CN111592654B

CN111592654B - Shale intercalation inhibitor prepared from environment-friendly hyperbranched polyamino acid

Info

Publication number: CN111592654B
Application number: CN202010288452.XA
Authority: CN
Inventors: 谢刚; 罗玉婧; 邓明毅; 白杨; 王平全; 罗平亚
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2020-04-14
Filing date: 2020-04-14
Publication date: 2022-02-01
Anticipated expiration: 2040-04-14
Also published as: CN111592654A

Abstract

The invention discloses a shale intercalation inhibitor prepared from environment-friendly hyperbranched polyamino acid, belonging to the technical field of oil and gas field drilling, wherein the hyperbranched polyamino acid is synthesized by taking monoprimary amino acid, N-phenylpiperazine and ester compounds containing double olefinic bonds with different hydrophobic chain lengths as raw materials according to the following steps: s1, synthesizing amino acid methyl ester; s2, synthesizing a hyperbranched polyamino acid intermediate; s3 and synthesizing hyperbranched polyamino acid. The shale intercalation inhibitor prepared from the hyperbranched polyamino acid is prepared by matching the hyperbranched polyamino acid with water, wherein the mass ratio of the hyperbranched polyamino acid in the shale intercalation inhibitor is 0.5-3%. The hyperbranched polyamino acid provided by the invention has good biodegradability, is safe and nontoxic, has obviously improved inhibition performance compared with similar shale intercalation inhibitors, is easy to obtain raw materials and low in price, and the provided synthesis method is stable and reliable and is suitable for industrial production.

Description

Shale intercalation inhibitor prepared from environment-friendly hyperbranched polyamino acid

Technical Field

The invention relates to the technical field of oil and gas field drilling, in particular to a shale intercalation inhibitor prepared from hyperbranched polyamino acid.

Background

Borehole wall instability has always been a worldwide problem to be overcome during drilling. It often results in complex accidents such as borehole wall collapse, hole shrinkage, stuck drill, etc., increasing drilling time and drilling cost. According to statistical data, 75% of the borehole wall instability problems mainly occur in shale formations, particularly water-sensitive formations, the shale formations have high clay mineral content, the horizontal sections of shale gas horizontal wells are long, the drilling fluid is in contact with the formations for a long time, the shale is more seriously hydrated, and the borehole wall instability is more prominent. Although the oil-based drilling fluid has the advantages of high temperature resistance, salt and calcium corrosion resistance, contribution to well wall stability, good lubricity, small damage degree to an oil-gas layer and the like, the preparation cost of the oil-based drilling fluid is much higher than that of the water-based drilling fluid, the oil-based drilling fluid often causes serious influence on the ecological environment nearby a well site when in use, the mechanical drilling speed is generally lower than that of the water-based drilling fluid, and the popularization and the application of the oil-based drilling fluid are greatly limited by the defects. The water-based drilling fluid is widely concerned due to the advantages of simple preparation, low price, small environmental pollution and good inhibition effect.

With the gradual improvement of environmental protection requirements in recent years, the development of water-based drilling fluid with the effect equivalent to that of oil-based drilling fluid to replace the oil-based drilling fluid is a trend of the current drilling fluid technical development. In order to overcome the defects of the existing inhibitor, researchers have conducted a great deal of experimental research on the inhibitor, but the inhibitor is not really accepted in the market but is still to be developed, particularly suitable for high-temperature high-density water-based drilling fluid. In recent years, amino acid substances are attracted by people due to the advantages of no biological toxicity, safety, degradability and the like, and hyperbranched polymers show three-dimensional structures due to a series of unique physicochemical characteristics of low viscosity, high rheological property, good solubility, a large number of modifiable terminal functional groups and the like. Therefore, hyperbranched polymers have become a hot point of research in recent years in the field of polymer science.

However, the polyamino acid inhibitors studied and applied at present are mostly linear structures, and for the linear polyamino acid inhibitors, the linear polyamino acid inhibitors usually have irregular linear configurations after being dissolved in water, and when the linear polyamino acid inhibitors are used in a shale gas drilling process, winding and coating on clay are uneven, so that repeated adsorption or no adsorption is easily caused. Meanwhile, the acting groups are generally arranged at two ends of a molecular chain, so that one molecular chain generally only comprises two acting groups, and the acting effect of the linear polyamino acid inhibitor also has certain limitation under the condition. And the high molecular weight polyamino acid compound is difficult to enter the clay interlayer, so that the inhibiting property thereof is limited.

Disclosure of Invention

In view of the above-mentioned problems, the present invention provides a shale intercalation inhibitor made of hyperbranched polyamino acid.

In order to achieve the purpose, the technical scheme of the invention is as follows: the shale intercalation inhibitor is prepared by mixing hyperbranched polyamino acid and water, wherein the mass percentage of the hyperbranched polyamino acid is 0.5-3% based on the water, the hyperbranched polyamino acid is prepared by taking monobasic amine amino acid, N-phenylpiperazine, anhydrous methanol and ester compounds containing diene bonds with different hydrophobic chain lengths as raw materials and adopting the following steps:

s1, synthesis of amino acid methyl ester: dissolving 0.02-0.03mol of primary amine amino acid in 100-150ml of anhydrous methanol at normal temperature, then placing the amino acid solution in a closed container, refluxing for 12-18h at the temperature of 90-120 ℃ under the condition of nitrogen atmosphere and stirring, and then carrying out reduced pressure distillation on the reaction product to obtain amino acid methyl ester;

s2, preparation of the hyperbranched polyamino acid intermediate: dissolving 0.01-0.02mol of the amino acid methyl ester obtained in the step S1 and 0.01-0.02mol of N-phenylpiperazine in 200ml of 100-one organic solvent, dissolving 0.02-0.04mol of ester compound containing diene bond in 200ml of 100-one organic solvent, dropwise adding the solution containing the compound with diene bond into the amino acid methyl ester solution under the conditions of ice water bath, nitrogen atmosphere and stirring, heating to 35-55 ℃ after dropwise adding, stirring for reaction for 5-10h, and after the reaction is finished, carrying out reduced pressure distillation on the product to obtain a hyperbranched polyamino acid intermediate;

s3, synthesis of hyperbranched polyamino acid: and (3) dissolving the product obtained in the step (S2) by using 80-100ml of organic solvent, placing the solution in a container, raising the temperature to 65-85 ℃ under the condition of nitrogen atmosphere and stirring, carrying out reflux reaction for 12-24h, and carrying out reduced pressure distillation to obtain a viscous product, namely the hyperbranched polyamino acid.

The primary monoamine amino acid in the step S1 is one of 3-methylamino alanine, 2-amino-4- (methylamino) butyric acid, D, L-delta-N-methyl ornithine, D, L-delta-N-methyl lysine and 2-amino-7- (methylamino) heptanoic acid.

The ester compound containing double ethylenic bonds is one of vinyl acrylate, vinyl acrylate and vinyl methacrylate.

The organic solvent is one of chloroform, tetrahydrofuran, DMSO and N, N-dimethylformamide.

The dripping time of the synthesis step S2 is controlled to be 25-50 min.

The drying temperature of the steps S2 and S3 under reduced pressure is 40-60 ℃.

In the step S1, the reduced pressure distillation temperature of S2 is 85 ℃, and the absolute vacuum degree is less than 3000 Pa; and the reduced pressure distillation temperature of the step S3 is 105 ℃, and the absolute vacuum degree is less than 3000 Pa.

The invention has the following beneficial effects:

1. the product provided by the invention responds to the environmental protection requirement, and has the advantages of low biological toxicity, safety, degradability and the like;

2. the synthesis method has stable and reliable technology, high yield and low price of raw materials required by the synthesized product, and is suitable for industrial production;

3. the shale inhibitor provided by the invention has stable performance and strong adaptability, can obviously improve the inhibition performance compared with similar products, and can meet the drilling requirements of various complex well conditions.

Drawings

FIG. 1 is a graph showing the molecular weight distribution of the hyperbranched polyamino acid of example 1;

FIG. 2 is a graph showing the molecular weight distribution of the hyperbranched polyamino acid of example 2.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

S1, synthesis of amino acid methyl ester: 3.0g of 3-methylamino alanine is accurately weighed and dissolved in 100mL of anhydrous methanol, then the 3-methylamino alanine methanol solution is transferred into a 500mL three-neck flask, the temperature is raised to 100 ℃ under the nitrogen atmosphere and the stirring, and the reflux reaction is carried out for 12 hours. After the reaction is finished, the 3-methylamino alanine methyl ester is obtained by rotary evaporation under the conditions of 85 ℃ and the absolute vacuum degree of less than 3000 Pa.

S2, synthesis of hyperbranched polyamino acid intermediate: accurately weighing 2.62g of the methyl 3-methylaminoalanine obtained in the step S1, 3.26g N-phenylpiperazine and 3.92g of vinyl acrylate, respectively dissolving in 200ml of chloroform, transferring the solution of the methyl 3-methylaminoalanine and the solution of N-phenylpiperazine into a three-neck flask, and dropwise adding the solution of the vinyl acrylate under the conditions of 0 ℃, nitrogen atmosphere and stirring for 25 min. After the dropwise addition, the temperature is raised to 45 ℃ and the reaction is carried out for 12 hours. After the reaction is finished, the hyperbranched polyamino acid intermediate is obtained by rotary evaporation at the temperature of 85 ℃ and the absolute vacuum degree of less than 3000 Pa.

S3, synthesis of hyperbranched polyamino acid: and (4) dissolving the hyperbranched polyamino acid intermediate obtained in the step (S2) by adopting N, N-dimethylformamide, placing the mixture into a flask, heating to 75 ℃ under the condition of nitrogen atmosphere and stirring, and refluxing for 24 hours. After the reaction is finished, the viscous hyperbranched polyamino acid is obtained by rotary evaporation at 105 ℃ and under the condition that the absolute vacuum degree is less than 3000 Pa.

Example 2

S1, synthesis of amino acid methyl ester: 3.5g D, L-delta-N-methyl ornithine is accurately weighed and dissolved in 100mL of anhydrous methanol, then the D, L-delta-N-methyl ornithine methanol solution is transferred to a 500mL three-neck flask, the temperature is raised to 100 ℃ under the condition of stirring in a nitrogen atmosphere, and reflux reaction is carried out for 12 hours. After the reaction is finished, performing rotary evaporation at 85 ℃ and under the absolute vacuum degree of less than 3000Pa to obtain D, L-delta-N-methyl ornithine methyl ester.

S2, synthesis of hyperbranched polyamino acid intermediate: 3.20g of the D, L-delta-N-methyl ornithine obtained in the step S1, 3.26g N-phenylpiperazine and 3.92g of vinyl acrylate were accurately weighed and dissolved in 200ml of chloroform, respectively, and the D, L-delta-N-methyl ornithine and N-methylpiperazine solutions were transferred to a 500ml three-necked flask, and the vinyl acrylate solution was added dropwise under stirring at 0 ℃ under a nitrogen atmosphere for 25 min. After the dropwise addition, the temperature is raised to 45 ℃ and the reaction is carried out for 8 hours. After the reaction is finished, the hyperbranched polyamino acid intermediate is obtained by rotary evaporation at the temperature of 85 ℃ and the absolute vacuum degree of less than 3000 Pa.

In order to further illustrate the effect of the environment-friendly shale intercalation inhibitor of the invention, the composite demulsifier in example 1 and example 2 was subjected to a performance test.

1. Molecular weight measurement

The hyperbranched polyamino acids synthesized in example 1 and example 2 were tested by TOF-LC/MS, and the results are shown in FIG. 1 and FIG. 2. As can be seen from the mass spectrum of the polymer (taking example 1 as an example), the polymer molecules respectively have ion peaks at 363.31,594.4327,825.5507,1056.6915,1287.929,1581.0229,1812.2961,2043.3557,2274.25, which are ion peaks of hyperbranched polyamino acids with different branching degrees, and the difference between adjacent ion peaks is 231, i.e., each ion peak differs from another ion peak by one repeating unit, which is consistent with the theoretical calculation value. Thus, the successful synthesis of the hyperbranched polyamino acid is proved.

2. Inhibition performance test

The hyperbranched polyamino acid obtained in the example 1-2 and clear water are prepared into a shale inhibitor and a conventional shale inhibitor (the conventional polyamine inhibitor and the hexamethylenediamine inhibitor are selected) according to a certain proportion (the mass ratio of the hyperbranched polyamino acid is 1%, 2% and 3%) for comparison experiments, and the clear water is used as a reference. The performance of the shale inhibitor prepared in the above example is evaluated by rolling recovery, and the specific operation steps refer to SY/T5971-1994 evaluation method of performance of clay stabilizer for water injection. The higher the rolling recovery, the better the inhibition performance of the shale inhibitor. The results of the experiment are shown in table 1.

TABLE 1 Rolling recovery test results

Components	Recovery (%)
		Clean water	19.54
1% hexamethylene diamine	34.31
		1% of polyamine	44.53
1% of the hyperbranched polyamino acid obtained in example 1	84.96
		2% of the hyperbranched polyamino acid obtained in example 1	87.25
3% of the hyperbranched polyamino acid obtained in example 1	89.95
		1% of the hyperbranched polyamino acid obtained in example 2	85.88
2% of the hyperbranched polyamino acid obtained in example 2	88.27
		3% of the hyperbranched polyamino acid obtained in example 2	90.21

The rolling recovery rate result shows that when the hexamethylenediamine, the polyamine and the hyperbranched polyamino acid obtained in the example are in the same mass ratio, the inhibition performance of the hyperbranched polyamino acid is obviously higher than that of the hexamethylenediamine and the polyamine shale inhibitor, and the result shows that the inhibition effect of the hyperbranched polyamino acid shale inhibitor is obviously higher than that of the conventional shale inhibitor. And the rolling recovery rate is increased and the inhibition effect is better along with the increase of the mass ratio (0.5-3%) of the inhibitor.

3. Evaluation of environmental protection

The hyperbranched polyamino acid serving as the shale intercalation inhibitor has the advantages of excellent inhibition performance, simple production process and easy biodegradation. Biodegradation of polymers refers to the phenomenon of converting them into simple inorganic substances under the action of microorganisms (fungi, molds, etc.). Biodegradability (BOD)₅CODcr) determination of BOD by inoculation and dilution₅The CODcr is measured by a potassium dichromate method (reference standard HJ/T505-2009), the ratio is 57 and 8 percent, the degradation is easy, and the amino acid substances have been proved to have the advantage of low biological toxicity, which indicates that the product is an environment-friendly shale inhibitor.

In conclusion, the preparation method of the hyperbranched polyamino acid provided by the invention has stable and reliable technology and higher yield, and is suitable for industrial production; the synthesized hyperbranched polyamino acid product is non-toxic and harmless, has good water solubility, and compared with similar products, the inhibition performance of the prepared shale intercalation inhibitor is obviously improved, the shale intercalation inhibitor can meet the drilling requirements of various complex well conditions, and the occurrence probability of unstable well wall caused by shale hydration dispersion is effectively reduced.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The shale intercalation inhibitor prepared from environment-friendly hyperbranched polyamino acid is characterized in that the shale intercalation inhibitor is prepared by mixing hyperbranched polyamino acid and water, the mass percentage of the hyperbranched polyamino acid is 0.5-3% based on the water, the hyperbranched polyamino acid is prepared by taking primary monoamino acid with different hydrophobic chain lengths, N-phenylpiperazine, anhydrous methanol and ester compounds containing diene bonds as raw materials and adopting the following steps:

s2, preparation of the hyperbranched polyamino acid intermediate: dissolving 0.01-0.02mol of the amino acid methyl ester obtained in the step S1 and 0.01-0.02mol of N-phenylpiperazine by using 200ml of 100-one organic solvent, dissolving 0.02-0.04mol of ester compound containing diene bond by using 200ml of 100-one organic solvent, dropwise adding a solution containing a diene bond compound into the amino acid methyl ester and N-phenylpiperazine solution under the conditions of ice water bath, nitrogen atmosphere and stirring, heating to 35-55 ℃ after dropwise adding, stirring for reacting for 5-10h, and after the reaction is finished, distilling the product under reduced pressure to obtain a hyperbranched polyamino acid intermediate;

2. The shale intercalation inhibitor of claim 1, wherein the primary monoamine amino acid of step S1 is one of 3-methylaminoalanine, 2-amino-4- (methylamino) butanoic acid, D, L- δ -N-methylornithine, D, L- δ -N-methyllysine, 2-amino-7- (methylamino) heptanoic acid.

3. The shale intercalation inhibitor according to claim 1, wherein the ester compound containing a diene bond is one of vinyl acrylate, vinyl allyl acrylate and vinyl methacrylate.

4. The shale intercalation inhibitor according to claim 1, wherein the organic solvent is one of chloroform, tetrahydrofuran, DMSO, N-dimethylformamide.

5. The shale intercalation inhibitor according to claim 1, wherein the dropping time of the synthesis step S2 is controlled within 25-50 min.

6. The shale intercalation inhibitor of claim 1, wherein the reduced pressure distillation temperature of steps S1, S2 is 85 ℃ and the absolute vacuum is less than 3000 Pa; and the reduced pressure distillation temperature of the step S3 is 105 ℃, and the absolute vacuum degree is less than 3000 Pa.