Fracturing hydrogen bond inhibitor capable of reducing adsorption of high-molecular compound and preparation method of fracturing hydrogen bond inhibitor

Abstract

The invention relates to the technical field of reservoir transformation, in particular to a hydrogen bond inhibitor for fracturing and capable of reducing adsorption of high-molecular compounds and a preparation method thereof.The hydrogen bond inhibitor for fracturing is obtained according to the following method that potassium cyanate, ammonium chloride and heterocyclic methylamine with the required amount are mixed to obtain a mixture, a solvent with the required amount is added into the mixture to obtain mixed liquid, and the mixed liquid is stirred to be uniform; and heating the mixed solution, continuously refluxing, and irradiating the refluxed mixed solution with an ultraviolet lamp to react, thereby obtaining the hydrogen bond inhibitor for fracturing capable of reducing the adsorption of the high-molecular compound. The preparation and synthesis process is simple, the cost is low, on one hand, the obtained hydrogen bond inhibitor for fracturing capable of reducing adsorption of the high-molecular compound can greatly reduce the adsorption amount of fracturing fluid residues on the rock wall surface, the adsorption amount is reduced by 30% or above, and the yield of a single well after fracturing can be increased; and on the other hand, the obtained hydrogen bond inhibitor for fracturing capable of reducing adsorption of the high-molecular compound does not need to be purified and can be directly applied, so that the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of reservoir stimulation technology, and is a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds, and its preparation method. Background Technology

[0002] Low-permeability tight oil and gas reservoirs, due to poor connectivity of the reservoir space, require fracturing to create artificial fractures to connect the reservoir space for effective production. Currently, fracturing mainly utilizes high-pressure pumps to inject fluids of a certain viscosity at high volumes, forcing open the reservoir and creating artificial fractures. The viscosity of the injected fluid relies primarily on the molecular chain interactions of polymer compounds, increasing the fluid's viscosity. These polymer compounds are non-ionic and water-soluble; after entering the well, they adsorb onto the reservoir rock surface, adhering to the rock surface. Simultaneously, due to the entanglement of polymer chain molecules within the micropores and fractures, they form clumps that easily block the channels of microfractures, significantly reducing the fluid flow capacity within the fracturing fractures and failing to achieve the desired stimulation. Literature research has found that the interaction between polymer compounds and the rock surface is through hydrogen bonds; therefore, disrupting these hydrogen bonds is an effective method to reduce polymer adhesion to the rock surface.

[0003] Chinese patent document CN112094632A discloses a nano-damage relief agent that modifies nanomaterials to disrupt the hydrogen bonds between injected polymers and the rock face, reducing the molecular weight of the polymers and promoting their return to the reservoir, thus reducing the damage caused by the polymers. However, this method uses nanomaterials at a high cost and has a complex synthesis route, which is not conducive to large-scale application in the current context of cost reduction and efficiency improvement in oilfields.

[0004] Therefore, there is a need to develop a low-cost inhibitor to reduce the interaction between polymers and rocks to solve the above problems. Summary of the Invention

[0005] This invention provides a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds and its preparation method, overcoming the shortcomings of the prior art. It can effectively solve the problem that in existing low-permeability tight oil and gas reservoirs, polymeric compounds in fracturing fluid adhere to the rock surface, resulting in excessive adsorption and affecting single-well production.

[0006] One of the technical solutions of the present invention is achieved through the following measures: a method for preparing a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds, comprising the following steps: The first step is to mix the required amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine to obtain a mixture; The second step is to add the required amount of solvent to the mixture to obtain a liquid mixture; The third step is to heat the mixture and then continuously reflux it; The fourth step involves irradiating the refluxed mixture with a UV lamp to produce a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0007] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: In the first step above, the heterocyclic methylamine is one of 4-cyanophenylamine hydrochloride, 3-nitrophenylamine hydrochloride, 4-aminomethylbenzoic acid, 2-furanmethylamine, and 4-pyridinemethylamine, and the molar amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine are 25% to 50%, 25% to 40%, and 25% to 50%, respectively.

[0008] In the second step above, the solvent is deionized water, and the amount of solvent added is 10 to 15 times the sum of the molar amounts of all reactants.

[0009] In the third step above, the heating temperature is 90℃ to 110℃.

[0010] In the fourth step above, the reaction time is 3 to 5 hours, and the UV lamp power is 125W with a wavelength of 254nm.

[0011] The second technical solution of the present invention is achieved through the following measures: a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds, obtained by the following method: The first step is to mix the required amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine to obtain a mixture; The second step is to add the required amount of solvent to the mixture to obtain a liquid mixture; The third step is to heat the mixture and then continuously reflux it; The fourth step involves irradiating the refluxed mixture with a UV lamp to produce a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0012] The following are further optimizations and / or improvements to the second technical solution of the above invention: In the first step above, the heterocyclic methylamine is one of 4-cyanophenylamine hydrochloride, 3-nitrophenylamine hydrochloride, 4-aminomethylbenzoic acid, 2-furanmethylamine, and 4-pyridinemethylamine, and the molar amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine are 25% to 50%, 25% to 40%, and 25% to 50%, respectively.

[0013] In the second step above, the solvent is deionized water, and the amount of solvent added is 10 to 15 times the sum of the molar amounts of all reactants.

[0014] In the third step above, the heating temperature is 90℃ to 110℃.

[0015] In the fourth step above, the reaction time is 3 to 5 hours, and the UV lamp power is 125W with a wavelength of 254nm.

[0016] The preparation and synthesis process of this invention is simple and inexpensive. On the one hand, the obtained hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds can significantly reduce the amount of fracturing fluid residue adsorbed on the rock wall by more than 30%, which is beneficial to improving the production of single wells after fracturing. On the other hand, the obtained hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds does not require purification and can be applied directly, thus reducing production costs. Detailed Implementation

[0017] This invention is not limited to the following embodiments; specific implementation methods can be determined according to the technical solution of this invention and actual conditions. Unless otherwise specified, all chemical reagents and chemical products mentioned in this invention are well-known and commonly used chemical reagents and chemical products in the prior art; room temperature in this invention generally refers to a temperature between 15°C and 25°C, and is generally defined as 25°C.

[0018] The present invention will be further described below with reference to embodiments: Example 1: The preparation method of the hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds is carried out according to the following steps: The first step is to mix the required amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine to obtain a mixture; The second step is to add the required amount of solvent to the mixture to obtain a liquid mixture; The third step is to heat the mixture and then continuously reflux it; The fourth step involves irradiating the refluxed mixture with a UV lamp to produce a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0019] This invention utilizes a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds. The amino groups on this inhibitor preferentially adhere to the rock surface, disrupting the hydrogen bonds between the fracturing fluid polymers and the rock. This prevents polymers from adhering to the rock surface, reducing the adsorption layer thickness and minimizing adsorption damage. Compared to existing technologies, this significantly reduces the amount of fracturing fluid residue adsorbed on the rock wall by ≥30%, which is beneficial for improving post-fracturing well production. Furthermore, the resulting hydrogen bond inhibitor for fracturing that reduces polymeric compound adsorption requires no purification and can be applied directly.

[0020] Example 2: As an optimization of the above example, in the first step, the heterocyclic methylamine is one of 4-cyanophenylamine hydrochloride, 3-nitrophenylamine hydrochloride, 4-aminomethylbenzoic acid, 2-furanmethylamine, and 4-pyridinemethylamine, and the molar amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine added are 25% to 50%, 25% to 40%, and 25% to 50%, respectively.

[0021] Example 3: As an optimization of the above example, in the second step, the solvent is deionized water, and the amount of solvent added is 10 to 15 times the sum of the molar amounts of all reactants.

[0022] Example 4: As an optimization of the above example, in the third step, the heating temperature is 90°C to 110°C.

[0023] Example 5: As an optimization of the above example, in the fourth step, the reaction time is 3h to 5h, the UV lamp power is 125W, and the wavelength is 254nm.

[0024] Example 6: This hydrogen bond inhibitor for fracturing, which reduces the adsorption of polymeric compounds, was obtained according to the following method: The first step is to mix the required amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine to obtain a mixture; The second step is to add the required amount of solvent to the mixture to obtain a liquid mixture; The third step is to heat the mixture and then continuously reflux it; The fourth step involves irradiating the refluxed mixture with a UV lamp to produce a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0025] The reaction mechanism of the preparation process in this invention is as follows: , where R represents one of 4-cyanophenyl, 3-nitrophenyl, 4-aminomethylphenyl, 2-furanyl, and 4-pyridyl.

[0026] Example 7: This hydrogen bond inhibitor for fracturing, which reduces the adsorption of polymeric compounds, was obtained according to the following method: First, add 1 mol of potassium cyanate, 1 mol of ammonium chloride and 1 mol of 4-cyanobenzoic acid hydrochloride to a three-necked flask to obtain a mixture; The second step is to add 30 mol of deionized water to the mixture to obtain a mixed solution; The third step is to heat the mixture to 100°C and then continuously reflux it. The fourth step involves irradiating the reaction flask with a UV lamp after reflux, reacting for 4 hours, and then cooling to room temperature to obtain a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0027] Example 8: This hydrogen bond inhibitor for fracturing, which reduces the adsorption of polymeric compounds, was obtained according to the following method: First, add 1 mol of potassium cyanate, 1 mol of ammonium chloride and 2 mol of 3-nitrophenylamine hydrochloride to a three-necked flask to obtain a mixture; The second step is to add 60 mol of deionized water to the mixture to obtain a mixed solution; The third step is to heat the mixture to 100°C and then continuously reflux it. The fourth step involves irradiating the reaction flask with a UV lamp after reflux, reacting for 4 hours, and then cooling to room temperature to obtain a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0028] Example 9: This hydrogen bond inhibitor for fracturing, which reduces the adsorption of polymeric compounds, was obtained according to the following method: First, add 2 mol of potassium cyanate, 2 mol of ammonium chloride and 1 mol of 4-aminomethylbenzoic acid to a three-necked flask to obtain a mixture; The second step is to add 60 mol of deionized water to the mixture to obtain a mixed solution; The third step is to heat the mixture to 100°C and then continuously reflux it. The fourth step involves irradiating the reaction flask with a UV lamp after reflux, reacting for 4 hours, and then cooling to room temperature to obtain a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0029] Example 10: This hydrogen bond inhibitor for fracturing, which reduces the adsorption of polymeric compounds, was obtained according to the following method: First, add 1 mol of potassium cyanate, 1.5 mol of ammonium chloride and 1 mol of 2-furanylamine to a three-necked flask to obtain a mixture; The second step is to add 44 mol of deionized water to the mixture to obtain a mixed solution; The third step is to heat the mixture to 100°C and then continuously reflux it. The fourth step involves irradiating the reaction flask with a UV lamp after reflux, reacting for 5 hours, and then cooling to room temperature to obtain a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0030] Example 11: This hydrogen bond inhibitor for fracturing, which reduces the adsorption of polymeric compounds, was obtained according to the following method: First, add 1.5 mol of potassium cyanate, 1.5 mol of ammonium chloride and 1 mol of 4-pyridinemethylamine to a three-necked flask to obtain a mixture; The second step is to add 40 mol of deionized water to the mixture to obtain a mixed solution; The third step is to heat the mixture to 100°C and then continuously reflux it. The fourth step involves irradiating the reaction flask with a UV lamp after reflux, reacting for 3 hours, and then cooling to room temperature to obtain a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

[0031] The hydrogen bond inhibitors for fracturing that reduce the adsorption of polymeric compounds obtained in Examples 7 to 11 of this invention were simultaneously subjected to adsorption tests and comparisons with a comparative example (without the hydrogen bond inhibitors for fracturing that reduce the adsorption of polymeric compounds). The results are shown in Table 1. As can be seen from Table 1, compared with the prior art, this invention can significantly reduce the amount of fracturing fluid residue adsorbed on the rock wall, reducing the adsorption amount by ≥30%, which is beneficial to improving the production of single wells after fracturing.

[0032] The rock adsorption test method is as follows: Add 0.3% fracturing fluid thickener and 0.3% of the fracturing hydrogen bond inhibitor of the present invention (which reduces the adsorption of polymer compounds) to 100ml of water, then add 5g of 100-120 mesh sandstone, soak for 2 hours, take the upper liquid and test the concentration of fracturing hydrogen bond inhibitor therein, and the difference between the concentration and the initial concentration is the amount of rock adsorbed thickener.

[0033] In summary, the preparation and synthesis process of this invention is simple and inexpensive. On the one hand, the obtained hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds can significantly reduce the amount of fracturing fluid residue adsorbed on the rock wall by more than 30%, which is beneficial to improving the production of single wells after fracturing. On the other hand, the obtained hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds does not require purification and can be applied directly, thus reducing production costs.

[0034] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for preparing a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds, characterized in that... Follow these steps: The first step is to mix the required amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine to obtain a mixture; The second step is to add the required amount of solvent to the mixture to obtain a liquid mixture; The third step is to heat the mixture and then continuously reflux it. The fourth step involves irradiating the refluxed mixture with a UV lamp to produce a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

2. The method for preparing the hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds according to claim 1, characterized in that... In the first step, the heterocyclic methylamine is one of 4-cyanophenylamine hydrochloride, 3-nitrophenylamine hydrochloride, 4-aminomethylbenzoic acid, 2-furanmethylamine, and 4-pyridinemethylamine, and the molar amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine are 25% to 50%, 25% to 40%, and 25% to 50%, respectively.

3. The method for preparing a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds according to claim 1 or 2, characterized in that... In the second step, the solvent is deionized water, and the amount of solvent added is 10 to 15 times the sum of the molar amounts of all reactants.

4. The method for preparing a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds according to any one of claims 1 to 3, characterized in that... In the third step, the heating temperature is 90℃ to 110℃.

5. The method for preparing a fracturing hydrogen bond inhibitor for reducing the adsorption of polymeric compounds according to any one of claims 1 to 4, characterized in that... In the fourth step, the reaction time is 3 to 5 hours, and the UV lamp power is 125W with a wavelength of 254nm.

6. A hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds, characterized in that... It is obtained using the following method: The first step is to mix the required amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine to obtain a mixture; The second step is to add the required amount of solvent to the mixture to obtain a liquid mixture; The third step is to heat the mixture and then continuously reflux it; The fourth step involves irradiating the refluxed mixture with a UV lamp to produce a hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds.

7. The hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds according to claim 6, characterized in that... In the first step, the heterocyclic methylamine is one of 4-cyanophenylamine hydrochloride, 3-nitrophenylamine hydrochloride, 4-aminomethylbenzoic acid, 2-furanmethylamine, and 4-pyridinemethylamine, and the molar amounts of potassium cyanate, ammonium chloride, and heterocyclic methylamine are 25% to 50%, 25% to 40%, and 25% to 50%, respectively.

8. The hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds according to claim 6 or 7, characterized in that... In the second step, the solvent is deionized water, and the amount of solvent added is 10 to 15 times the sum of the molar amounts of all reactants.

9. The hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds according to any one of claims 6 to 8, characterized in that... In the third step, the heating temperature is 90℃ to 110℃.

10. The hydrogen bond inhibitor for fracturing that reduces the adsorption of polymeric compounds according to any one of claims 5 to 9, characterized in that... In the fourth step, the reaction time is 3 to 5 hours, and the UV lamp power is 125W with a wavelength of 254nm.

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