Discharge aiding agent for fracturing and preparation method thereof

Abstract

The invention relates to the technical field of oilfield chemistry, in particular to a discharge aiding agent for fracturing and a preparation method thereof.The discharge aiding agent for fracturing comprises, by mass, 10 parts of composite surfactant and the balance water; the composite surfactant comprises the following components in percentage by weight: 80 to 95 percent of an anionic surfactant, 0 to 5 percent of a carboxylic acid betaine surfactant and 0 to 15 percent of a glycosyl cationic surfactant. According to the discharge aiding agent for fracturing, the surface and interface tension of an aqueous solution can be effectively reduced, the technical specification of the discharge aiding agent for fracturing is met, the preparation method is simple and convenient to operate, the raw materials are green and degradable, environmental pollution is not caused, industrial production, popularization and application are facilitated, and the discharge aiding agent has wide market prospects.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemistry and is a drainage aid for fracturing and a preparation method thereof. Background Art

[0002] Fracturing transformation technology is an important measure for the efficient development of oil and gas fields. It is the main technical means to achieve the exploration and development of unconventional oil and gas resources, increase and stabilize the production of conventional oil and gas fields, and improve the effect of reservoir transformation. In the process of acid fracturing, it is usually necessary to rely on the formation pressure to quickly discharge the return fluid in the well to the ground. When the formation pressure gradually decreases, the return rate decreases significantly, and the residue in the return fluid will cause blockage after precipitation, resulting in secondary pollution of the formation, which seriously affects the construction efficiency and the effect of acid fracturing transformation. In order to solve the problem of difficulty in returning the return fluid after oil acid fracturing, the use of drainage aids is a conventional method.

[0003] A drainage aid is a type of fracturing fluid additive that can effectively reduce surface tension and interfacial tension, reduce capillary resistance, increase flowback rate and flowback ratio, and thus reduce formation damage. There are many types of drainage aids currently used at home and abroad, but most of them are made by compounding fluorocarbon surfactants with other surfactants. Fluorocarbon surfactants generally contain perfluorooctane carboxylic acid and its salts (PFOA), perfluorooctane sulfonic acid and its salts (PFOS), and their fluorocarbon chains are relatively long, which poses problems such as difficulty in degradation and persistent bioaccumulation.

[0004] As my country attaches more and more importance to environmental protection, China National Petroleum Corporation has begun to introduce new industry standards for drainage aids, and no longer uses fluorocarbon surfactants. In view of this, the development of a green and environmentally friendly drainage aid system has become an urgent issue to be solved. Summary of the invention

[0005] The present invention provides a fracturing drainage aid, which overcomes the deficiencies of the prior art and can effectively solve the problems of the prior fracturing drainage aid being difficult to degrade, polluting the environment, and having high biological toxicity.

[0006] One of the technical solutions of the present invention is achieved through the following measures: a drainage aid for fracturing, wherein the raw materials, calculated by weight, include: 10 parts of a composite surfactant and the rest is water; the composite surfactant component includes: 80wt% to 95wt% of anionic surfactant, 0 to 5wt% of carboxylic acid betaine surfactant, and 0 to 15wt% of sugar-based cationic surfactant; the required amounts of anionic surfactant, carboxylic acid betaine surfactant, sugar-based cationic surfactant and water are mixed, and stirred evenly at room temperature to obtain the drainage aid for fracturing.

[0007] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0008] The above anionic surfactant is sodium fatty alcohol polyoxyethylene ether carboxylate, and its chemical structural formula is:

[0009]

[0010] The above R1 is C 12 To C 18 Aliphatic hydrocarbon group, n is an integer greater than or equal to 2.

[0011] The above-mentioned carboxylic acid betaine surfactant is a long-chain alkyl pyridine-4-ammonium carboxylate, and its chemical structural formula is:

[0012]

[0013] The above R2 is C 12 To C 16 of aliphatic hydrocarbon groups.

[0014] The chemical structural formula of the above-mentioned sugar-based cationic surfactant is:

[0015]

[0016] The above R3 is C 12 To C 16 An aliphatic hydrocarbon group, X is a halogen chlorine or bromine.

[0017] The second technical solution of the present invention is achieved through the following measures: a method for preparing a drainage agent for fracturing, comprising the following steps: mixing the required amounts of anionic surfactant, carboxylic acid betaine surfactant, sugar-based cationic surfactant and water, stirring evenly at room temperature to obtain a drainage agent for fracturing.

[0018] The invention provides a fracturing drainage agent, which can effectively reduce the interfacial tension of the aqueous solution, meets the technical specifications of the fracturing drainage agent, and has a preparation method. The preparation method is simple to operate, the raw materials are green and degradable, and no environmental pollution is caused, which is conducive to industrial production and promotion and application, and has broad market prospects. DETAILED DESCRIPTION

[0019] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0020] The present invention will be further described below in conjunction with embodiments:

[0021] Embodiment 1: The raw materials of the fracturing drainage agent include, by weight, 10 parts of a composite surfactant and the rest water; the composite surfactant component includes: 80wt% to 95wt% of anionic surfactant, 0 to 5wt% of carboxylic acid betaine surfactant, and 0 to 15wt% of sugar-based cationic surfactant; the required amounts of anionic surfactant, carboxylic acid betaine surfactant, sugar-based cationic surfactant and water are mixed and stirred evenly at room temperature to obtain a fracturing drainage agent.

[0022] Example 2: As an optimization of the above example, the anionic surfactant is sodium fatty alcohol polyoxyethylene ether carboxylate, and its chemical structural formula is:

[0023]

[0024] Example 3: As an optimization of the above example, R1 is C 12 To C 18 Aliphatic hydrocarbon group, n is an integer greater than or equal to 2.

[0025] Example 4: As an optimization of the above example, the carboxylic acid betaine surfactant is a long-chain alkyl pyridine-4-ammonium carboxylate, and its chemical structure is:

[0026]

[0027] Embodiment 5: As an optimization of the above embodiment, R2 is an aliphatic hydrocarbon group of C12 to C16.

[0028] Example 6: As an optimization of the above example, the chemical structural formula of the sugar-based cationic surfactant is:

[0029]

[0030] Embodiment 7: As an optimization of the above embodiment, R3 is an aliphatic hydrocarbon group of C12 to C16, and X is a halogen chlorine or bromine.

[0031] Embodiment 8: A method for preparing a fracturing drainage agent, comprising the following steps:

[0032] The required amounts of anionic surfactant, carboxylic acid betaine surfactant, sugar-based cationic surfactant and water are mixed and stirred evenly at room temperature to obtain a drainage aid for fracturing.

[0033] Embodiment 9:

[0034] Weigh 9 parts by mass of sodium lauryl polyoxyethylene ether (3) carboxylate and 1 part by mass of glucosamidopropyl-N,N-dimethyl-N-tetradecyl ammonium chloride and dissolve them in 90 parts by mass of water. Stir at room temperature and dissolve them uniformly to prepare 100 parts by mass of a fracturing drainage agent.

[0035] The indoor experimental test results of the fracturing drainage agent show that the surface tension of the fracturing drainage agent is 25.811 mN / m and the interfacial tension is 0.072 mN / m at a concentration of 0.3% by mass, which meets the industry standards for non-fluorocarbon drainage agents.

[0036] Embodiment 10:

[0037] Weigh 9 parts by mass of sodium lauryl polyoxyethylene ether (3) carboxylate and 1 part by mass of cetylpyridinium-4-ammonium carboxylate and dissolve them in 90 parts by mass of water. Stir at room temperature to dissolve them uniformly to prepare 100 parts by mass of a fracturing drainage agent.

[0038] The indoor experimental test results of the fracturing drainage agent show that at a concentration of 0.3% by mass, the surface tension of the fracturing drainage agent is 22.922 mN / m and the interfacial tension is 1.007 mN / m, which meets the industry use standards for non-fluorocarbon drainage agents.

[0039] Embodiment 11:

[0040] Weigh 9 parts by mass of sodium lauryl polyoxyethylene ether (3) carboxylate, 0.5 parts by mass of glucosamidopropyl-N,N-dimethyl-N-tetradecyl ammonium chloride, and 0.5 parts by mass of cetylpyridinium-4-ammonium carboxylate, and dissolve them in 90 parts by mass of water. Stir at room temperature to uniformly dissolve them to prepare 100 parts by mass of a fracturing drainage agent.

[0041] The indoor experimental test results of the fracturing drainage agent show that the surface tension of the fracturing drainage agent is 23.546 mN / m and the interfacial tension is 0.248 mN / m at a concentration of 0.3% by mass, which meets the industry use standards for non-fluorocarbon drainage agents.

[0042] Embodiment 12:

[0043] Weigh 9 parts by mass of sodium hexadecanol polyoxyethylene ether (2) carboxylate, 0.5 parts by mass of glucose amidopropyl-N,N-dimethyl-N-dodecyl ammonium bromide, and 0.5 parts by mass of hexadecylpyridinium-4-ammonium carboxylate, and dissolve them in 90 parts by mass of water. Stir at room temperature to uniformly dissolve them to prepare 100 parts by mass of a fracturing drainage agent.

[0044] The indoor experimental test results of the fracturing drainage agent show that the surface tension of the fracturing drainage agent is 22.811 mN / m and the interfacial tension is 0.127 mN / m at a concentration of 0.3% by mass, which meets the industry standards for non-fluorocarbon drainage agents.

[0045] Embodiment 13:

[0046] Weigh 9 parts by mass of sodium stearyl alcohol polyoxyethylene ether (2) carboxylate, 0.5 parts by mass of glucose amidopropyl-N,N-dimethyl-N-hexadecyl ammonium bromide, and 0.5 parts by mass of dodecylpyridine-4-ammonium carboxylate, and dissolve them in 90 parts by mass of water. Stir at room temperature to uniformly dissolve them to prepare 100 parts by mass of a fracturing drainage agent.

[0047] The indoor experimental test results of the fracturing drainage agent show that the surface tension of the fracturing drainage agent is 23.769 mN / m and the interfacial tension is 0.632 mN / m at a concentration of 0.3% by mass, which meets the industry use standards for non-fluorocarbon drainage agents.

[0048] Embodiment 14:

[0049] Weigh 9 parts by mass of sodium hexadecanol polyoxyethylene ether (2) carboxylate, 0.5 parts by mass of glucose amidopropyl-N,N-dimethyl-N-dodecyl ammonium chloride, and 0.5 parts by mass of dodecylpyridine-4-ammonium carboxylate, and dissolve them in 90 parts by mass of water. Stir at room temperature to uniformly dissolve them to prepare 100 parts by mass of a fracturing drainage agent.

[0050] The indoor experimental test results of the fracturing drainage agent show that the surface tension of the fracturing drainage agent is 22.174 mN / m and the interfacial tension is 0.388 mN / m at a concentration of 0.3% by mass, which meets the industry use standards for non-fluorocarbon drainage agents.

[0051] In summary, the fracturing drainage agent and its preparation method of the present invention, the surfactants used in the raw materials of the fracturing drainage agent are all degradable, non-biotoxic, green and environmentally friendly, and can effectively avoid damage to the environment and organisms; the different types of surfactants in the raw materials have good composite synergistic characteristics, which can effectively reduce the surface and interfacial tension of oil and gas field fracturing fluids, and the raw material components are simple, only two or three, and the surfactants only account for 10% of the total raw materials. At the same time, the dosage of betaine-type surfactants is low, and the production cost is low. The fracturing drainage agent does not contain flammable, explosive, and volatile substances, and can adapt to the needs of acid fracturing operations under different operating environments.

[0052] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A fracturing drainage agent, characterized in that The raw materials include, by weight, 10 parts of a composite surfactant and the rest of water; the composite surfactant component includes 80 wt% to 95 wt% of anionic surfactant, 0 to 5 wt% of carboxylic acid betaine surfactant, and 0 to 15 wt% of sugar-based cationic surfactant; required amounts of anionic surfactant, carboxylic acid betaine surfactant, sugar-based cationic surfactant and water are mixed, and stirred evenly at room temperature to obtain a drainage agent for fracturing.

2. The fracturing drainage agent according to claim 1, characterized in that The anionic surfactant is sodium fatty alcohol polyoxyethylene ether carboxylate, and its chemical structure is:

3. The fracturing drainage agent according to claim 2, characterized in that R1 is a C12 to C18 aliphatic hydrocarbon group, and n is an integer greater than or equal to 2.

4. The fracturing drainage agent according to any one of claims 1 to 3, characterized in that The carboxylic acid betaine surfactant is a long-chain alkyl pyridine-4-ammonium carboxylate with the chemical formula:

5. The fracturing drainage agent according to claim 4, characterized in that R2 is a C12 to C16 aliphatic hydrocarbon group.

6. The fracturing drainage agent according to any one of claims 1 to 5, characterized in that The chemical structure of sugar-based cationic surfactants is:

7. The fracturing drainage agent according to claim 6, characterized in that R3 is a C12 to C16 aliphatic hydrocarbon group, and X is a halogen chlorine or bromine.

8. A method for preparing a fracturing drainage agent according to any one of claims 1 to 7, characterized in that The method comprises the following steps: mixing required amounts of anionic surfactant, carboxylic acid betaine surfactant, sugar-based cationic surfactant and water, and stirring them uniformly at room temperature to obtain a drainage aid for fracturing.

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