Degradable drag reducer for fracturing and preparation method thereof

Abstract

The invention belongs to the technical field of fracturing fluid additives for increasing production in oil and gas fields, and specifically relates to a degradable drag reducer for fracture and a preparation method thereof. The drag reducer is prepared from the following raw materials in percentage by weight: 2-5% of a water-soluble polymer, 10-15% of a surfactant, 8-10% of organic solvent, 0.1% of aldehydes and the balance of water. The water-soluble polymer is polyacrylamide, polyvinyl alcohol or any one of a mixture of polyacrylamide and polyvinyl alcohol in proportion ranged from 1:1 to 1:2. The organic solvent is any one of methanol or ethanol. The aldehyde is formaldehyde, oxalaldehyde or any one of a mixture of formaldehyde and oxalaldehyde in proportion ranging from 1:1 to 1:2. The drag reducer has the advantages that the drag reducer is good in resistance dimishing performance and heat stability; after fracturing construction, the residual drag reducer in the well can be degraded by microorganisms; the pollution to the stratum is avoided.

Description

Technical field

[0001] The invention belongs to the technical field of fracturing fluid additives for increasing production in oil and gas fields, and specifically relates to a degradable drag reducer for fracturing and a preparation method thereof. Background technique

[0002] Acid fracturing is the main way to increase production in oil and gas fields. The proportion of additives in the fracturing fluid components in the fracturing fluid is very small, less than 1% of the total fracturing fluid, but it is very important for increasing the production of oil and gas wells. of. When a large amount of liquid is driven into the ground, reducing the frictional resistance of the liquid is a top priority. The function of the drag reducer is to reduce the friction coefficient when the fracturing fluid flows, thereby reducing the construction pressure. The most commonly used water-soluble drag reducers are polyacrylamide or other compounds of polyacrylamide, synthetic polyethylene oxi...

Examples

Embodiment 1

[0026] The present invention is made from the following raw materials in parts by weight: 2% water-soluble polymer, 10% surfactant, 8% organic solvent, 0.1% aldehydes and 79.9% water; the water-soluble polymer is polyacrylamide, The organic solvent is methanol; the aldehyde is formaldehyde; the surfactant is a gemini quaternary ammonium salt type surfactant, and its structure is as follows:

[0027]

[0028] Among them, the synthesis reaction equation is:

[0029] RN(CH 2 CH 2 OH) 2 +BrCH 2 CH 2 Br→(CH 2 CH 2 OH) 2 R 1 N + CH 2 CH 2 N + R 2 (CH 2 CH 2 OH) 2

[0030] In the reaction formula, R is coconut oil base, representing a mixture of C8~C22 alkyl groups, R 1 And R 2 It is C8~C22 long-chain alkyl component, when R 1 And R 2 When the carbon number is the same, a symmetric gemini quaternary ammonium salt surfactant is generated, when R 1 And R 2 When the number of carbons is not the same, asymmetric gemini quaternary ammonium salt surfactants are formed. In the synthesis reaction, ...

Embodiment 2

[0037] The present invention is made from the following raw materials in parts by weight: 3.5% water-soluble polymer, 12.5% ​​surfactant, 9% organic solvent, 0.1% aldehydes and 74.9% water; the water-soluble polymer is polyvinyl alcohol, The organic solvent is ethanol; the aldehyde is glyoxal; the surfactant is a gemini quaternary ammonium salt type surfactant, and its structure is as follows:

[0038]

[0039] Among them, the synthesis reaction equation is:

[0040] RN(CH 2 CH 2 OH) 2 +BrCH 2 CH 2 Br→(CH 2 CH 2 OH) 2 R 1 N + CH 2 CH 2 N + R 2 (CH 2 CH 2 OH) 2

[0041] In the reaction formula, R is coconut oil base, representing a mixture of C8~C22 alkyl groups, R 1 And R 2 It is C8~C22 long-chain alkyl component, when R 1 And R 2 When the carbon number is the same, a symmetric gemini quaternary ammonium salt surfactant is generated, when R 1 And R 2 When the number of carbons is not the same, asymmetric gemini quaternary ammonium salt surfactants are formed. In the synthesis reactio...

Embodiment 3

[0049] The present invention is made from the following raw materials in parts by weight: water-soluble polymer 5%, surfactant 15%, organic solvent 10%, aldehyde 0.1% and water 69.9%; the water-soluble polymer is polyacrylamide and The ratio of polyvinyl alcohol is 1:1, the organic solvent is methanol; the aldehyde is formaldehyde, the ratio of glyoxal is 1:1; the surfactant is a gemini quaternary ammonium salt type surfactant , And its structure is as follows:

[0050]

[0051] Among them, the synthesis reaction equation is:

[0052] RN(CH 2 CH 2 OH) 2 +BrCH 2 CH 2 Br→(CH 2 CH 2 OH) 2 R 1 N + CH 2 CH 2 N + R 2 (CH 2 CH 2 OH) 2

[0053] In the reaction formula, R is coconut oil base, representing a mixture of C8~C22 alkyl groups, R 1 And R 2 It is C8~C22 long-chain alkyl component, when R 1 And R 2 When the carbon number is the same, a symmetric gemini quaternary ammonium salt surfactant is generated, when R 1 And R 2 When the number of carbons is not the same, asymmetric gemini qua...

Technical field

[0001] The invention belongs to the technical field of fracturing fluid additives for increasing production in oil and gas fields, and specifically relates to a degradable drag reducer for fracturing and a preparation method thereof. Background technique

[0002] Acid fracturing is the main way to increase production in oil and gas fields. The proportion of additives in the fracturing fluid components in the fracturing fluid is very small, less than 1% of the total fracturing fluid, but it is very important for increasing the production of oil and gas wells. of. When a large amount of liquid is driven into the ground, reducing the frictional resistance of the liquid is a top priority. The function of the drag reducer is to reduce the friction coefficient when the fracturing fluid flows, thereby reducing the construction pressure. The most commonly used water-soluble drag reducers are polyacrylamide or other compounds of polyacrylamide, synthetic polyethylene oxi...

Examples

Embodiment 1

[0026] The present invention is made from the following raw materials in parts by weight: 2% water-soluble polymer, 10% surfactant, 8% organic solvent, 0.1% aldehydes and 79.9% water; the water-soluble polymer is polyacrylamide, The organic solvent is methanol; the aldehyde is formaldehyde; the surfactant is a gemini quaternary ammonium salt type surfactant, and its structure is as follows:

[0027]

[0028] Among them, the synthesis reaction equation is:

[0029] RN(CH 2 CH 2 OH) 2 +BrCH 2 CH 2 Br→(CH 2 CH 2 OH) 2 R 1 N + CH 2 CH 2 N + R 2 (CH 2 CH 2 OH) 2

[0030] In the reaction formula, R is coconut oil base, representing a mixture of C8~C22 alkyl groups, R 1 And R 2 It is C8~C22 long-chain alkyl component, when R 1 And R 2 When the carbon number is the same, a symmetric gemini quaternary ammonium salt surfactant is generated, when R 1 And R 2 When the number of carbons is not the same, asymmetric gemini quaternary ammonium salt surfactants are formed. In the synthesis reaction, ...

Embodiment 2

[0037] The present invention is made from the following raw materials in parts by weight: 3.5% water-soluble polymer, 12.5% ​​surfactant, 9% organic solvent, 0.1% aldehydes and 74.9% water; the water-soluble polymer is polyvinyl alcohol, The organic solvent is ethanol; the aldehyde is glyoxal; the surfactant is a gemini quaternary ammonium salt type surfactant, and its structure is as follows:

[0038]

[0039] Among them, the synthesis reaction equation is:

[0040] RN(CH 2 CH 2 OH) 2 +BrCH 2 CH 2 Br→(CH 2 CH 2 OH) 2 R 1 N + CH 2 CH 2 N + R 2 (CH 2 CH 2 OH) 2

[0041] In the reaction formula, R is coconut oil base, representing a mixture of C8~C22 alkyl groups, R 1 And R 2 It is C8~C22 long-chain alkyl component, when R 1 And R 2 When the carbon number is the same, a symmetric gemini quaternary ammonium salt surfactant is generated, when R 1 And R 2 When the number of carbons is not the same, asymmetric gemini quaternary ammonium salt surfactants are formed. In the synthesis reactio...

Embodiment 3

[0049] The present invention is made from the following raw materials in parts by weight: water-soluble polymer 5%, surfactant 15%, organic solvent 10%, aldehyde 0.1% and water 69.9%; the water-soluble polymer is polyacrylamide and The ratio of polyvinyl alcohol is 1:1, the organic solvent is methanol; the aldehyde is formaldehyde, the ratio of glyoxal is 1:1; the surfactant is a gemini quaternary ammonium salt type surfactant , And its structure is as follows:

[0050]

[0051] Among them, the synthesis reaction equation is:

[0052] RN(CH 2 CH 2 OH) 2 +BrCH 2 CH 2 Br→(CH 2 CH 2 OH) 2 R 1 N + CH 2 CH 2 N + R 2 (CH 2 CH 2 OH) 2

[0053] In the reaction formula, R is coconut oil base, representing a mixture of C8~C22 alkyl groups, R 1 And R 2 It is C8~C22 long-chain alkyl component, when R 1 And R 2 When the carbon number is the same, a symmetric gemini quaternary ammonium salt surfactant is generated, when R 1 And R 2 When the number of carbons is not the same, asymmetric gemini qua...

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