CN103387827A - Nano-material associated clean fracturing fluid system and application thereof in oil and gas fields - Google Patents

Abstract

The invention provides a nano-material associated clean fracturing fluid system; the system comprises a nano-material, a clean fracturing fluid and a dispersing auxiliary liquid trihydric alcohol. The nano-material associated clean fracturing fluid system can be applied to oil and gas fields with the temperature as high as 130 DEG C above, and can still maintain a certain viscosity at the temperature. The obviously improved temperature tolerance of the prepared nano-material associated clean fracturing fluid system is beneficial to the application of the system in high temperature deep-well oil fields. Through use of the system, nanotechnology and petroleum industry are closely combined, and the market prospect is broad.

Description

Clean fracturing fluid system associated with nanomaterials and its application in oil and gas fields

technical field

The invention relates to a nanometer material association clean fracturing fluid system and its application in oil and gas fields, especially the application in oil and gas field stimulation and transformation.

Background technique

Hydraulic fracturing technology has played an important role in the exploitation of oil and gas fields, and is the main technology for increasing single well production in low-permeability and ultra-low-permeability reservoirs. Clean fracturing fluid without residue has little damage to propped fractures and formations, and is the development trend and hot spot of fracturing fluid research at home and abroad. With the deepening of oil and gas exploration and development in deep and ultra-deep wells, the thermal shear viscosity of conventional fracturing fluid systems decreases too quickly at high temperatures, which cannot meet the requirements of ultra-deep well fracturing reconstruction. The technical key to the progress of the cracking process. Nanomaterials and technology are the cutting-edge technology in the development of science and technology in the past ten years. Due to the small size of the particles that make up nanomaterials, the number of surface atoms, surface energy and surface tension increase sharply with the decrease of particle size, and they show many differences from conventional The novel properties of materials make nanomaterials widely used in many fields. In recent years, nanomaterials have gradually attracted the attention of oilfield developers, and have been applied in oilfield drilling, injection-production development, oilfield sewage treatment, and oil and gas pipeline protection. Nanomaterials are introduced into clean fracturing fluid to form a nanomaterial-associated clean fracturing fluid system, which can withstand higher oil and gas field temperatures, thereby extending the depth of oil and gas drilling and development. These nanoparticles can act as stabilizers and fluid loss control agents for well completion and oil and gas stimulation fluids in the petroleum industry, and can maintain high viscosity of fluids at high temperatures and reduce fluid loss without causing damage to oil formations.

How to develop a high-temperature-resistant nano-material association clean fracturing fluid system has become a topic of concern to those skilled in the art. For example, Chinese patent application 102093874A relates to an anionic nanocomposite cleaning fracturing fluid and its preparation method. The quality components of the product are as follows: anionic viscoelastic surfactant: 3-7 parts, cosurfactant: 0.05-0.5 part, counter ion salt: 3-10 parts, nanoparticle: 0.05-0.5 part, water 100 parts. An anionic nano-composite cleaning fracturing fluid can be prepared by blending and stirring the above components according to the proportion of the solution. This product has high viscoelasticity and good sand-carrying performance, which can fully meet the requirements of fracturing fluid and sand-carrying on-site in oil and gas fields. The document SPE 552-558, 2008, Nanotechnology applications in viscoelastic surfactantstimulation fuids introduced viscoelastic surfactant fracturing fluid (VES) combined with nanotechnology. cause harm. The nanoparticle is a 35nm inorganic crystal, which has a unique surface activity, which can prevent VES micelles from being filtered out at higher temperatures (250°F or 121°C) through chemical adsorption.

However, the improvement of the temperature resistance of the nanomaterial-associated clean fracturing fluid system needs to be further developed and improved.

Contents of the invention

The invention provides a clean fracturing fluid system associated with nanometer materials. The system comprises nanomaterials, clean fracturing fluid and a dispersion aid, wherein the dispersion aid is liquid trihydric alcohol.

The nanomaterial association clean fracturing fluid system provided by the present invention can be applied to oil and gas fields at temperatures above 130° C., and can still maintain a certain system viscosity at this temperature, and has good application prospects in oil fields.

The nanometer material in the present invention is one or more of MgC ₂ O ₄ , Al(OH) ₃ , γ-Al ₂ O ₃ , SiO ₂ , TiO ₂ and ZnO powder. The nanomaterials of the present invention can be purchased commercially; but it is more preferable that the nanomaterials are obtained by a laboratory self-made method, and the self-made process can be based on the needs of the nanoparticle particle size and its application to the characteristics of clean fracturing fluid , on the basis of the traditional nanomaterial preparation method, the preparation method is properly adjusted to make it especially suitable for the formation of the nanomaterial association clean fracturing fluid system described in the present invention. The method for preparing nanomaterials adopted in Examples 1-6 of the present invention is simple, the reaction conditions are mild, the yield is high, and the reproducibility is strong.

In the present invention, the volume fraction of the triol in the clean fracturing fluid system is preferably 5-50%, more preferably 10-20%; such an amount of dispersing aid triol makes the nanomaterial It can be completely dissolved in the clean fracturing fluid, and the application effect and cost of the clean fracturing fluid system will not be damaged due to excessive dosage.

In the present invention, a large number of experiments have proved that the mass fraction of the nanomaterials in the clean fracturing fluid system is preferably 0.01-20%, more preferably 0.1-1%.

The clean fracturing fluid of the present invention is, for example, an aqueous solution containing a viscoelastic surfactant at a concentration of 0.1-4 wt%.

The present invention also provides the application of the nanometer material association clean fracturing fluid system in oil and gas field stimulation reconstruction. Wherein, the application temperature is 120-180°C, more preferably, the application temperature is 125-175°C.

The preparation method of the nanomaterial-associated clean fracturing fluid system of the present invention is, for example, dispersing 0.1 g of nanomaterials in 5 ml of dispersing aid, and adding it to 40 ml of clean fracturing fluid to form a clean fracturing fluid system.

The temperature resistance of the nano-material association clean fracturing fluid system prepared by the invention is obviously improved, which is beneficial to its application in high-temperature deep well oilfields. This system makes the nanotechnology and the petroleum industry closely combine, and the market prospect is broad.

Description of drawings

Fig. 1 is the XRD spectrogram of nano MgC ₂ O ₄ powder in embodiment 1;

Fig. 2 is nanometer Al(OH) in embodiment ₂ XRD spectrogram of powder;

Fig. 3 is the XRD spectrogram of nano γ-Al ₂ O ₃ powder in embodiment 3;

Fig. 4 is nano-SiO in embodiment 4 The _XRD spectrogram of powder;

Fig. 5 is nano TiO in embodiment 5 The _XRD spectrogram of powder;

Fig. 6 is the XRD spectrogram of nano ZnO powder in embodiment 6;

Figure 7 shows the viscosity of the clean fracturing fluid without using nanomaterials at 130°C and 170s ^-1 shear rate in Comparative Example 1;

Fig. 8 is the viscosity of the clean fracturing fluid using nano _-SiO2 at 130°C and 170s ^-1 shear rate in Example 7;

Fig. 9 is the viscosity of the clean fracturing fluid using nano- _TiO2 at 130°C and 170s ^-1 shear rate in Example 8;

Figure 10 shows the viscosity of the clean fracturing fluid using nano _-SiO2 at 150°C and 170s ^-1 shear rate in Example 9;

Fig. 11 shows the viscosity of the clean fracturing fluid using nano TiO ₂ in Example 10 at 170°C and 170s ^-1 shear rate.

Detailed ways

The present invention will be further described below through examples, and the protection scope of the present invention is not limited thereto.

Example 1

The preparation method of nano MgC ₂ O ₄ : magnesium chloride hexahydrate, disodium oxalate tetraacetate (C ₁₀ H ₁₄ N ₂ O ₈ Na ₂ 2H ₂ O) and sodium oxalate with a molar ratio of 50:1:50 were dissolved Make a solution in distilled water, wherein the concentration of magnesium chloride is 0.5mol/L, stir for 1h, age for 20h, dry at 80°C, and roast at 500°C for 3h to obtain nano-MgC ₂ O ₄ powder with a particle size of 11.8nm. Its spectrum characterized by XRD is shown in Fig. 1 .

Example 2

The preparation method of nano-Al(OH) ₃ : prepare aluminum nitrate and ammonium bicarbonate solutions with mass fractions of 27% and 12%, respectively. Add a certain amount of CTAB into the aluminum nitrate solution, the ratio of aluminum nitrate and CTAB is 1:0.006, and stir to obtain a clear solution. Then slowly add the ammonium bicarbonate solution dropwise to the vigorously stirred aluminum nitrate solution, after the dropwise addition, continue to stir for 1 hour, age for 48 hours, and dry the wet gel at 80°C to obtain nanometer Al(OH) ₃ powder , whose particle size is 37.8nm, and its XRD characterization spectrum is shown in Figure 2.

Example 3

The preparation method of nanometer gamma- _Al2O3 : the nanometer Al(OH) ₃ powder that is prepared in embodiment 2 is roasted 3h at 500 _℃ to obtain nanometer gamma- _Al2O3 powder, and its particle diameter is 18.7nm _, Its spectrum characterized by XRD is shown in Fig. 3 .

Example 4

The preparation method of nano- _SiO2 : prepare 25ml of aqueous acetic acid solution with a concentration of 0.01mol/l, then add 2.5g of polyethylene glycol, stir thoroughly to dissolve it, then add 11.25ml of methyl silicate, and bathe in ice water for half an hour. Aged for 1 day after forming a gel in a water bath at 40°C, added 0.01mol/l ammonia water, placed in a reaction kettle, heated at 120°C for 6 hours, dried at 80°C, calcined at 550°C, and ground to obtain nano- _SiO2 powder. is 0.8nm, and its XRD characterization spectrum is shown in Figure 4.

Example 5

The preparation method of nano-TiO ₂ : slowly drop 5 mL of butyl titanate into 15 mL of anhydrous C ₂ H ₅ OH under vigorous stirring, and continue stirring for 20 min to obtain a uniform and transparent first solution. In addition, deionized water was added to anhydrous C ₂ H ₅ OH at room temperature to prepare an ethanol solution with a volume ratio of 1:4 to obtain a second solution. Under the condition of vigorous stirring, drop the first solution into the second solution, continue to stir for 30 minutes after the dropwise addition, evaporate to dryness in a water bath at 80°C, dry in an oven at 80°C, and roast at 400°C for 3h to obtain nano The TiO ₂ powder has a particle size of 10.8nm, and its XRD characterization spectrum is shown in Figure 5.

Example 6

The preparation method of nano-ZnO: prepare 200ml of sodium carbonate solution with a concentration of 0.5mol/l and 300ml of zinc sulfate solution with a concentration of 0.1mol/l, and then slowly add the zinc sulfate solution to the sodium carbonate solution under vigorous stirring. In the solution, after the dropwise addition, continue to stir for half an hour, after aging for 1 hour, fully wash, dry at 80°C, and roast at 300°C for 3 hours to obtain nano-ZnO powder with a particle size of 10.5nm, which is characterized by XRD The graph is shown in Figure 6.

Comparative example 1

After the rheometer sample cup was filled with clean fracturing fluid without added nanomaterials, the sample was heated. At the same time, the rotor rotates at a shear rate of 170s ^-1 , and the temperature rise rate is controlled at 3°C±0.2°C/min to the test temperature of 130°C±0.3°C, and this temperature is maintained throughout the test process to evaluate the temperature resistance of the clean fracturing fluid system Shear resistance and rheology at high temperature, the resulting viscosity curves are shown in Figure 7. The left ordinate and □ in the figure represent the viscosity, the right ordinate and △ represent the temperature, and the abscissa represents the time. It can be seen from the figure that the viscosity decreases as the temperature rises. When the temperature reaches 130°C, there is no nanomaterial Under normal circumstances, the viscosity of the clean fracturing fluid drops below 30 mPa·s within 60 min.

Example 7

After dispersing 0.1g of nano- _SiO2 prepared in Example 4 in 5ml of dispersing aid glycerin, it was added to 40ml of clean fracturing fluid (containing a viscoelastic surfactant concentration of 0.8%) to form a cleaning solution containing nanomaterials. For the fracturing fluid system, after the rheometer sample cup is filled with the clean fracturing fluid system containing nanomaterials, the sample is heated. At the same time, the rotor rotates at a shear rate of 170s ^-1 , and the temperature rise rate is controlled at 3°C±0.2°C/min to the test temperature of 130°C±0.3°C, and this temperature is maintained throughout the test process to evaluate the clean fracturing fluid containing nanomaterials The temperature and shear resistance of the system and the rheology at high temperature, the obtained viscosity curve is shown in Figure 8. The left ordinate and □ in the figure represent the viscosity, the right ordinate and △ represent the temperature, and the abscissa represents the time. It can be seen from the figure that the viscosity decreases with the increase of the temperature. When the temperature reaches 130°C, add SiO _2nm In the case of materials, the viscosity of clean fracturing fluid can be maintained at 50 mPa·s or above at 130 °C. The graphed results show that the nanomaterial-associated clean fracturing fluid can stabilize the viscosity of the fluid at high temperature.

Example 8

After dispersing 0.45g of nano- _TiO2 prepared in Example 5 in 5ml of dispersing aid glycerin, it was added to 40ml of clean fracturing fluid (with a viscoelastic surfactant concentration of 0.8%) to form a cleaning solution containing nanomaterials. For the fracturing fluid system, after the rheometer sample cup is filled with the clean fracturing fluid system containing nanomaterials, the sample is heated. At the same time, the rotor rotates at a shear rate of 170s ^-1 , and the temperature rise rate is controlled at 3°C±0.2°C/min to the test temperature of 130°C±0.3°C, and this temperature is maintained throughout the test process to evaluate the fracturing fluid system containing nanomaterials The temperature resistance and shear resistance and rheology at high temperature, the obtained viscosity curve is shown in Figure 9. The left ordinate and □ in the figure represent the viscosity, the right ordinate and △ represent the temperature, and the abscissa represents the time. It can be seen from the figure that the viscosity decreases with the increase of the temperature. When the temperature reaches 130°C, add TiO ₂ nano In the case of materials, the viscosity of clean fracturing fluid can be maintained at 60 mPa·s or above at 130 °C. The graphed results show that the nanomaterial-associated clean fracturing fluid can stabilize the viscosity of the fluid at high temperature.

Example 9

After dispersing 1.0g of nano- _SiO2 prepared in Example 4 in 5ml of dispersing aid glycerin, it was added to 40ml of clean fracturing fluid (containing a viscoelastic surfactant concentration of 0.8%) to form a clean fracturing fluid containing nanomaterials. For the fracturing fluid system, after the rheometer sample cup is filled with the clean fracturing fluid system containing nanomaterials, the sample is heated. At the same time, the rotor rotates at a shear rate of 170s ^-1 , and the temperature rise rate is controlled at 3°C±0.2°C/min to the test temperature of 150°C±0.3°C, and this temperature is maintained throughout the test process to evaluate clean fracturing fluids containing nanomaterials The temperature and shear resistance of the system and the rheology at high temperature, the obtained viscosity curve is shown in Figure 10. The left ordinate and □ in the figure represent the viscosity, the right ordinate and △ represent the temperature, and the abscissa represents the time. It can be seen from the figure that the viscosity decreases as the temperature rises. When the temperature reaches 150°C, add SiO ₂ nanometers In the case of materials, the viscosity of clean fracturing fluid can be maintained at 50 mPa·s or above at 150 °C. The graphed results show that the nanomaterial-associated clean fracturing fluid can stabilize the viscosity of the fluid at high temperature.

Example 10

After dispersing 2.25g of nano- _TiO2 prepared in Example 5 in 5ml of dispersing aid glycerol, it was added to 40ml of clean fracturing fluid (with a viscoelastic surfactant concentration of 0.8%) to form a clean fracturing fluid containing nanomaterials. For the fracturing fluid system, after the rheometer sample cup is filled with the clean fracturing fluid system containing nanomaterials, the sample is heated. At the same time, the rotor rotates at a shear rate of 170s ^-1 , and the temperature rise rate is controlled at 3°C±0.2°C/min to the test temperature of 170°C±0.3°C, and this temperature is maintained throughout the test process to evaluate clean fracturing fluids containing nanomaterials The temperature resistance and shear resistance of the system and the rheology at high temperature, the obtained viscosity curve is shown in Figure 11. The left ordinate and □ in the figure represent the viscosity, the right ordinate and △ represent the temperature, and the abscissa represents the time. It can be seen from the figure that the viscosity decreases with the increase of the temperature. When the temperature reaches 170°C, add SiO _2nm In the case of materials, the viscosity of clean fracturing fluid can be maintained at 50 mPa·s or above at 170 °C. The graphed results show that the nanomaterial-associated clean fracturing fluid can stabilize the viscosity of the fluid at high temperature.

Claims (10)

1. A clean fracturing fluid system associated with nanomaterials, characterized in that the system comprises nanomaterials, clean fracturing fluid and a dispersion aid, wherein the dispersion aid is a liquid trihydric alcohol. 2. The system according to claim 1, wherein the nanomaterial is one of MgC ₂ O ₄ , Al(OH) ₃ , γ-Al ₂ O ₃ , SiO ₂ , TiO ₂ and ZnO powder one or more species. 3. The system according to claim 1 or 2, wherein the volume fraction of the trihydric alcohol in the clean fracturing fluid system is 5-50%. 4. The system according to claim 3, wherein the volume fraction of the trihydric alcohol in the clean fracturing fluid system is 10-20%. 5. The system according to claim 1 or 2, wherein the mass fraction of the nanomaterial in the clean fracturing fluid system is 0.01-20%. 6. The system according to claim 5, wherein the mass fraction of the nanomaterial in the clean fracturing fluid system is 0.1-1%. 7. The system according to claim 1 or 2, characterized in that the clean fracturing fluid is an aqueous solution containing a viscoelastic surfactant at a concentration of 0.1-4 wt%. 8. An application of the nanomaterial association clean fracturing fluid system in any one of claims 1 to 7 in oil and gas field stimulation. 9. The application according to claim 8, characterized in that the application temperature is 120-180°C. 10. The application according to claim 8, characterized in that the application temperature is 125-175°C. the

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