CN117285924A - Preparation method of nano oil-permeable water-blocking propping agent - Google Patents

Abstract

The invention discloses a preparation method of an oil-penetrating water-blocking propping agent, which comprises the steps of firstly, carrying out soaking etching pretreatment on the surface of propping agent aggregate by adopting acid liquor to enable the surface of propping agent aggregate to be in an uneven state; then preparing a modifier: the modifier comprises the following raw materials in parts by weight: 3-5 parts of nano silicon dioxide, 3-5 parts of micron silicon dioxide, 40-80 parts of organic solvent, 0.5-3 parts of thickener and 10-20 parts of polysiloxane; the thickener is one of methylcellulose, carboxymethylcellulose, carbomer, xanthan gum and gelatin. And finally, uniformly mixing the pretreated proppant aggregate with a modifier, placing the mixture in an environment of 40-70 ℃ for soaking for 2-4 hours, filtering out the proppant, and placing the proppant in an oven of 80-110 ℃ for drying to obtain the oil-permeable water-blocking proppant. The preparation method of the propping agent has the advantages of stable film coating, simple process, low cost and good oil-penetrating and water-repellent effects of the obtained propping agent.

Description

Preparation method of nano oil-permeable and water-blocking proppant

Technical field

The invention relates to the technical field of oil and gas production, in particular to a new type of nano oil-permeable and water-blocking proppant used for hydraulic fracturing.

Background technique

As oil and gas extraction intensity gradually increases and the extraction time increases. When oil and gas reservoirs are close to water layers or when oil and gas are extracted for a period of time, the problem of large amounts of water usually occurs. According to statistics, the current comprehensive water content of oil fields has reached as high as 83%, while the comprehensive water content of major oil fields in the east has reached as high as 90%. Therefore, how to control water has become a key issue in oil and gas production. At the same time, hydraulic fracturing technology has become the main production stimulation and transformation measure to increase the production of oil and gas wells, and is one of the most important measures to stabilize production in oil and gas fields. The process of hydraulic fracturing is to use high pressure to open the formation, and then inject sand-carrying liquid mixed with proppant into the formed fracture, so that the proppant spreads in the fracture to form support for the fracture. Finally, a highly conductive channel formed by proppant filling is left in the formation, thereby improving the formation's seepage capacity. Therefore, researchers combine hydraulic fracturing technology with water control technology, and treat the proppant to make the proppant oil-permeable and hydrophobic, thereby achieving the purpose of oil-permeability and water-resistance.

The existing patent CN 111607374 B discloses a low-temperature curing oil-permeable and water-blocking coated sand and its preparation method. The coated sand of the invention includes a proppant and a coating layer covering the surface of the proppant. The coating The layers include a thermosetting phenolic resin layer, a thermosetting acrylic resin layer and an oil-permeable and water-blocking layer arranged sequentially from the inside to the outside; the oil-permeable and water-blocking layer is a polyurethane resin layer; the proppant, thermosetting phenolic resin layer and thermosetting acrylic layer are The mass ratio of the thermosetting acrylic resin in the resin layer is 100: (1～2): (1～2). Although this technology can achieve oil permeability and water resistance of the proppant, this method achieves oil permeability and water resistance through multi-layer coating. At the same time, the coating layers selected are phenolic resin and polyurethane resin, and their dosage is also large. Therefore, its raw material cost and processing cost are high, which increases the cost of proppant, which is not in line with the direction of reducing costs and increasing efficiency in oil fields. Patent CN 102443387 B provides a hydrophobic proppant and a preparation method thereof. The aggregate particles of the hydrophobic proppant are coated with a coating resin. The coating resin includes a hydrophobic resin and nanoparticles. The nanoparticles can be evenly distributed in the Coated resin to achieve oil-permeable and hydrophobic effect. This method uses resin and adds nanoparticles to increase hydrophobicity, but the use of a large amount of resin and nanoparticles will inevitably increase the cost. At the same time, during the processing, the proppant needs to be heated to a high temperature of 200-220°C, so that Its processing technology is more complex.

Contents of the invention

In view of the above-mentioned deficiencies in the existing methods for preparing oil-permeable and hydrophobic proppant in the prior art, the present invention provides a new method for preparing an oil-permeable and water-blocking proppant, which can achieve the advantages of simple processing technology and low cost.

The preparation method of the oil-permeable and water-blocking proppant provided by the invention has the following steps:

S1. Use acid solution to perform immersion etching pretreatment on the surface of the proppant aggregate to make the surface of the proppant aggregate appear uneven. The proppant aggregate is one of quartz sand, ceramsite, steel slag, walnut shells, resin materials, rubber materials, glass materials, slag, and furnace slag.

S2. Prepare the modifier, including the following sub-steps:

S21. Add nano-silica to ultrasonically disperse it in an organic solvent, then add a thickener, stir in an environment of 50 to 80°C until there are no obvious particles, and obtain a mixed liquid; the thickener is methylcellulose, carboxyl One of methylcellulose, carbomer, xanthan gum, and gelatin. The organic solvent is one or a mixture of two or more of toluene, xylene, absolute ethanol, cyclohexane, methanol, diethyl ether, ethyl acetate, acetone, and carbon tetrachloride.

S22. Add micron-sized silica to the mixed solution, stir and mix evenly, and then disperse ultrasonically for 10 to 20 minutes. Then add polysiloxane, stir and mix evenly to obtain the modifier.

Among them, the proportion by weight of each component is as follows: 3 to 5 parts of nanometer silica, 3 to 5 parts of micron silica, 40 to 80 parts of organic solvent, 0.5 to 3 parts of thickener, and 10 parts of polysiloxane. ~20 servings.

S3. Mix the pretreated proppant aggregate and modifier evenly, place it in an environment of 40-70°C, soak for 2-4 hours, then filter out the proppant and dry it in an oven at 80-110°C to obtain Oil-permeable and water-blocking proppant.

Preferably, the acid solution used in step S1 is hydrofluoric acid with a mass fraction of 8-12%, hydrochloric acid with a mass fraction of 10-15%, sulfuric acid with a mass fraction of 30-50%, and a mass fraction of 2-4 % of polyhydric acids.

It is further preferred that step S1 is specifically: add the acid solution to the proppant aggregate, soak it for 5 to 10 minutes, then filter out the proppant aggregate, wash it with clean water, and dry it in an oven to obtain the pretreated of proppant aggregate.

Preferably, the amounts of proppant aggregate, modifier, and acid solution are as follows:

10 to 20 parts of proppant aggregate, 20 to 40 parts of acid solution, and 10 to 20 parts of modifier.

Compared with the prior art, the benefits of the present invention are:

The preparation method of the oil-permeable and water-blocking proppant provided by the present invention is to perform modification treatment on the surface of the proppant aggregate to obtain the oil-permeable and water-blocking proppant. The preparation process of this proppant is simple and does not require high-temperature operation. The oil-permeable and water-blocking performance of the modified proppant is significantly better than the existing technical level, and the performance is stable and the economic cost is also reduced.

Other advantages, objects, and features of the present invention will be apparent in part from the description below, and in part will be understood by those skilled in the art through study and practice of the present invention.

Description of drawings

Figure 1. Comparison of water phase penetration pressure between the oil-permeable and water-blocking quartz sand core and the original sandstone core in Example 1.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

Example 1

A nano oil-permeable and water-blocking proppant prepared through the following steps:

(1) Add 20 parts of hydrofluoric acid with a mass fraction of 10% to 10 parts of quartz sand (proppant aggregate), soak at room temperature for 5 minutes, then filter out the quartz sand, clean the surface with clean water, and then Place it in an oven and dry it to obtain pretreated quartz sand;

(2) Add 4 parts of nano-silica to 40 parts of toluene and stir until there are no obvious particles. Use ultrasonic to disperse for 5 minutes to obtain mixed liquid A; then add 1 part of xanthan gum to mixed liquid A and stir at 50~ Stir in an 80°C environment until there are no obvious particles to obtain mixed liquid B; add 3 parts of micron-grade silica to mixed liquid B, then stir and mix evenly, and then ultrasonically disperse the solution for 20 minutes to obtain mixed liquid C; then add 3 parts of micron-grade silica to mixed liquid B. Add 15 parts of polysiloxane to C, then stir the whole mixture evenly to obtain the modifier.

(3) Mix 10 parts of pretreated quartz sand and 15 parts of modifier evenly, then place the whole thing in a 40°C environment, soak for 2 hours, then filter out the quartz sand, and place the quartz sand in a 105°C oven After drying, nanometer oil-permeable and water-blocking quartz sand is obtained, that is, oil-permeable and water-blocking proppant.

Example 2

A nano oil-permeable and water-blocking proppant prepared through the following steps:

(1) Add 20 parts of hydrofluoric acid with a mass fraction of 10% to 10 parts of ceramsite (proppant aggregate), soak at room temperature for 10 minutes, then filter out the ceramsite, clean the surface with clean water, and then Place it in an oven and dry it to obtain pretreated ceramsite;

(2) Add 4 parts of nano-silica to 40 parts of toluene and stir until there are no obvious particles. Use ultrasonic to disperse for 5 minutes to obtain mixed liquid A; then add 1 part of xanthan gum to mixed liquid A and stir at 50~ Stir in an 80°C environment until there are no obvious particles to obtain mixed liquid B; add 3 parts of micron-grade silica to mixed liquid B, then stir and mix evenly, and then ultrasonically disperse the solution for 20 minutes to obtain mixed liquid C; then add 3 parts of micron-grade silica to mixed liquid B. Add 15 parts of polysiloxane to C, then stir the whole mixture evenly to obtain the modifier.

(3) Mix 10 parts of pretreated ceramsite and 15 parts of modifier evenly, then place the whole thing in a 40°C environment, soak for 2 hours, then filter out the ceramsite and place it in a 105°C oven to dry, to obtain Nano oil-permeable and water-blocking ceramsite is an oil-permeable and water-blocking proppant.

Performance Testing:

Test method: Prepare the oil-permeable and water-blocking quartz sand and untreated original quartz sand prepared in Example 1 into standard cores, and then use the core displacement device to test their performance during displacement with clean water under a confining pressure of 5 mPa. Displacement pressure, experimental results are shown in Figure 1. It can be concluded that compared with the untreated original quartz sand, the water phase penetration pressure of the nano oil-permeable and water-blocking quartz sand prepared in Example 1 is increased by 120%.

The same method was used to test the nano-oil-permeable and water-blocking ceramsite of Example 2. The results showed that compared with the untreated original ceramsite, the water-phase penetration pressure of the nano-oil-permeable and water-blocking ceramsite was increased by 110%.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed above in preferred embodiments, they are not intended to limit the present invention. Anyone familiar with this field will Skilled persons can make some changes or modifications to equivalent embodiments using the technical content disclosed above without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the invention still fall within the scope of the technical solution of the present invention.

Claims (7)

1. The preparation method of the oil-permeable water-blocking propping agent is characterized by comprising the following steps:

s1, carrying out soaking etching pretreatment on the surface of the propping agent aggregate by adopting acid liquor, so that the surface of the propping agent aggregate is in an uneven state;

s2, preparing a modifier, which comprises the following substeps:

s21, adding nano silicon dioxide into an organic solvent for ultrasonic dispersion, then adding a thickening agent, and stirring in an environment of 50-80 ℃ until no obvious particles exist, thus obtaining a mixed solution; the thickener is one of methylcellulose, carboxymethyl cellulose, carbomer, xanthan gum and gelatin;

s22, adding micron-sized silicon dioxide into the mixed solution, stirring and uniformly mixing, performing ultrasonic dispersion for 10-20 min, then adding polysiloxane, and stirring and uniformly mixing to obtain a modifier;

s3, uniformly mixing the pretreated proppant aggregate with a modifier, placing the mixture in an environment of 40-70 ℃ for soaking for 2-4 hours, filtering out the proppant, and placing the proppant in an oven of 80-110 ℃ for drying to obtain the oil-permeable water-blocking proppant.

2. The method for preparing the oil-permeable water-blocking propping agent according to claim 1, wherein the propping agent aggregate is one of quartz sand, ceramsite, steel slag, walnut shell, resin material, rubber material, glass material, slag and slag.

3. The method for preparing the oil-permeable water-blocking propping agent according to claim 2, wherein the acid liquid used in the step S1 is one of 8-12% by mass of hydrofluoric acid, 10-15% by mass of hydrochloric acid, 30-50% by mass of sulfuric acid and 2-4% by mass of polyhydrogenated acid.

4. The method for preparing the oil-permeable water-blocking propping agent according to claim 3, wherein the step S1 specifically comprises the following steps: adding acid liquor into the proppant aggregate, soaking for 5-10 min, filtering out the proppant aggregate, cleaning with clear water, and drying in an oven to obtain the pretreated proppant aggregate.

5. The method for preparing the oil-permeable water-blocking propping agent according to claim 1, wherein in the step S2, the following raw material components are used in parts by weight:

3 to 5 parts of nano silicon dioxide, 3 to 5 parts of micron silicon dioxide, 40 to 80 parts of organic solvent, 0.5 to 3 parts of thickener and 10 to 20 parts of polysiloxane.

6. The method for preparing the oil-permeable water-blocking propping agent according to claim 5, wherein the organic solvent is one or more of toluene, xylene, absolute ethyl alcohol, cyclohexane, methanol, diethyl ether, ethyl acetate, acetone and carbon tetrachloride.

7. The method for preparing the oil-permeable water-blocking propping agent according to claim 1, wherein the propping agent aggregate, the modifying agent and the acid solution are used in the following parts by weight:

10-20 parts of propping agent aggregate, 20-40 parts of acid liquor and 10-20 parts of modifier.