Temperature-resistant shale inhibitor and preparation method thereof
Technical Field
The invention belongs to the technical field of oil field additives, and particularly relates to a temperature-resistant shale inhibitor and a preparation method thereof.
Background
The instability of the well wall caused by hydration expansion and dispersion of the shale is always a technical problem in oil and gas well engineering. Statistically, 75% of borehole wall instability occurs primarily in shale formations, particularly water sensitive formations. The clay mineral content of the shale stratum is high, the horizontal section of the shale gas horizontal well is long, the contact time of the drilling fluid and the stratum is long, the shale hydration is more serious, and the borehole wall instability is more prominent. Particularly, in recent years, the exploration and development of unconventional oil and gas resources such as shale gas and the like are increased, the problem of shale borehole wall stability is more and more prominent, the traditional shale inhibitor cannot meet the requirements, and the development of a novel efficient shale inhibitor is particularly urgent.
Amine (ammonium) inhibitors are shale inhibitors which are commonly used at present, and the main action mechanism of the inhibitors is that the shale surface is usually negatively charged and can adsorb amine groups; the amine (ammonium) group can enter clay layers and extrude water molecules in the clay layers, so that the water adsorption capacity of shale is reduced, and meanwhile, the hydrophobic end of the amine (ammonium) inhibitor can be positioned on the clay surface to further prevent water from entering clay layers. In particular, polyamine inhibitors have a plurality of amine groups, provide a large number of attachment sites, and have a high adsorption capacity. However, the existing polyamine shale inhibitors only consider more attachment sites and do not consider discharging adsorbed water molecules, so that the shale inhibition performance is limited; meanwhile, the temperature resistance of the existing amine (ammonium) inhibitor needs to be improved.
Disclosure of Invention
In order to solve at least one problem, the invention provides a temperature-resistant shale inhibitor which has good shale inhibition performance and good temperature resistance.
The technical scheme of the invention is as follows: a preparation method of a temperature-resistant shale inhibitor comprises the following steps:
respectively dissolving polyamine compounds and dimethyl diallyl ammonium in a solvent, simultaneously dissolving unsaturated sulfonate in the solvent, dropwise adding a dimethyl diallyl ammonium solution and an unsaturated sulfonate solution into the polyamine compound solution under the conditions of 20-50 ℃, nitrogen atmosphere and continuous stirring, continuously reacting for 15-24 hours after dropwise adding, heating to 50-80 ℃, adding water with the volume being at least one time of that of the reaction solution, adjusting the pH to be alkaline, continuously stirring, reacting for 2-20 hours, and then separating and purifying to obtain the compound;
in the polyamine compound, the number of hydrogen atoms on an amino group is n, and the molar ratio of the polyamine compound, the dimethyl diallyl ammonium and the unsaturated sulfonate is 1:0.3n to 0.4n:0.1n to 0.15n, the reason why the addition amount of dimethyldiallylammonium and unsaturated sulfonic acid ester is limited by the number of hydrogen atoms in the amino group is that, in the present invention, dimethyldiallylammonium and unsaturated sulfonic acid ester are both subjected to Michael addition reaction with a polyamine-based compound, and both primary amine and secondary amine groups are capable of being subjected to Michael addition reaction with a double bond. For primary amines, which have 2 hydrogen atoms in the amine group, two michael addition reactions can occur; the secondary amine has 1 hydrogen atom on it, and is capable of undergoing a michael addition reaction.
The unsaturated sulfonate refers to a sulfonate compound having one double bond, and is not a lactone. The structural general formula is as follows:
in the formula, R1 is one of hydrogen, methyl and methoxy, n is 0-4, and R2 is one of methyl, ethyl or propyl.
Meanwhile, dimethyldiallylammonium, which functions in the present invention as follows: and the branched polyamine is reacted with a polyamine compound to generate branched polyamine, and the branched polyamine is easier to adsorb on a clay layer due to the quaternary ammonium group contained in the branched polyamine, so that the branched polyamine is more tightly adsorbed, and the shale inhibition effect is better finally.
Meanwhile, the sum of the addition amount of the dimethyldiallylammonium and the unsaturated sulfonic acid ester is less than n in consideration of: for polyamine inhibitors, primary amines are relatively more effective, secondary amines are less effective, and tertiary amines are less effective. Therefore, when the sum is less than n, the branched polyamine finally obtained still has primary and secondary amines, so that the effect is better.
Meanwhile, in the present invention, the selected solvent should generally have a certain solubility to all 3 raw materials at the same time, or the solvent includes two kinds of solvents, but the two kinds of solvents can be mutually soluble, and a solvent system formed after mutual solubility can dissolve all 3 raw materials at the same time.
Meanwhile, after the reaction is completed, the solvent needs to be removed, and the solvent removal method can be performed by a method such as rotary evaporation or distillation under reduced pressure.
In one embodiment of the present invention, the polyamine-based compound is one of polyethylene polyamine and alkyldiamine, and the unsaturated sulfonic acid ester is one of methyl allylsulfonate, ethyl allylsulfonate, methyl vinylsulfonate and ethyl vinylsulfonate.
Further, the polyethylene polyamine is one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine: the alkyl diamine is one of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine and hexylenediamine.
One embodiment of the present invention is that the solvent is one of N, N-dimethylformamide and dimethylsulfoxide.
In one embodiment of the present invention, the molar ratio of the polyamine-based compound, dimethyldiallylammonium, and unsaturated sulfonic acid ester is 1:0.3n to 0.35n:0.1n to 0.15n.
One embodiment of the present invention is to maintain the alkalinity of the reaction mixture during the reaction after the reaction mixture is heated to 50 to 80 ℃ and added with water.
The invention also aims to disclose a temperature-resistant shale inhibitor which is prepared by any one of the above methods, and the shale inhibitor has a good shale inhibition effect and strong temperature resistance.
The invention has the beneficial effects that:
the temperature-resistant shale inhibitor has a good shale inhibitor effect, the rolling recovery rate at 120 ℃ can reach 94.9% to the maximum, and the rolling recovery rate at 260 ℃ can reach 91.9% to the maximum, which shows that the shale inhibitor effect is relatively good; meanwhile, the addition amount of the polyamine inhibitor is less than that of the conventional polyamine inhibitor, and a better effect can be achieved only by 1.5 percent, which shows that the performance of the polyamine inhibitor is stronger; meanwhile, the oil-water separator has strong temperature resistance, can resist the high temperature of 260 ℃, and can be applied to high-temperature oil reservoirs.
Detailed Description
In order to make the technical solutions and technical advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the implementation process of the present invention with reference to the embodiments.
The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.
Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.
In the following examples, the allyl methyl sulfonate is of the formula
The catalyst can be prepared by adopting allyl sulfonyl chloride and methanol under the catalysis of alkali, but is not limited to the preparation method.
Example 1
Dissolving 11.6g of hexamethylenediamine in 15ml of dimethyl sulfoxide, dissolving 6.7g of methyl allyl sulfonate (0.1 n) in 15ml of dimethyl sulfoxide, dissolving 22.6g of dimethyldiallylammonium chloride (0.35 n) in 30ml of dimethyl sulfoxide, dropwise adding the methyl allyl sulfonate solution and the dimethyldiallylammonium chloride solution into the hexamethylenediamine solution at 40 ℃ under the conditions of nitrogen atmosphere and continuous stirring, continuing to react for 13 hours after the dropwise addition is finished, adding 110ml of water after the reaction is finished, heating to 70 ℃, adding a sodium hydroxide solution to adjust the pH to 10, reacting for 8 hours, keeping the pH to 10 in the reaction process, and removing the solvent by rotary evaporation at 70 ℃ after the reaction is finished to obtain the temperature-resistant shale inhibitor Y1.
Example 2
Dissolving 10.6g of diethylenetriamine in 20ml of dimethyl sulfoxide, dissolving 10g of methyl allyl sulfonate (0.12 n) in 15ml of dimethyl sulfoxide, dissolving 24.2g of dimethyl diallyl ammonium chloride (0.3 n) in 30ml of dimethyl sulfoxide, dropwise adding the methyl allyl sulfonate solution and the dimethyl diallyl ammonium chloride solution into the diethylenetriamine solution at the temperature of 25 ℃ under the conditions of nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after dropwise addition is finished, adding 120ml of water after the reaction is finished, heating to 55 ℃, adding a sodium hydroxide solution to adjust the pH to 8.5, reacting for 16 hours, and removing the solvent by rotary evaporation at the temperature of 70 ℃ after the reaction is finished to obtain the temperature-resistant shale inhibitor Y2.
Example 3
Dissolving 11.6g of hexamethylenediamine in 15ml of dimethyl sulfoxide, dissolving 10g of methyl allyl sulfonate (0.15 n) in 15ml of dimethyl sulfoxide, dissolving 25.8g of dimethyl diallyl ammonium chloride (0.4 n) in 30ml of dimethyl sulfoxide, dropwise adding the methyl allyl sulfonate solution and the dimethyl diallyl ammonium chloride solution into the hexamethylenediamine solution under the conditions of 40 ℃, nitrogen atmosphere and continuous stirring, continuously reacting for 15 hours after dropwise addition is finished, adding 120ml of water, heating to 70 ℃, adding a sodium hydroxide solution to adjust the pH to 10, reacting for 8 hours, keeping the pH to 10 in the reaction process, and performing rotary evaporation at 70 ℃ to remove the solvent after the reaction is finished to obtain the temperature-resistant shale inhibitor Y3.
Example 4
Dissolving 11.6g of hexamethylenediamine in 15ml of dimethyl sulfoxide, dissolving 6.7g of methyl allyl sulfonate (0.1 n) in 15ml of dimethyl sulfoxide, dissolving 22.6g of dimethyldiallylammonium chloride (0.35 n) in 30ml of dimethyl sulfoxide, dropwise adding the methyl allyl sulfonate solution and the dimethyldiallylammonium chloride solution into the hexamethylenediamine solution at 40 ℃ under the conditions of nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after dropwise addition is finished, adding 110ml of water after the reaction is finished, heating to 70 ℃, adding a sodium hydroxide solution to adjust the pH value to 10, reacting for 8 hours, and removing the solvent by rotary evaporation at 70 ℃ after the reaction is finished to obtain the temperature-resistant shale inhibitor Y1.
Comparative example 1
Dissolving 11.6g of hexamethylenediamine in 15ml of dimethyl sulfoxide, dissolving 4.9g of allyl sulfonic acid in 10ml of dimethyl sulfoxide, dissolving 22.6g of dimethyldiallylammonium chloride (0.35 n) in 30ml of dimethyl sulfoxide, dropwise adding the allyl methyl sulfonate solution and the dimethyldiallylammonium chloride solution into the hexamethylenediamine solution under the conditions of 40 ℃, nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after the dropwise addition is finished, adding 100ml of water after the reaction is finished, heating to 70 ℃, adding a sodium hydroxide solution to adjust the pH to 10, reacting for 8 hours, keeping the pH to 10 in the reaction process, and removing the solvent by rotary evaporation at 70 ℃ after the reaction is finished to obtain the temperature-resistant shale inhibitor D1.
Comparative example 2
Dissolving 11.6g of hexamethylenediamine in 15ml of dimethyl sulfoxide, dissolving 6.7g of methyl allyl sulfonate (0.1 n) in 10ml of dimethyl sulfoxide, dissolving 32.3g of dimethyldiallylammonium chloride (0.5 n) in 40ml of dimethyl sulfoxide, dropwise adding the methyl allyl sulfonate solution and the dimethyldiallylammonium chloride solution into the hexamethylenediamine solution at 40 ℃ under the conditions of nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after the dropwise addition is finished, adding 120ml of water after the reaction is finished, heating to 70 ℃, adding a sodium hydroxide solution to adjust the pH to 10, reacting for 8 hours, keeping the pH to 10 in the reaction process, and removing the solvent by rotary evaporation at 70 ℃ after the reaction is finished to obtain the temperature-resistant shale inhibitor D2.
To further illustrate the effects of the temperature tolerant shale inhibitors prepared in the above examples, the temperature tolerant shale inhibitors prepared above were tested as follows.
1. Roll recovery
Temperature-resistant shale inhibitors Y1-Y4 and D1-D2 are taken and prepared into inhibitors with different concentrations by clear water, the rolling recovery rate is measured by adopting a method disclosed in the petroleum and gas industry standard SY/T6335-1997 shale inhibitor for drilling fluid evaluation method, and the final test result is shown in Table 1.
TABLE 1 Rolling recovery
As can be seen from Table 1, the inhibitors prepared in examples 1 to 4 have high rolling recovery rate, and the rolling recovery rate can reach 94.9% at the addition of 1.5%, which indicates that the inhibitors have good shale inhibition performance; when the addition amount is 0.8%, the rolling recovery rate can reach 79.6% at most, which shows that the performance is better, and the shale inhibition purpose can be achieved only by adding less inhibitors; when the rolling temperature is 260 ℃, the rolling recovery rate can reach 91.9 percent at most, which shows that the rolling material has better temperature resistance.
Comparing Y1 with D1, the difference is that the allyl methyl sulfonate is replaced by the conventional allyl sulfonic acid, and for the allyl sulfonic acid, although the sulfonic acid group is an electron-withdrawing group, the electron cloud density of double bonds on the allyl can be reduced, and the Michael addition reaction is promoted, because the polyamine compound is basic, the sulfonic acid group can be changed into a sulfonic acid group, and the sulfonic acid group belongs to an electron-donating group, so that the Michael addition reaction of the allyl sulfonic acid is difficult to occur. Therefore, as is clear from table 1, D1 is difficult to apply to a high-temperature environment, and the rolling recovery rate is low and decreases rapidly under high-temperature conditions.
Comparing Y1 and D2, the difference is that the addition of methyl allylsulfonate and dimethyldiallylammonium chloride is adjusted to give a molar ratio of: 1:0.1n:0.5n, under the condition of the molar ratio, the product after the reaction basically does not contain primary amine and secondary amine, and although a part of quaternary ammonium is contained, the quaternary ammonium can only play an adsorption role, so the effect is relatively poor; meanwhile, the quaternary ammonium group has a strong electron-withdrawing effect, so that the reaction efficiency is higher than that of the allylic methyl sulfonate, the number of the allylic methyl sulfonate grafted in the final compound is small, and the temperature resistance of the compound is poor.
Although the present invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present invention.