CN113136198A - Composite buffer for low-permeability oil field oil exploitation acidification - Google Patents
Composite buffer for low-permeability oil field oil exploitation acidification Download PDFInfo
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- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/62—Compositions for forming crevices or fractures
- C09K8/72—Eroding chemicals, e.g. acids
- C09K8/74—Eroding chemicals, e.g. acids combined with additives added for specific purposes
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- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
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Abstract
The invention discloses a composite buffer for low-permeability oilfield oil exploitation acidification, which comprises a plant corrosion inhibitor component A, a plant corrosion inhibitor component B, a modified Mannich alkali corrosion inhibitor, a corrosion inhibitor synergist and an organic solvent, wherein the raw materials of the plant buffer component A are fresh tea seed shells and walnut green husks, the raw material of the plant buffer component B is bagasse, and the extraction steps of the plant buffer component B comprise S1, bagasse lignin extraction, S2, ether purification and classification bagasse alkali lignin extraction, S3, methanol purification and classification bagasse alkali lignin extraction, S4 and amination modified bagasse alkali lignin extraction. The compound buffer agent has excellent corrosion inhibition effect, and extracts of natural green plants are used as one of main components of the slow release agent, so that the components of harmful chemicals in the corrosion inhibitor are reduced, the corrosion inhibitor is more efficient, the environmental pollution is less, and the compound buffer agent has certain application value and development potential.
Description
Technical Field
The invention relates to the technical field of oil exploitation acidification, in particular to a composite buffer for oil exploitation acidification of a low-permeability oil field.
Background
In recent decades, the economy of China has developed at a high speed, and the exploitation and utilization of petroleum play a vital role. In recent years, petroleum in China is in a state of short supply and short demand, so that the exploration and development of native petroleum resources are required to be increased. In western regions of China, the oil reserves are abundant, but most of the oil reserves are low-permeability oil reservoirs, the exploitation difficulty is high, and the scale of economic exploitation is difficult to achieve by using conventional means, so that the method for improving the low-permeability oil reservoir by selecting the acidification process is a common and reliable method for increasing the yield and efficiency of the low-permeability oil reservoir.
The acidification is to recover or improve the permeability of the stratum pores and cracks through the dissolving and corrosion action of acid liquor on rock cement or stratum pores, plugs in the cracks and the like. The main components of the acid liquor system are surfactant and corrosion inhibitor, the corrosion inhibitor is used for preventing the acid liquor from corroding the pipeline and construction equipment of the acidification process during construction, but due to the difference of the types and components of the corrosion inhibitor, the corrosion inhibitor and the surfactant have compatibility problem, and if the compatibility effect of the corrosion inhibitor and the surfactant is not good, the viscosity of the acid liquor after the acid liquor reacts with the rock stratum and the corrosion inhibition effect of the corrosion inhibitor can be simultaneously influenced.
At present, the organic corrosion inhibitors commonly used in the acidification process mainly comprise alkynols, quaternary ammonium salts and Mannich bases. In addition, the plant extract is a natural product, has biodegradability and wide utilization value, and some natural plants contain effective functional groups required by corrosion prevention, so that a plurality of plant extracts are used as green corrosion inhibitors of metals in acidic solutions, and the green corrosion inhibitors can meet industrial requirements only by taking system elements such as effects, raw materials, processes, post-treatment and the like into consideration. Patent CN108102625A discloses a self-diverting acid-acidifying corrosion inhibitor and a preparation method thereof, wherein the corrosion inhibitor comprises the following components in a mass ratio of 1: (1.5-1.8): (3-3.5) taking organic amine, organic ketone and organic aldehyde as main corrosion inhibitor synthesis raw materials in proportion, firstly adding the organic amine into ethanol, mechanically stirring, adjusting the pH value of the solution to 3 by hydrochloric acid, then adding the organic ketone, then slowly dropwise adding the organic aldehyde, and reacting at the temperature of 60-80 ℃ for 4-6 hours to obtain the main corrosion inhibitor for self-diverting acid acidification; dissolving the main agent of the corrosion inhibitor into the organic solvent according to the proportion, adding the synergist and the water, mixing and stirring uniformly to obtain the self-diverting acid-acidifying corrosion inhibitor. Compared with the existing corrosion inhibitor, the corrosion inhibitor has good compatibility, does not influence the steering viscosity of the self-steering acid, has good corrosion inhibition effect in the self-steering acid, and can meet the index requirement of first-grade products in the industry. But the property is easy to change under the high-temperature strong acid environment, the effect on the low-permeability oil reservoir is not obvious, the degradation is not easy, and the environment is easy to be damaged. Therefore, a novel corrosion inhibitor which has good compatibility with acid liquor and is easy to transport and degrade is needed.
Disclosure of Invention
Aiming at the existing problems, the invention provides a compound buffer for oil exploitation and acidification in a low-permeability oil field.
The technical scheme of the invention is as follows:
a composite buffer for acidification of low permeability oilfield petroleum exploitation comprises a plant corrosion inhibitor component A, a plant corrosion inhibitor component B, a modified Mannich base corrosion inhibitor, a corrosion inhibitor synergist and an organic solvent, wherein the raw materials of the components comprise, by weight, 8-12 parts, 15-16 parts, 22-28 parts, 2-3 parts and 130 parts of 120-organic solvent,
the plant corrosion inhibitor component A is prepared from fresh tea seed shells and walnut green husks, and the plant corrosion inhibitor component B is prepared from bagasse.
Further, the organic solvent is ethanol with the mass concentration of 75%, and the solubility of the plant corrosion inhibitor in an ethanol solution is high.
Further, the extraction step of the plant corrosion inhibitor component A is as follows: fresh tea seed shells and walnut green husks are mixed according to the mass ratio of 3: 1, after natural air drying, drying at 50-60 ℃ to constant weight, grinding into fine powder, putting into an extractor, simultaneously adding an organic solvent 13-14 times the weight of the plant powder, extracting at 85-95 ℃ for 1.5-2h, then carrying out vacuum filtration on an extracting solution to remove insoluble substances, dropwise adding petroleum ether 0.05-0.1 time the weight of the tea seed shell powder, degreasing and decolorizing, drying at 50-60 ℃ for 3-4h to obtain a plant corrosion inhibitor component A, and taking an extract of a natural green plant as one of main components of a slow release agent, thereby reducing harmful chemical components in the corrosion inhibitor.
Further, the extraction step of the plant corrosion inhibitor component B comprises the following steps:
s1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 0.5-1.5h, performing water bath heating for 2h at 95 ℃, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 5.7-6, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume of 3 times of that of the concentrated solution, standing for 2-3h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5-5.3, standing for 1-2h, filtering, and washing and drying filter residues with distilled water to obtain bagasse lignin;
s2, extracting alkali lignin from the bagasse by ether purification and classification: mixing the bagasse lignin obtained in the step S1 with an ether solution with the concentration of 5mol/L in a volume ratio of 1: 2, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove an ether solution, repeating the processes for three times to obtain concentrated bagasse lignin, adding an organic solvent which is 5-6 times the volume of the concentrated bagasse lignin, heating in a water bath to 95 ℃, stirring and evaporating to remove water, and obtaining ether purified graded bagasse alkali lignin and bagasse lignin solid;
s3, extracting alkali lignin from bagasse by methanol purification and classification: mixing the bagasse lignin solid obtained in the step S2 with a methanol solution with the mass concentration of 8mol/L in a volume ratio of 1: 5, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove the methanol solution, repeating the above processes for three times to obtain a concentrated solution, adding an organic solvent with the volume 3-4 times of that of the concentrated solution, heating in a water bath to 95 ℃, stirring and evaporating to remove water, and obtaining the methanol purified and graded bagasse alkali lignin;
s4, extracting aminated modified bagasse alkali lignin: mixing the methanol-purified and graded bagasse alkali lignin obtained in the step S3 with ultrapure water in a ratio of 1: 20, stirring for 0.5h at normal temperature, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 3-4, and adding FeCl with the weight 2 times that of the alkali lignin of the bagasse purified and classified by methanol2·4H2Stirring and reacting a mixed solution of an O solution and hydrogen peroxide for 1 hour at the temperature of 60-70 ℃, then adding a NaOH solution with the mass concentration of 10% until the pH value is increased to 9.5-10, adding diethylenetriamine with the weight 2 times that of the bagasse alkali lignin purified and graded by methanol, then adding an organic solvent with the weight 2-3 times that of the diethylenetriamine, mixing and stirring for reacting for 0.5 hour at the temperature of 85-90 ℃, filtering and evaporating, and washing and drying with distilled water for three times to obtain the aminated modified bagasse alkali lignin.
Furthermore, the power of the ultrasonic wave in the step S1 is 125-150W, the diffusivity of the solvent can be higher through the ultrasonic treatment, the solvent can be promoted to permeate into the bagasse tissue, and the extraction of the bagasse lignin is more efficient.
Further, FeCl in the step S42·4H2The mass fraction ratio of the O solution to the hydrogen peroxide is 1: and 4, modifying the bagasse lignin by amination to further improve the adsorption performance of the bagasse lignin on heavy metals.
Further, the modified Mannich base corrosion inhibitor is prepared from Mannich base quaternary ammonium salt, unsaturated ketene, an emulsifier OP-10 and unsaturated alcohol according to a mass ratio of 10: 3: 2: 1, the modified Mannich base corrosion inhibitor has low cost, good slow release effect and good compatibility with plant extractant.
Furthermore, the unsaturated ketene is one of ketene or diethylketene, and can meet the use requirement of the Mannich base corrosion inhibitor.
Furthermore, the unsaturated alcohol is one of methylpentylenol, ethyloctynol, hexynol or propargyl alcohol, the physical properties of the unsaturated alcohol may be different, but the unsaturated alcohol has similar structures and all contains alkynyl (-C is equal to CH), polar group-OH and non-polar group hydrocarbon group, and the existence of the alkynyl enables the alkynol compound to have good corrosion inhibition performance.
Further, the corrosion inhibitor synergist is a bisimidazoline quaternary ammonium salt, dimethyl ketoxime and fatty alcohol-polyoxyethylene ether in a mass ratio of 4: 6: 1, the slow-release agent is used as a surfactant and can further improve the slow-release effect of the corrosion inhibitor.
The invention has the beneficial effects that:
(1) the compound buffer agent has excellent corrosion inhibition effect, the corrosion inhibition effect on steel reaches the second-level standard of the petroleum industry, the selected natural green plant extract contains rich heteroatoms, electronegative groups and conjugated n bonds, which are effective adsorption centers of the corrosion inhibitor, and the extract of the natural green plant is used as one of the main components of the slow release agent, so that the components of harmful chemicals in the corrosion inhibitor are reduced, the cooperativity and compatibility between the plant extract and the chemical corrosion inhibitor are adjusted, the corrosion inhibitor is more efficient, the environmental pollution is less, and the compound buffer agent has certain application value and development potential.
(2) The composite buffer agent has the advantages of wide natural green plant component sources, low cost and small harm to the environment in the preparation process, and can ensure that the diffusivity of a solvent is higher through ultrasonic treatment, promote the solvent to permeate into bagasse tissues and ensure that the extraction of bagasse lignin is more efficient.
Drawings
FIG. 1 is a graph showing the relationship between the effect of the component B of the plant buffer in the composite buffer on the corrosion rate and the corrosion inhibition rate under different ultrasonic powers.
Detailed Description
Example 1
A composite buffering agent for low-permeability oilfield oil exploitation acidification comprises a plant buffering agent component A, a plant buffering agent component B, a modified Mannich base corrosion inhibitor, a buffering agent synergist and an organic solvent, wherein the raw materials of the components comprise 8 parts, 15 parts, 24 parts, 3 parts and 130 parts by weight respectively, and the organic solvent is ethanol with the mass concentration of 75%.
The raw materials of the plant buffer component A are fresh tea seed shells and walnut green husks, and the extraction step of the plant buffer component A is as follows: fresh tea seed shells and walnut green husks are mixed according to the mass ratio of 3: 1, naturally drying the mixture after air drying, drying the mixture at 50 ℃ to constant weight, grinding the mixture into fine powder, putting the fine powder into an extractor, wherein the extractor is a commercially available Soxhlet extractor, simultaneously adding an organic solvent 13 times the weight of the plant powder, the extraction temperature is 85 ℃, the extraction time is 1.5 hours, then carrying out vacuum filtration on an extracting solution to remove insoluble substances, dropwise adding petroleum ether 0.05 times the weight of the tea seed shell powder, degreasing and decolorizing, and drying the mixture at 50 ℃ for 3 hours to obtain the plant buffer component A.
The raw material of the plant buffer component B is bagasse, and the extraction step of the plant buffer component B comprises the following steps:
s1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 0.5h by adopting 125W ultrasonic power, heating in a water bath at 95 ℃ for 2h, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 5.7, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume of 3 times of that of the concentrated solution, standing for 2.5h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5.3, standing for 1.5h, filtering, and washing and drying filter residues by using distilled water to obtain bagasse lignin;
s2, extracting alkali lignin from the bagasse by ether purification and classification: mixing the bagasse lignin obtained in the step S1 with an ether solution with the concentration of 5mol/L in a volume ratio of 1: 2, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove an ether solution, repeating the processes for three times to obtain concentrated bagasse lignin, adding an organic solvent which is 5 times of the volume of the concentrated bagasse lignin, heating in a water bath to 95 ℃, stirring and evaporating to remove water, and obtaining ether purified graded bagasse alkali lignin and bagasse lignin solids;
s3, extracting alkali lignin from bagasse by methanol purification and classification: mixing the bagasse lignin solid obtained in the step S2 with a methanol solution with the mass concentration of 8mol/L in a volume ratio of 1: 5, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove the methanol solution, repeating the above processes for three times to obtain a concentrated solution, adding an organic solvent with the volume 3 times that of the concentrated solution, heating in a water bath to 95 ℃, stirring and evaporating to remove water, thus obtaining the methanol purified graded bagasse alkali lignin;
s4, extracting aminated modified bagasse alkali lignin: mixing the methanol-purified and graded bagasse alkali lignin obtained in the step S3 with ultrapure water in a ratio of 1: 20, stirring for 0.5h at normal temperature, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 3, and adding FeCl with the weight 2 times that of the alkali lignin in the methanol purification and classification bagasse2·4H2Mixed solution of O solution and hydrogen peroxide, FeCl2·4H2The mass fraction ratio of the O solution to the hydrogen peroxide is 1: and 4, stirring and reacting for 1 hour at the temperature of 60 ℃, then adding a NaOH solution with the mass concentration of 10% until the pH value is increased to 9.5, adding diethylenetriamine with the weight of 2 times that of the methanol purification grading bagasse alkali lignin, then adding an organic solvent with the weight of 2 times that of the diethylenetriamine, mixing and stirring and reacting for 0.5 hour at the temperature of 85 ℃, filtering and evaporating, and washing and drying for three times by using distilled water to obtain the amination modified bagasse alkali lignin.
The modified Mannich base corrosion inhibitor is prepared from Mannich base quaternary ammonium salt, unsaturated ketene, an emulsifier OP-10 and unsaturated alcohol in a mass ratio of 10: 3: 2: 1, and mixing the components in a ratio of 1. The unsaturated ketene is one of ketene or diethylketene. The unsaturated alcohol is one of methylpentylenol, ethyloctynol, hexynol or propargyl alcohol.
The buffer synergist is bisimidazoline quaternary ammonium salt, dimethyl ketoxime and fatty alcohol-polyoxyethylene ether according to a mass ratio of 4: 6: 1, mixing and preparing.
Example 2
This embodiment is substantially the same as embodiment 1, except that: the composite buffer agent has different mass fraction ratios of raw materials.
A composite buffering agent for low-permeability oilfield oil exploitation acidification comprises a plant buffering agent component A, a plant buffering agent component B, a modified Mannich base corrosion inhibitor, a buffering agent synergist and an organic solvent, wherein the raw materials of the components comprise 10 parts, 15 parts, 26 parts, 3 parts and 128 parts by weight respectively, and the organic solvent is ethanol with the mass concentration of 75%.
The extraction steps of the plant buffer component A are as follows: fresh tea seed shells and walnut green husks are mixed according to the mass ratio of 3: 1, naturally drying the mixture after the mixture ratio is 1, drying the mixture at the temperature of 55 ℃ to constant weight, grinding the mixture into fine powder, putting the fine powder into an extractor, simultaneously adding an organic solvent which is 13.5 times of the weight of the plant powder, the extraction temperature is 90 ℃, the extraction time is 1.7h, then carrying out vacuum filtration on an extracting solution to remove insoluble substances, dropwise adding petroleum ether which is 0.07 time of the weight of the tea seed shell powder for degreasing and decoloring, and drying the mixture for 3.5h at the temperature of 55 ℃ to obtain the plant buffer component A.
Example 3
This embodiment is substantially the same as embodiment 1, except that: the composite buffer agent has different mass fraction ratios of raw materials.
A composite buffering agent for low-permeability oilfield oil exploitation acidification comprises a plant buffering agent component A, a plant buffering agent component B, a modified Mannich base corrosion inhibitor, a buffering agent synergist and an organic solvent, wherein the raw materials of the components comprise 12 parts, 16 parts, 22 parts, 2 parts and 124 parts by weight respectively, and the organic solvent is ethanol with the mass concentration of 75%.
The extraction steps of the plant buffer component A are as follows: fresh tea seed shells and walnut green husks are mixed according to the mass ratio of 3: 1, naturally drying the mixture at 60 ℃, drying the mixture to constant weight, grinding the mixture into fine powder, putting the fine powder into an extractor, simultaneously adding an organic solvent with the weight 14 times that of the plant powder, extracting at 95 ℃ for 2 hours, then carrying out vacuum filtration on the extract to remove insoluble substances, dropwise adding petroleum ether with the weight 0.1 time that of the tea seed shell powder, degreasing and decolorizing, and drying the mixture at 60 ℃ for 4 hours to obtain the plant buffer component A.
Example 4
This embodiment is substantially the same as embodiment 1, except that: the composite buffer agent has different mass fraction ratios of raw materials.
A composite buffering agent for low-permeability oilfield oil exploitation acidification comprises a plant buffering agent component A, a plant buffering agent component B, a modified Mannich base corrosion inhibitor, a buffering agent synergist and an organic solvent, wherein the raw materials of the components comprise 12 parts, 16 parts, 22 parts, 2 parts and 120 parts by weight respectively, and the organic solvent is ethanol with the mass concentration of 75%.
Example 5
This embodiment is substantially the same as embodiment 1, except that: the ultrasonic power and duration in the extraction step S1 of the plant buffer component B were varied.
S1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 1h by adopting 125W ultrasonic power, heating in a water bath for 2h at 95 ℃, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 6, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume 3 times that of the concentrated solution, standing for 2.5h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5, standing for 1.5h, filtering, and washing and drying filter residues by using distilled water to obtain bagasse lignin;
s2, extracting alkali lignin from the bagasse by ether purification and classification: mixing the bagasse lignin obtained in the step S1 with an ether solution with the concentration of 5mol/L in a volume ratio of 1: 2, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove an ether solution, repeating the processes for three times to obtain concentrated bagasse lignin, adding an organic solvent with the volume 5.5 times of that of the concentrated bagasse lignin, heating in a water bath to 95 ℃, stirring and evaporating to remove water, and obtaining ether purified graded bagasse alkali lignin and bagasse lignin solids;
s3, extracting alkali lignin from bagasse by methanol purification and classification: mixing the bagasse lignin solid obtained in the step S2 with a methanol solution with the mass concentration of 8mol/L in a volume ratio of 1: 5, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove the methanol solution, repeating the above processes for three times to obtain a concentrated solution, adding an organic solvent with the volume 3.5 times of that of the concentrated solution, heating in a water bath to 95 ℃, stirring and evaporating to remove water, thus obtaining the methanol purified and graded bagasse alkali lignin;
s4, extracting aminated modified bagasse alkali lignin: mixing the methanol-purified and graded bagasse alkali lignin obtained in the step S3 with ultrapure water in a ratio of 1: 20, stirring for 0.5h at normal temperature, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 3.5, and adding FeCl with the weight 2 times that of the alkali lignin of the bagasse purified and classified by methanol2·4H2Mixed solution of O solution and hydrogen peroxide, FeCl2·4H2The mass fraction ratio of the O solution to the hydrogen peroxide is 1: and 4, stirring and reacting for 1 hour at 65 ℃, then adding a NaOH solution with the mass concentration of 10% until the pH value is increased to 10, adding diethylenetriamine with the weight of 2 times that of the methanol purified and graded bagasse alkali lignin, then adding an organic solvent with the weight of 2.5 times that of the diethylenetriamine, mixing and stirring and reacting for 0.5 hour at 88 ℃, filtering and evaporating, washing and drying for three times by using distilled water, and thus obtaining the aminated and modified bagasse alkali lignin.
Example 6
This embodiment is substantially the same as embodiment 1, except that: the ultrasonic power and duration in the extraction step S1 of the plant buffer component B were varied.
S1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 1.5h by adopting 125W ultrasonic power, heating in a water bath at 95 ℃ for 2h, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 6, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume of 3 times of that of the concentrated solution, standing for 2.5h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5, standing for 1.5h, filtering, and washing and drying filter residues by using distilled water to obtain bagasse lignin;
s2, extracting alkali lignin from the bagasse by ether purification and classification: mixing the bagasse lignin obtained in the step S1 with an ether solution with the concentration of 5mol/L in a volume ratio of 1: 2, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove an ether solution, repeating the processes for three times to obtain concentrated bagasse lignin, adding an organic solvent with the volume 6 times that of the concentrated bagasse lignin, heating in a water bath to 95 ℃, stirring and evaporating to remove water, and obtaining ether purified graded bagasse alkali lignin and bagasse lignin solids;
s3, extracting alkali lignin from bagasse by methanol purification and classification: mixing the bagasse lignin solid obtained in the step S2 with a methanol solution with the mass concentration of 8mol/L in a volume ratio of 1: 5, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove the methanol solution, repeating the above processes for three times to obtain a concentrated solution, adding an organic solvent with the volume 4 times that of the concentrated solution, heating in a water bath to 95 ℃, stirring and evaporating to remove water, thus obtaining the methanol purified graded bagasse alkali lignin;
s4, extracting aminated modified bagasse alkali lignin: mixing the methanol-purified and graded bagasse alkali lignin obtained in the step S3 with ultrapure water in a ratio of 1: 20, stirring for 0.5h at normal temperature, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 4, and adding FeCl with the weight 2 times that of the alkali lignin in the methanol purification and classification bagasse2·4H2Mixed solution of O solution and hydrogen peroxide, FeCl2·4H2The mass fraction ratio of the O solution to the hydrogen peroxide is 1: and 4, stirring and reacting for 1 hour at 70 ℃, then adding a NaOH solution with the mass concentration of 10% until the pH value is increased to 10, adding diethylenetriamine with the weight 2 times that of the bagasse alkali lignin purified and graded by methanol, then adding an organic solvent with the weight 3 times that of the diethylenetriamine, mixing and stirring and reacting for 0.5 hour at 90 ℃, filtering and evaporating, and washing and drying for three times by using distilled water to obtain the aminated modified bagasse alkali lignin.
Example 7
This embodiment is substantially the same as embodiment 1, except that: the ultrasonic power and duration in the extraction step S1 of the plant buffer component B were varied.
S1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 1h by adopting 130W of ultrasonic power, heating in a water bath for 2h at 95 ℃, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 6, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume 3 times that of the concentrated solution, standing for 2.5h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5, standing for 1.5h, filtering, and washing and drying filter residues by using distilled water to obtain bagasse lignin;
example 8
This embodiment is substantially the same as embodiment 1, except that: the ultrasonic power and duration in the extraction step S1 of the plant buffer component B were varied.
S1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 1h by adopting 140W of ultrasonic power, heating in a water bath for 2h at 95 ℃, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 6, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume 3 times that of the concentrated solution, standing for 2.5h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5, standing for 1.5h, filtering, and washing and drying filter residues by using distilled water to obtain bagasse lignin;
example 9
This embodiment is substantially the same as embodiment 1, except that: the ultrasonic power and duration in the extraction step S1 of the plant buffer component B were varied.
S1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 1h by adopting 150W ultrasonic power, heating in a water bath for 2h at 95 ℃, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 6, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume 3 times that of the concentrated solution, standing for 2.5h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5, standing for 1.5h, filtering, and washing and drying filter residues by using distilled water to obtain bagasse lignin;
examples of the experiments
The performance of the composite buffer in examples 1-9 was tested by the following methods: hydrochloric acid with the mass concentration of 15 is taken as a corrosion medium, an N80 steel sheet is taken as a corrosion object, the corrosion temperature is 70 ℃, the corrosion time is 2 hours, and the corrosion rate of the steel sheet without the buffer is 578 g/(m)2·h)-1The test results after 1% addition of buffer are shown in table 1:
table 1 composite buffer performance test results
The first-level standard of the corrosion inhibitor is less than 4.0 g/(m) according to the national oil industry standard GB/T35491-2017 corrosion inhibitor vapor phase corrosion inhibitor2H) secondary standard of 4.0-30.0 g/(m)2H), the performance of the composite buffer agent disclosed by the invention reaches the second-level standard of the shelf petroleum industry and is close to the first-level standard, and the composite buffer agent can meet the application of acidification construction in a petroleum exploitation field.
The experimental results of comparative examples 1 to 4 show that when the content of the plant buffer component A, B is adjusted and increased, the corrosion inhibition effect of the buffer is positively influenced, the corrosion rate of the steel sheet is reduced, the corrosion inhibition effect is strong, but the corrosion inhibition effect is not too high, and the compound buffer component proportion in example 3 is taken as the optimal proportion.
It can be seen from the results of the experiments of comparative examples 1, 5 and 6 that the corrosion inhibition effect of the buffer agent is firstly enhanced and then weakened when the ultrasonic treatment time is adjusted to be increased, so that the ultrasonic treatment time is not required to be too long, and the treatment time of 1 hour in example 5 is optimal.
The experimental results of comparative examples 1 and 7-9 show that the bagasse lignin extraction rate increases when the ultrasonic power is adjusted and increased, which indicates that the ultrasonic treatment can increase the solvent diffusivity, promote the solvent to penetrate into the bagasse tissue, make the extraction of the bagasse lignin more efficient, and improve the corrosion inhibition rate of the composite buffer, so that the composite buffer obtained by selecting the ultrasonic power of 140W in example 8 has the best performance.
Claims (10)
1. A composite buffer for low-permeability oilfield oil exploitation acidification is characterized by comprising a plant buffer component A, a plant buffer component B, a modified Mannich base corrosion inhibitor, a buffer synergist and an organic solvent, wherein the raw materials of the components comprise, by weight, 8-12 parts, 15-16 parts, 22-28 parts, 2-3 parts and 130 parts of 120-organic solvent respectively,
the raw materials of the plant buffering agent component A are fresh tea seed shells and walnut green husks, and the raw materials of the plant buffering agent component B are bagasse.
2. The compound buffer for low-permeability oilfield oil exploitation acidification according to claim 1, wherein the organic solvent is 75% by mass ethanol.
3. The compound buffer for oil exploitation acidification in low permeability oilfield according to claim 1, wherein the extraction step of the plant buffer component A is as follows: fresh tea seed shells and walnut green husks are mixed according to the mass ratio of 3: 1, naturally drying the mixture after air drying, drying the mixture at the temperature of between 50 and 60 ℃ to constant weight, grinding the mixture into fine powder, putting the fine powder into an extractor, simultaneously adding an organic solvent which is 13 to 14 times of the weight of the plant powder, the extraction temperature is between 85 and 95 ℃, the extraction time is between 1.5 and 2 hours, then carrying out vacuum filtration on an extracting solution to remove insoluble substances, dropwise adding petroleum ether which is 0.05 to 0.1 time of the weight of the tea seed shell powder, degreasing and decoloring, and drying the mixture for 3 to 4 hours at the temperature of between 50 and 60 ℃ to obtain the plant buffer component A.
4. The composite buffer for low-permeability oilfield oil exploitation acidification according to claim 1, wherein the extraction step of the plant buffer component B comprises:
s1, extracting bagasse lignin: the bagasse lignin is prepared from bagasse and a NaOH solution with the concentration of 1mol/L in a mass ratio of 1: 25, mixing, performing ultrasonic treatment for 0.5-1.5h, performing water bath heating for 2h at 95 ℃, filtering to remove impurities, adding an acetic acid solution with the concentration of 5mol/L until the pH value is reduced to 5.7-6, performing reduced pressure concentration to obtain a concentrated solution, adding an organic solvent with the volume of 3 times of that of the concentrated solution, standing for 2-3h, performing reduced pressure concentration to remove ethanol, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 5-5.3, standing for 1-2h, filtering, and washing and drying filter residues with distilled water to obtain bagasse lignin;
s2, extracting alkali lignin from the bagasse by ether purification and classification: mixing the bagasse lignin obtained in the step S1 with an ether solution with the concentration of 5mol/L in a volume ratio of 1: 2, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove an ether solution, repeating the processes for three times to obtain concentrated bagasse lignin, adding an organic solvent which is 5-6 times the volume of the concentrated bagasse lignin, heating in a water bath to 95 ℃, stirring and evaporating to remove water, and obtaining ether purified graded bagasse alkali lignin and bagasse lignin solid;
s3, extracting alkali lignin from bagasse by methanol purification and classification: mixing the bagasse lignin solid obtained in the step S2 with a methanol solution with the mass concentration of 8mol/L in a volume ratio of 1: 5, mixing, stirring for 3 hours at normal temperature, then concentrating under reduced pressure to remove the methanol solution, repeating the above processes for three times to obtain a concentrated solution, adding an organic solvent with the volume 3-4 times of that of the concentrated solution, heating in a water bath to 95 ℃, stirring and evaporating to remove water, and obtaining the methanol purified and graded bagasse alkali lignin;
s4, extracting aminated modified bagasse alkali lignin: mixing the methanol-purified and graded bagasse alkali lignin obtained in the step S3 with ultrapure water in a ratio of 1: 20, stirring for 0.5h at normal temperature, adding a hydrochloric acid solution with the mass concentration of 10% until the pH value is reduced to 3-4, and adding FeCl with the weight 2 times that of the alkali lignin of the bagasse purified and classified by methanol2·4H2Mixing the O solution and hydrogen peroxide, stirring and reacting for 1h at the temperature of 60-70 ℃, then adding a NaOH solution with the mass concentration of 10% until the pH value is increased to 9.5-10, and then addingPurifying and grading diethylenetriamine 2 times the weight of the bagasse alkali lignin by using methanol, adding an organic solvent 2-3 times the weight of the diethylenetriamine, mixing and stirring for reaction for 0.5h at 85-90 ℃, filtering and evaporating, and washing and drying by using distilled water for three times to obtain the aminated modified bagasse alkali lignin.
5. The composite buffer for oil extraction and acidification in low-permeability oil fields as claimed in claim 4, wherein the power of the ultrasonic wave in step S1 is 125-150W.
6. The compound buffer for low-permeability oilfield oil exploitation acidification according to claim 4, wherein FeCl is used in the step S42·4H2The mass fraction ratio of the O solution to the hydrogen peroxide is 1: 4.
7. the compound buffer for low-permeability oilfield oil exploitation acidification according to claim 1, wherein the modified Mannich base corrosion inhibitor is a Mannich base quaternary ammonium salt, an unsaturated ketene, an emulsifier OP-10, and an unsaturated alcohol in a mass ratio of 10: 3: 2: 1, and mixing the components in a ratio of 1.
8. The composite buffer for acidification of low permeability oilfield oil production according to claim 7, wherein the unsaturated ketene is one of ketene or diethylketene.
9. The compound buffer for acidification of low permeability oilfield oil extraction according to claim 7, wherein the unsaturated alcohol is one of methylpentylenol, ethyloctynol, hexynol or propargyl alcohol.
10. The compound buffer for low-permeability oilfield oil exploitation acidification according to claim 1, wherein the buffer synergist is bis-imidazoline quaternary ammonium salt, dimethyl ketoxime and fatty alcohol-polyoxyethylene ether in a mass ratio of 4: 6: 1, mixing and preparing.
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