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CN-122012061-A - High-elasticity glue solution for oilfield fracturing and preparation method thereof

CN122012061ACN 122012061 ACN122012061 ACN 122012061ACN-122012061-A

Abstract

The invention provides a high-elasticity glue solution for oilfield fracturing and a preparation method thereof, belonging to the technical field of petrochemical industry. Including high molecular weight surfactants, cosurfactants and water. The high molecular weight surfactant is used as the main agent of the fracturing fluid, has certain viscosity when the dosage is 0.7wt%, is favorable for the transportation of the fracturing fluid in a pipeline, can promote physical crosslinking of the fracturing fluid to form a strong network structure by adding a certain cosurfactant, has good sand suspension property, can break gel by a simple method, has less residues, has low damage to stratum, has good temperature resistance, salt resistance and shearing resistance, and has low price and wide application prospect.

Inventors

  • ZHANG LIUJIE
  • LI JIANXUE
  • WANG ZHONGPENG
  • ZHAO PENGCHENG
  • ZHAO GUANGSHENG
  • MAO QIANQIAN
  • LIANG YOUFANG

Assignees

  • 东营市宝泽能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. The high-elasticity glue solution for oilfield fracturing is characterized by comprising a high-molecular-weight surfactant, a cosurfactant and water, wherein the structure of the high-molecular-weight surfactant is shown as a formula I: A formula I; Wherein R=C12-C18 alkyl chain, x: y: z=10-15:15-25:10-15, A is hydrophobic group of AEO-10 molecule; The cosurfactant is alkyl sulfonate, sulfate or benzene sulfonate containing 12-18 carbon atoms or a mixture of the salts, wherein the sulfonate, sulfate or benzene sulfonate comprises sodium salt, potassium salt and ammonium salt, namely sodium alkyl sulfonate, potassium alkyl sulfonate and ammonium alkyl sulfonate, sodium alkyl sulfate, potassium alkyl sulfate and ammonium alkyl sulfate, and sodium alkyl benzene sulfonate, potassium alkyl benzene sulfonate and ammonium alkyl benzene sulfonate.
  2. 2. The high-elasticity glue solution for oilfield fracturing according to claim 1, wherein the mass ratio of the high-molecular-weight surfactant to the cosurfactant to the water is 2-6:0.5-1:100, and the high-molecular-weight surfactant is prepared from a monomer 1, a monomer 2 and 2-acrylamido-2-methylpropanesulfonic acid according to the mass ratio of 151-228:138-273:22-35; the structural formula of the monomer 1 is shown as a formula II; A formula II; wherein A is a hydrophobic group of AEO-10 molecule; The structural formula of the monomer 2 is shown in a formula III: Formula III; Wherein r=c12-C18 alkyl chain.
  3. 3. The high-elasticity glue solution for oilfield fracturing according to claim 2, wherein the preparation method of the monomer 1 is as follows: s1, AEO-10 and thionyl chloride are reacted to prepare an intermediate 1, wherein the structure is as follows: ; s2, reacting the intermediate 1 with 4, 4-vinylidene bis (N, N-dimethylaniline) to prepare the monomer 1.
  4. 4. A highly elastic glue solution for oilfield fracturing according to claim 3, wherein the molar ratio of AEO-10 to thionyl chloride in step S1 is 1:1.2-1.5, the reaction temperature is 40-50 ℃ and the time is 1-3h.
  5. 5. The high-elasticity glue solution for oilfield fracturing according to claim 3, wherein in the step S2, the molar ratio of the intermediate 1 to the 4, 4-ethylenebis (N, N-dimethylaniline) is 2-2.2:1, and a base is added, wherein the base is NaOH or KOH, the reaction temperature is 65-75 ℃ and the reaction time is 3-5h, and the structural formula of the 4, 4-ethylenebis (N, N-dimethylaniline) is as follows: 。
  6. 6. the high-elasticity glue solution for oilfield fracturing according to claim 2, wherein the preparation method of the monomer 2 is as follows: t1. reacting 4, 4-ethylenebis (N, N-dimethylaniline) with sodium 3-chloro-2-hydroxypropanesulfonate to obtain intermediate 2, the structure of which is as follows: ; T2. Reacting intermediate 2 with haloalkane to obtain monomer 2.
  7. 7. The high-elasticity glue solution for oilfield fracturing according to claim 6, wherein in the step T1, the molar ratio of the 4, 4-ethylenebis (N, N-dimethylaniline) to the sodium 3-chloro-2-hydroxypropanesulfonate is 1:2-2.2, and a base is added, wherein the base is NaOH or KOH, the reaction temperature is 65-75 ℃ and the reaction time is 3-5h, and the structural formula of the 4, 4-ethylenebis (N, N-dimethylaniline) is as follows: 。
  8. 8. The high-elasticity glue solution for oilfield fracturing according to claim 6, wherein in the step T2, the molar ratio of the intermediate 2 to the haloalkane is 1:2-2.2, and a base is added, wherein the base is at least one selected from triethylamine, naOH and KOH, the reaction temperature is 50-60 ℃ and the reaction time is 2-4 hours, and the haloalkane is chlorine or bromine substituted C12-C18 alkane.
  9. 9. The high-elasticity glue solution for oilfield fracturing according to claim 2, wherein the preparation method of the high-molecular-weight surfactant comprises the steps of adding 151-228 parts by weight of monomer 1, 138-273 parts by weight of monomer 2 and 22-35 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid into water to prepare an aqueous solution with the total mass concentration of the monomer of 32-37wt%, adding an initiating system and water under the protection of inert gas to prepare an aqueous solution with the total mass concentration of the monomer of 25-30wt%, stirring and reacting for 3-5 hours at 40-50 ℃, washing, drying and crushing the product to obtain the high-molecular-weight surfactant, wherein the initiating system comprises a mixture of an initiator and sodium sulfite, the mass ratio of the initiating system is 1.2-1.5:1, the adding amount of the initiating system is 0.5-1wt% of the total mass of the system, and the initiator is at least one of sodium persulfate, ammonium persulfate and potassium persulfate.
  10. 10. A method for preparing the high-elasticity glue solution for oilfield fracturing according to any one of claims 1 to 9, which is characterized by comprising the following steps of dissolving a high-molecular-weight surfactant in water, adding a cosurfactant, heating to 45-55 ℃, stirring and mixing uniformly, cooling to room temperature, and standing to prepare the high-elasticity glue solution for oilfield fracturing.

Description

High-elasticity glue solution for oilfield fracturing and preparation method thereof Technical Field The invention relates to the technical field of petrochemical industry, in particular to a high-elasticity glue solution for oilfield fracturing and a preparation method thereof. Background Hydraulic fracturing technology is one of the common technologies for low permeability hydrocarbon reservoir development, while fracturing fluid is an important component of hydraulic fracturing technology, and the performance of the fracturing fluid is critical to the fracturing result. The hydraulic fracturing technology includes the steps of 1) injecting fracturing fluid into a well by using a ground high-pressure pump set at a displacement greatly exceeding the absorption capacity of stratum, holding the bottom of the well at high pressure, 2) generating cracks in stratum nearby the bottom of the well when the pressure is greater than the ground stress nearby the well wall and the tensile strength of stratum rock, 3) continuously injecting sand-carrying fluid with propping agent, enabling the cracks to extend forwards and fill the propping agent, and 4) closing the cracks on the propping agent after well closing, so that sand-filled cracks with certain geometric dimension and flow conductivity are formed in stratum nearby the bottom of the well. At present, the most widely used polymer guanidine gum fracturing fluids have the advantages of low cost and good temperature resistance. However, there are also problems such as large damage to the formation, high content of residues, and poor salt tolerance. In recent years, viscoelastic surfactant (VES) fracturing fluids have been increasingly used in oil fields as a new fracturing fluid system. Since the viscosity of VES fracturing fluids is primarily due to the formation of wormlike micelles (WLMs) of surfactants in aqueous solution, the fracturing fluid spontaneously converts to a low viscosity fluid upon contact with hydrocarbons and is free of insoluble residues and is readily expelled from the formation. Compared with polymer guanidine gum fracturing fluid, the VES fracturing fluid has the advantages of less damage to a reservoir and easiness in flowback. Therefore, it is also referred to as "clean fracturing fluid". The types of surfactants used in VES fracturing fluids can be categorized into four classes, anionic, amphoteric, nonionic and cationic surfactants. The cationic surfactant has the advantages of wide application, mature synthesis process, low cost and the like. However, VES fracturing fluids formed with cationic surfactants are susceptible to the type and content of counterions in the water, commonly used counterions are monovalent inorganic salts such as potassium chloride, ammonium chloride, and the like. In addition, when the inorganic salt exceeds a certain content, certain destructive influence is generated on the worm-like micelle structure, so that the viscosity of the VES fracturing fluid is obviously reduced, and the development and application of the VES fracturing fluid in high-mineralization oil reservoirs and offshore oil fields are limited. The preparation method of the high-density water-based clean fracturing fluid and the thickening agent thereof in China patent CN109735319B not only meets the current requirements of hydraulic fracturing of high-pressure and ultrahigh-pressure reservoirs, but also effectively solves the problem that the residues damage the stratum after the polymer fracturing fluid is broken by using a viscoelastic surfactant (VES) as the thickening agent. But the temperature resistance is lower, and the method is not suitable for the transformation of oil layers with the height Wen Shenceng. Some prominent problems of the current VES fracturing fluid system are that (1) the use cost is high, and because VES reported in the literature is mainly of quaternary ammonium salt type or betaine type, the synthesis of the VES fracturing fluid system needs to take higher aliphatic amine as a raw material, and the product cost is high. (2) The heat resistance is low (lower than 80 ℃) and cannot be suitable for oil layer transformation with the height Wen Shenceng. (3) the synthesis process is complex. (4) The fracturing fluid system has complex composition, needs a plurality of components such as cosurfactants, electrolytes, counter ions and the like, and is complex to prepare. Disclosure of Invention The invention aims to provide a high-elasticity glue solution for oilfield fracturing and a preparation method thereof, wherein a high-molecular surfactant is used as a main agent of the fracturing fluid, has certain viscosity when the dosage is 0.7wt%, is favorable for the transportation of the fracturing fluid in a pipeline, can promote physical crosslinking of the fracturing fluid to form a strong network structure by adding a certain cosurfactant, has good sand suspension property, can break glue by a simple method, has less resid