High-temperature-resistant scale inhibitor for oil field and preparation method and application thereof

Abstract

The application belongs to the technical field of water treatment, and particularly relates to an oilfield high-temperature-resistant scale inhibitor as well as a preparation method and application thereof. The preparation method comprises the following steps: introducing nitrogen into a reaction kettle, and sequentially adding butene diacid, vinyl phosphonic acid, sodium allyl sulfonate, undecylenic acid, buffer salt and deionized water, stirring uniformly, and adjusting pH to 7-8; adding an initiator into a high-position dropping groove, and slowly dropping into the reaction kettle; after the dropping is completed, the solution becomes viscous, the solution is automatically heated, when the temperature no longer continues to rise, heating is performed to 60-70 DEG C, and the temperature is kept for 1-2 h, the temperature is reduced to below 40 DEG C, and pH is adjusted to 7-8 by using a sodium hydroxide solution; the reaction product is dried and granulated to obtain the product high-temperature-resistant scale inhibitor. The scale inhibitor has the characteristics of wide raw material sources, simple synthesis process, no pollution and good scale inhibition effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and particularly relates to an oilfield high-temperature-resistant scale inhibitor as well as a preparation method and application thereof. BACKGROUND

[0002] In the process of oilfield operation, fluids such as oil, gas, water and mud need to be transported through the formation or pipeline. When the temperature, pressure, pH and other conditions change, some components in these fluids may deposit in the formation channel or transmission equipment, forming oil scale, water scale or mud scale. In particular, when the oilfield development enters the middle and late stages, the water injection oil production process is generally adopted, and the reinjection water contains a large amount of calcium, magnesium and strontium, barium and other ions. When these ions encounter changes in temperature, pressure and other conditions or incompatible water, they will combine to form salt molecules with very small solubility, and then crystallize to form scale.

[0003] The scaling problem of water injection wells and pipelines is particularly serious. The formation of scale not only leads to a decrease in water injection efficiency and a reduction in oil well production, but also can cause pipe blockage, pump jamming, injection pressure rise and other failures, and in severe cases, can even cause damage to downhole and surface equipment, resulting in the shutdown or abandonment of oil and gas wells. Therefore, the scaling problem of oilfield water injection has become one of the key factors restricting the production efficiency and equipment safety of oilfields.

[0004] The use of scale inhibitors is an important means to effectively solve this problem, which not only inhibits the formation of scale and improves the water injection efficiency, but also prolongs the service life of equipment and reduces maintenance costs.

[0005] In "Performance of Copolymer Scale Inhibitor MA / AM / HPA", MA / AM / HPA copolymer scale inhibitor was synthesized by Fei Chengjun et al., and comprehensive detection was carried out in the oilfield water environment. The inhibitory efficiency of the polymer on calcium carbonate, calcium sulfate, barium sulfate and strontium sulfate was investigated under different pH, temperature, sodium chloride content and other factors. The scale inhibition rate of 25 mg / L polymer after 60℃ constant temperature for 24 h in the oilfield water indoor test can reach more than 90%, and the scale inhibition rate needs to be further improved.

[0006] CN109705831A discloses an oilfield scale inhibitor, which comprises a first scale inhibitor, a second scale inhibitor and a third scale inhibitor. The first scale inhibitor comprises: sodium ethylenediaminetetramethylene phosphonate, aminotri-methylene phosphonic acid, hydroxyethylidene diphosphonic acid and 2-phosphonobutane-1, 2, 4-tricarboxylic acid; the second scale inhibitor comprises: maleic anhydride, acrylic acid, hydroxypropyl acrylate and ammonium persulfate; and the third scale inhibitor comprises: polyepoxysuccinic acid, polyaspartic acid, modified imidazoline, modified quaternary ammonium salt and sodium polyacrylate. This scale inhibitor is stable in nature, can be slowly released after being injected into the oil well, effectively reduces the wellbore scaling, and prolongs the pump inspection period. However, the raw materials are relatively complex, and the construction is relatively complex during the use process. SUMMARY

[0007] The present application provides an oilfield high-temperature resistant scale inhibitor, a preparation method and application thereof.

[0008] In order to achieve the above-mentioned purposes:

[0009] In a first aspect, the present application discloses a preparation method of an oilfield high-temperature resistant scale inhibitor, which comprises the following steps:

[0010] (1) nitrogen is introduced into a reaction kettle to remove air in the system; butene diacid, vinyl phosphonic acid, sodium allylsulfonate, undecylenic acid, buffer salt and deionized water are sequentially added and stirred uniformly, and the pH value is adjusted to 7-8 by using a sodium hydroxide solution;

[0011] (2) an initiator is added into a high-position dropping tank and slowly dropped into the reaction kettle; after the dropping is completed, the solution becomes viscous, the solution is automatically heated, and when the temperature no longer continues to rise, the temperature is increased to 60-70℃, and the reaction is maintained for 1-2h, and then the temperature is decreased to below 40℃, and the pH value is adjusted to 7-8 by using a sodium hydroxide solution;

[0012] (3) the reaction product in (2) is dried and granulated to obtain a product of the high-temperature resistant scale inhibitor.

[0013] In the present application, preferably, based on 1 mole of butene diacid, the amount of the vinyl phosphonic acid, the sodium allylsulfonate and the undecylenic acid is 0.1-0.5 moles, 0.05-0.2 moles and 0.1-0.5 moles, respectively.

[0014] In the present application, preferably, the buffer salt in step (1) is one of sodium dihydrogen phosphate, potassium dihydrogen phosphate and ammonium dihydrogen phosphate, and the weight ratio of the buffer salt to butene diacid is 0.01-0.02:1.

[0015] In the present application, preferably, the weight ratio of the deionized water to butene diacid in step (1) is 8-10:1.

[0016] In the present application, preferably, the initiator in step (2) is a mixed solution of persulfate and sodium bisulfite, wherein the concentration of the persulfate is 10-12wt%, and the concentration of the sodium bisulfite is 3-5wt%.

[0017] Preferably, the mass ratio of the initiator to butene diacid is 0.3-0.6:1.

[0018] Preferably, the persulfate is one of sodium persulfate, potassium persulfate and ammonium persulfate.

[0019] The reaction equation of the oilfield high-temperature resistant scale inhibitor of the present application is as follows:

[0020]

[0021] In another aspect, the present application discloses an oilfield high-temperature resistant scale inhibitor, and the molecular structure formula of the scale inhibitor is as follows:

[0022]

[0023] Wherein, a = 1000-10000;

[0024] b = 1000-5000;

[0025] c = 500-2000;

[0026] d = 1000-5000.

[0027] Preferably, the viscosity average molecular weight of the scale inhibitor is 100000-500000.

[0028] In a third aspect, the present application discloses the application of the above scale inhibitor in oilfield sewage treatment.

[0029] The oilfield high-temperature resistant scale inhibitor of the present application belongs to a quaternary high-molecular compound, and has good scale inhibition and scale prevention performance. Butene diacid provides a large number of carboxyl groups, has strong chelating ability to various high-valence ions, and also has dispersion effect, which can disperse the already formed small particles in water to prevent them from gathering to form large scale blocks; vinyl phosphonic acid has good chelating ability and thermal stability, can form stable complexes with metal ions such as calcium, magnesium and iron, and prevent metal ions from combining with anions such as carbonate and sulfate; allyl sulfonic acid has good temperature resistance, can effectively disperse sticky mud, stabilize metal ions and organic phosphoric acid, has long-lasting drug efficacy, is not easy to gel, and has strong scale prevention comprehensive ability; undecylenic acid not only provides carboxyl groups, but also makes the whole molecule more flexible, so that the growth of scale crystal grains is disturbed and distorted to be difficult to form. The present application is a linear high-molecular polymer, which can change the conformation by internal rotation, affect the crystal lattice and hinder the growth of crystal nucleus to effectively inhibit the generation of scale. In addition to the functional groups, the present application is all saturated carbon-carbon single bond, which has stable structure, is not easy to hydrolyze, and has excellent temperature resistance.

[0030] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0031] (1) The raw materials of the oilfield high-temperature resistant scale inhibitor of the present application are widely available, the synthesis process is simple, the synthesis method is one-pot method, there is no by-product, and there is no environmental pollution;

[0032] (2) The oilfield high-temperature resistant scale inhibitor of the present application has good preventive effect on various scales, and the scale inhibition effect on GaSO4 and GaCO3 is 93% or above, and the scale inhibition effect on BaSO4 and SrSO4 is 86% or above;

[0033] (3) The oilfield high-temperature resistant scale inhibitor of the present application has good temperature resistance, and basically does not affect the scale inhibition effect at 140°C. DETAILED DESCRIPTION

[0034] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not considered critical for the present application. The endpoints of the ranges and the individual values are not to be understood as limited to the exact values recited as the exact dimensions are not considered critical for the present application. The ranges and individual points within those ranges can be combined to form new ranges, which are also contemplated as being within the scope of the present application.

[0035] The present application will be further described below in conjunction with specific examples:

[0036] Example 1

[0037] (1) Nitrogen was introduced into the reaction kettle to remove air in the system. 0.1 mol of butenedioic acid, 0.01 mol of vinyl phosphonic acid, 0.02 mol of sodium allylsulfonate, 0.05 mol of undecylenic acid, 0.132 g of sodium dihydrogen phosphate, and 105.6 g of deionized water were sequentially added and stirred uniformly, and the pH was adjusted to 7-8 with a sodium hydroxide solution.

[0038] (2) 3.96 g of initiator was added to the high-position dropping tank, the initiator was a mixture of sodium persulfate and sodium bisulfite, the concentration of sodium persulfate was 12 wt%, and the concentration of sodium bisulfite was 4 wt%. The reaction kettle was slowly dripped, after the dripping was completed, the solution became sticky, the solution automatically heated, when the temperature no longer continued to rise, the heating was increased to 60°C, and the temperature was kept for 1 h, and then the temperature was reduced to below 40°C, and the pH was adjusted to 7-8 with a sodium hydroxide solution.

[0039] (3) The reaction product in (2) was dried and granulated to obtain the product high-temperature resistant scale inhibitor.

[0040] Example 2

[0041] (1) Nitrogen was introduced into the reaction kettle to remove air in the system. 0.1 mol of butenedioic acid, 0.01 mol of vinyl phosphonic acid, 0.02 mol of sodium allylsulfonate, 0.05 mol of undecylenic acid, 0.132 g of sodium dihydrogen phosphate, and 105.6 g of deionized water were sequentially added and stirred uniformly, and the pH was adjusted to 7-8 with a sodium hydroxide solution.

[0042] (2) High-position dropping tank 6.96 g initiator, initiator is a mixture of potassium persulfate and sodium bisulfite, the concentration of potassium persulfate is 10wt%, the concentration of sodium bisulfite is 3wt%. Slowly drop into the reaction kettle, after the drop is completed, the solution becomes sticky, the solution automatically heats up, when the temperature no longer continues to rise, heat up to 70℃, keep the temperature for 2h, cool down to below 40℃, adjust pH 7-8 with sodium hydroxide solution.

[0043] (3) The reaction product in (2) is dried and granulated to obtain a product of high-temperature resistant scale inhibitor.

[0044] Example 3

[0045] (1) The reaction kettle is purged with nitrogen to remove air in the system. 0.1 mol butenedioic acid, 0.03 mol vinyl phosphonic acid, 0.016 mol sodium allyl sulfonate, 0.04 mol undecenoic acid, 0.213 g sodium dihydrogen phosphate, and 116 g deionized water are added in turn and stirred uniformly, and the pH is adjusted to 7-8 with sodium hydroxide solution.

[0046] (2) High-position dropping tank 4.29 g initiator, initiator is a mixture of potassium persulfate and sodium bisulfite, the concentration of potassium persulfate is 12wt%, the concentration of sodium bisulfite is 5wt%. Slowly drop into the reaction kettle, after the drop is completed, the solution becomes sticky, the solution automatically heats up, when the temperature no longer continues to rise, heat up to 70℃, keep the temperature for 2h, cool down to below 40℃, adjust pH 7-8 with sodium hydroxide solution.

[0047] (3) The reaction product in (2) is dried and granulated to obtain a product of high-temperature resistant scale inhibitor.

[0048] Example 4

[0049] (1) The reaction kettle is purged with nitrogen to remove air in the system. 0.1 mol butenedioic acid, 0.04 mol vinyl phosphonic acid, 0.012 mol sodium allyl sulfonate, 0.03 mol undecenoic acid, 0.222 g potassium dihydrogen phosphate, and 92.8 g deionized water are added in turn and stirred uniformly, and the pH is adjusted to 7-8 with sodium hydroxide solution.

[0050] (2) High-position dropping tank 6.08 g initiator, initiator is a mixture of potassium persulfate and sodium bisulfite, the concentration of potassium persulfate is 11wt%, the concentration of sodium bisulfite is 5wt%. Slowly drop into the reaction kettle, after the drop is completed, the solution becomes sticky, the solution automatically heats up, when the temperature no longer continues to rise, heat up to 60℃, keep the temperature for 1h, cool down to below 40℃, adjust pH 7-8 with sodium hydroxide solution.

[0051] (3) The reaction product in (2) is dried and granulated to obtain the product high-temperature resistant scale inhibitor.

[0052] Example 5

[0053] (1) Nitrogen is introduced into the reaction kettle to remove air in the system. 0.1 mol of butenedioic acid, 0.05 mol of vinyl phosphonic acid, 0.01 mol of sodium allyl sulfonate, 0.01 mol of undecylenic acid, 0.185 g of potassium dihydrogen phosphate, and 102 g of deionized water are sequentially added and stirred uniformly, and the pH is adjusted to 7-8 with a sodium hydroxide solution.

[0054] (2) 5.77 g of initiator is added to the high-position dropping tank, the initiator is a mixture of sodium persulfate and sodium bisulfite, the concentration of sodium persulfate is 10 wt%, and the concentration of sodium bisulfite is 3 wt%. Slowly drop into the reaction kettle, after the drop is completed, the solution becomes sticky, the solution automatically heats up, when the temperature no longer continues to rise, heat to 65℃, keep warm for 1.5 h, cool down to below 40℃, adjust the pH to 7-8 with a sodium hydroxide solution.

[0055] (3) The reaction product in (2) is dried and granulated to obtain the product high-temperature resistant scale inhibitor.

[0056] Example 6

[0057] (1) Nitrogen is introduced into the reaction kettle to remove air in the system. 0.1 mol of butenedioic acid, 0.05 mol of vinyl phosphonic acid, 0.01 mol of sodium allyl sulfonate, 0.01 mol of undecylenic acid, 0.185 g of potassium dihydrogen phosphate, and 102 g of deionized water are sequentially added and stirred uniformly, and the pH is adjusted to 7-8 with a sodium hydroxide solution.

[0058] (2) 5.77 g of initiator is added to the high-position dropping tank, the initiator is a mixture of sodium persulfate and sodium bisulfite, the concentration of sodium persulfate is 10 wt%, and the concentration of sodium bisulfite is 3 wt%. Slowly drop into the reaction kettle, after the drop is completed, the solution becomes sticky, the solution automatically heats up, when the temperature no longer continues to rise, heat to 65℃, keep warm for 1.5 h, cool down to below 40℃, adjust the pH to 7-8 with a sodium hydroxide solution.

[0059] (3) The reaction product in (2) is dried and granulated to obtain the product high-temperature resistant scale inhibitor.

[0060] Example 7

[0061] (1) The reaction kettle is purged with nitrogen to remove air in the system. 0.1 mol of butenedioic acid, 0.04 mol of vinyl phosphonic acid, 0.005 mol of allyl sulfonic acid sodium, 0.025 mol of undecenoic acid, 0.116 g of ammonium dihydrogen phosphate, and 103 g of deionized water are added in sequence, stirred uniformly, and the pH is adjusted to 7-8 with sodium hydroxide solution.

[0062] (2) 6.8 g of initiator is added to the high-position dropping tank, the initiator is a mixture of ammonium persulfate and sodium bisulfite, the concentration of sodium persulfate is 10 wt%, and the concentration of sodium bisulfite is 4 wt%. Slowly drop into the reaction kettle, after the drop is completed, the solution becomes sticky, the solution automatically heats up, when the temperature no longer continues to rise, heat to 68℃, keep warm for 1.6 h, cool down to below 40℃, adjust the pH to 7-8 with sodium hydroxide solution.

[0063] (3) The reaction product in (2) is dried and granulated to obtain the product of high-temperature resistant scale inhibitor.

[0064] Example 8 Evaluation of scale inhibition effect

[0065] The oilfield high-temperature resistant scale inhibitor (Examples 1-7) of the present application was tested and evaluated, the test method referred to SY / T5673-2020 "General Technical Conditions for Oilfield Scale Inhibitors", and the oilfield special scale inhibitor (YZ-010) of Shandong Haoxin Environmental Protection Technology Co., Ltd. was used as a comparative sample, and the test results are shown in Table 1.

[0066] Table 1 Scale inhibition rate determination results (%)

[0067]

[0068] From Table 1, it can be seen that:

[0069] (1) The oilfield high-temperature resistant scale inhibitor (Examples 1-7) of the present application has good preventive effect on various scales, the scale inhibition effect on GaSO4 and GaCO3 is 93% or more, and the comparative examples are less than 90%; the scale inhibition effect on BaSO4 and SrSO4 is 86% or more, and the comparative examples are not more than 70%.

[0070] (2) The oilfield high-temperature resistant scale inhibitor (Examples 1-7) of the present application has good temperature resistance, and basically does not affect the scale inhibition effect at 140℃.

[0071] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0072] It should be further noted that each of the various technical features described in the above embodiments can be combined with any other technical features in any suitable manner, and the present application shall be deemed to disclose all possible combinations thereof, without causing unnecessary repetition.

[0073] Furthermore, any combination of the various embodiments of the present application can be made, as long as it does not deviate from the spirit of the present application, and it shall be deemed to be disclosed by the present application.

Claims

1. A method for preparing a high temperature resistant scale inhibitor for oil field, characterized in that, The preparation method comprises: (1) nitrogen is introduced into the reaction kettle to remove air in the system; butene diacid, vinyl phosphonic acid, sodium allyl sulfonate, undecylenic acid, buffer salt and deionized water are sequentially added and stirred uniformly, and the pH value is adjusted to 7-8 by sodium hydroxide solution; (2) the initiator is added into the high-position dropping groove, and is slowly dropped into the reaction kettle; after the dropping is completed, the solution becomes viscous, the solution is automatically heated, when the temperature no longer continues to rise, the temperature is heated to 60-70 DEG C, and the reaction is kept for 1-2 h, and the temperature is cooled to below 40 DEG C, and the pH value is adjusted to 7-8 by sodium hydroxide solution; (3) the reaction product in (2) is dried and granulated to obtain the product heat-resistant scale inhibitor; Based on 1 mole of butene diacid, the amount of vinyl phosphonic acid, sodium allyl sulfonate and undecylenic acid is 0.1-0.5 mole, 0.05-0.2 mole and 0.1-0.5 mole respectively.

2. The production method according to claim 1, characterized by, The buffer salt in step (1) is one of sodium dihydrogen phosphate, potassium dihydrogen phosphate and ammonium dihydrogen phosphate, and the weight ratio of the buffer salt to butene diacid is 0.01-0.02:

1.

3. The preparation method according to claim 1, characterized in that, The weight ratio of deionized water to butene diacid in step (1) is 8-10:

1.

4. The method of claim 1, wherein, The initiator in step (2) is a mixed solution of persulfate and sodium bisulfite, wherein the concentration of persulfate is 10-12 wt%, and the concentration of sodium bisulfite is 3-5 wt%.

5. The production method according to claim 1 or 4, characterized by, The mass ratio of the initiator to butene diacid is 0.3-0.6:

1.

6. The preparation method according to claim 4, characterized in that, The persulfate is one of sodium persulfate, potassium persulfate and ammonium persulfate.

7. The oilfield heat-resistant scale inhibitor prepared by the preparation method according to any one of claims 1-6.

8. The application of the scale inhibitor according to claim 7 in oilfield sewage treatment.

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