An environmentally friendly corrosion and scale inhibitor for oilfield use and its preparation method

Abstract

This invention relates to the field of oilfield water treatment chemistry, and discloses an environmentally friendly corrosion-inhibiting and scale-inhibiting agent for oilfield use and its preparation method. The preparation method includes four steps: diatomaceous earth acidification and activation, clinoptilolite sodium regeneration, preparation of tannic acid-sodium-based bentonite intercalation composite, and composite formulation. This invention achieves a completely phosphate-free formulation, meeting oilfield discharge standards. Natural maifanite volcanic ash reacts in situ to generate C-S-H gel, solidifying mineral particles into a porous mineral composite protective film with high flow rate and erosion resistance. The organic-inorganic double-layer composite corrosion-inhibiting film provides complementary coverage, eliminating blind spots in metal surface protection. The two-stage tandem scale inhibition defense line has a wide range of applications for scale-prone produced water. The C-S-H cemented phase is thermally stable below 200℃, making it suitable for high-temperature thermal recovery conditions.

Description

Technical Field

[0001] This invention relates to the field of oilfield water treatment chemistry, and more specifically, to an environmentally friendly corrosion-inhibiting and scale-inhibiting agent for oilfield use and its preparation method. Background Technology

[0002] Throughout the entire process of crude oil extraction, water injection for oil recovery, and produced water treatment in oilfields, metal components such as pipelines, water injection lines, and heat exchange equipment are in long-term contact with highly salinized produced water, facing the dual threats of corrosion and scaling. Dissolved compounds in the produced water... , and Corrosive media cause continuous corrosion to steel pipelines; high concentrations of corrosive media in extracted water... (usually greater than) ), , When scale-forming cations change temperature or pressure, they form hard scale such as calcium carbonate, barium sulfate, and strontium sulfate, which clog pipelines and accelerate corrosion damage. Existing oilfield corrosion and scale inhibitors are mainly divided into three categories: phosphorus-based scale inhibitors, inorganic corrosion inhibitors, and synthetic polymer scale inhibitors. All have varying degrees of environmental and performance limitations: phosphorus-based scale inhibitors, represented by organophosphonic acid compounds such as HEDP and ATMP, result in severely excessive phosphorus levels in discharged water, causing eutrophication of surface water bodies; traditional inorganic corrosion inhibitors such as chromates and nitrites are highly toxic and their use has been restricted by regulations in many regions; synthetic polymer scale inhibitors such as polyacrylic acid and polymaleic anhydride have poor biodegradability and accumulate in the environment over a long period.

[0003] In corrosion and scale inhibition systems based on natural minerals, the functional components accumulate only as loose particles on the pipe surface, even in high-velocity produced water (pipe flow velocity). Under continuous scouring, the protective film is easily eroded and detached from the pipe wall, resulting in a short lifespan. In high-temperature thermal recovery conditions such as steam injection and SAGD (steam-assisted gravity drainage) (produced water temperature...), the protective film is also prone to erosion and detachment. Under these conditions, organic functional components rapidly fail due to high-temperature hydrolysis and decarboxylation, while inorganic mineral particles cannot maintain effective protection due to the loss of the synergistic effect of organic components. Summary of the Invention

[0004] This invention provides an environmentally friendly corrosion and scale inhibitor for oilfield use and its preparation method, solving the technical problems in related technologies such as the easy erosion and peeling of the protective film of natural mineral-based corrosion and scale inhibitor systems under high flow rate scouring, the rapid failure of organic components under high temperature thermal recovery conditions, and the excessive phosphorus emission of phosphorus-based scale inhibitors.

[0005] This invention provides an environmentally friendly corrosion-inhibiting scale inhibitor for oilfield use. The scale inhibitor is a uniform suspension composed of activated natural diatomaceous earth, activated natural clinoptilolite, tannic acid-sodium bentonite intercalation complex, natural maifanite powder, and a mixed aqueous solution of citric acid and tartaric acid. The activated natural diatomaceous earth has a silica mass fraction of not less than 70%; the activated natural clinoptilolite has sodium ion exchange sites. The tannic acid-sodium bentonite intercalation composite is prepared by embedding tannic acid into the interlayer space of sodium bentonite by interlayer adsorption, and the mass ratio of tannic acid to sodium bentonite is 1:8-1:15. The natural maifanite powder contains 38%-60% active silica and 10%-18% active alumina. The mass ratio of the activated natural diatomite, activated natural clinoptilolite, tannic acid-sodium bentonite intercalation composite to the natural maifanite powder is 2-4:1-3:2-5:1-3. The mass ratio of citric acid to tartaric acid is 1:1-2:1, and the total mass of citric acid and tartaric acid is 15%-30% of the total mass of the above four types of solid components.

[0006] Preferably, the particle size of the activated natural diatomaceous earth, activated natural clinoptilolite, and natural maifanite powder is 75-150 μm.

[0007] Preferably, the tannic acid in the tannic acid-sodium bentonite intercalation complex is hydrolyzed tannic acid, extracted from gallnut (Galla chinensis), with a tannic acid mass fraction of not less than 80%.

[0008] Preferably, the mass ratio of the activated natural diatomaceous earth, activated natural clinoptilolite, tannic acid-sodium bentonite intercalation composite, and natural maifanite powder is 3:2:3:2.

[0009] Preferably, the mass ratio of citric acid to tartaric acid is 2:1, and the total mass of citric acid and tartaric acid is 20% of the total mass of the above four types of solid components.

[0010] Preferably, the total mass fraction of organic acids in the homogeneous suspension is 5%-15%.

[0011] This invention also provides a method for preparing an environmentally friendly corrosion and scale inhibitor for oilfield use, comprising the following steps: Step 1, diatomaceous earth acidification and activation: Grind natural diatomaceous earth with a silica mass fraction of not less than 70% to a particle size of 75-150μm, place it in a 5%-10% dilute hydrochloric acid aqueous solution and soak it at room temperature for 2-4 hours, filter it, wash it with deionized water until the pH of the washing solution is 6-7, and dry it at 80-105℃ to obtain activated natural diatomaceous earth; Step 2, sodium regeneration of clinoptilolite: Grind natural clinoptilolite to a particle size of 75-150 μm, soak it in a 5%-10% sodium chloride aqueous solution at room temperature for 4-8 hours, filter and wash it, and dry it at 80-105℃ to obtain activated natural clinoptilolite with sodium ion exchange sites. Step 3, preparation of tannic acid-sodium bentonite intercalation composite: Dissolve tannic acid in water to prepare a tannic acid aqueous solution with a mass fraction of 5%-15%, add sodium bentonite and control the mass ratio of tannic acid to sodium bentonite to be 1:8-1:15, stir and mix thoroughly for 2-4 hours, let stand and age for more than 12 hours, filter and dry at 60-80℃ to obtain tannic acid-sodium bentonite intercalation composite; Step 4, compound preparation: Grind the natural maifan stone powder to a particle size of 75-150μm, and mix it with the activated natural diatomaceous earth obtained in Step 1, the activated natural clinoptilolite obtained in Step 2, and the tannic acid-sodium bentonite intercalation composite obtained in Step 3 at a mass ratio of (2-4):(1-3):(2-5):(1-3). Add a mixed aqueous solution of citric acid and tartaric acid at a mass ratio of 1:1-2:1 and stir thoroughly to disperse. The total mass of citric acid and tartaric acid is 15%-30% of the total mass of the above four solid components. Prepare a uniform suspension liquid scale inhibitor with a total organic acid mass fraction of 5%-15%.

[0012] Preferably, the mass fraction of the dilute hydrochloric acid aqueous solution in step one is 8%, the liquid-to-solid mass ratio is 4:1, and the immersion time is 3 hours.

[0013] Preferably, the sodium chloride aqueous solution in step two has a mass fraction of 7%, a liquid-to-solid mass ratio of 4:1, and a soaking time of 6 hours.

[0014] Preferably, the tannic acid aqueous solution in step three has a mass fraction of 10%, the mass ratio of tannic acid to sodium bentonite is 1:10, the thorough stirring and mixing time is 3 hours, the standing and aging time is 18 hours, and the product is dried at 70°C.

[0015] The beneficial effects of this invention are as follows: All functional components of this invention do not contain phosphate groups, completely avoiding the environmental pollution problem of excessive phosphorus content in effluent after the use of traditional phosphorus-based scale inhibitors. All components are derived from natural minerals and plant extracts or fermentation products, and the organic components in the effluent can be naturally degraded. Natural maifanite generates CSH gel in situ through volcanic ash reaction, solidifying mineral particles into a porous mineral composite protective membrane with mechanical strength, endowing the protective membrane with high flow rates (… The corrosion resistance under produced water flushing conditions; the organic-inorganic dual-layer composite corrosion inhibitor membrane (iron-silicate inorganic barrier membrane and iron-tannic acid organic protective membrane) complementarily covers the metal surface, eliminating the coverage blind spots of a single membrane layer, and the comprehensive corrosion inhibition effect is better than any single membrane layer; clinoptilolite ion exchange and organic acid complexation form a series of two-stage scale inhibition defense lines, which are effective against scale buildup. , and Multiple scale types are integrated for control; CSH cemented phase in Internal thermal stability ensures that the overall protection system maintains effective performance under high-temperature thermal recovery conditions such as steam injection and SAGD. Attached Figure Description

[0016] Figure 1 This is a bar chart comparing the mineral protective film quality retention rate under different flow rates according to the present invention; Figure 2 This is a bar chart comparing the scale inhibition rates of the complete formula of this invention with those of various control samples for three types of scale. Figure 3 This is a comparison chart of Tafel polarization curves of various formulations in the simulated produced water system of this invention; Figure 4 This is a FESEM image of the cross-section of the organic-inorganic double-layer composite protective film formed on the inner wall of the pipe according to the formulation of Example 1 of the present invention; Figure 5 This is a line graph showing the scale inhibition rate as a function of temperature under high-temperature thermal recovery conditions according to the present invention. Figure 6 This is a line graph showing the change in corrosion inhibition rate with temperature under high-temperature thermal recovery conditions according to the present invention. Detailed Implementation

[0017] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, some features described in the examples may be combined in other examples.

[0018] Example 1 This embodiment discloses a method for preparing an environmentally friendly corrosion and scale inhibitor for oilfield use, the method comprising the following steps: Step 1, Diatomaceous earth acidification and activation: Take... mass fraction Natural diatomaceous earth, ground to a particle size Add quality fraction In a dilute hydrochloric acid aqueous solution (liquid-solid mass ratio of 1:1), ), soaked at room temperature After filtration, wash with deionized water until the pH of the washing solution is [value missing]. ,At Drying yields activated natural diatomaceous earth.

[0019] Step 2, Sodium regeneration of clinoptilolite: Grind natural clinoptilolite to the specified particle size. Add quality fraction In an aqueous solution of sodium chloride (liquid-solid mass ratio of 1:1), Soak at room temperature After filtration and washing, Drying yields activated natural clinoptilolite with sodium ion exchange sites.

[0020] Step 3, Preparation of tannic acid-sodium bentonite intercalation complex: Take the mass fraction Hydrolyzable tannins (extracted from gallnuts) are dissolved in water to prepare a mass fraction. A tannic acid aqueous solution was prepared; sodium bentonite was added to the above tannic acid solution, controlling the mass ratio of tannic acid to sodium bentonite to be [value missing]. Mix thoroughly ; let it stand and age Afterwards, filtering and Low-temperature drying yields a tannic acid-sodium bentonite intercalation complex.

[0021] Step 4, Compound Preparation: Take active ingredients... mass fraction ,active mass fraction Natural maifan stone powder, ground to a particle size For later use; the activated natural diatomaceous earth obtained in step one, the activated natural clinoptilolite obtained in step two, and the tannic acid-sodium bentonite intercalation composite obtained in step three are mixed with the above-mentioned natural maifanite powder in the following mass ratio. Mix; citric acid and tartaric acid in a mass ratio The mixture is prepared as a whole, and the total mass of the two is equal to the total mass of the four types of solid components mentioned above. The organic acid was dissolved in water to prepare an aqueous solution, which was then added to the above solid mixture and stirred thoroughly to disperse it. Water was added to adjust the concentration, resulting in a solution with a total organic acid mass fraction of [missing value]. The finished product is a uniformly suspended liquid corrosion and scale inhibitor.

[0022] Example 2 This embodiment discloses a method for preparing an environmentally friendly corrosion and scale inhibitor for oilfield use, the method comprising the following steps: Step 1, Diatomaceous earth acidification and activation: Take... mass fraction Natural diatomaceous earth, ground to a particle size Add quality fraction In a dilute hydrochloric acid aqueous solution (liquid-solid mass ratio of 1:1), ), soaked at room temperature After filtration, wash with deionized water until the pH of the washing solution is [value missing]. ,At Drying yields activated natural diatomaceous earth.

[0023] Step 2, Sodium regeneration of clinoptilolite: Grind natural clinoptilolite to the specified particle size. Add quality fraction In an aqueous solution of sodium chloride (liquid-solid mass ratio of 1:1), Soak at room temperature After filtration and washing, Drying yields activated natural clinoptilolite with sodium ion exchange sites.

[0024] Step 3, Preparation of tannic acid-sodium bentonite intercalation complex: Take the mass fraction Hydrolyzable tannins (extracted from gallnuts) are dissolved in water to prepare a mass fraction. A tannic acid aqueous solution was prepared; sodium bentonite was added to the above tannic acid solution, controlling the mass ratio of tannic acid to sodium bentonite to be [value missing]. Mix thoroughly ; let it stand and age Afterwards, filtering and Low-temperature drying yields a tannic acid-sodium bentonite intercalation complex.

[0025] Step 4, Compound Preparation: Take active ingredients... mass fraction ,active mass fraction Natural maifan stone powder, ground to a particle size For later use; the activated natural diatomaceous earth obtained in step one, the activated natural clinoptilolite obtained in step two, and the tannic acid-sodium bentonite intercalation composite obtained in step three are mixed with the above-mentioned natural maifanite powder in the following mass ratio. Mix; citric acid and tartaric acid in a mass ratio The mixture is prepared as a whole, and the total mass of the two is equal to the total mass of the four types of solid components mentioned above. The organic acid was dissolved in water to prepare an aqueous solution, which was then added to the above solid mixture and stirred thoroughly to disperse it. Water was added to adjust the concentration, resulting in a solution with a total organic acid mass fraction of [missing value]. The finished product is a uniformly suspended liquid corrosion and scale inhibitor.

[0026] Example 3 This embodiment discloses a method for preparing an environmentally friendly corrosion and scale inhibitor for oilfield use, the method comprising the following steps: Step 1, Diatomaceous earth acidification and activation: Take... mass fraction Natural diatomaceous earth, ground to a particle size Add quality fraction In a dilute hydrochloric acid aqueous solution (liquid-solid mass ratio of 1:1), ), soaked at room temperature After filtration, wash with deionized water until the pH of the washing solution is [value missing]. ,At Drying yields activated natural diatomaceous earth.

[0027] Step 2, Sodium regeneration of clinoptilolite: Grind natural clinoptilolite to the specified particle size. Add quality fraction In an aqueous solution of sodium chloride (liquid-solid mass ratio of 1:1), Soak at room temperature After filtration and washing, Drying yields activated natural clinoptilolite with sodium ion exchange sites.

[0028] Step 3, Preparation of tannic acid-sodium bentonite intercalation complex: Take the mass fraction Hydrolyzable tannins (extracted from gallnuts) are dissolved in water to prepare a mass fraction. A tannic acid aqueous solution was prepared; sodium bentonite was added to the above tannic acid solution, controlling the mass ratio of tannic acid to sodium bentonite to be [value missing]. Mix thoroughly ; let it stand and age Afterwards, filtering and Low-temperature drying yields a tannic acid-sodium bentonite intercalation complex.

[0029] Step 4, Compound Preparation: Take active ingredients... mass fraction ,active mass fraction Natural maifan stone powder, ground to a particle size For later use; the activated natural diatomaceous earth obtained in step one, the activated natural clinoptilolite obtained in step two, and the tannic acid-sodium bentonite intercalation composite obtained in step three are mixed with the above-mentioned natural maifanite powder in the following mass ratio. Mix; citric acid and tartaric acid in a mass ratio The mixture is prepared as a whole, and the total mass of the two is equal to the total mass of the four types of solid components mentioned above. The organic acid was dissolved in water to prepare an aqueous solution, which was then added to the above solid mixture and stirred thoroughly to disperse it. Water was added to adjust the concentration, resulting in a solution with a total organic acid mass fraction of [missing value]. The finished product is a uniformly suspended liquid corrosion and scale inhibitor.

[0030] Example 4 This embodiment discloses a method for preparing an environmentally friendly corrosion and scale inhibitor for oilfield use, the method comprising the following steps: Step 1, Diatomaceous earth acidification and activation: Take... mass fraction Natural diatomaceous earth, ground to a particle size Add quality fraction In a dilute hydrochloric acid aqueous solution (liquid-solid mass ratio of 1:1), ), soaked at room temperature After filtration, wash with deionized water until the pH of the washing solution is [value missing]. ,At Drying yields activated natural diatomaceous earth.

[0031] Step 2, Sodium regeneration of clinoptilolite: Grind natural clinoptilolite to the specified particle size. Add quality fraction In an aqueous solution of sodium chloride (liquid-solid mass ratio of 1:1), Soak at room temperature After filtration and washing, Drying yields activated natural clinoptilolite with sodium ion exchange sites.

[0032] Step 3, Preparation of tannic acid-sodium bentonite intercalation complex: Take the mass fraction Hydrolyzable tannins (extracted from gallnuts) are dissolved in water to prepare a mass fraction. A tannic acid aqueous solution was prepared; sodium bentonite was added to the above tannic acid solution, controlling the mass ratio of tannic acid to sodium bentonite to be [value missing]. Mix thoroughly ; let it stand and age Afterwards, filtering and Low-temperature drying yields a tannic acid-sodium bentonite intercalation complex.

[0033] Step 4, Compound Preparation: Take active ingredients... mass fraction ,active mass fraction Natural maifan stone powder, ground to a particle size For later use; the activated natural diatomaceous earth obtained in step one, the activated natural clinoptilolite obtained in step two, and the tannic acid-sodium bentonite intercalation composite obtained in step three are mixed with the above-mentioned natural maifanite powder in the following mass ratio. Mix; citric acid and tartaric acid in a mass ratio The mixture is prepared as a whole, and the total mass of the two is equal to the total mass of the four types of solid components mentioned above. The organic acid was dissolved in water to prepare an aqueous solution, which was then added to the above solid mixture and stirred thoroughly to disperse it. Water was added to adjust the concentration, resulting in a solution with a total organic acid mass fraction of [missing value]. The finished product is a uniformly suspended liquid corrosion and scale inhibitor.

[0034] Example 5 This embodiment discloses a method for preparing an environmentally friendly corrosion and scale inhibitor for oilfield use, the method comprising the following steps: Step 1, Diatomaceous earth acidification and activation: ... Quality score not lower than Natural diatomaceous earth ground to particle size Then, add the mass fraction. In a dilute hydrochloric acid aqueous solution (liquid-solid mass ratio of 1:1), ), soaked at room temperature After filtration, wash with deionized water until the pH of the washing solution is [value missing]. ,At Drying yields activated diatomaceous earth powder. Dilute hydrochloric acid simultaneously removes carbonate and iron oxide impurities from the surface of the diatomaceous earth, fully exposing active silicate dissolution sites. This significantly increases the silicate dissolution rate of the activated diatomaceous earth in pipe water, accelerating the formation of an iron-silicate inorganic barrier film on the pipe's metal surface.

[0035] Step 2, Sodium regeneration of clinoptilolite: Grind natural clinoptilolite to the specified particle size. Then, add the mass fraction. In an aqueous solution of sodium chloride (liquid-solid mass ratio of 1:1), Soak at room temperature After filtration and washing, Drying removes the original components from the zeolite. Type and Type 2 exchange sites are fully converted to Type, maximizing its effect on scale-forming cations ( , , The available exchange capacity of ) is used to obtain activated clinoptilolite.

[0036] Step 3, Preparation of Tannic Acid-Sodium Bentonite Intercalation Complex: Dissolve tannic acid in water to prepare a mass fraction A tannic acid aqueous solution; sodium bentonite is added to the above tannic acid solution, the mass ratio of tannic acid to sodium bentonite is . Mix thoroughly This allows tannic acid to embed into the interlayer space of sodium-based bentonite through interlayer adsorption; static aging... Afterwards, filtering, at Low-temperature drying was used to obtain a tannic acid-sodium bentonite intercalation complex. The purpose of low-temperature drying is to control the drying temperature within the range of gallic acid, which contains multiple gallate bonds in its molecular structure. It can protect the integrity of the ester bond structure of tannic acid in the intercalation complex.

[0037] Step 4, Preparation of Compound Formulation: Pre-grind the natural maifanite powder to the specified particle size. Reserved; by mass ratio The activated diatomaceous earth obtained in step one, the activated clinoptilolite obtained in step two, and the tannic acid-sodium bentonite intercalation composite obtained in step three are mixed with the above-mentioned natural maifanite powder; citric acid and tartaric acid (in a mass ratio of [missing information]) are added. The combined mass of the two is equal to the total mass of the four types of solid components mentioned above. Dissolve the organic acid in water to prepare an aqueous solution, add it to the above solid mixture, stir thoroughly to disperse, and adjust with water to prepare a solution with a total organic acid mass fraction of [missing value]. The product is a uniformly suspended liquid corrosion and scale inhibitor (the sodium-based bentonite component expands when it comes into contact with water and has a certain thickening effect, which helps to slow down the sedimentation of mineral particles; the product may settle and stratify after storage or transportation, and must be thoroughly stirred before use).

[0038] The suspended liquid product can be directly added to the oilfield water injection pipeline or produced water transportation pipeline. The amount added is determined according to the pipeline water volume and the concentration of scale-forming ions, with the aim of gradually forming a porous mineral composite protective film on the inner wall of the pipeline and maintaining the effective scale inhibition concentration of the solution phase.

[0039] Experimental verification Experiment 1: Test of the mechanical stability of mineral protective film against erosion 1. Experimental Objective Simulating the high-velocity produced water pipeline transportation conditions in oilfields, the mineral protective film mass retention rate and unit area mass loss of the complete formula containing maifanite (Example 1) and the control formula without maifanite were compared under different pipeline flow velocities. This verified the effect of the in-situ cementation mechanism of volcanic ash introduced by natural maifanite on improving the erosion resistance mechanical stability of the mineral protective film, and quantitatively characterized the erosion behavior of the protective film under different flow velocities.

[0040] 2. Preparation of experimental samples Example 1 Scale Inhibitor (hereinafter referred to as "Example 1"): Prepared according to the method described in Example 1, with all raw materials and process parameters being completely consistent with those in Example 1. The resulting product is the product with a total organic acid mass fraction. A uniformly suspended liquid scale inhibitor.

[0041] Control Sample 1: The preparation method of Example 1 is followed, but natural maifanite powder is not added in step four. The mass ratio of the remaining components (activated natural diatomite, activated natural clinoptilolite, tannic acid-sodium bentonite intercalation complex) and the amount of citric acid and tartaric acid are kept the same as in Example 1. A uniform suspension with the same solid content as in Example 1 is prepared.

[0042] 3. Experimental conditions A pipeline flow scouring device was used. The sample was... Carbon steel pipe section (inner diameter) ,length ), in advance After sanding and degreasing with acetone, the initial mass is accurately weighed and recorded. (Sense of quantity The composition of the simulated produced water is shown in Table 1-1, and the dosage of chemicals is as follows: (Based on product quality) Static pre-formed film ( , ), and then respectively , , , Continuous flushing .

[0043] Table 1-1 Composition of Simulated Produced Water 4. Experimental Procedure (1) Weigh the pretreated carbon steel pipe section precisely and record the initial mass. .

[0044] (2) Install the pipe section on the flow device and add scale inhibitor to the simulated produced water. ),exist Pre-film formation under static cycling conditions .

[0045] (3) After film formation, remove the tube section and gently rinse with deionized water to remove loose particles from the surface. Blow-air drying The mass was weighed later and recorded as the mass before flushing. The quality of the protective film is .

[0046] (4) Reinstall the membrane-forming tube section and continuously flush it at the set flow rate. After being removed, it is processed in the same way as in step (3), weighed, and recorded as the mass after rinsing. Calculate the protective film quality retention rate and mass loss per unit area ( ).

[0047] (5) For each flow rate condition, three parallel measurements were performed for each group, and the average value was taken. The relative standard deviation should not exceed 100%. .

[0048] 5. Experimental Results Table 1-2 Mineral protective film mass retention rate and mass loss per unit area at different flow rates Figure 1 A bar chart comparing the retention rates of mineral protective films at different flow rates.

[0049] 6. Analysis and Summary From Table 1-2 and Figure 1 It can be seen that, in Within the scouring flow rate range, the mass retention rate of the mineral protective film in Example 1 was consistently significantly better than that of the control sample 1, which did not contain maifanite. When the flow rate decreased from... Rise to At that time, the retention rate of control sample 1 was from sharp drop (decline) percentage points), corresponding to a quality loss from Increase to Example 1: Retention rate is determined solely by Down to (decline) percentage points), quality loss only .

[0050] The results showed that the active substances in natural maifanite... ( ) and activity ( ) and extracted water The CSH gel generated in situ through the reaction of volcanic ash cements mineral particles into a porous composite protective membrane with a certain mechanical strength. This is the key reason why the protective membrane maintains a high quality retention rate at high flow rates. Formulas without maifanite are rapidly eroded and detached under high-flow-rate hydraulic shearing due to the lack of chemical bonding between mineral particles.

[0051] Experiment 2: Test of the Synergistic Scale Inhibition Efficiency of Two-Stage Scale Inhibition Defense Lines 1. Experimental Objective By comparing the complete formulation of Example 1, the control sample containing only organic acids, the control sample containing only activated natural clinoptilolite, and the blank control in high-salinity simulated produced water, the effects were observed. dirt, Scale and Scale inhibition rate, verification of clinoptilolite ion exchange (first stage: ... , , The synergistic scale inhibition effect of the two-stage scale inhibition defense line, consisting of direct removal from the aqueous phase to the solid phase and complexation with organic acids (second stage: complexing residual scale-forming ions and preventing their precipitation), on scale-prone produced water.

[0052] 2. Preparation of experimental samples Example 1 Scale inhibitor: Prepared according to the method described in Example 1, the resulting product has a total organic acid mass fraction. A uniformly suspended liquid scale inhibitor.

[0053] Control sample A (organic acids only): Citric acid and tartaric acid were mixed in a mass ratio of... Dissolve in deionized water to prepare a solution with a total organic acid mass fraction. It is a mixed aqueous solution that contains no mineral components.

[0054] Control sample B (clinoptilolite only): Activated natural clinoptilolite was prepared according to the method described in step two of Example 1. quality score Liquid-to-solid mass ratio ,soak , (Dried), prepared into a suspension with the same solid content as in Example 1, without organic acids and other mineral components.

[0055] Blank control: No scale inhibitor added.

[0056] 3. Experimental conditions The method was adjusted according to GB / T 16632—2008 "Determination of Scale Inhibition Performance of Water Treatment Agents - Rotary Coil Method" and tailored to the characteristics of oilfield produced water. The composition of the test solutions for each scale type is shown in Table 2-1, and the dosage for each sample is as follows. (All figures are based on product quality, i.e., the amount added per liter of test solution) (Each product), temperature , Magnetic stirring reaction time , , , The three types of scale were tested independently.

[0057] Table 2-1 Composition of test solutions for three types of scale (each scale type is prepared independently and not mixed) (Unit: mg / L; pH of all test solutions was adjusted to 7.5; the anion and cation solutions required for each scale type test were prepared separately and then mixed.) 4. Experimental Procedure (1) Prepare test solutions for each scale type according to Table 2-1: Scale test solution is made from Solution ( concentration ,join in (Supplementing background mineralization) and Solution ( concentration ,join in (Supplementing background mineralization) is mixed after the addition of chemicals (at pH 7.5). (Preferred carbonate form); Scale test solution is made from Solution ( concentration ,join in (Supplementing background mineralization) and Solution ( concentration ,join in (Supplementing background mineralization) is mixed after the addition of the drug; The preparation method of the scale test solution is the same as that of the test solution. ,by replace ( concentration Each scale type test solution should be prepared independently and not mixed.

[0058] (2) Add the appropriate amount of scale inhibitor to each ionic solution to adjust the solution. to Then, mix the anion and cation solutions and place them in a container. In a constant temperature water bath Magnetic stirring reaction .

[0059] (3) After the reaction is complete, allow it to cool to room temperature and then pass through the sieve. The filter membrane collects the precipitate, which settles in... drying Weigh it afterward and record it as follows The mass of the precipitate obtained under the same conditions as the blank control is recorded as . ; Calculate the scale inhibition rate: .

[0060] (4) Each group was measured in parallel three times, and the average value was taken. The relative standard deviation should not exceed 100%. .

[0061] 5. Experimental Results Table 2-2 Scale inhibition rate of each formulation for three scale types Figure 2 A bar chart comparing the scale inhibition rates of each formulation for the three scale types.

[0062] 6. Analysis and Summary From Table 2-2 and Figure 2 It can be seen that the complete formula of Example 1 is effective. , and The scale inhibition rates of the three scale types reached respectively , and The levels were significantly higher than those of the two single-mechanism control samples. Control sample A (organic acid only) showed significantly higher levels than the two single-mechanism control samples. It has a good scale inhibition effect. ), but for ( )and ( The scale inhibition rate dropped sharply, which is related to... ( )and ( The solubility is extremely low, and the carboxyl complexation capacity of organic acids is difficult to control effectively at high concentrations. and Concentration consistent; Control sample B (climacteric zeolite only) was consistent with... ( )and ( It has a good scale inhibition effect, but for Scale inhibition rate ( The results were lower than in Example 1, indicating that removal was achieved solely through ion exchange. Controlling calcium carbonate scale is not as precise as controlling organic acid complexation.

[0063] Example 1 demonstrates a two-stage series protection system that significantly reduces the absolute concentration of scale-forming ions through zeolite-based first-stage ion exchange and controls the concentration of residual ions through organic acid-based second-stage complexation. This system achieves comprehensive and integrated control of three scale types, and the synergistic scale inhibition rate of the two-stage series protection is significantly higher than that of any single protection.

[0064] Experiment 3: Corrosion Inhibition Performance Test of Organic-Inorganic Bilayer Composite Corrosion Inhibiting Film 1. Experimental Objective Electrochemical polarization curves and electrochemical impedance spectroscopy (EIS) were used to compare the corrosion inhibition performance of the complete formulation of Example 1 (containing iron-silicate inorganic film components and iron-tannic acid organic film components), the control sample containing only inorganic corrosion inhibitors, the control sample containing only organic corrosion inhibitors, and the blank control. This verified that the comprehensive corrosion inhibition effect of the complementary coverage mechanism of the organic-inorganic bilayer composite corrosion inhibitor film is better than that of any single film layer.

[0065] 2. Preparation of experimental samples Example 1 Scale inhibitor: Prepared according to the method described in Example 1, the resulting product has a total organic acid mass fraction. A uniformly suspended liquid scale inhibitor.

[0066] Control sample A (inorganic corrosion inhibitor film only): The preparation method of Example 1 is followed, but the tannic acid-sodium bentonite intercalation complex is not added in step four, that is, it does not contain iron-tannic acid organic corrosion inhibitor components. The remaining components (activated natural diatomaceous earth, activated natural clinoptilolite, natural maifanite powder, organic acid) and their proportions remain unchanged.

[0067] Control sample B (without iron-silicate inorganic corrosion inhibitor): The preparation method of Example 1 is followed, but activated natural diatomaceous earth is not added in step four. That is, the formulation does not contain corrosion inhibitors that can form an iron-silicate inorganic barrier film on the metal surface. The remaining components (activated natural clinoptilolite, tannic acid-sodium bentonite intercalation complex, natural maifanite powder, organic acid) and their proportions remain unchanged. The formulation still contains the CSH cementing phase introduced by maifanite and the iron-tannic acid organic protective film component.

[0068] Blank control: No scale inhibitor added.

[0069] 3. Experimental conditions A three-electrode system is adopted. Carbon steel is used as the working electrode (exposed area) Pre-polishing to (Acetone defatting), saturated calomel electrode (SCE) as reference electrode, platinum sheet as auxiliary electrode, electrochemical workstation (CHI760E) in The test was conducted using simulated produced water (same as in Table 1-1), with the dosage... (Based on product quality) Pre-soaking Post-measurement polarization curve (scan rate) Scan range ) and EIS (frequency range) AC excitation amplitude ).

[0070] 4. Experimental Procedure (1) Prepare solutions for each group according to experimental conditions, immerse the working electrode in simulated produced water containing the corresponding concentration of scale inhibitor, and then... Pre-soaking The protective film is fully formed.

[0071] (2) After pre-soaking, with The Tafel polarization curve was determined by scanning rate, and the corrosion potential was determined by linear extrapolation. and corrosion current density The corrosion rate (mm / a) was calculated according to Faraday's law; the corrosion inhibition rate was calculated according to... calculate.

[0072] (3) with AC excitation measurement of EIS, fitting of equivalent circuit ( Dual time constant model for obtaining membrane resistance and charge transfer resistance The sum of the two reflects the overall impedance of the interface. .

[0073] (4) Each group was measured in parallel three times, and the average value was taken. The relative standard deviation should not exceed 100%. .

[0074] 5. Experimental Results Table 3-1 Electrochemical corrosion parameters of each formulation Figure 3 A comparison of Tafel polarization curves for each formulation in simulated produced water.

[0075] Figure 4 The image shows the cross-sectional FESEM morphology of the organic-inorganic bilayer composite protective film formed on the inner wall of the pipe according to the formulation of Example 1.

[0076] 6. Analysis and Summary From Table 3-1 and Figure 3 It can be seen that the corrosion current density of the complete formulation in Example 1 is... Corresponding corrosion rate Corrosion inhibition rate reaches Charge transfer resistance Both were significantly superior to the two single-film control samples. The corrosion inhibition rate of control sample A, containing only an inorganic corrosion inhibitor film, was [missing value]. The corrosion inhibition rate of control sample B, which does not contain iron-silicate inorganic corrosion inhibitors, was [missing information]. Both were lower than in Example 1.

[0077] The polarization curves show the polarization curves of Example 1. Positive shift compared to blank control This indicates that the complete formulation has the dual effects of anodic inhibition (iron-silicate inorganic barrier film covers the smooth metal surface, blocking anodic dissolution) and cathodic inhibition (iron-tannic acid organic protective film covers the rust layer area, blocking corrosion microcells). The value reached nearly the same as that of control sample A. Double, control sample B The results show that the organic-inorganic bilayer composite corrosion inhibitor film complementarily covers metal surface defects and active sites, eliminating corrosion concentration points caused by the blind spots covered by a single film layer.

[0078] Experiment 4: Test on the scale inhibition and corrosion inhibition performance of scale inhibitors under high-temperature thermal recovery conditions as a function of temperature 1. Experimental Objective exist Within a temperature range (covering conventional water injection and steam injection, SAGD and other high-temperature thermal recovery conditions), the scale inhibition rates of the complete formulation of Example 1, the control sample containing only organic acid, and the traditional phosphorus-based scale inhibitor HEDP (reference) were compared. The corrosion inhibition rates of Example 1 and the control sample containing only organic acid were also compared with temperature to verify the supporting role of the thermal stability of the CSH cemented phase in maintaining the performance of the overall organic-inorganic synergistic protection system under high-temperature conditions.

[0079] 2. Preparation of experimental samples Example 1 Scale inhibitor: Prepared according to the method described in Example 1, the resulting product has a total organic acid mass fraction. A uniformly suspended liquid scale inhibitor.

[0080] Control sample A (organic acids only): Citric acid and tartaric acid were mixed in a mass ratio of... Dissolve in deionized water to prepare a solution with a total organic acid mass fraction. It is a mixed aqueous solution that contains no mineral components.

[0081] Reference HEDP: Industrial grade HEDP (hydroxyethylidene diphosphonic acid, purity) Prepare an aqueous solution with the same concentration of effective ingredient as the organic acid concentration in Example 1, for use only as a reference for scale inhibition rate comparison.

[0082] 3. Experimental conditions High-temperature sealing tests were conducted using a high-pressure reactor (to ensure water was properly sealed). , (Non-vaporized). Simulated SAGD produced water: , , , , TDS , Dosage (Based on product quality) Reactions under various temperature conditions The corrosion inhibition rate was tested using the plate method. Carbon steel sheet ( (Pre-treated and accurately weighed) Static immersion in the above solution at various temperatures. After removal, the sample is cleaned, descaled, dried, and weighed to calculate the corrosion rate and corrosion inhibition rate.

[0083] 4. Experimental Procedure Scale inhibition rate test (autoclave method): (1) Prepare simulated SAGD produced water according to experimental conditions, and then... and After preparing the solutions separately, add the scale inhibitor and mix (to prevent premature precipitation). Place the mixture in a high-pressure reactor, seal it, and heat it to the target temperature. , , , And keep warm .

[0084] (2) After cooling to room temperature, pass through Filter membrane collects precipitate, After drying, weigh the sample and calculate the scale inhibition rate using the precipitate mass of the blank control (the calculation formula is the same as in Experiment 2).

[0085] Corrosion inhibition rate test (coated plate method): (3) Weigh the pretreated material Carbon steel sheets are placed in an autoclave, and simulated produced water containing a suitable scale inhibitor is added. After sealing, the mixture is heated to the target temperature and then kept at that temperature. .

[0086] (4) Remove the plate, gently remove the surface corrosion products with an eraser, and clean it in sequence with acetone, alcohol, and deionized water. After drying by forced air, weigh accurately and follow the instructions. (mm / a, Calculate the corrosion rate and corrosion inhibition rate. .

[0087] (5) Each temperature group was measured in parallel 3 times, and the average value was taken.

[0088] 5. Experimental Results Table 4-1 Scale inhibition rate of each formulation with temperature Table 4-2 Corrosion inhibition rate of each formulation with temperature Figure 5 The graph shows the scale inhibition rate of each formulation as a function of temperature.

[0089] Figure 6 This is a line graph showing the corrosion inhibition rate of each formulation as a function of temperature.

[0090] 6. Analysis and Summary From Table 4-1, Table 4-2 and Figure 5 It can be seen that, The scale inhibition rate of Example 1 and Control Sample A (organic acid only) and ) and corrosion inhibition rate ( and The levels are basically equivalent, indicating that organic acids and tannins can still function normally at room temperature. However, the differences widen significantly with increasing temperature: At that time, the scale inhibition rate of control sample A decreased to (compared) reduce (percentage points), corrosion inhibition rate decreased to (reduce This percentage point is consistent with the pattern of organic acids being deactivated at high temperatures due to hydrolysis and decarboxylation; while Example 1 in Maintain scale inhibition rate Corrosion inhibition rate The performance retention rate is far superior to that of control sample A.

[0091] A comparison with the traditional phosphorus-based scale inhibitor HEDP further demonstrates that Example 1, in... and The scale inhibition rate ( , Both are superior to HEDP ( , This indicates that the CSH gel-bound phase is in The thermal stability within a certain range effectively maintains the overall structure of the mineral protective film. The porous structure of the mineral film ensures the continuous replenishment of organic functional components at high temperatures, enabling the scale inhibitor of this invention to maintain effective scale and corrosion inhibition capabilities under high-temperature thermal recovery conditions such as steam injection and SAGD.

[0092] The embodiments of the present invention have been described above. However, the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments under the guidance of the present embodiments, and all of them are within the protection scope of the present embodiments.

Claims

1. A method for preparing an environmentally friendly corrosion-inhibiting and scale-inhibiting agent for oilfield use, characterized in that, Includes the following steps: Step 1, Diatomaceous Earth Acidification and Activation: Grind natural diatomaceous earth with a silica content of not less than 70% to a particle size of 75-150 μm, immerse it in a 5%-10% dilute hydrochloric acid aqueous solution at room temperature for 2-4 hours, filter, wash with deionized water until the pH of the washing solution reaches 6-7, and dry at 80-105℃ to obtain activated natural diatomaceous earth; Step 2, Clinoptilolite Sodium Regeneration: Grind natural clinoptilolite to a particle size of 75-150 μm, immerse it in a 5%-10% sodium chloride aqueous solution at room temperature for 4-8 hours, filter, wash, and dry at 80-105℃ to obtain activated natural clinoptilolite with sodium ion exchange sites; Step 3, Preparation of Tannic Acid-Sodium Bentonite Intercalation Composite: Dissolve tannic acid in water to prepare a 5%-15% tannic acid aqueous solution, add sodium bentonite and control the temperature... The mass ratio of tannic acid to sodium bentonite is 1:8-1:

15. After thorough mixing for 2-4 hours, the mixture is allowed to stand and age for more than 12 hours. It is then filtered and dried at 60-80℃ to obtain a tannic acid-sodium bentonite intercalation composite. Step four, compound preparation: Natural maifanite powder with 50% active SiO2 and 14% active Al2O3 is ground to a particle size of 75-150μm and then mixed with the activated natural diatomite obtained in step one, the activated natural clinoptilolite obtained in step two, and the tannic acid-sodium bentonite intercalation composite obtained in step three at a mass ratio of 3:2:3:

2. A mixed aqueous solution of citric acid and tartaric acid with a mass ratio of 2:1 is added and thoroughly stirred and dispersed. The total mass of citric acid and tartaric acid is 20% of the total mass of the above four solid components. A uniform suspension liquid scale inhibitor with a total organic acid mass fraction of 9% is prepared.

2. The preparation method according to claim 1, characterized in that, The dilute hydrochloric acid aqueous solution in step one has a mass fraction of 8%, a liquid-to-solid mass ratio of 4:1, and an immersion time of 3 hours.

3. The preparation method according to claim 1, characterized in that, In step two, the sodium chloride aqueous solution has a mass fraction of 7%, a liquid-to-solid mass ratio of 4:1, and a soaking time of 6 hours.

4. The preparation method according to claim 1, characterized in that, In step three, the tannic acid aqueous solution has a mass fraction of 10%, the mass ratio of tannic acid to sodium bentonite is 1:10, the thorough stirring and mixing time is 3 hours, the standing and aging time is 18 hours, and the solution is filtered and dried at 70°C.

5. The preparation method according to claim 1, characterized in that, The tannic acid in the tannic acid-sodium bentonite intercalation complex is hydrolyzed tannic acid, extracted from gallnut, and the tannic acid mass fraction is not less than 80%.

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