High-temperature-resistant anti-scaling agent for oil field as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a high-temperature-resistant anti-scaling agent for an oil field as well as a preparation method and application thereof. The preparation method comprises the following steps: introducing nitrogen into a reaction kettle, sequentially adding butenedioic acid, vinylphosphonic acid, sodium allysulfonate, undecylenic acid, buffer salt and deionized water, uniformly stirring, and adjusting the pH value to 7-8; adding an initiator into a high-position dropwise adding tank, slowly dropwise adding the initiator into the reaction kettle, after dropwise adding, enabling the solution to become viscous and automatically heating the solution, when the temperature does not continue to rise, heating to 60-70 DEG C, carrying out heat preservation reaction for 1-2 hours, cooling to 40 DEG C or below, and adjusting the pH value to 7-8 by using a sodium hydroxide solution; and drying and granulating the reaction product to obtain the high-temperature-resistant scale inhibitor. The scale inhibitor provided by the invention has the characteristics of wide raw material source, simple synthesis process, no pollution and good scale inhibition effect.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to an oilfield high temperature resistant anti-scaling agent and a preparation method and application thereof. Background Art

[0002] During oilfield operations, fluids such as oil, gas, water and mud need to be transported through formations or pipelines. When conditions such as temperature, pressure, and pH change, some components of these fluids may be deposited in formation channels or transmission equipment to form oil scale, water scale or mud scale. Especially when oilfield development enters the middle and late stages, water injection oil recovery technology is commonly used, and the reinjection water contains a large amount of calcium, magnesium, 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 low solubility, which will then crystallize to form scale.

[0003] The scaling problem of water injection wells and water injection pipelines is particularly serious. The formation of scale will not only lead to a decrease in water injection efficiency and oil well production, but may also cause pipe blockage, pump jam, increased water injection pressure and other faults. In severe cases, it may even cause damage to underground and surface equipment, causing oil and gas wells to stop production or be scrapped. Therefore, the scaling problem of oilfield water injection has become one of the key factors restricting oilfield production efficiency and equipment safety.

[0004] The use of anti-scaling and anti-scaling agents is an important means to effectively solve this problem. It can not only inhibit the formation of scale and improve water injection efficiency, but also extend the life of equipment and reduce maintenance costs.

[0005] Tie Chengjun et al. synthesized the MA / AM / HPA copolymer scale inhibitor in "Performance of Copolymer Scale Inhibitor MA / AM / HPA" and conducted comprehensive tests in the oilfield water environment. They examined the inhibition efficiency of the polymer on calcium carbonate, calcium sulfate, barium sulfate, and strontium sulfate under different pH, temperature, sodium chloride content and other factors. In indoor tests in oilfield water, the scale inhibition rate of 25 mg / L polymer after constant temperature at 60°C for 24 hours can reach more than 90%, and the scale inhibition rate needs to be further improved.

[0006] CN109705831A discloses an oilfield scale inhibitor, which includes a first scale inhibitor, a second scale inhibitor and a third scale inhibitor, wherein the first scale inhibitor includes: sodium ethylenediaminetetramethylenephosphonate, aminotrimethylenephosphonic acid, hydroxyethylidenediphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid; the second scale inhibitor includes: maleic anhydride, acrylic acid, hydroxypropyl acrylate, ammonium persulfate; the third scale inhibitor includes: polyepoxysuccinic acid, polyaspartic acid, modified imidazolines, modified quaternary ammonium salts, sodium polyacrylate. This scale inhibitor is stable in nature and will be slowly released after being injected into the oil well, which effectively reduces wellbore scaling and prolongs the pump inspection cycle. However, the raw materials are relatively complex, and it needs to be injected continuously in sections during use, and the construction is relatively complicated. Summary of the invention

[0007] The present invention aims at the deficiencies of the current prior art and provides an oilfield high temperature resistant anti-scaling agent and its preparation method and application. The anti-scaling agent of the present invention has the characteristics of wide source of raw materials, simple synthesis process, no pollution and good anti-scaling effect.

[0008] In order to achieve the above objectives:

[0009] In a first aspect, the present invention discloses a method for preparing a high temperature resistant antiscalant for oil fields, the preparation method comprising:

[0010] (1) nitrogen is introduced into the reaction kettle to remove air from the system; butenedioic acid, vinylphosphonic acid, sodium allyl sulfonate, undecylenic acid, buffer salt, and deionized water are added in sequence, stirred evenly, and the pH is adjusted to 7-8 with sodium hydroxide solution;

[0011] (2) Add the initiator into the high-position dropping tank and slowly drip it into the reactor. After the dripping is completed, the solution becomes viscous and the temperature of the solution automatically rises. When the temperature no longer continues to rise, heat it to 60-70°C and keep it for 1-2 hours. Then cool it to below 40°C and adjust the pH to 7-8 with sodium hydroxide solution;

[0012] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0013] In the present invention, preferably, based on 1 mol part of butenedioic acid, the amounts of vinylphosphonic acid, sodium allyl sulfonate and undecylenic acid are 0.1-0.5 mol part, 0.05-0.2 mol part and 0.1-0.5 mol part respectively.

[0014] In the present invention, 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 butenedioic acid is 0.01-0.02:1.

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

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

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

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

[0019] The reaction equation for the synthesis of the oilfield high temperature resistant antiscalant of the present invention is as follows:

[0020]

[0021] In another aspect, the present invention discloses an oilfield high temperature resistant anti-scaling agent, the molecular structure of the anti-scaling agent 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 antiscalant is 100,000-500,000.

[0028] In a third aspect, the present invention discloses the application of the above-mentioned antiscalant in oilfield wastewater treatment.

[0029] The oilfield high temperature resistant anti-scaling agent of the present invention belongs to a quaternary polymer compound and has good anti-scaling performance. Butenedioic acid provides a large number of carboxyl groups, has a strong chelating ability for various high-valent ions, and also has a dispersing effect, which can disperse the already formed tiny particles in the water to prevent them from aggregating to form large scale blocks; vinylphosphonic 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 slime, stabilize metal ions and organic phosphoric acid, has long-lasting efficacy, is not easy to gel, and has a strong comprehensive anti-scaling ability; undecylenic acid, in addition to providing carboxyl groups, makes the entire molecule softer, and the growth of scale grains is disturbed and distorted and difficult to form. The present invention is a linear high molecular polymer, which can undergo internal rotation to change the conformation, affect the crystal lattice and hinder the growth of the crystal nucleus to effectively inhibit the generation of scale. In addition to the functional groups, the present invention is all saturated carbon-carbon single bonds, with a stable structure, not easy to hydrolyze, and excellent temperature resistance.

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

[0031] (1) The raw material sources of the oilfield high temperature resistant anti-scaling agent of the present invention are wide, the synthesis process is simple, the synthesis method is a one-pot process, there are no by-products, and there is no environmental pollution;

[0032] (2) The oilfield high temperature resistant anti-scaling agent of the present invention has a good preventive effect on various scales, with an anti-scaling effect of 93% or more on GaSO4 and GaCO3, and an anti-scaling effect of 86% or more on BaSO4 and SrSO4;

[0033] (3) The oilfield high temperature resistant anti-scaling agent of the present invention has good temperature resistance and has little influence on the anti-scaling effect under the condition of 140°C. DETAILED DESCRIPTION

[0034] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0035] The present invention will be further described below in conjunction with specific embodiments:

[0036] Example 1

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

[0038] (2) 3.96 g of initiator was added to the high-position drop tank. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 12 wt % and the concentration of sodium bisulfite was 4 wt %. The mixture was slowly added to the reactor. After the addition was completed, the solution became viscous and the temperature of the solution automatically increased. When the temperature did not continue to increase, the mixture was heated to 60° C. and kept for 1 h. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0039] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0040] Example 2

[0041] (1) Nitrogen was introduced into the reaction kettle to remove air from the system. 0.1 mol of butenedioic acid, 0.02 mol of vinylphosphonic acid, 0.018 mol of sodium allyl sulfonate, 0.045 mol of undecylenic acid, 0.186 g of sodium dihydrogen phosphate, and 110.3 g of deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0042] (2) 6.96 g of initiator was added to the high-position drop tank. The initiator was a mixture of potassium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 10 wt % and the concentration of sodium bisulfite was 3 wt %. The mixture was slowly added dropwise to the reactor. After the addition was completed, the solution became viscous and the temperature of the solution automatically increased. When the temperature did not continue to increase, the temperature was raised to 70° C., kept at this temperature for 2 h, cooled to below 40° C., and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0043] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0044] Example 3

[0045] (1) Nitrogen was introduced into the reaction kettle to remove air from the system. 0.1 mol of butenedioic acid, 0.03 mol of vinylphosphonic acid, 0.016 mol of sodium allyl sulfonate, 0.04 mol of undecylenic acid, 0.213 g of sodium dihydrogen phosphate, and 116 g of deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0046] (2) 4.29 g of initiator was added to the high-position drop tank. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 12 wt % and the concentration of sodium bisulfite was 5 wt %. The mixture was slowly added dropwise to the reactor. After the addition was completed, the solution became viscous and the temperature of the solution automatically increased. When the temperature did not continue to increase, the temperature was raised to 70° C., kept at this temperature for 2 h, cooled to below 40° C., and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0047] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0048] Example 4

[0049] (1) Nitrogen was introduced into the reaction kettle to remove air from the system. 0.1 mol of butenedioic acid, 0.04 mol of vinylphosphonic acid, 0.012 mol of sodium allyl sulfonate, 0.03 mol of undecylenic acid, 0.222 g of potassium dihydrogen phosphate, and 92.8 g of deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0050] (2) 6.08 g of initiator was added to the high-position drop tank. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 11 wt % and the concentration of sodium bisulfite was 5 wt %. The mixture was slowly added dropwise to the reactor. After the addition was completed, the solution became viscous and the temperature of the solution automatically increased. When the temperature did not continue to increase, the temperature was raised to 60° C., kept at this temperature for 1 h, cooled to below 40° C., and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0051] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0052] Example 5

[0053] (1) Nitrogen was introduced into the reaction kettle to remove air from the system. 0.1 mol of butenedioic acid, 0.05 mol of vinylphosphonic 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 were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0054] (2) 5.77 g of initiator was added to the high-position drop tank. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 10 wt % and the concentration of sodium bisulfite was 3 wt %. The mixture was slowly added dropwise to the reactor. After the addition was completed, the solution became viscous and the temperature of the solution automatically increased. When the temperature did not continue to increase, the temperature was raised to 65° C. and the reaction was kept at this temperature for 1.5 h. The temperature was then lowered to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0055] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0056] Example 6

[0057] (1) Nitrogen was introduced into the reaction kettle to remove air from the system. 0.1 mol of butenedioic acid, 0.045 mol of vinylphosphonic acid, 0.008 mol of sodium allyl sulfonate, 0.02 mol of undecylenic acid, 0.232 g of ammonium dihydrogen phosphate, and 112 g of deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0058] (2) 3.48 g of initiator was added to the high-position drop tank. The initiator was a mixture of ammonium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 11 wt % and the concentration of sodium bisulfite was 4 wt %. The mixture was slowly added dropwise to the reactor. After the addition was completed, the solution became viscous and the temperature of the solution automatically increased. When the temperature did not continue to increase, the temperature was raised to 62° C. and the reaction was kept at this temperature for 1.2 h. The temperature was then lowered to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0059] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0060] Example 7

[0061] (1) Nitrogen was introduced into the reaction kettle to remove air from the system. 0.1 mol of butenedioic acid, 0.04 mol of vinylphosphonic acid, 0.005 mol of sodium allyl sulfonate, 0.025 mol of undecylenic acid, 0.116 g of ammonium dihydrogen phosphate, and 103 g of deionized water were added in sequence, stirred evenly, and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0062] (2) 6.8 g of initiator was added to the high-position drop tank. The initiator was a mixture of ammonium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 10 wt % and the concentration of sodium bisulfite was 4 wt %. The mixture was slowly added dropwise to the reactor. After the addition was completed, the solution became viscous and the temperature of the solution automatically increased. When the temperature did not continue to increase, the temperature was raised to 68° C. and the reaction was kept at this temperature for 1.6 h. The temperature was then lowered to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide solution.

[0063] (3) Drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent.

[0064] Example 8 Evaluation of anti-scaling effect

[0065] The high temperature resistant anti-scaling agent for oil fields (Examples 1-7) of the present invention were tested and evaluated. The test method referred to SY / T5673-2020 "General Technical Conditions for Anti-scaling Agents for Oil Fields", and the special anti-scaling agent for oil fields (YZ-010) of Shandong Haoxin Environmental Protection Technology Co., Ltd. was used as a comparison sample. The test results are shown in Table 1.

[0066] Table 1 Anti-scaling rate measurement results (%)

[0067]

[0068] From Table 1 we can see that:

[0069] (1) The high temperature resistant anti-scaling agent for oil fields of the present invention (Examples 1-7) has a good preventive effect on various scales. The anti-scaling effect on GaSO4 and GaCO3 is 93% or more, and the comparative ratio is less than 90%; the anti-scaling effect on BaSO4 and SrSO4 is 86% or more, and the comparative ratio is no more than 70%.

[0070] (2) The oilfield high temperature resistant anti-scaling agent (Examples 1-7) of the present invention has good temperature resistance and does not substantially affect the anti-scaling effect at 140°C.

[0071] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0072] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0073] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a high temperature resistant anti-scaling agent for oil fields, characterized in that: The preparation method comprises: (1) nitrogen is introduced into the reaction kettle to remove air from the system; butenedioic acid, vinylphosphonic acid, sodium allyl sulfonate, undecylenic acid, buffer salt, and deionized water are added in sequence, stirred evenly, and the pH is adjusted to 7-8 with sodium hydroxide solution; (2) Add the initiator into the high-position dropping tank and slowly drip it into the reactor. After the dripping is completed, the solution becomes viscous and the temperature of the solution automatically rises. When the temperature no longer continues to rise, heat it to 60-70°C and keep it for 1-2 hours. Then cool it to below 40°C and adjust the pH to 7-8 with sodium hydroxide solution; (3) drying and granulating the reaction product in (2) to obtain a high temperature resistant anti-scaling agent; Based on 1 mol of butenedioic acid, the amounts of vinylphosphonic acid, sodium allyl sulfonate and undecylenic acid are 0.1-0.5 mol, 0.05-0.2 mol and 0.1-0.5 mol respectively.

2. The preparation method according to claim 1, characterized in that: 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 the butenedioic acid is 0.01-0.02:

1.

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

1.

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

5. The preparation method according to claim 1 or 4, characterized in that: The mass ratio of the initiator to the butenedioic acid 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. An oilfield high temperature resistant anti-scaling agent, characterized in that: The molecular structural formula of the antiscalant is as follows: Wherein, a=1000-10000; b＝1000-5000； c＝500-2000； d＝1000-5000。 8. The oilfield high temperature resistant anti-scaling agent according to claim 7, characterized in that: The viscosity average molecular weight of the antiscalant is 100,000-500,000.

9. Use of the antiscalant according to claim 7 or 8 in oilfield wastewater treatment.

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