KR20200129391A - A double-coated proppant - Google Patents

Abstract

The present invention discloses a double-coated proppant produced by producing an aggregate using industrial waste as a raw material, and coating the aggregate with two layers of polymer in which an outer-layer polymer is a melamine-formaldehyde resin. The double-coated proppant can form a stable suspension in a water-based medium, reduce crushing costs, and reduce environmental pollution.

Description

Double-coated proppant {A double-coated proppant}

The present invention relates to the field of proppants, and in particular to double-coated proppants produced from industrial wastes as raw materials.

Proppant is a solid particle dedicated to fracturing. After crushing, the proppant can support the wall surface of the crushed rock so that the rock cannot recombine, and the resulting hydraulic fracture is a flow-conduction channel leading to the well bore. ). In 1977, the United States developed an artificial proppant called sintered bauxite, which is characterized by high compressive strength and high flow conductivity under high closing pressure. In China, this artificial proppant produced by sintering or jetting bauxite as the main raw material is collectively referred to as ceramsite. At home and abroad, the relative density of ceramsite proppant is in the range of 2.70-3.60, and its bulk density is in the range of 1.60-2.10 g/cm ³ , both of which are higher than the relative density and bulk density of natural quartz sand. Bigger.

Currently, some domestic crushing processes use a coating process to produce proppant. Typically, only one layer of film is coated during coating, and the resin used in the coating is mostly acrylic acid ethyl ester or phenolic resin. The effect of the melamine-formaldehyde resin currently used in proppant coating is to increase the hardness of the proppant and reduce the breakage rate of the proppant, but the obtained proppant only meets the strength and hardness requirements. Can be satisfied and cannot realize self-suspension. It is necessary to re-prep a carrier liquid with viscoelasticity during construction, but this construction method can lead to high crushing costs, serious damage to the reservoir stratum and environmental pollution. have.

It is an object of the present invention to provide a double-coated proppant produced by producing an aggregate using industrial waste as a raw material and coating the aggregate with two layers of resin. The double-coated proppant can form a stable suspension in a water-based medium, and there is no need to add a thickener during crushing, reducing crushing costs and reducing environmental pollution.

The double-coated proppants of the present invention mainly comprise aggregates, inner-layer polymers and outer-layer polymers.

The aggregate is produced using industrial waste as raw material, and the industrial waste is preferably selected from blast furnace slag and refractory material waste.

By using industrial waste as the raw material of the aggregate, the present invention not only realizes the efficient utilization of resources, recycles waste, and avoids environmental pollution caused by the waste, but also obtains a performance comparable to that of propane aggregates such as quartz sand.

The inner-layer polymer is prepared with acrylic acid ethyl ester and acrylic acid ethyl ester curing agents.

The outer-layer polymer is formed of a melamine-formaldehyde resin.

The acrylic acid ethyl ester curing agent preferably has a degree of functionality of more than 2 in order to improve the reaction.

The double-coated proppant is produced by a method comprising the following steps:

(a) weighing the aggregate, acrylic acid ethyl ester, acrylic acid ethyl ester curing agent, melamine-formaldehyde resin, and catalyst in order;

(b) pouring the aggregate into a sand mixing kettle, heating to 170-240° C., and performing sand mixing;

(c) adding an acrylic acid ethyl ester and an acrylic acid ethyl ester curing agent into a sand mixing kettle, and performing a first coating at 150-190°C;

(d) adding a melamine-formaldehyde resin and a catalyst into a sand mixing kettle, and performing sand mixing at 70-100°C; And

(e) lowering the temperature to 50-65° C. and taking out the product.

By adopting the above technical solution, the present invention can achieve the following beneficial effects:

1. Due to the strong reaction accompanying the release of heat, some bubbles and projections are formed on the outer surface, thereby achieving the effect of increasing buoyancy.

2. The gas layer encapsulating the proppant particles is formed at the interface between the outer layer of proppant and the aqueous medium, and the presence of the gas layer causes the individual proppant particles to collide with each other in the water body, resulting in a loose agglomerated structure. (flocculated structure) can be formed, thereby reducing the relative density of proppant in water and improving the suspension performance.

3. By providing a high-strength acrylic acid ethyl ester inner layer, the present invention overcomes the insufficient strength defect of the melamine-formaldehyde resin outer layer, and reduces the breakage rate of proppant.

4. By using industrial waste as a raw material for aggregate, the present invention realizes recycling of resources and effectively avoids environmental pollution caused by industrial waste.

5. Since the proppant of the present invention can be stably suspended in an aqueous medium, as a result, a thickener widely used in conventional crushing liquids is omitted, thereby reducing cost and simplifying the process.

Hereinafter, the present invention will be further described by specific embodiments, but it should be understood that the present invention is not limited to the specific embodiments described below.

Manufacturing Example 1

Preparation of ceramsite proppant aggregate 1

40 parts by weight of bauxite tailings were weighed and added into a hammer crusher and pulverized for about 30 minutes, then a bauxite coarse powder material was obtained and taken out. 35 parts by weight of kaolin and 2 parts by weight of a ball milling aid were each weighed and added to the ball mill together with the bauxite stray coarse powder material, after which 50 parts by weight of water were added, and the product was about 45 Ball milling for minutes to obtain a mixed powdery material. The obtained powder material was added into a disc granulator and sprayed with water vapor to obtain granules, and the granules were sieved with a 120 mesh sieve, and then 7 parts by weight of a sintering aid (sintering). aid) in a rotary kilin and sintering at 1280-1350°C to produce a ceramsite blank. After polishing the ceramsite blank by adding 5 parts by weight of alumina powder, the alumina powder was removed to obtain ceramsite proppant aggregate 1.

Manufacturing Example 2

Preparation of ceramsite proppant aggregate 2

45 parts by weight of bauxite stray light was weighed and added to a hammer mill and pulverized for about 30 minutes, then a bauxite stray coarse powder material was obtained and taken out. 37 parts by weight of kaolin and 1.5 parts by weight of a ball milling aid were each weighed and added to the ball mill together with the bauxite light coarse powder material, then 60 parts by weight of water were added, and the product was ball milled for about 45 minutes to mix powder. The material was obtained. The obtained powdery material was added to a disk granulator and sprayed with steam to obtain granules, and the granules were sieved through a 120 mesh sieve, and then added to a rotary kiln together with 9 parts by weight of a sintering aid and sintered at 1280-1350°C. A ceramsite blank was produced. After polishing the ceramsite blank by adding 4 parts by weight of alumina powder, the alumina powder was removed to obtain a ceramsite proppant aggregate 2.

Manufacturing Example 3

Preparation of ceramsite proppant aggregate 3

53 parts by weight of bauxite stray light was weighed and added to a hammer mill and pulverized for about 35 minutes, then a bauxite stray coarse powder material was obtained and taken out. 40 parts by weight of kaolin and 2 parts by weight of a ball milling aid were each weighed and added to the ball mill together with the bauxite light coarse powder material, and then 55 parts by weight of water were added, and the product was ball milled for about 40 minutes. The material was obtained. The obtained powder material was added to a disk granulator and sprayed with steam to obtain granules, and the granules were sieved through a 120 mesh sieve, and then added to a rotary kiln together with 8 parts by weight of a sintering aid and sintered at 1280-1350°C. A ceramsite blank was produced. After polishing the ceramsite blank by adding 5.5 parts by weight of alumina powder, the alumina powder was removed to obtain a ceramsite proppant aggregate 3.

Manufacturing Example 4

Preparation of ceramsite proppant aggregate 4

49 parts by weight of bauxite stray light was weighed and added to a hammer mill and pulverized for about 40 minutes, then a bauxite stray coarse powder material was obtained and taken out. A powder mixed by weighing 32 parts by weight of kaolin and 1 part by weight of a ball milling aid into a ball mill together with a bauxite light coarse powder material, then adding 50 parts by weight of water, and ball milling the product for about 30 minutes. The material was obtained. The obtained powder material was added into a disk granulator and sprayed with water vapor to obtain granules, and the granules were sieved through a 120 mesh sieve, and then added to a rotary kiln together with 5 parts by weight of a sintering aid and sintered at 1280-1350°C. A ceramsite blank was produced. After polishing the ceramsite blank by adding 4 parts by weight of alumina powder, the alumina powder was removed to obtain a ceramsite proppant aggregate 4.

Manufacturing Example 5

Preparation of ceramsite proppant aggregate 5

44 parts by weight of bauxite stray light was weighed and added to a hammer mill and pulverized for about 40 minutes, then a bauxite stray coarse powder material was obtained and taken out. 38 parts by weight of kaolin and 1.5 parts by weight of a ball milling aid were each weighed and added to the ball mill together with the bauxite light coarse powder material, then 50 parts by weight of water were added, and the product was ball milled for about 30 minutes. The material was obtained. The obtained powder material was added into a disk granulator and sprayed with steam to obtain granules, and the granules were sieved through a 120 mesh sieve, and then added to a rotary kiln together with 6 parts by weight of a sintering aid and sintered at 1280-1350°C. A ceramsite blank was produced. After the ceramsite blank was polished by adding 4.7 parts by weight of alumina powder, the alumina powder was removed to obtain a ceramsite proppant aggregate 5.

Example 1

70 parts by weight of aggregate 1 was put into a sand mixing kettle and heated to 210° C., followed by sand mixing at 80 rpm for 30 minutes. 5 parts by weight of acrylic acid ethyl ester was added thereto, the temperature was lowered to 160° C., 4 parts by weight of a curing agent was added, and the product was further sand-mixed for 45 minutes to form an acrylic acid ethyl ester inner layer on the aggregate. The temperature was further lowered to 90° C., 5 parts by weight of melamine-formaldehyde resin was added into the sand mixing kettle, followed by 0.01 parts by weight of catalyst, 0.5 parts by weight of diethylenetriamine, and 7 parts by weight of TDI. As added, the product was sand-mixed at 80° C. for 50 minutes, after which the temperature was lowered to 50° C., and the product was taken out to obtain coated propant 1.

Example 2

75 parts by weight of aggregate 2 was put into a sand mixing kettle and heated to 210° C., followed by sand mixing at 80 rpm for 30 minutes. 6 parts by weight of acrylic acid ethyl ester was added thereto, the temperature was lowered to 160°C, 4.5 parts by weight of an amine curing agent was added, and the product was further sand-mixed for 45 minutes to form an inner layer of acrylic acid ethyl ester on the aggregate. Formed. The temperature was further lowered to 90° C., 4.4 parts by weight of melamine-formaldehyde resin was added into the sand mixing kettle, and then 0.01 parts by weight of catalyst, 0.7 parts by weight of diethylenetriamine and 5.1 parts by weight of TDI were added in that order. , The product was sand-mixed at 80° C. for 50 minutes, after which the temperature was lowered to 50° C., and the product was taken out to obtain coated propant 2.

Example 3

90 parts by weight of aggregate 3 was put into a sand mixing kettle and heated to 220° C., followed by sand mixing at 80 rpm for 40 minutes. To it, 8 parts by weight of acrylic acid ethyl ester was added, the temperature was lowered to 180° C., 4.3 parts by weight of a curing agent was added, and the product was further sand-mixed for 45 minutes to form an acrylic acid ethyl ester inner layer on the aggregate. The temperature was further lowered to 100° C., 3.6 parts by weight of melamine-formaldehyde resin was added into the sand mixing kettle, and then 0.01 parts by weight of catalyst, 0.5 parts by weight of diethylenetriamine and 4.1 parts by weight of TDI were sequentially added. , The product was sand-mixed at 80° C. for 50 minutes, after which the temperature was lowered to 50° C., and the product was taken out to obtain coated propant 3.

Example 4

65 parts by weight of aggregate 4 was put into a sand mixing kettle and heated to 210° C., followed by sand mixing at 80 rpm for 30 minutes. 5 parts by weight of acrylic acid ethyl ester was added thereto, the temperature was lowered to 160° C., 3.2 parts by weight of a hardener was added, and the product was further sand-mixed for 40 minutes to form an acrylic acid ethyl ester inner layer on the aggregate. The temperature was further lowered to 80° C., 3.9 parts by weight of melamine-formaldehyde resin was added into the sand mixing kettle, and then 0.01 parts by weight of catalyst, 0.7 parts by weight of diethylenetriamine and 5 parts by weight of TDI were added in order. , The product was sand-mixed at 70° C. for 50 minutes, after which the temperature was lowered to 50° C., and the product was taken out to obtain coated propant 4.

Example 5

66 parts by weight of aggregate 5 was placed in a sand mixing kettle and heated to 210° C., followed by sand mixing at 80 rpm for 30 minutes. 9 parts by weight of acrylic acid ethyl ester was added thereto, the temperature was lowered to 160° C., 4 parts by weight of an amine curing agent was added, and the product was further sand-mixed for 40 minutes to form an inner layer of acrylic acid ethyl ester on the aggregate. The temperature was further lowered to 90° C., 5 parts by weight of melamine-formaldehyde resin were added into the sand mixing kettle, and then 0.005 parts by weight of catalyst, 0.75 parts by weight of diethylenetriamine and 7.3 parts by weight of TDI were added in that order. , The product was sand-mixed at 70° C. for 50 minutes, after which the temperature was lowered to 50° C., and the product was taken out to obtain coated propant 5.

Comparative Example 1

A coated proppant was produced in the same manner as in Example 1, except that the outer layer was formed using a phenol resin.

Comparative Example 2

A coated proppant was produced using the same method as in Example 3, except that only acrylic acid ethyl ester was coated as an inner layer to form a single-layer coated proppant.

The properties of the coated proppants prepared in Examples 1-5 and Comparative Examples 1-2 are shown in Table 1 below:

Table 1

Note: Suspension time refers to the longest time to self-suspend in water.

As can be seen from the data in Table 1, compared with Comparative Example 1-2, the coated proppant produced in Example 1-5 maintained a breakage ratio comparable to that of the conventional coated proppant, while proppant bulk density It further reduces and significantly prolongs the self-suspension time of the proppant particles in water.

Claims (5)

Industrial waste is used as a raw material to produce aggregate, and the inner-layer polymer is acrylic acid ethyl ester, and the outer-layer polymer is a two-layered melamine-formaldehyde resin. A double-coated proppant produced by coating a polymer on the aggregate. The double-coated proppant according to claim 1, wherein the industrial waste is blast furnace slag or refractory material waste. The double-coated proppant of claim 1, wherein the aggregate has a particle size of 0.100mm-3.100mm. A method of producing a double-coated proppant according to claim 1 comprising the following steps:
(a) weighing the aggregate, acrylic acid ethyl ester, acrylic acid ethyl ester curing agent, melamine-formaldehyde resin, and catalyst in order;
(b) pouring the aggregate into a sand mixing kettle, heating to 170-240° C., and performing sand mixing;
(c) adding an acrylic acid ethyl ester and an acrylic acid ethyl ester hardener into a sand mixing kettle, and performing a first coating at 150-190°C;
(d) adding a melamine-formaldehyde resin and a catalyst into a sand mixing kettle, and performing sand mixing at 70-100°C; And
(e) lowering the temperature to 50-65° C. and taking out the product. Use of the double-coated proppant according to claim 1 in hydraulic fracturing.