CN105647507A - Preparation method of water-dispersible guanidine gum fracturing fluid cross-linking agent - Google Patents

Abstract

The invention discloses a preparation method of a water-dispersible guanidine gum fracturing fluid cross-linking agent. The preparation method includes the following steps that inorganic boron containing boric acid ions is added into a reaction medium with the pH of 4-11 and the temperature of 20-70 DEG C, and the mixture is stirred for 0.5-1 h at the constant speed within 150-300 rpm; then, an organosilicon compound containing reactable functional groups is added, the mixture is stirred for 1-8 h at the constant temperature within 20-120 DEG C, and a cross-linking material is obtained; the cross-linking material is subjected to suction filtration and dried to obtain a solid cross-linking agent, or the cross-linking material is subjected to reduced-pressure distillation to obtain an emulsion-type cross-linking agent. The adopted preparation process is simple, the cross-linking agent can be rapidly dispersed into water at normal temperatures and pressure, cross-linking density and cross-linking time can be regulated and controlled, and controllable time can be obtained for construction; meanwhile, friction drag between fracturing fluid and a delivery pipeline in the construction process can be effectively reduced, and energy consumption can be lowered.

Description

A kind of preparation method of water-dispersed guar gum fracturing fluid crosslinking agent

technical field

The invention belongs to the technical field of nanometer materials, and in particular relates to a preparation method of a water-dispersed guar gum fracturing fluid crosslinking agent.

Background technique

82% of my country's proven oil geological reserves are low-permeability oil and gas fields, and fracturing and fracture-making technology is one of the main technical means to enhance the recovery of low-permeability oil and gas fields. Fracturing fluid is an important part and key link of fracturing and fracture creation technology. High quality, low damage and low cost are the main directions for the development of fracturing fluid. As a thickener for water-based fracturing fluid, hydroxypropyl guar gum has the characteristics of strong thickening ability, good shear resistance, good thermal stability, and strong filtration loss control ability, so it is widely used in domestic oil and gas field fracturing .

The hydroxypropyl guar gum fracturing fluid system uses inorganic boron as the crosslinking agent, which has problems such as slow liquid preparation, insufficient dissolution, low crosslinking efficiency, and too fast crosslinking speed; for the problems existing in the boron crosslinking agent, it is now commonly used The best solution is to carry out organic compounding or use transition metal and organometallic crosslinking agents as substitutes. Performance problems such as shearing, gel breaking, and residue content are not up to standard; and high-temperature-resistant organoboron crosslinking agents also have problems such as low chelation degree, high concentration, and complex synthesis industry, which limit their use.

Contents of the invention

Based on the deficiencies of the prior art, the present invention provides a method for preparing a water-dispersed guar gum fracturing fluid crosslinking agent, using an organosilicon compound containing a reactive functional group as a carrier to prepare a guar gum fracturing fluid surface-modified with borate groups. Split liquid cross-linked material, small particle size, can be quickly dispersed in water system under normal temperature and pressure.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A method for preparing a water-dispersed guar gum fracturing fluid crosslinking agent, comprising the following steps: adding inorganic boron containing borate groups to a reaction medium with a pH of 4 to 11 and a temperature of 20 to 70°C at 150 to 300 rpm Stir at a constant speed for 0.5 to 1 hour per minute; then add an organosilicon compound containing a reactive functional group, and stir at a constant temperature of 20 to 120°C for 1 to 8 hours to obtain a cross-linked material; the cross-linked material is filtered and dried to obtain Solid cross-linking agent, or the cross-linking material is distilled under reduced pressure to obtain an emulsion-type cross-linking agent; wherein, the mass ratio of inorganic boron containing borate, organosilicon compound containing reactive functional groups, and reaction medium is 1 ~3:2~7:3~20.

Preferably, the borate-containing inorganic boron is boric acid and/or borax.

Preferably, the reaction medium is one or more of water, formamide, C1-C5 alkyl alcohol and C1-C5 alkyl acid.

Preferably, the organosilicon compound containing a reactive functional group refers to an organosilicon compound with epoxy or amine groups.

Preferably, the pH of the reaction medium is adjusted by one or more of sodium hydroxide, potassium hydroxide, ammonium chloride and ammonia water.

Wherein, the inorganic boron containing borate and the organosilicon compound containing reactive functional groups are common commercially available products.

The preparation process of the present invention is simple. The reactive functional groups on the surface of the organosilicon compound are used to graft borate groups that can participate in the crosslinking of guar gum molecules to the surface of the organosilicon compound, and the self-polymerization function of the organosilicon compound itself is used to form a Structured organic-inorganic composite cross-linked materials. The crosslinking agent prepared by the invention can be quickly dispersed in water under normal temperature and pressure, and its performance is obviously better than that of commonly used organic or inorganic boron crosslinking agents. By controlling the particle size of the crosslinking agent and the loading amount of borate on the surface, the crosslinking density and crosslinking time can be adjusted to achieve the expected viscoelasticity of the guar gum fracturing fluid, and can effectively reduce the fracturing fluid during the construction process. The friction with the transmission pipeline reduces energy consumption and realizes an effective and economical fracturing construction process.

Description of drawings

Fig. 1 is the particle size distribution of the cross-linking agent prepared in embodiment 1 in the laser particle size test analysis;

Fig. 2 is the graph that the crosslinking agent crosslinking time that embodiment 1 prepares and the viscosity change of guar gum solution;

Fig. 3 is a comparison chart of the temperature resistance of the guar gum fracturing fluid between the crosslinking agent prepared in Example 1 and the boric acid crosslinking agent.

detailed description

The present invention will be described in further detail below through preferred embodiments, but the protection scope of the present invention is not limited thereto.

Example 1

A preparation method of a water-dispersed guar gum fracturing fluid cross-linking agent, comprising the following steps: adding 4 g of boric acid to 50 mL of glycerol, adding ammonia water to adjust the pH to 8, heating up to 40° C., stirring at a constant speed of 300 rpm for 0.5 h, adding boric acid Dissolve completely; raise the temperature to 60°C, add 14g of γ-aminoethylaminopropyltrimethoxysilane, stir at a constant speed of 200rpm for 4h, raise the temperature to 90°C, continue to stir for 1h, suction filter and dry to obtain solid guar gum fracturing fluid crosslinking agent.

As shown in Figure 1, the particle size of the guar gum fracturing fluid crosslinking agent prepared above was measured by a laser particle size tester to be about 2 nanometers. The cross-linking agents prepared above were respectively configured into cross-linking solutions with mass fractions of 0.5%, 1%, 2% and 3%, and their light transmittances were 91.5%, 92.7%, 77.7% and 65.8%, respectively, indicating that cross-linking The agent has good dispersibility in water.

The cross-linking agent prepared above was configured into a cross-linking liquid with a mass fraction of 1%, and a guar gum solution with a mass fraction of 0.3%. Get 100 milliliters of mass fractions and be 0.3% guar gum solution, add 2.5 milliliters of mass fractions and be 1% cross-linking solution, as shown in Figure 2, the nano cross-linking agent prepared by embodiment has 5 minutes delay cross-linking when using Interval, enter stable cross-linking after 9 minutes. Take 2 ml of cross-linking liquid and add it to 100 ml of guar gum solution with a mass fraction of 0.3% and stir. Compare the state of the guar gum solution at the initial stage of cross-linking and the state of the later stage of cross-linking. After 5 to 6 minutes, the hanging performance is good, and the cross-linking effect can be seen. obvious. Take 100 ml of guar gum solution, add 20-40 mesh standard ceramsite, stir evenly, then add 3 ml of cross-linking liquid, stir until no flow, pour into a 100 ml measuring cylinder, after 2 hours, the ceramsite will slightly settle, and the cross-linking effect can be seen Better, excellent sand suspension performance. Take another 100 ml of guar gum solution, add 20-40 mesh standard ceramsite, stir evenly, then add 3 ml of cross-linking solution with a mass fraction of 1%, and add gel breaker at the same time, ceramsite after breaking gel at 80°C for 2 hours All settled. After testing, the viscosity of the gel breaking solution is about 2.0mPa.s, which shows that the final gel breaking state is relatively ideal.

The cross-linking agent prepared above is configured into a cross-linking liquid with a mass fraction of 3%, and a boric acid solution with a mass fraction of 3% is configured at the same time, and 1 mL of each is added to two 100 mL of guar gum solutions with a mass fraction of 0.3%. As shown in Figure 3, as the temperature increases, the viscosity of the two guar gum solutions gradually decreases, but the crosslinking performance and temperature resistance of the crosslinking agent prepared in this example are obviously better than boric acid.

Example 2

A preparation method of a water-dispersed guar gum fracturing fluid cross-linking agent, comprising the following steps: adding 5 g of borax to 50 mL of formamide, adding sodium hydroxide solution to adjust the pH to 7, heating up to 40° C., and stirring at a constant speed of 300 rpm for 0.5 h Until the borax is completely dissolved; heat up to 60°C, slowly add 10g of γ-aminoethylaminopropyltrimethoxysilane dropwise, stir at a constant speed of 150rpm for 4h, and distill under reduced pressure to obtain an emulsion-like guar gum fracturing fluid crosslinking agent.

The particle size of the guar gum fracturing fluid crosslinking agent prepared above was measured by a laser particle size tester to be about 2 nanometers. The cross-linking agent prepared above was configured into a cross-linking liquid with a mass fraction of 1%, and a guar gum solution with a mass fraction of 0.3%. Take 2 ml of cross-linking solution and add it to 100 ml of guar gum solution with a mass fraction of 0.3% and stir. Compare the state of the guar gum solution at the initial stage of cross-linking and the state of the later stage of cross-linking. After 5-6 minutes, the hanging performance is good, and the cross-linking effect can be seen. obvious. Take 100 ml of guar gum solution, add 20-40 mesh standard ceramsite, stir evenly, then add 3 ml of cross-linking solution, stir until it cannot flow, pour it into a 100 ml measuring cylinder, and after 2 hours, the ceramsite will slightly settle, and the cross-linking effect can be seen Better, excellent sand suspension performance. Then take 100 ml of guar gum solution, add 20-40 mesh standard ceramsite, stir evenly, then add 3 ml of cross-linking solution with a mass fraction of 1%, and add gel breaker at the same time, ceramsite after breaking gel at 80°C for 2 hours All settled. After testing, the viscosity of the gel breaking solution is about 2.0mPa.s, which shows that the final gel breaking state is relatively ideal.

Example 3

A preparation method of a water-dispersed guar gum fracturing fluid cross-linking agent, comprising the following steps: adding 4 g of boric acid to 20 mL of ethanol, adding ammonia water to adjust the pH to 8, raising the temperature to 40° C., and stirring at a constant speed of 300 rpm for 1 hour until the boric acid is completely dissolved; Raise the temperature to 60°C, add 4g of γ-(2,3-glycidoxy)propyltrimethoxysilane, stir at a constant speed of 200rpm for 4h, raise the temperature to 90°C, continue to stir for 1h, suction filter and dry to obtain solid guar gum Fracturing fluid crosslinker.

The particle size of the guar gum fracturing fluid crosslinking agent prepared above was measured by a laser particle size tester to be about 2 nanometers. The nano-crosslinking agent prepared above was configured into a crosslinking solution with a mass fraction of 1%, and a guar gum solution with a mass fraction of 0.3%. Take 2 ml of cross-linking solution and add it to 100 ml of guar gum solution with a mass fraction of 0.3% and stir. Compare the state of the guar gum solution at the initial stage of cross-linking and the state of the later stage of cross-linking. After 5-6 minutes, the hanging performance is good, and the cross-linking effect can be seen. obvious. Take 100 ml of guar gum solution, add 20-40 mesh standard ceramsite, stir evenly, then add 3 ml of cross-linking solution, stir until it cannot flow, pour it into a 100 ml measuring cylinder, and after 2 hours, the ceramsite will slightly settle, and the cross-linking effect can be seen Better, excellent sand suspension performance. Then take 100 ml of guar gum solution, add 20-40 mesh standard ceramsite, stir evenly, then add 3 ml of cross-linking solution with a mass fraction of 1%, and add gel breaker at the same time, ceramsite after breaking gel at 80°C for 2 hours All settled. After testing, the viscosity of the gel breaking solution is about 2.0mPa.s, which shows that the final gel breaking state is relatively ideal.

Claims (5)

1. the preparation method that a moisture dissipates guanidine gum fracturing fluid cross-linking agent, it is characterised in that comprise the following steps: the Inorganic Boron containing borate is added pH is 4 ~ 11, and temperature is in the reaction medium of 20 ~ 70 DEG C, 150 ~ 300 revs/min of constant speed stir 0.5 ~ 1 hour; Adding the organo-silicon compound containing reactable functional group, in 20 ~ 120 DEG C, constant temperature stirs 1 ~ 8 hour, obtains cross-linked material; Cross-linked material, through sucking filtration, drying, obtains the cross-linking agent of solid-state, or by cross-linked material decompression distillation, obtains the cross-linking agent of emulsion-type; Wherein, the mass ratio of the Inorganic Boron containing borate, the organo-silicon compound containing reactable functional group and reaction medium is 1 ~ 3:2 ~ 7:3 ~ 20.

2. the preparation method that moisture according to claim 1 dissipates guanidine gum fracturing fluid cross-linking agent, it is characterised in that: the Inorganic Boron containing borate is boric acid and/or Borax.

3. the preparation method that moisture according to claim 1 dissipates guanidine gum fracturing fluid cross-linking agent, it is characterised in that: reaction medium is one or more in water, Methanamide, the alkylol of C1 ~ C5 and the alkyl acid of C1 ~ C5.

4. the preparation method that moisture according to claim 1 dissipates guanidine gum fracturing fluid cross-linking agent, it is characterised in that: the described organo-silicon compound containing reactable functional group refer to the organo-silicon compound with epoxy or amido.

5. the preparation method that moisture according to claim 1 dissipates guanidine gum fracturing fluid cross-linking agent, it is characterised in that: the pH of reaction medium is regulated by one or more in sodium hydroxide, potassium hydroxide, ammonium chloride and ammonia.