Temperature-resistant shale inhibitor and preparation method thereof
Technical Field
The invention belongs to the technical field of assistants for oil fields, 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 shale is always a technical problem in oil and gas well engineering. It is counted that 75% of the borehole wall instability occurs mainly in shale formations, particularly water sensitive formations. The shale stratum has high clay mineral content, the horizontal section of the shale gas horizontal well is long, the contact time of the drilling fluid and the stratum is long, shale hydration is more serious, and well wall instability is more prominent. Especially, in recent years, the exploration and development force of unconventional oil and gas resources such as shale gas is increased, the problem of shale well wall stability is more remarkable, the traditional shale inhibitor can not meet the requirements, and the development of novel efficient shale inhibitor is urgent.
Amine (ammonium) inhibitors are currently more commonly used shale inhibitors, and the main action mechanism is that the shale surface is usually negatively charged and can adsorb amine groups; amine (ammonium) groups can enter clay layers and drain water molecules in the clay layers, so that the adsorption quantity of shale to water is reduced, and meanwhile, the hydrophobic end of the amine (ammonium) inhibitor can be positioned on the clay surface, so that water is further prevented from entering the clay layers. In particular, polyamine inhibitors, which have a plurality of amine groups, can provide a large number of attachment sites and have a high adsorption capacity. However, the current polyamine shale inhibitor only considers more attachment sites and does not consider the discharge of 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 of the problems, the invention provides a temperature-resistant shale inhibitor which has good shale inhibition performance and also has good temperature resistance.
The technical scheme of the invention is as follows: the preparation method of the temperature-resistant shale inhibitor comprises the following steps:
respectively dissolving polyamine compound and dimethyl diallyl ammonium in a solvent, dissolving unsaturated sulfonate in the solvent, dropwise adding dimethyl diallyl ammonium solution and unsaturated sulfonate solution into the polyamine compound solution under the conditions of 20-50 ℃ and nitrogen atmosphere and continuous stirring, continuously reacting for 15-24 hours after dropwise adding, heating to 50-80 ℃ and adding water at least one time of the volume of the reaction solution, regulating the pH value to be alkaline and continuously stirring, reacting for 2-20 hours, and separating and purifying to obtain the product;
in the polyamine compound, the number of hydrogen atoms on an amino group is n, and the mole ratio of the polyamine compound, the dimethyldiallylammonium and the unsaturated sulfonate is 1:0.3 n-0.4 n: the addition amount of the dimethyldiallylammonium or the unsaturated sulfonate is limited by the number of hydrogen atoms on the amine group of 0.1n to 0.15n, because in the invention, the dimethyldiallylammonium, the unsaturated sulfonate and the polyamine compound all undergo Michael addition reaction, wherein, primary amine and secondary amine groups can undergo Michael addition reaction with double bonds. For primary amines, the amine group has 2 hydrogen atoms, which can undergo two Michael addition reactions; the secondary amine has 1 hydrogen atom and can undergo a Michael addition reaction.
Wherein the unsaturated sulfonate is a sulfonate compound having one double bond and not being internallyAn ester. The structural general formula is as follows:wherein R1 is one of hydrogen, methyl and methoxy, n is 0-4, and R2 is one of methyl, ethyl or propyl.
Meanwhile, dimethyldiallylammonium, its role in the present invention is as follows: and the polyamine compound reacts to generate branched polyamine, and meanwhile, the branched polyamine is easier to adsorb on a clay layer due to the quaternary ammonium group, so that the adsorption is tighter, and finally, the shale inhibition effect is better.
Meanwhile, the addition amount sum of the dimethyldiallylammonium and the unsaturated sulfonate is smaller than n, considering that: for polyamine inhibitors, primary amines have a relatively large effect, secondary amines have a weaker effect, and tertiary amines have a weaker effect. Therefore, when the sum of the addition amounts is less than n, the branched polyamine finally obtained still has primary amine and secondary amine, making it more effective.
Meanwhile, in the present invention, the selected solvent should generally have a certain solubility for all 3 raw materials at the same time, or the solvents include two solvents, but the two solvents are mutually soluble, and the solvent system formed after mutual dissolution can simultaneously dissolve 3 raw materials.
Meanwhile, after the completion of the reaction, the solvent needs to be removed, and the method of removing the solvent may be performed by rotary evaporation, reduced pressure distillation, or the like, but rotary evaporation is preferable, and the evaporation rate is faster.
In one embodiment of the present invention, the polyamine compound is one of polyethylene polyamine and alkyl diamine, and the unsaturated sulfonate 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, pentylene diamine and hexamethylenediamine.
In one embodiment of the present invention, the solvent is one of N, N-dimethylformamide and dimethylsulfoxide.
One embodiment of the present invention is characterized in that the molar ratio of the polyamine-based compound, dimethyldiallylammonium, and unsaturated sulfonate is 1:0.3 n-0.35 n:0.1n to 0.15n.
One embodiment of the present invention is to keep the reaction alkaline all the time after heating to 50 to 80 ℃ and adding water to react.
The invention further aims to disclose a temperature-resistant shale inhibitor, which is prepared by adopting any one of the methods, and has a good shale inhibition effect and a strong temperature resistance.
The invention has the beneficial effects that:
the temperature-resistant shale inhibitor has good shale inhibition effect, the rolling recovery rate at 120 ℃ can reach 94.9% at most, and the rolling recovery rate at 260 ℃ can reach 91.9% at most, which indicates that the shale inhibition effect is relatively good; meanwhile, compared with the conventional polyamine inhibitor, the addition amount of the polyamine inhibitor is less, and a better effect can be achieved only by 1.5%, which shows that the performance of the polyamine inhibitor is stronger; meanwhile, the high-temperature-resistant oil deposit 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 scheme and technical advantages of the present invention more clear, the technical scheme in the implementation process of the present invention will be clearly and completely described below with reference to the embodiments.
The experimental methods used in the following examples are conventional methods unless otherwise specified.
Materials, reagents and the like used in the examples described below are commercially available unless otherwise specified.
In the following examples, the methyl allylsulfonate has the formulaIt can be prepared by using 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 allyl methyl sulfonate (0.1 n) in 15ml of dimethyl sulfoxide, dissolving 22.6g of dimethyl diallyl ammonium chloride (0.35 n) in 30ml of dimethyl sulfoxide, dropwise adding the allyl methyl sulfonate solution and the dimethyl diallyl ammonium chloride solution into the hexamethylenediamine solution under the conditions of 40 ℃ and nitrogen atmosphere and continuous stirring, continuing to react for 13h after the dropwise adding, adding 110ml of water and heating to 70 ℃ after the reaction is finished, adding sodium hydroxide solution to adjust the pH to 10, reacting for 8h, keeping the pH to 10 in the reaction process, and rotationally steaming at 70 ℃ to remove the solvent 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 allyl methyl 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 allyl methyl sulfonate solution and the dimethyl diallyl ammonium chloride solution into the diethylenetriamine solution under the conditions of 25 ℃ and nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after the dropwise adding, adding 120ml of water and heating to 55 ℃ after the reaction is finished, adding sodium hydroxide solution to adjust the pH to 8.5, reacting for 16 hours, and removing the solvent by spin evaporation at 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 allyl methyl 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 allyl methyl sulfonate solution and the dimethyl diallyl ammonium chloride solution into the hexamethylenediamine solution under the conditions of 40 ℃ and nitrogen atmosphere and continuous stirring, continuing to react for 15h after the dropwise adding, adding 120ml of water and heating to 70 ℃, adding sodium hydroxide solution to adjust the pH to 10, reacting for 8h, keeping the pH 10 in the reaction process, and removing the solvent by rotary evaporation under the condition of 70 ℃ after the reaction is finished to obtain the temperature-resistant shale inhibitor Y3.
Example 4
Taking 11.6g of hexamethylenediamine to dissolve in 15ml of dimethyl sulfoxide, taking 6.7g of allyl methyl sulfonate (0.1 n) to dissolve in 15ml of dimethyl sulfoxide, taking 22.6g of dimethyl diallyl ammonium chloride (0.35 n) to dissolve in 30ml of dimethyl sulfoxide, dropwise adding the allyl methyl sulfonate solution and the dimethyl diallyl ammonium chloride solution into the hexamethylenediamine solution under the conditions of 40 ℃ and nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after the dropwise adding, adding 110ml of water and heating to 70 ℃ after the reaction is finished, adding sodium hydroxide solution to regulate the pH to 10, reacting for 8 hours, and removing the solvent by rotary evaporation at 70 ℃ after the reaction is finished, thus obtaining the temperature-resistant shale inhibitor Y1.
Comparative example 1
Taking 11.6g of hexamethylenediamine to dissolve in 15ml of dimethyl sulfoxide, taking 4.9g of allyl sulfonic acid to dissolve in 10ml of dimethyl sulfoxide, taking 22.6g of dimethyl diallyl ammonium chloride (0.35 n) to dissolve in 30ml of dimethyl sulfoxide, dropwise adding the allyl sulfonic acid methyl ester solution and the dimethyl diallyl ammonium chloride solution into the hexamethylenediamine solution under the conditions of 40 ℃ and nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after the dropwise adding, adding 100ml of water and heating to 70 ℃ after the reaction is finished, adding 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 allyl methyl sulfonate (0.1 n) in 10ml of dimethyl sulfoxide, dissolving 32.3g of dimethyl diallyl ammonium chloride (0.5 n) in 40ml of dimethyl sulfoxide, dropwise adding the allyl methyl sulfonate solution and the dimethyl diallyl ammonium chloride solution into the hexamethylenediamine solution under the conditions of 40 ℃ and nitrogen atmosphere and continuous stirring, continuing to react for 22 hours after the dropwise adding, adding 120ml of water and heating to 70 ℃ after the reaction is finished, adding sodium hydroxide solution to adjust the pH to 10, reacting for 8 hours, keeping the pH at 10 in the reaction process, and rotationally steaming at 70 ℃ to remove the solvent after the reaction is finished to obtain the temperature-resistant shale inhibitor D2.
To further illustrate the effect of the temperature resistant shale inhibitor prepared in the above examples, the temperature resistant shale inhibitor prepared above was tested as follows.
1. Rolling recovery rate
The temperature-resistant shale inhibitors Y1-Y4 and D1-D2 are prepared into inhibitors with different concentrations by clear water, the rolling recovery rate is measured by a method disclosed in a shale inhibitor evaluation method for drilling fluid of the oil and gas industry standard SY/T6335-1997, 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 amount 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 maximum, which shows that the performance is better, and the aim of shale inhibition can be achieved by adding less inhibitor; when the rolling temperature is 260 ℃, the rolling recovery rate can reach 91.9% at maximum, which shows that the material has better temperature resistance.
Compared with Y1 and D1, the difference is that methyl allylsulfonate is replaced by more conventional allylsulfonic acid, and in the allylsulfonic acid, the sulfonate group is an electron-withdrawing group, so that the electron cloud density of double bonds on the allyl can be reduced, and the Michael addition reaction is promoted, but because the polyamine compound is alkaline, the sulfonate group can become sulfonate, and the sulfonate belongs to an electron-donating group, so that the Michael addition reaction of allylsulfonic acid is difficult to occur. Thus, as can be seen from table 1, D1 is difficult to apply to a high temperature environment, and its rolling recovery rate is low and drops rapidly under the high temperature condition.
The difference between the comparison of Y1 and D2 is that the addition of allyl sulfonic acid methyl ester and dimethyl diallyl ammonium chloride is adjusted to make the mole ratio: 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 contains a part of quaternary ammonium, but the quaternary ammonium can only play a role of adsorption, 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 allyl methyl sulfonate, so that the grafted allyl methyl sulfonate in the final compound is less, and the final appearance is poor in temperature resistance.
The present invention is not limited to the above-mentioned embodiments, but is intended to be limited to the following embodiments, and any modifications, equivalents and modifications can be made to the above-mentioned embodiments without departing from the scope of the invention.