Composition for enhancing extrusion of scale inhibitor and extrusion treatment method of scale inhibitor

Abstract

The invention provides a composition for enhancing squeezing of a scale inhibitor and a squeezing treatment method of the scale inhibitor. The composition for enhancing squeezing of the scale inhibitor comprises prepad fluid, main fluid and post-prepad fluid, the prepad fluid comprises a first scale inhibitor and tetramethylammonium chloride; the main liquid comprises a second scale inhibitor; the post liquid comprises a third scale inhibitor and tetramethylammonium chloride. According to the composition for enhancing squeezing of the scale inhibitor, the adsorption capacity of the scale inhibitor on the rock surface can be improved, and the validity period of squeezing treatment can be prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield anti-scaling, and specifically relates to a composition for enhancing antiscalant squeezing and a method for treating antiscalant squeezing. Background Art

[0002] In the middle and late stages of oil well production, water injection is one of the common measures to maintain formation pressure. Changes in physical conditions and the mixing of incompatible water bodies (i.e., injected water and formation water containing barium, strontium, and calcium) can lead to inorganic salt scaling in the production system. That is, as pressure, temperature, or ionic strength changes, compounds such as carbonates and sulfates of calcium, barium, and strontium may precipitate in oil wells or production equipment.

[0003] Scaling in production systems can lead to a significant drop in oil production or even well closure. Scaling in oil wells is commonly found in the formations around the bottom of the well, the inner surface of the tubing, the perforation section, downhole safety valves, and surface pipelines and equipment. In order to prevent the formation of these inorganic salt scales in the system, the most economical and effective method is to continuously inject chemical antiscalants or periodically perform antiscalant squeezing treatments.

[0004] Squeeze-injection antiscalants can generally be adsorbed onto the surface of rock materials through electrostatic forces, van der Waals forces, and hydrogen bonding. The degree of adsorption is affected by many factors, including solution pH, salinity, temperature, rock surface properties, and the properties of the antiscalant.

[0005] The effective period of the squeeze treatment depends on the amount of scale inhibitor adsorbed on the surface of the formation rock. The adsorption of scale inhibitors on the surface of the rock material means that they may be slowly released into the water phase in contact with the rock material. Generally, a larger amount of adsorption means that the effective concentration of scale inhibitors may have a longer release time in the liquid in contact with the rock material, and the longer the effective period of the squeeze treatment. That is, the higher the amount of scale inhibitor adsorbed, the longer the effective period of the squeeze treatment, thereby reducing the frequency of treatment, saving expensive construction and chemical costs, and the loss of crude oil production caused by well closure construction.

[0006] At present, the existing technology only uses antiscalants, which has the problem of short effective period of squeezing treatment. Therefore, it is necessary to provide a new antiscalant squeezing treatment method to improve the above problem. Summary of the invention

[0007] In order to solve the above technical problems, the purpose of the present invention is to provide a composition for enhanced scale inhibitor squeezing and a scale inhibitor squeezing treatment method, which can increase the adsorption amount of scale inhibitor on the rock surface and extend the effective period of squeezing treatment.

[0008] To achieve the above-mentioned purpose, the present invention provides a composition for enhanced antiscalant squeezing, which comprises a pre-fluid, a main fluid and a post-fluid. The pre-fluid comprises tetramethylammonium chloride; the main fluid comprises a second antiscalant; the post-fluid comprises tetramethylammonium chloride; in the pre-fluid, the mass concentration of tetramethylammonium chloride is 1 to 10%; in the post-fluid, the mass concentration of tetramethylammonium chloride is 1 to 3%. Based on this, the present invention can achieve the following beneficial effects:

[0009] The pre-fluid can push most of the formation water deeper into the formation to avoid the incompatibility problem between the main fluid and the formation water. In addition, the cooling effect caused by the injection of the pre-fluid can also slow down the adsorption rate of the scale inhibitor, so more scale inhibitors can be adsorbed on the reservoir rocks far away from the wellbore. The post-fluid can push the pre-fluid and the main scale inhibitor solution deeper into the formation, providing more rock surface for adsorption of scale inhibitors.

[0010] In particular, the introduction of tetramethylammonium chloride, which has a surfactant effect and enhances the squeeze effect, can change the wettability of the rock to make it more water-wet, so as to enhance the affinity of the scale inhibitor on the rock surface and facilitate the adsorption of the scale inhibitor, thereby extending the squeeze treatment life. The positively charged methylammonium ions are conducive to neutralizing the negatively charged rock surface, thereby enhancing the above-mentioned squeeze effect. This technology is based on modifying the surface charge of the rock to make it more positively charged and reduce the repulsion of negatively charged scale inhibitors. The adsorbed tetramethylammonium chloride makes the rock surface present less negatively charged surface than the rock itself, changes the double layer structure, and thus changes the interaction force between the chemical substance and the rock surface, so that more scale inhibitors will be adsorbed to the rock surface covered by the additive through electrostatic forces, hydrogen bonds and van der Waals forces. Therefore, by introducing tetramethylammonium chloride, the adsorption of scale inhibitors can be enhanced through this "bridge connection" mechanism, and scale inhibitors are usually more adsorbed to the rock surface, thereby extending the squeeze treatment cycle. In addition, in addition to enhancing the adsorption capacity of scale inhibitors, tetramethylammonium chloride can also stabilize clay and avoid damage to the formation caused by clay migration.

[0011] In summary, the above-mentioned enhanced scale inhibitor squeezing composition can be more suitably applied in the scale inhibitor squeezing treatment process, enhance the treatment cycle and reduce the squeezing treatment frequency under limited injection volume, and avoid the problems of crude oil production reduction caused by scaling of oil wells, crude oil production loss caused by shut-in construction, expensive construction and chemical agent costs, etc. for a longer period of time, thereby bringing considerable economic benefits to the oil field and saving operating costs.

[0012] Furthermore, the pH value of the pre-fluid is 2.5 to 7. Within this pH range, the positively charged methylammonium ions are beneficial to neutralize the negatively charged rock surface and enhance the above-mentioned squeezing effect.

[0013] Furthermore, the solvents in the pre-fluid and the main fluid are independently selected from brine; the solvent in the post-fluid is selected from brine and / or a non-aqueous fluid with a specific gravity of 1.05 to 1.30. In some optional embodiments, the pre-fluid, the main fluid and the post-fluid are usually prepared with brine, which is a solution of salt compounds, such as an aqueous solution containing one or more salts dissolved therein, recycled production water, filtered seawater, etc.; in other optional embodiments, in order to speed up the return flow after shut-in, the post-fluid can also use a non-aqueous fluid with a low specific gravity, such as diesel, etc.

[0014] In some optional embodiments, the mass concentration of tetramethylammonium chloride in the pre-pad solution is 2-5%. The pre-pad solution also includes a first antiscalant, and the mass concentration of the first antiscalant is 0.05-3%.

[0015] In some optional embodiments, the mass concentration of the second antiscalant in the main liquid is 2-20%.

[0016] In some optional embodiments, the post-dip liquid further includes a third antiscalant, and the mass concentration of the third antiscalant is 1-3%.

[0017] Furthermore, the first scale inhibitor, the second scale inhibitor and the third scale inhibitor are each independently selected from organic phosphonate scale inhibitors, such as diethylene triamine penta methylene phosphonic acid. The requirements of the squeeze injection technology for chemical scale inhibitors are: high anti-scaling efficiency, which can avoid the formation of scale in the near-well formation, perforation holes, oil well pipes, oil nozzles and ground equipment; good thermal stability suitable for oil layer temperature conditions, and easy to detect trace amounts; the scale inhibitor is easy and can be well adsorbed in the formation, and can be slowly desorbed and released; good compatibility with formation fluids and other chemical treatment agents; no damage to the formation. From an economic point of view, the minimum effective concentration (MEC) of the scale inhibitor should be as low as possible, and it should be non-toxic and non-polluting.

[0018] In some optional embodiments, the volume ratio of the pre-pad fluid to the main fluid is 1:1 to 8; in some optional embodiments, the volume ratio of the pre-pad fluid to the main fluid is 1:3 to 8. In some optional embodiments, the volume of the post-pad fluid is such that the main fluid enters the formation to a depth of 1 to 10 m in the radial direction; in some optional embodiments, the volume of the post-pad fluid is such that the main fluid enters the formation to a depth of 3 to 5 m in the radial direction.

[0019] The present invention also provides a scale inhibitor squeezing treatment method, wherein the aforementioned enhanced scale inhibitor squeezing composition is used for scale inhibitor squeezing treatment, and the treatment method includes: pre-flushing the formation with a pre-flushing liquid; squeezing the main liquid into the formation; using a post-flushing liquid to push the pre-flushing liquid and the main liquid into the deep part of the formation; and shutting in the well.

[0020] First, pre-flushing by injecting pre-flushing fluid can push most of the formation water deeper into the formation to avoid incompatibility issues between the main fluid and the formation water. The cooling effect caused by the injection of pre-flushing fluid can also slow down the adsorption rate of scale inhibitors, so that more scale inhibitors can be adsorbed on the reservoir rocks far away from the wellbore.

[0021] Secondly, the introduction of tetramethylammonium chloride, which has a surfactant effect and enhances the squeezing effect, can change the wettability of the rock, making it more water-wet, so as to enhance the affinity of the scale inhibitor on the rock surface and facilitate the adsorption of the scale inhibitor, thereby extending the squeezing treatment life. The positively charged methylammonium ion is conducive to neutralizing the negatively charged rock surface, thereby enhancing the above-mentioned squeezing effect. This technology is based on modifying the surface charge of the rock to make it more positively charged and reduce the repulsion of negatively charged scale inhibitors. The adsorbed tetramethylammonium chloride makes the rock surface present less negatively charged surface than the rock itself, changes the double layer structure, and thus changes the interaction force between the chemical substance and the rock surface, so that more scale inhibitors will be adsorbed on the rock surface covered by the additive through electrostatic force, hydrogen bonding and van der Waals force. Therefore, by introducing tetramethylammonium chloride, the adsorption of scale inhibitors can be enhanced through this "bridge connection" mechanism, and scale inhibitors are usually more adsorbed on the rock surface, thereby extending the squeezing treatment cycle. Once the scale inhibitor is squeezed into the formation, the adsorbed scale inhibitor will automatically desorb and return to the ground with the fluid. The above method is cost-effective and does not require additional energy. In addition, in addition to enhancing the adsorption of scale inhibitors, tetramethylammonium chloride can also stabilize clay to avoid damage to the formation caused by clay migration.

[0022] Furthermore, the post-fluid can push the pre-fluid and the main antiscalant solution to the depth of the formation, providing more rock surface to adsorb the antiscalant.

[0023] In summary, the above-mentioned scale inhibitor squeezing treatment process can reduce the frequency of squeezing treatment, avoid the problems of crude oil production reduction caused by scaling of oil wells, crude oil production loss caused by shut-in construction, expensive construction and chemical agent costs, etc. for a longer period of time, thereby bringing considerable economic benefits to the oil field and saving operating costs.

[0024] In addition, the present invention allows the pre-fluid, main fluid and post-fluid to enter the formation through the production well.

[0025] Furthermore, during the injection phase of injecting the antiscalant main solution into the formation, the pump injection pressure should be monitored, and signs of sudden pressure surges may be a sign of incompatibility issues between the injection fluid and the reservoir.

[0026] In some optional embodiments, the organic phosphonate scale inhibitor has a faster adsorption rate than the polymer scale inhibitor, and the shut-in time is 6 to 24 hours. For the polymer scale inhibitor, the shut-in time may need to exceed 24 hours.

[0027] In some optional embodiments, after the squeezing treatment, the well can be started for production. During production, water samples can be collected for antiscalant concentration determination, and brine samples can be collected regularly to analyze ions and antiscalant concentrations. Once the antiscalant concentration drops below the minimum antiscalant effective concentration (MEC) required to control inorganic salt scale deposition, a new cycle of antiscalant squeezing treatment is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a scale inhibitor squeezing process in one embodiment of the present invention is shown;

[0029] Figure 2 The antiscalant reflux curves of the comparative group and the experimental group in Example 2 of the present invention are shown;

[0030] Figure 3 The squeezing effect test diagram of the comparison group and the experimental group in Example 3 of the present invention is shown. DETAILED DESCRIPTION

[0031] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0032] Example 1

[0033] Providing a test adsorption carrier: Commercially supplied acid-washed quartz sand (particle size of 0.1-0.3 mm) was used as a test adsorption carrier.

[0034] Providing sodium chloride aqueous solution: using a sodium chloride aqueous solution with a sodium chloride mass concentration of 6%.

[0035] Preparation of tetramethylammonium chloride solution: A sodium chloride aqueous solution with a sodium chloride mass concentration of 6% is used as a solvent to prepare a tetramethylammonium chloride solution, wherein the content of tetramethylammonium chloride in the tetramethylammonium chloride solution is 10000 ppm.

[0036] Preparation of diethylenetriaminepenta(methylenephosphonic acid) solution: A sodium chloride aqueous solution with a sodium chloride mass concentration of 6% is used as a solvent to prepare a diethylenetriaminepenta(methylenephosphonic acid) solution, wherein the content of diethylenetriaminepenta(methylenephosphonic acid) in the diethylenetriaminepenta(methylenephosphonic acid) solution is 10000ppm.

[0037] Experimental group (two parallel groups 1-2): Bottle No. 1 contained 16 g of sand and 32 mL of tetramethylammonium chloride solution; Bottle No. 2 contained 16 g of sand and 32 mL of tetramethylammonium chloride solution.

[0038] Control group (two parallel groups 3-4): Bottle No. 3 contained 16 g of sand and 32 mL of sodium chloride aqueous solution; Bottle No. 4 contained 16 g of sand and 32 mL of sodium chloride aqueous solution.

[0039] Blank group (two parallel groups 5-6): Bottle No. 5 contained 32 mL of sodium chloride aqueous solution; Bottle No. 6 contained 32 mL of sodium chloride aqueous solution.

[0040] Adsorption experiment: After stirring bottles 1-6 evenly, place them in an oven preheated to 90°C and let them stand for 5 hours. Carefully remove 20 mL of supernatant from each bottle to avoid removing any quartz sand. Then add 20 mL of diethylenetriamine penta (methylenephosphonic acid) solution to each bottle and stir the solution with a glass rod, then return it to the oven and let it stand for 24 hours.

[0041] Analysis of adsorption results: After standing for 24 hours, take it out of the oven, take out about 10 mL of the supernatant as the sample to be tested and add it to a marked 15 mL test tube, and analyze the sample for organic phosphonates by ICP-AES.

[0042] Theoretically, bottles 5-6 can provide 6250 mg / L of organic phosphonate (10000 mg / L×20 / 32=6250 mg / L). The actual average values ​​of the two groups measured are 6280 mg / L of organic phosphonate.

[0043] Bottle No. 3-4, organic phosphonate adsorption amount = (6280 mg / L - organic phosphonate concentration measured after adsorption) × solution volume 32 mL / acid-washed quartz sand weight 16 g. The calculation results are shown in Table 1.

[0044] Bottle No. 1-2, organic phosphonate adsorption amount = (6280 mg / L - organic phosphonate concentration measured after adsorption) × solution volume 32 mL / acid-washed quartz sand weight 16 g. The calculation results are shown in Table 1.

[0045] Table 1

[0046]

[0047] It can be found from Table 1 that the introduction of tetramethylammonium chloride increases the adsorption amount of organic phosphonate scale inhibitor on the surface of quartz sand, which is nearly 64% higher than that without tetramethylammonium chloride.

[0048] Example 2

[0049] Normal temperature and pressure (i.e. environmental conditions) stage:

[0050] 1. Crushed limestone particles with a diameter of 0.6-1.00 mm produced by the British SSL Company were assembled in a Hasler type core holder with a fluororubber sleeve as the core, and the core size was 4 inches (length) × 1.5 inches (width), and the core holder tightness pressure test was performed to ensure that the core holder tightly sealed the joint between the filled core particles and the core holder;

[0051] 2. Clean the core with methanol and toluene;

[0052] 3. Under normal temperature and pressure conditions, the brine saturation is 100% Sw (i.e., the volume of brine in the pores of the core accounts for 100% of the total pore volume);

[0053] 4. Carry out brine flow rate test at normal temperature and pressure with brine saturation of 100% Sw to ensure smooth flow of brine and clean the core;

[0054] 5. Raise the temperature to the reservoir temperature (T = 90°C, i.e., test temperature) when the brine saturation is 100% Sw.

[0055] Pretreatment stage (T = 90 ° C):

[0056] 1. The saturation of pretreated brine is 100% Sw;

[0057] 2. Pre-treated brine pore volume / porosity measured by lithium tracer;

[0058] 3. Pre-treatment brine permeability measurement.

[0059] Injection stage (W>F direction, T=90°C):

[0060] 1. Pre-rinse: (see details below)

[0061] 2. Main Processing: (see details below)

[0062] Comparison group:

[0063] 1. Flushing the core with pre-fluid: the volume of the pre-fluid is 0.8 times the volume of the core voids, and the pre-fluid is a potassium chloride aqueous solution with a potassium chloride mass concentration of 2% (pH value is not adjusted);

[0064] 2. Injection of the main liquid into the core: The volume of the main liquid is 0.8 times the volume of the core voids. In the main liquid, the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 10%, the solvent is a potassium chloride aqueous solution with a mass concentration of 2% potassium chloride, and the pH value is 4.0;

[0065] Experimental Group:

[0066] 1. Flushing the core with pre-fluid: The volume of the pre-fluid is 0.8 times the void volume of the core, the mass concentration of tetramethylammonium chloride is 3%, the solvent is a potassium chloride aqueous solution with a mass concentration of 2%, and the pH value of the pre-fluid is 2.8.

[0067] 2. Injection of the main liquid into the core: The volume of the main liquid is 0.8 times the volume of the core voids. In the main liquid, the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 10%, the solvent is a potassium chloride aqueous solution with a mass concentration of 2% potassium chloride, and the pH value is 4.0;

[0068] 3. The post-flushing liquid over-flushes the core: the volume of the post-flushing liquid is 0.5 times the void volume of the core. In the post-flushing liquid, the mass concentration of tetramethylammonium chloride is 1%, the solvent is a potassium chloride aqueous solution with a mass concentration of 2%, and the pH value of the post-flushing liquid is 2.8.

[0069] The core flow was shut off for 16 hours.

[0070] The cores were washed with brine over 10 days until the antiscalant concentration reached the minimum effective concentration (MEC).

[0071] Post-processing (formation damage) evaluation (T = 90 ° C):

[0072] 1. Post-processing brine permeability measurement.

[0073] Cooling and core cleaning phase

[0074] 1. Cool the oven to ambient temperature;

[0075] 2. Cleaning with methanol and toluene at T = ambient temperature;

[0076] Carefully reduce the temperature and containment pressure to ambient pressure.

[0077] Note: In the above brine, the sodium ion content is 13004 mg / L, the calcium ion content is 474 mg / L, the magnesium ion content is 1648 mg / L, and the sulfate ion content is 3339 mg / L;

[0078] Forward flow (F>W) = direction from formation to wellbore

[0079] Reverse flow (W>F) = wellbore to formation direction

[0080] Permeability was measured in the F>W direction and the wellbore to formation direction (W>F). Injection was performed in the W>F direction and post-processing was performed in the F>W direction.

[0081] No significant permeability changes were observed during the squeeze period. Figure 2 The antiscalant flowback curves observed in the absence (control group) and presence (experimental group) of the squeeze enhancer are shown, with a significant increase in antiscalant concentration observed in the experimental group. It is also noted that in the control group, the shutdown was performed while the antiscalant main solution was still present in the core, which would maximize the potential for antiscalant adsorption / retention. In contrast, in the experimental group, the antiscalant main solution was replaced by the post-flushing solution before the shutdown. Therefore, the increased retention / antiscalant flowback curves observed in the experimental group are considered evidence of the effectiveness of the squeeze enhancer.

[0082] Example 3

[0083] Experimental Group:

[0084] (1) This experimental group provides a composition for enhancing scale inhibitor squeezing, which comprises:

[0085] Pre-flushing liquid: 15 cubic meters. The mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 0.1%, the mass concentration of tetramethylammonium chloride is 3%, the solvent is a potassium chloride aqueous solution with a mass concentration of 2%, and the pH value of the pre-flushing liquid is 5-6.

[0086] Antiscalant main solution: 118 cubic meters, wherein the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 10%, and the solvent is a potassium chloride aqueous solution with a mass concentration of 2%.

[0087] Post-flushing liquid: 125 cubic meters, wherein the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 0.1%, the mass concentration of tetramethylammonium chloride is 1%, and the solvent is a potassium chloride aqueous solution with a mass concentration of 2%.

[0088] (2) This experimental group provides a scale inhibitor squeezing treatment method, including the following steps (such as Figure 1 shown):

[0089] Pre-flushing the formation with pre-flushing fluid;

[0090] The main liquid is squeezed and injected into the formation;

[0091] Use post-flushing fluid to propel the pre-flushing fluid and main fluid to a depth of 3-5m in the formation;

[0092] The volume of the tubing string (referring to the tubing, i.e. the tubing section from the oil-producing section of the formation to the wellhead) is 12 cubic meters. Among them, the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 0.1%, and the solvent is a potassium chloride aqueous solution with a mass concentration of 2%.

[0093] The well was shut down for 15 hours to complete the squeeze injection treatment.

[0094] Comparison group:

[0095] (1) The comparative group of compositions for injection did not contain an injection enhancer, and included:

[0096] Pre-fluid: 15 cubic meters, wherein the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 1%, and the solvent is a potassium chloride aqueous solution with a mass concentration of 2%.

[0097] Antiscalant main solution: 118 cubic meters, wherein the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 10%, and the solvent is a potassium chloride aqueous solution with a mass concentration of 2%.

[0098] Post-flushing liquid: 125 cubic meters, wherein the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 0.1%, and the solvent is a potassium chloride aqueous solution with a mass concentration of 2%.

[0099] (2) This comparative group provides a scale inhibitor squeezing treatment method, comprising the following steps:

[0100] Pre-flushing the formation with pre-flushing fluid;

[0101] The main liquid is squeezed and injected into the formation;

[0102] Use post-flushing fluid to propel the pre-flushing fluid and main fluid to a depth of 3-5m in the formation;

[0103] The volume of the tubing string (referring to the oil pipe, i.e. the part of the oil pipe from the oil-producing section of the formation to the wellhead) is 12 cubic meters, wherein the mass concentration of diethylenetriaminepenta(methylenephosphonic acid) is 0.1%, and the solvent is a potassium chloride aqueous solution with a mass concentration of 2%.

[0104] The well was shut down for 15 hours to complete the squeeze injection treatment.

[0105] Performance evaluation:

[0106] After the squeeze treatment, the well was opened for operation, and water samples were collected during operation for the determination of the antiscalant concentration. The time interval for collecting water samples was: once an hour within 24 hours of opening the well, then once a day within a week, and then once a month. The longer the number of days of the effective concentration of the antiscalant over time means the longer the treatment period. That is, the oil well is protected from scaling by the antiscalant for a longer time. Figure 3 The results show that the protection period of the organic phosphonate scale inhibitor in the control group without the addition of the squeeze enhancer is about 250 days, while the treatment period of the experimental group with the addition of the squeeze enhancer is increased to 360 days. It can be seen that the use of the squeeze enhancer can significantly increase the life of the downhole squeeze treatment. The reduction in crude oil production caused by scaling in the oil well can be avoided for a longer period of time, thus bringing considerable economic benefits to the oil field and saving operating costs.

Claims

1. A composition for enhancing scale inhibitor squeezing, wherein: The composition comprises a pre-fluid, a main fluid and a post-fluid; The pre-fluid comprises tetramethylammonium chloride; The main liquid includes a second antiscalant; The post-fluid comprises tetramethylammonium chloride; The mass concentration of tetramethylammonium chloride in the pre-fluid is 1-10%; the mass concentration of tetramethylammonium chloride in the post-fluid is 1-3%.

2. The enhanced antiscalant squeezing composition according to claim 1, wherein: The pH value of the pre-liquid is 2.5-7.

3. The enhanced antiscalant squeezing composition according to claim 1, wherein: The solvents in the pre-liquid and the main solution are each independently selected from saline.

4. The enhanced antiscalant squeezing composition according to claim 1, wherein: The solvent in the post-flushing liquid is selected from brine and / or a non-aqueous fluid with a specific gravity of 1.05 to 1.

30.

5. The enhanced antiscalant squeezing composition according to claim 1, wherein: The pre-fluid also includes a first antiscalant, and the mass concentration of the first antiscalant is 0.05-3%.

6. The enhanced antiscalant squeezing composition according to claim 1, wherein: In the main liquid, the mass concentration of the second antiscalant is 2-20%.

7. The enhanced antiscalant squeezing composition according to claim 5, wherein: The post-flushing liquid also includes a third antiscalant, and the mass concentration of the third antiscalant is 1-3%.

8. The enhanced antiscalant squeezing composition according to claim 7, wherein: The first antiscalant, the second antiscalant and the third antiscalant are each independently selected from organic phosphonate antiscalants.

9. The enhanced antiscalant squeezing composition according to claim 8, wherein: The organic phosphonate scale inhibitor is selected from diethylene triamine penta (methylene phosphonic acid).

10. The enhanced antiscalant squeezing composition according to claim 1, wherein: The volume ratio of the pre-liquid to the main liquid is 1:1-8.

11. The enhanced antiscalant squeezing composition according to claim 10, wherein: The volume of the post-fluid is such that the main fluid enters the formation at a depth of 1 to 10 m in the radial direction.

12. A scale inhibitor squeezing treatment method, wherein: The scale inhibitor squeezing treatment is carried out using the enhanced scale inhibitor squeezing composition according to any one of claims 1 to 11, and the treatment method comprises: Pre-flushing the formation with pre-flushing fluid; Squeeze the main fluid into the formation; Using post-fluid to propel the pre-fluid and the main fluid into the deep formation; Close the well.

13. The scale inhibitor squeezing treatment method according to claim 12, wherein: The well shut-in time is 6 to 24 hours.

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