecting valve between the gas tree and the plugging agent filling cylinder;

[0033] S8. The wellhead pressure and the pressure in the plugging remover filling tube are quickly balanced, and the plugging remover falls into the wellbore under the action of gravity and contacts with the hydrate plugging material in the wellbore and the water injected in the early stage;

[0034] S9. The unblocking agent gradually dissolves in water, and the blockage is dissolved by heat generated by the reaction;

[0035] S10. Return to S5 until the wellbore blockage is completely dissolved and the unblocking operation is completed.

[0036] In a fifth aspect, an embodiment of the present invention provides the use of the blockage remover for removing blockage in a wellbore.

[0037] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0038] A blocking remover, preparation method, use method and purpose of the embodiment of the present invention dissolves dense hydrate blockages and viscous organic blockages such as wax and asphalt in the wellbore through nitrite, ammonium salt, amine, polyformaldehyde, phosphorus pentachloride, ionic liquid, ice-melting salt and adhesive to achieve blocking; the adhesive can bond various components together to form a single solid substance, and has good surface activity. Under the action of the gas generated by blocking, the blocking removal product dissolved in the water produces foam and is quickly discharged from the wellbore. In addition, the embodiment of the present invention uses the blocking remover as a uniform solid reagent, avoiding the cumbersome process of alternately injecting oxidants, reductants and catalysts in existing chemical reaction heat-generating agents, and the problem of uneven distribution of agents in the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 It is the temperature rise curve of the plugging removal performance of the embodiment.

[0041] Figure 2 This is a photo of the finished product of the rod-shaped plugging remover.

[0042] Figure 3 This is a photo of the finished product of the spherical plugging remover.

[0043] Figure 4 This is a schematic diagram of adding plugging agent.

[0044] Marks and corresponding parts names in the attached drawings:

[0045] 1-curve of Example 1, 2-curve of Example 2, 3-curve of Example 3, 4-valve on filling cylinder, 5-blocking agent filling cylinder, 6-valve under filling cylinder, 7-gas production tree. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0047] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that these specific details are not required to practice the present invention.

[0048] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0050] Example

[0051] In order to solve the technical problems that the prior art requires the components of the plugging remover to be added separately, resulting in cumbersome construction process and the plugging remover cannot be mixed evenly in the wellbore according to the designed proportion, the embodiments of the present invention provide a plugging remover, a preparation method, a use method and purpose; in the first aspect, the embodiments of the present invention provide a plugging remover, which is made into a uniform solid reagent from the following components: amine, paraformaldehyde, phosphorus pentachloride, an exothermic agent for reacting with water, a dissolution inhibitor for accelerating the dissolution of hydrates and inhibiting the secondary formation of hydrates, and a water-soluble adhesive.

[0052] Furthermore, the exothermic agent for reacting with water consists of nitrite and ammonium salt.

[0053] Furthermore, the dissolution inhibitor for accelerating the dissolution of hydrates and inhibiting the secondary formation of hydrates consists of ionic liquids and ice-melting salts.

[0054] Furthermore, the water-soluble adhesive is a water-soluble fatty acid metal salt.

[0055] Furthermore, the blocking agent is a spherical or rod-shaped solid.

[0056] Thus, the embodiments of the present invention use amines, paraformaldehyde, phosphorus pentachloride, an exothermic agent for reacting with water, a dissolution inhibitor for accelerating the dissolution of hydrates and inhibiting the secondary formation of hydrates, and a water-soluble adhesive to dissolve dense hydrate blockages and viscous organic blockages such as wax and asphalt in the wellbore to achieve unblocking; among them, nitrite and ammonium salt serve as exothermic agents. After contacting with water in the wellbore, only a small amount of nitrite and ammonium salt need to be dissolved to produce a small amount of hydrogen ions as a catalyst, which promotes the redox reaction of nitrate and ammonium salt, generating a large amount of heat to dissolve the blockage; the increase in temperature will also promote the The reaction of polyformaldehyde with ammonium salt further produces a large number of hydrogen ions, which causes nitrite to further react with amine, releasing a large amount of heat and further dissolving hydrates; ionic liquids and ice-melting salts as dissolution inhibitors have a certain dissolving effect on hydrates, accelerate the dissolution of hydrates, and have a good hydrate inhibition effect, avoiding the re-generation of hydrates after the temperature is lowered in the later stage of the unblocking process; the adhesive can bond various components together to form a single solid substance, and has good surface activity. Under the action of the gas generated by unblocking, the unblocking products dissolved in the water produce foam and are quickly discharged from the wellbore.

[0057] In addition, the embodiment of the present invention makes the unblocking agent into a uniform solid reagent, thereby avoiding the cumbersome process of alternately injecting oxidants, reductants and catalysts in existing chemical reaction heat-generating reagents and the problem of uneven distribution of reagents in the wellbore.

[0058] In a second aspect, an embodiment of the present invention provides a plugging remover, which is made into a uniform solid reagent by the following components in mass percentage: 20%-30% nitrite; 10%-15% ammonium salt; 10%-15% amine; 1%-2% paraformaldehyde; 1%-2% phosphorus pentachloride; 5%-8% ionic liquid; 5%-8% de-icing salt and the remainder adhesive.

[0059] Furthermore, the nitrite is at least one of sodium nitrite, potassium nitrite, and calcium nitrite; the ammonium salt is at least one of ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonium nitrate, and ammonium sulfate; and the amine is at least one of urea and acetamide.

[0060] Further, the ionic liquid is at least one of 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butylpyridinium bromide, 1-butylpyridinium chloride, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium bromide, 1-butyl-3-methylpyridinium chloride, 1-butyl-4-methylpyridinium chloride, 1-ethylpyridinium bromide, and 1-butyl-3-methylpyridinium hexafluorophosphate.

[0061] Furthermore, the ice-melting salt is at least one of magnesium chloride, sodium chloride, magnesium nitrate and sodium nitrate.

[0062] Furthermore, the water-soluble adhesive is a water-soluble fatty acid metal salt; the water-soluble fatty acid metal salt is a water-soluble fatty acid metal salt with a carbon atom number of C10-C18; the water-soluble fatty acid metal salt is at least one of sodium fatty acid and potassium fatty acid.

[0063] The binder is at least one of water-soluble fatty acid metal salts. Further, (1) the water-soluble fatty acid metal salt is at least one of a sodium salt of a fatty acid and a potassium salt of a fatty acid, and the general structural formulas are R-CO 2 Na, R-CO 2 K; (2) the carbon number of the fatty acid metal salt is 10-18.

[0064] In a third aspect, an embodiment of the present invention provides a method for preparing a blocking agent, comprising:

[0065] Evenly mixing nitrite, paraformaldehyde, ionic liquid and ice-melting salt, and vacuum drying to obtain a first mixture;

[0066] adding ammonium salt, amine and binder to the first mixture, mixing evenly, and vacuum drying to obtain a second mixture;

[0067] Phosphorus pentachloride is added to the second mixture, mixed evenly, and vacuum dried to obtain a blocking remover.

[0068] Furthermore, the method also includes: pressing and molding the blocking agent into a spherical or rod-shaped solid blocking agent, and storing the agent in a vacuum-packed plastic bag.

[0069] Specifically, the preparation method comprises: mixing nitrite, paraformaldehyde, ionic liquid and ice-melting salt in proportion, placing in a vacuum reactor, and vacuum drying at room temperature for 1-2 days; then adding ammonium salt, amine and adhesive, mixing evenly, and continuing to vacuum dry at room temperature for 1-2 days; then adding phosphorus pentachloride, mixing evenly; adding the mixture into a spherical or rod-shaped mold, pressing into a spherical object or a rod-shaped object as the blocking remover, taking out, and vacuuming and storing in a plastic bag.

[0070] In a fourth aspect, an embodiment of the present invention provides a method for using a blocking agent, comprising:

[0071] S1. Open and depressurize the blocked well;

[0072] S2. Use a pump to inject a certain amount of water into the wellbore;

[0073] S3. Close the wellhead;

[0074] S4. Install the plugging agent filling cylinder on the top of the gas tree;

[0075] S5. Adding the blocking agent to the blocking agent filling cylinder;

[0076] S6. Close the valve on the plugging remover filling cylinder;

[0077] S7. Open the connecting valve between the gas tree and the plugging agent filling cylinder;

[0078] S8. The wellhead pressure and the pressure in the plugging remover filling tube are quickly balanced, and the plugging remover falls into the wellbore under the action of gravity and contacts with the hydrate plugging material in the wellbore and the water injected in the early stage;

[0079] S9. The unblocking agent gradually dissolves in water, and the blockage is dissolved by heat generated by the reaction;

[0080] S10. Return to S5 until the wellbore blockage is completely dissolved and the unblocking operation is completed.

[0081] Specifically, refer to Figure 4 As shown, the specific steps include: opening the well to relieve the pressure of the blocked well; injecting a certain amount of water into the well with a pump; closing the wellhead; installing the unblocking agent filling cylinder 5 on the top of the gas production tree 7 of the measure well; adding the rod-shaped unblocking agent into the unblocking agent filling cylinder; closing the valve 4 on the unblocking agent filling cylinder, and opening the connecting valve (the valve 6 under the filling cylinder) between the gas production tree and the unblocking agent filling cylinder; the wellhead pressure and the pressure in the unblocking agent filling cylinder are quickly balanced, and the rod-shaped unblocking agent falls into the wellbore under the action of gravity, and contacts with the blockage in the wellbore and the water injected in the early stage; the rod-shaped unblocking agent gradually dissolves in the water, generates heat through reaction, and further accelerates the reaction, releases a large amount of heat, and dissolves the blockage by heat; repeats the unblocking agent filling process until the wellbore is completely dissolved and the unblocking operation is completed.

[0082] The specific principle is: amine, paraformaldehyde, phosphorus pentachloride, exothermic agent for reacting with water, dissolution inhibitor for accelerating hydrate dissolution and inhibiting secondary formation of hydrate are pressurized in the mold through a water-soluble adhesive to form a spherical or rod-shaped solid to form a plugging remover. The plugging remover is added to the wellbore through an injection tube and falls into the blocked part by gravity. The plugging remover gradually dissolves in the water of the blocked part or the water of the blockage or is added to the water of the wellbore in other ways. Phosphorus pentachloride is hydrolyzed into hydrogen chloride and phosphoric acid when dissolved in water. The exothermic agent for reacting with water reacts under the catalytic action of acid to generate nitrogen, inorganic salts and water, and releases a large amount of heat to dissolve the blockage; at the same time, paraformaldehyde and ammonium salt will also react with the heat released by the exothermic agent. Paraformaldehyde first generates formaldehyde and water under heating conditions, and formaldehyde reacts with ammonium salt under heating conditions to generate acid (determined by the anion of the ammonium salt), water and hexamethylenetetramine; in addition, amines will also react with ammonium under acidic and heating conditions to further release a large amount of heat. The acid produced in the above process can also dissolve, peel and disperse some acid-soluble blockages. Ionic liquids and ice-melting salts have a dissolving effect on hydrates and can inhibit the regeneration of hydrates, especially under heating conditions. The main function of the adhesive is to bond various components together under pressure to form spherical or rod-shaped unblocking agents; at the same time, the adhesive is a water-soluble fatty acid metal salt that can be dissolved in water and has a cleaning and dispersing effect on oil stains in the blockage. In the backflow process after unblocking, foam can be generated to improve the backflow effect of the unblocking liquid.

[0083] In a fifth aspect, an embodiment of the present invention provides the use of the blockage remover for removing blockage in a wellbore.

[0084] Example 1

[0085] The unblocking agent is a uniform solid reagent, which is made of the following components in mass fraction: 25% nitrite, 12% ammonium salt, 12% amine, 1% paraformaldehyde, 1% phosphorus pentachloride, 5% ionic liquid, 5% ice-melting salt, and the balance is a binder.

[0086] The nitrite is calcium nitrite, the ammonium salt is ammonium chloride, the amine is urea, the ionic liquid is 1-butyl-3-methylimidazolium bromide, the ice-melting salt is magnesium chloride, and the binder is sodium dodecanoate.

[0087] Preparation method of the blocking remover: calcium nitrite, paraformaldehyde, 1-butyl-3-methylimidazolium bromide and magnesium chloride are mixed evenly according to a proportion, put into a vacuum reactor, and vacuum-dried at room temperature for 1 day; then ammonium chloride, urea and sodium dodecanoate are added, mixed evenly, put into a vacuum reactor, and vacuum-dried at room temperature for 1 day; then phosphorus pentachloride is added, mixed evenly; the mixture is added into a rod-shaped mold, pressed into a rod-shaped object, which is the blocking remover, taken out, and vacuum-dried in a plastic bag for storage.

[0088] Usage of the plugging remover: open the well to relieve the pressure of the blocked well; use a pump to inject a certain amount of water into the wellbore; close the wellhead; install the plugging remover filling cylinder on the top of the gas production tree of the measure well; add the rod-shaped plugging remover into the plugging remover filling cylinder; close the valve on the plugging remover filling cylinder, and open the connecting valve between the gas production tree and the plugging remover filling cylinder (the valve under the plugging remover filling cylinder); the wellhead pressure and the pressure in the plugging remover filling cylinder are quickly balanced, and the rod-shaped plugging remover falls into the wellbore under the action of gravity, and contacts with the blockage in the wellbore and the water injected in the early stage; the rod-shaped plugging remover gradually dissolves in the water, generates heat through reaction, and further accelerates the reaction, releasing a large amount of heat, and dissolving the blockage by heat; repeat the plugging remover filling process until the wellbore is completely dissolved and the unblocking operation is completed.

[0089] Example 2

[0090] The blocking remover is a uniform solid reagent, which is made of the following components in mass fraction: 28% nitrite, 15% ammonium salt, 12% amine, 2% paraformaldehyde, 1% phosphorus pentachloride, 6% ionic liquid, 6% ice-melting salt, and the balance is a binder.

[0091] The nitrite is potassium nitrite, the ammonium salt is ammonium carbonate, the amine is acetamide, the ionic liquid is 1-butylpyridinium chloride, the ice-dissolving salt is sodium nitrate, and the binder is sodium tetradecanoate.

[0092] Preparation method of the blocking remover: potassium nitrite, paraformaldehyde, 1-butylpyridinium chloride and sodium nitrate are mixed evenly according to a proportion, put into a vacuum reactor, and vacuum-dried at room temperature for 1 day; then ammonium carbonate, acetamide and sodium tetradecanoate are added, mixed evenly, put into a vacuum reactor, and vacuum-dried at room temperature for 2 days; then phosphorus pentachloride is added and mixed evenly; the above mixture is added into a spherical shaping mold, pressed into a spherical object as the blocking remover, taken out, and vacuum-dried in a plastic bag for storage.

[0093] Usage of the plugging remover: open the well to relieve the pressure of the blocked well; use a pump to inject a certain amount of water into the wellbore; close the wellhead; install the plugging remover filling cylinder on the top of the gas production tree of the measure well; add the spherical plugging remover into the plugging remover filling cylinder; close the valve on the plugging remover filling cylinder, and open the connecting valve between the gas production tree and the plugging remover filling cylinder (the valve under the plugging remover filling cylinder); the wellhead pressure and the pressure in the plugging remover filling cylinder are quickly balanced, and the spherical plugging remover falls into the wellbore under the action of gravity, and contacts with the blockage in the wellbore and the water injected in the early stage; the spherical plugging remover gradually dissolves in the water, generates heat through reaction, and further accelerates the reaction, releasing a large amount of heat, and dissolving the blockage by heat; repeat the plugging remover filling process until the wellbore is completely dissolved and the unblocking operation is completed.

[0094] Example 3

[0095] The blocking remover is a uniform solid reagent, which is made of the following components in mass fraction: 26% nitrite, 12% ammonium salt, 15% amine, 2% paraformaldehyde, 2% phosphorus pentachloride, 6% ionic liquid, 5% ice-melting salt, and the balance is a binder.

[0096] The nitrite is sodium nitrite, the ammonium salt is ammonium bicarbonate, the amine is urea, the ionic liquid is 1-butylpyridinium hexafluorophosphate, the ice-melting salt is magnesium nitrate, and the binder is potassium hexadecanoate.

[0097] Preparation method of the blocking remover: Sodium nitrite, paraformaldehyde, 1-butylpyridinium hexafluorophosphate and magnesium nitrate are mixed evenly according to a proportion, put into a vacuum reactor, and vacuum-dried at room temperature for 2 days; then ammonium bicarbonate, urea and potassium hexadecanoate are added, mixed evenly, put into a vacuum reactor, and vacuum-dried at room temperature for 2 days; then phosphorus pentachloride is added, mixed evenly; the mixture is added into a rod-shaped shaping mold, pressed into a spherical object, which is the blocking remover, taken out, and vacuum-dried in a plastic bag for storage.

[0098] Usage of the plugging remover: open the well to relieve the pressure of the blocked well; use a pump to inject a certain amount of water into the wellbore; close the wellhead; install the plugging remover filling cylinder on the top of the gas production tree of the measure well; add the rod-shaped plugging remover into the plugging remover filling cylinder; close the valve on the plugging remover filling cylinder, and open the connecting valve between the gas production tree and the plugging remover filling cylinder (the valve under the plugging remover filling cylinder); the wellhead pressure and the pressure in the plugging remover filling cylinder are quickly balanced, and the rod-shaped plugging remover falls into the wellbore under the action of gravity, and contacts with the blockage in the wellbore and the water injected in the early stage; the rod-shaped plugging remover gradually dissolves in the water, generates heat through reaction, and further accelerates the reaction, releasing a large amount of heat, and dissolving the blockage by heat; repeat the plugging remover filling process until the wellbore is completely dissolved and the unblocking operation is completed.

[0099] Example Performance

[0100] The unblocking performance of the unblocking agent of the embodiment of the present invention is characterized by a temperature rise curve and the amount of dissolved hydrate. Temperature rise curve: add 200 mL of water to an insulated reactor, then add 50 g of unblocking agent, seal it, and monitor the temperature of the water in the reactor after different reaction times; draw a curve with the reaction time and the temperature of the water in the reactor. The faster the heating rate and the higher the final temperature, the better the performance of the unblocking agent in dissolving hydrates.

[0101] The hydrate inhibition performance of the plugging remover of the present invention is characterized by the supercooling degree of hydrate formation: the reaction product solution obtained by the plugging removal performance test is added to the hydrate generation device, methane gas is introduced, and the hydrate formation temperature is tested at a certain temperature, pressure and stirring speed. Figure 1-4 And Table 1. Figure 1 The three curves in are respectively curve 1 of Example 1, curve 2 of Example 2 and curve 3 of Example 3.

[0102] Table 1 Hydrate inhibition performance (generation time) of the examples

[0103]

[0104] It can be seen that the plugging removers of Examples 1-3 of the present invention have good heating performance. 50g of the plugging remover can heat 200mL of water to above 80°C. Under the condition of supercooling of 5°C, for methane gas containing 1% hydrogen sulfide, the hydrate formation time is ≥35min. Therefore, Examples 1-3 of the present invention have good plugging removal performance and hydrate formation inhibition performance.

[0105] Example 4

[0106] A blocking remover is prepared into a uniform solid reagent from the following components in mass percentage: 20% nitrite, 10% ammonium salt, 10% amine, 1% paraformaldehyde, 1% phosphorus pentachloride, 8% ionic liquid, 5% ice-melting salt and the remainder adhesive.

[0107] The nitrite is sodium nitrite, potassium nitrite or calcium nitrite; the ammonium salt is ammonium chloride, ammonium carbonate or ammonium bicarbonate; and the amine is urea or acetamide.

[0108] The ionic liquid is 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butylpyridinium bromide, 1-butylpyridinium chloride, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium bromide, 1-butyl-3-methylpyridinium chloride, 1-butyl-4-methylpyridinium chloride, 1-ethylpyridinium bromide or 1-butyl-3-methylpyridinium hexafluorophosphate.

[0109] The ice-melting salt is magnesium chloride, sodium chloride, magnesium nitrate or sodium nitrate.

[0110] The water-soluble adhesive is a water-soluble fatty acid metal salt; the water-soluble fatty acid metal salt is a water-soluble fatty acid metal salt with carbon atoms of C10-C18; the water-soluble fatty acid metal salt is sodium fatty acid or potassium fatty acid.

[0111] Preparation method of the blocking remover: nitrite, paraformaldehyde, ionic liquid and ice-melting salt are mixed evenly according to a proportion, put into a vacuum reactor, and vacuum-dried at room temperature for 2 days; then ammonium salt, amine and water-soluble fatty acid metal salt are added, mixed evenly, put into a vacuum reactor, and vacuum-dried at room temperature for 2 days; then phosphorus pentachloride is added and mixed evenly; the mixture is added into a rod-shaped shaping mold, pressed into a spherical object as the blocking remover, taken out, and vacuum-dried in a plastic bag for storage.

[0112] Usage of the plugging remover: open the well to relieve the pressure of the blocked well; use a pump to inject a certain amount of water into the wellbore; close the wellhead; install the plugging remover filling cylinder on the top of the gas production tree of the measure well; add the rod-shaped plugging remover into the plugging remover filling cylinder; close the valve on the plugging remover filling cylinder, and open the connecting valve between the gas production tree and the plugging remover filling cylinder (the valve under the plugging remover filling cylinder); the wellhead pressure and the pressure in the plugging remover filling cylinder are quickly balanced, and the rod-shaped plugging remover falls into the wellbore under the action of gravity, and contacts with the blockage in the wellbore and the water injected in the early stage; the rod-shaped plugging remover gradually dissolves in the water, generates heat through reaction, and further accelerates the reaction, releasing a large amount of heat, and dissolving the blockage by heat; repeat the plugging remover filling process until the wellbore is completely dissolved and the unblocking operation is completed.

[0113] Example 5

[0114] The only difference from Example 4 is: a plugging remover, which is made into a uniform solid reagent with the following components in mass percentage: 30% nitrite; 15% ammonium salt; 15% amine; 2% paraformaldehyde; 2% phosphorus pentachloride; 8% ionic liquid; 8% deicing salt and the remainder adhesive.

[0115] Example 6

[0116] The only difference from Example 4 is: a plugging remover, which is made into a uniform solid reagent with the following components in mass percentage: 22% nitrite; 12% ammonium salt; 13% amine; 1.5% paraformaldehyde; 1.5% phosphorus pentachloride; 6% ionic liquid; 7% deicing salt and the remainder adhesive.

[0117] The specific implementation methods 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 implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A blocking agent, It is characterized in that A uniform solid reagent is prepared from the following components in mass percentage: 20%-30% nitrite; 10%-15% ammonium salt; 10%-15% amine; 1%-2% paraformaldehyde; 1%-2% phosphorus pentachloride; 5%-8% ionic liquid; 5%-8% deicing salt and the remainder adhesive; The water-soluble adhesive is a water-soluble fatty acid metal salt; The amine is at least one of urea and acetamide.

2. The blocking agent according to claim 1, It is characterized in that The blocking agent is a spherical or rod-shaped solid.

3. The blocking agent according to claim 1, It is characterized in that The nitrite is at least one of sodium nitrite, potassium nitrite and calcium nitrite; the ammonium salt is at least one of ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonium nitrate and ammonium sulfate.

4. The blocking agent according to claim 1, It is characterized in that The ionic liquid is at least one of 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butylpyridinium bromide, 1-butylpyridinium chloride, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium bromide, 1-butyl-3-methylpyridinium chloride, 1-butyl-4-methylpyridinium chloride, 1-ethylpyridinium bromide, and 1-butyl-3-methylpyridinium hexafluorophosphate.

5. The blocking agent according to claim 1, It is characterized in that The ice-melting salt is at least one of magnesium chloride, sodium chloride, magnesium nitrate and sodium nitrate.

6. The blocking agent according to claim 1, It is characterized in that The water-soluble fatty acid metal salt is a water-soluble fatty acid metal salt having carbon atoms of C10-C18.

7. The blocking agent according to claim 1 or 6, It is characterized in that The water-soluble fatty acid metal salt is at least one of sodium fatty acid and potassium fatty acid.

8. A method for preparing a blocking agent according to claim 1, It is characterized in that include: Evenly mixing nitrite, paraformaldehyde, ionic liquid and ice-melting salt, and vacuum drying to obtain a first mixture; adding ammonium salt, amine and binder to the first mixture, mixing evenly, and vacuum drying to obtain a second mixture; Phosphorus pentachloride is added to the second mixture, mixed evenly, and vacuum dried to obtain a blocking remover.

9. The method for preparing the blocking agent according to claim 8, It is characterized in that Also includes: The plugging remover is pressed and molded into a spherical or rod-shaped solid plugging remover, and is vacuum-stored in a plastic bag.

10. A method for using a blocking agent, It is characterized in that include: S1. Open and depressurize the blocked well; S2. Use a pump to inject a certain amount of water into the wellbore; S3. Close the wellhead; S4. Install the plugging agent filling cylinder on the top of the gas tree; S5. Add the blocking agent according to any one of claims 1 to 7 or the blocking agent prepared by any one of claims 8 to 9 into the blocking agent filling cylinder; S6. Close the valve on the plugging remover filling cylinder; S7. Open the connecting valve between the gas tree and the plugging agent filling cylinder; S8. The wellhead pressure and the pressure in the plugging remover filling tube are quickly balanced, and the plugging remover falls into the wellbore under the action of gravity and contacts with the hydrate plugging material in the wellbore and the water injected in the early stage; S9. The unblocking agent gradually dissolves in water, and the blockage is dissolved by heat generated by the reaction; S10. Return to S5 until the wellbore blockage is completely dissolved and the unblocking operation is completed.

11. Use of the blocking remover according to any one of claims 1 to 7 for removing blockage in a wellbore.

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