CN110257042A

CN110257042A - A kind of reservoir breaks the clean fracturing fluid and preparation method thereof of glue automatically

Info

Publication number: CN110257042A
Application number: CN201910606708.4A
Authority: CN
Inventors: 郑存川; 黄志宇; 张太亮
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2019-07-06
Filing date: 2019-07-06
Publication date: 2019-09-20
Anticipated expiration: 2039-07-06
Also published as: CN110257042B

Abstract

The invention discloses the clean fracturing fluids and preparation method thereof that a kind of reservoir breaks glue automatically, are related to oil gas field volume increase field.Its technical solution is: (1) 1:1~3 are stirred at room temperature and react for 24 hours in molar ratio for the methacrylate of short carbon chain and dimethylamine agueous solution, and rotary evaporation removes excessive dimethylamine solution to get to tertiary amine product, has CO₂/CH₄Response property, as stimuli responsive type counter ion；(2) tertiary amine 0.5~2% is passed through CO₂To clear, quaternary ammonium salt is obtained as counter ion salt, is then added 1~5% anionic surfactant thickening agent, and clay stabilizer 0.3~2%, remaining is water to get arriving viscoelastic clean fracturing fluid.Tertiary amine is by CO₂It is unstable under natural gas effect to protonate the quaternary ammonium salt counter ion generated, slow deprotonation becomes tertiary amine, and broken glue, viscosity decline to a great extent, facilitates the row of returning, have broad application prospects in tight gas, coal bed gas and shale gas pressure break clean fracturing fluid automatically.

Description

A kind of reservoir breaks the clean fracturing fluid and preparation method thereof of glue automatically

Technical field

The present invention relates to the clean fracturing liquid systems and preparation method thereof that a kind of reservoir breaks glue automatically.

Background technique

Surfactant Used in Viscoelastic Fracturing Fluids (viscoelastic surfactant, VES) clean fracturing fluid is researched and developed in recent years New Fracturing Fluid system, have prop-carrying capacity is strong, filter loss is low, without residue injury, return the advantages such as discharge capacity height, especially suitable for low Permeate the fracturing yield increasing of oil-gas reservoir and untraditional reservoir.

Viscoelastic surfactant clean fracturing fluid can easily break glue encountering oil or water, in general oil well or It is all out of question that person's water well drilling breaks glue, but when for pressing crack constructions such as the natural gas well, coal bed gas wells, clean fracturing fluid breaks glue still So there is a degree of difficulty, clean fracturing fluid broken glue in natural gas is still undesirable, and a degree of reservoir is caused to hurt Evil.

In addition, clean fracturing fluid is generally used cationic surfactant, but cationic surfactant is in reservoir Absorption is serious, changes the wetability of reservoir, will also result in a degree of injury to reservoir.

Therefore, the present invention uses anionic surfactant as thickening agent, with CO₂/CH₄Stimuli responsive type tertiary amine conduct Counter ion, the tertiary amine have CO₂Responsiveness, in CO₂It can protonate to form quaternary ammonium salt under effect, so as to living as surface Property agent counter ion, reduce surfactant between electrostatic repulsion, formed vermiculate glues.It is being continually fed into CH₄Under the conditions of, Quaternary ammonium salt is unstable, can be transformed into tertiary amine with deprotonation, and clean fracturing fluid breaks glue automatically.Especially suitable for the natural gas well, Coal bed gas well and shale gas well fracturing yield increasing use.

Summary of the invention

A kind of the purpose of the present invention is to provide solid-carrying performances good, reservoir can break automatically glue and the low cleaning of reservoir damage Fracturing fluid, the clean fracturing fluid use CO₂/CH₄Response type tertiary amine is as counter ion, in logical CO₂When, tertiary amine protonation is as anti- Ion salt has good gel-forming property, can break glue automatically under reservoir temperature and natural gas effect.

In order to achieve the above object, the present invention uses following technical scheme.

Its prepare the following steps are included: (1) short carbon chain methacrylate and dimethylamine agueous solution in molar ratio 1:1~ 3 are stirred at room temperature reaction for 24 hours, and rotary evaporation removes excessive dimethylamine solution to get to tertiary amine product, have CO₂/CH₄Response Property, as stimuli responsive type counter ion；(2) tertiary amine 0.5~2% is passed through CO₂To clear, quaternary ammonium salt is obtained as anti- Then 1~5% anionic surfactant thickening agent is added in ion salt, clay stabilizer 0.3~2%, remaining is water, i.e., Obtain viscoelastic clean fracturing fluid.

Stimuli responsive type tertiary amine counter ion chemical mechanical formula is as shown in the figure:

Wherein R is normal chain alkyl, and carbon number is 4~8.

Anionic surfactant be enuatrol, erucic acid sodium, lauryl sodium sulfate, in neopelex extremely Few one kind.The quaternary ammonium salt counter ion that tertiary amine is generated by CO2 protonation is unstable under reservoir temperature and natural gas effect, slowly goes Protonation becomes tertiary amine again, and clean fracturing fluid can break glue automatically.

The present invention compared with the prior art, the beneficial effect is that:

(1) small to reservoir damage using anionic surfactant as thickening agent；

(2)CO₂/CH₄Response type tertiary amine is by CO₂Counter ion is used as after protonation, in reservoir CH₄It can be broken automatically under effect Glue is particularly suitable for fracturing reform in the natural gas well with conducive to the row of returning.

Specific embodiment

Below by embodiment, the present invention will be further described:

Embodiment 1

1) 1:3 is stirred at room temperature and reacts for 24 hours in molar ratio for butyl methacrylate and dimethylamine agueous solution, and rotary evaporation removes Fall excessive dimethylamine solution to get tertiary amine product is arrived；2) tertiary amine 0.5% is passed through CO₂To clear, quaternary ammonium salt work is obtained For counter ion salt, 2% enuatrol thickening agent is then added, clay stabilizer 0.3%, remaining is viscoelastic to get arriving for water Clean fracturing fluid.Clean fracturing fluid temperature resistance reaches 60 DEG C or more.When being continually fed into CH into clean fracturing fluid at 60 DEG C₄Or it will Enter a small amount of sodium hydroxide, by CO₂For the tertiary amine of protonation by deprotonation, clean fracturing fluid breaks glue, viscosity drop to 5mPa.s with Under.

Embodiment 2

1) 1:3 is stirred at room temperature and reacts for 24 hours in molar ratio for hexyl methacrylate and dimethylamine agueous solution, and rotary evaporation removes Fall excessive dimethylamine solution to get tertiary amine product is arrived；2) tertiary amine 0.8% is passed through CO₂To clear, quaternary ammonium salt work is obtained For counter ion salt, 3% erucic acid sodium thickening agent is then added, clay stabilizer 0.5%, remaining is viscoelastic to get arriving for water Clean fracturing fluid.Clean fracturing fluid temperature resistance reaches 90 DEG C or more.When being continually fed into CH into clean fracturing fluid at 60 DEG C₄Or it will Enter a small amount of sodium hydroxide, by CO₂For the tertiary amine of protonation by deprotonation, clean fracturing fluid breaks glue, viscosity drop to 5mPa.s with Under.

Embodiment 3

1) 1:3 is stirred at room temperature and reacts for 24 hours in molar ratio for 2-Propenoic acid, 2-methyl-, octyl ester and dimethylamine agueous solution, and rotary evaporation removes Fall excessive dimethylamine solution to get tertiary amine product is arrived；2) tertiary amine 0.8% is passed through CO₂To clear, quaternary ammonium salt work is obtained For counter ion salt, it is then added 4% lauryl sodium sulfate thickening agent, clay stabilizer 0.1%, remaining is water to get arriving Viscoelastic clean fracturing fluid.Clean fracturing fluid temperature resistance reaches 80 DEG C or more.When being continually fed at 60 DEG C into clean fracturing fluid CH₄Or a small amount of sodium hydroxide will be entered, by CO₂The tertiary amine of protonation breaks glue by deprotonation, clean fracturing fluid, and viscosity drops to 5mPa.s or less.

Embodiment 4

1) 1:3 is stirred at room temperature and reacts for 24 hours in molar ratio for butyl methacrylate and dimethylamine agueous solution, and rotary evaporation removes Fall excessive dimethylamine solution to get tertiary amine product is arrived；2) tertiary amine 1% is passed through CO₂To clear, quaternary ammonium salt conduct is obtained Counter ion salt, the neopelex for being then added 5% is thickening agent, and clay stabilizer 1%, remaining is water to get arriving Viscoelastic clean fracturing fluid.Clean fracturing fluid temperature resistance reaches 90 DEG C or more.When being continually fed at 60 DEG C into clean fracturing fluid CH₄Or a small amount of sodium hydroxide will be entered, by CO₂The tertiary amine of protonation breaks glue by deprotonation, clean fracturing fluid, and viscosity drops to 5mPa.s or less.

Claims

1. a kind of reservoir breaks the clean fracturing fluid of glue automatically, the methacrylate the following steps are included: (1) short carbon chain is prepared 1:1~3 are stirred at room temperature and react for 24 hours in molar ratio with dimethylamine agueous solution, and rotary evaporation removes excessive dimethylamine solution, i.e., Tertiary amine product is obtained, there is CO₂/CH₄Response property, as stimuli responsive type counter ion；(2) tertiary amine 0.5~2% is passed through CO₂ To clear, quaternary ammonium salt is obtained as counter ion salt, 1~5% anionic surfactant thickening agent, clay is then added Stabilizer 0.3~2%, remaining for water to get arrive viscoelastic clean fracturing fluid.

2. a kind of reservoir as described in claim 1 breaks the clean fracturing fluid of glue automatically, it is characterized in that: the tertiary amine of preparation has CO₂/CH₄Response, in CO₂It acts on lower proton and is melted into quaternary ammonium salt, can be used as counter ion；It is continually fed into CH₄After can be with deprotonation Change, and be transformed into tertiary amine, chemical mechanical formula is as shown in the figure:

Wherein R is normal chain alkyl, and carbon number is 4~8.

3. a kind of reservoir as described in claim 1 breaks the clean fracturing fluid of glue automatically, it is characterized in that: anionic surfactant It is at least one of enuatrol, erucic acid sodium, lauryl sodium sulfate, neopelex.

4. a kind of reservoir as described in claim 1 breaks the clean fracturing fluid of glue automatically, it is characterized in that: tertiary amine is by CO₂Proton metaplasia At quaternary ammonium salt counter ion it is unstable under reservoir temperature and natural gas effect, slow deprotonation becomes tertiary amine again, and cleaning is pressed Glue can be broken automatically by splitting liquid.