KR20210041265A - A coated proppant - Google Patents

Abstract

Disclosed is coated proppant comprising an aggregate and a resin layer material for coating the aggregate, wherein the aggregate is produced from bauxite tailings as raw materials, and the resin layer material contains a methyl acrylate resin and a methyl acrylate resin curing agent.

Description

Coated proppant{A COATED PROPPANT}

The present invention relates to the field of coated proppants, and in particular to coated proppants resulting from the raw material bauxite tailing.

Proppant is a solid particle designated for fracturing. After crushing, the proppant supports the wall surface of the crushed rock so that the rock cannot be resealed, and the resulting hydraulic fracture becomes a flow-conduction channel leading to the wellbore. . In China, this artificial proppant produced by sintering or jetting the main raw material bauxite is collectively referred to as ceramsite. Inside and outside China, the relative density of ceramsite proppant is in the range of 2.70 to 3.60, and its bulk density is in ^{the range of 1.60-2.10 g/cm 3} , both of which are greater than that of natural silica sand.

With the rapid development of the steel and aluminum industry in China, the amount of bauxite tailings discharged also increases, destroying the ecological environment and seriously affecting people's daily life. In order to completely recycle the tailings, improve the ecological environment, turn harm into good, and turn waste into useful ones, a method of producing ceramsite proppant from the raw material tailings is proposed. However, when it is applied to deep oil well destruction, the ceramsite is destroyed under high closing pressure, producing a large amount of debris and finely powdered sand. The finely powdered sand moves within the crack and blocks the flow channel, greatly deteriorating the flow conductivity of the crack. The coated proppant is produced by coating a layer of a polymer material on the surface of the ceramsite proppant aggregate and has the characteristics of low relative density, high strength, low fracture rate, and good roundness, spherical and chemical inertness. However, in the coating process of these products, ceramsite needs to be heated, causing energy consumption, and smoke and gases are generated during the production process, causing environmental pollution.

In view of the problems of the prior art described above, the present invention provides a coated proppant by coating a resin film on the ceramsite proppant.

The technical problem to be solved by the present invention is solved by the following technical solution:

A coated proppant comprising an aggregate and a resin layer material for coating the aggregate, wherein the aggregate is produced from waste selected from the raw material bauxite tailings, and the resin layer material includes methyl acrylate resin and methyl acrylate resin curing agent. do.

Preferably, an aggregate having a weight part of 150 to 300 (weight part) and a resin layer material having a weight part of 10 to 20 are used.

The degree of functionality of the methyl acrylate resin curing agent is 2 or more. The methyl acrylate resin curing agent having a degree of functionality of 2 or more has good reaction activity, and can improve the surface compression performance and chemical inertness of the resin film body of the proppant surface coating layer.

The methyl acrylate resin curing agent is used in an amount of 20 to 35 wt% based on the total weight of the resin layer material.

The particle size of the aggregate is 0.100mm to 2.800mm.

Aggregates are produced from the main raw material bauxite tailings through the following steps:

(1) By parts by weight, 40 to 75 bauxite tailings, 60 to 65 fly ash, 20 to 25 sintering aid, 5 to 10 silica sand, 3 to 7 alumina powder, 1 to 2 Metering the phosphorus ball milling aid and water of 20 to 50;

(2) crushing the bauxite tailings, and continuously dry grinding the crushed bauxite tailings;

(3) placing the result of step (2) on a ball mill together with fly ash, silica sand and ball milling aid, and adding water to thoroughly mix to obtain a mixed material;

(4) drying the mixed material of step (3) and forming pellets therefrom;

(5) adding a sintering aid and sintering at high temperature to obtain a ceramsite blank;

(6) Alumina powder is added to the ceramsite blank to be polished, and the powder is removed to obtain an aggregate.

There is no limitation on the type of bauxite, but it is preferable to use Shanxi bauxite.

The bauxite tailings have the main chemical composition _{of Al 2} O ₃ ≥55%, Fe ₂ O ₃ ≤3%, CaO≤2% and K ₂ O+Na _{2 O≤1%.}

Coated proppant is produced by the following steps:

(a) feeding the aggregate into the sand mixer;

(b) mixing the methyl acrylate resin and the methyl acrylate resin curing agent, adding a solvent, and stirring evenly to completely dissolve to obtain a mixture;

(c) adding a mixture of methyl acrylate resin and methyl acrylate resin curing agent to the aggregate, stirring, and completely curing;

(d) air drying and uniformly spreading; And

(e) sieving and packaging.

The coated proppant of the present invention is produced by coating a layer of a polymer material on the surface of a ceramsite proppant aggregate, a simple production process, low product relative density, high strength, low fracture rate, good sphericity and chemical inertness, and Has the advantage of no pollution during production; The coated proppant of the present invention is widely used in oil and gas field crushing operations, can reduce the amount of crushing fluid used, improve crack flow conductivity, and extend the shelf life of crushing; The coated proppant of the present invention can help to improve oil production, and is very important for the utilization of low permeability oil fields.

The invention will be further explained by the following specific embodiments, but the invention is not limited to the specific embodiments described below.

Manufacturing Example 1

Preparation of ceramsite proppant aggregate 1

Bauxite tailings with a weight of 40 were measured and added into a hammer crusher and pulverized for about 30 minutes, and then a bauxite coarse powder material was obtained and taken out. Kaolin with a weight of 35 and a ball milling aid with a weight of 2 were weighed, respectively, and added into the ball mill with the coarse bauxite powder material, water of 50 weight was then added, and the resultant was for about 45 minutes. Ball milled to obtain a mixed powder material. The obtained powder material was added into a disk granulator, water vapor was sprayed, and granulated to obtain a granule, which was sieved into a 120 mesh sieve, followed by a sintering aid having a weight of 7 And added into a rotary kiln and sintered at 1280 to 1350° C. to produce a ceramsite blank. Alumina powder of 5 parts by weight was added to polish the ceramsite blank, and then the alumina powder was removed to obtain ceramsite proppant aggregate 1.

Manufacturing example 2

Preparation of ceramsite proppant aggregate 2

Bauxite tailings having a weight of 45 were measured and added into a hammer crusher and pulverized for about 30 minutes, and then a coarse bauxite powder material was obtained and taken out. Kaolin with a weight of 37 and a ball milling aid with a weight of 1.5 were weighed, respectively, and added into the ball mill with the coarse bauxite powder material, water with a weight of 60 was added next, and the resultant was ball milled for about 45 minutes. A mixed powder material was obtained. The obtained powder material was added into a disk granulator, water vapor was sprayed and granulated to obtain granules, which were sieved into a 120 mesh sieve and then added into a rotary kiln together with a sintering aid of 9 parts by weight to It was sintered at 1350° C. to produce a ceramsite blank. Alumina powder of 4 parts by weight was added to polish the ceramsite blank, and then the alumina powder was removed to obtain ceramsite proppant aggregate 2.

Manufacturing Example 3

Preparation of ceramsite proppant aggregate 3

Bauxite tailings having a weight of 53 were measured and added into a hammer crusher and crushed for about 35 minutes, and then a coarse bauxite powder material was obtained and taken out. Kaolin with a weight of 40 and a ball milling aid with a weight of 2 were weighed, respectively, and added into the ball mill together with the coarse bauxite powder material, water with a weight of 55 was added next, and the resultant was ball milled for about 40 minutes. A mixed powder material was obtained. The obtained powder material was added into a disk granulator, water vapor was sprayed and granulated to obtain granules, which were sieved with a mesh sieve of 120 and then added into a rotary kiln together with a sintering aid of 8 parts by weight and added from 1280 to It was sintered at 1350° C. to produce a ceramsite blank. Alumina powder having a weight of 5.5 was added to polish the ceramsite blank, and then the alumina powder was removed to obtain a ceramsite proppant aggregate 3.

Manufacturing Example 4

Preparation of ceramsite proppant aggregate 4

Bauxite tailings having a weight of 49 were measured and added into a hammer crusher and pulverized for about 40 minutes, and then a coarse bauxite powder material was obtained and taken out. Kaolin with a weight of 32 and a ball milling aid with a weight of 1 were weighed, respectively, and added into the ball mill together with the coarse bauxite powder material, water of 50 weight was added next, and the resultant was for about 30 minutes. Ball milled to obtain a mixed powder material. The obtained powder material was added into a disk granulator, and water vapor was sprayed and granulated to obtain granules, which were sieved with a mesh sieve of 120 and then added into a rotary kiln with a sintering aid of 5 parts by weight and 1280 to It was sintered at 1350° C. to produce a ceramsite blank. Alumina powder of 4 parts by weight was added to polish the ceramsite blank, and then the alumina powder was removed to obtain a ceramsite proppant aggregate 4.

Manufacturing Example 5

Preparation of ceramsite proppant aggregate 5

Bauxite tailings having a weight of 44 were measured and added into a hammer crusher and crushed for about 40 minutes, and then a coarse bauxite powder material was obtained and taken out. Kaolin with a weight of 38 and a ball milling aid with a weight of 1.5 were weighed, respectively, and added into the ball mill together with the coarse bauxite powder material, water with a weight of 50 was then added, and the resultant was ball milled for about 30 minutes. A mixed powder material was obtained. The obtained powder material was added into a disk granulator, and water vapor was sprayed and granulated to obtain granules, which were sieved with a mesh sieve of 120 and then added into a rotary kiln with a sintering aid of 6 parts by weight to It was sintered at 1350° C. to produce a ceramsite blank. Alumina powder having 4.7 parts by weight was added to polish the ceramsite blank, and then the alumina powder was removed to obtain a ceramsite proppant aggregate 5.

Example 1

Aggregate 1 with a weight of 200, methyl acrylate resin with a weight of 15, and a curing agent with a weight of 3 were weighed. The aggregate was placed in a sand mixing kettle and heated to 200 °C and then sand mixed at a rotational speed of about 100 rpm for 1 hour. Methyl acrylate resin was added here, after the temperature was lowered to 150 °C, a curing agent was added, and the resultant was further sand mixed for 30 minutes at a rotation speed of 70 rpm, and then the temperature was lowered to 50 °C. And the resultant was taken out to obtain coated propant 1.

Example 2

Aggregate 2 with a weight of 260, methyl acrylate resin with a weight of 20, and a curing agent with a weight of 6 were weighed. The aggregate was placed in a sand mixing kettle and heated to 200 °C and then sand mixed at a rotation speed of about 100 rpm for 1.5 hours. Methyl acrylate resin was added here, after the temperature was lowered to 150 °C, a curing agent was added, and the resultant was further sand mixed for 45 minutes at a rotation speed of 70 rpm, then the temperature was lowered to 50 °C. And the resultant was taken out to obtain coated propant 2.

Example 3

Aggregate 3 with a weight of 300, methyl acrylate resin with a weight of 20, and a curing agent with a weight of 7 were weighed. The aggregate was placed in a sand mixing kettle and heated to 200 °C and then sand mixed at a rotation speed of about 100 rpm for 1.5 hours. Methyl acrylate resin was added here, after the temperature was lowered to 150 °C, a curing agent was added, and the resultant was sand mixed for an additional hour at a rotation speed of 70 rpm, and then the temperature was lowered to 50 °C. And the resultant was taken out to obtain coated propant 3.

Example 4

Aggregate 4 with a weight of 200, methyl acrylate resin with a weight of 15, and a curing agent with a weight of 3.5 were weighed. The aggregate was placed in a sand mixing kettle and heated to 200 °C, then sand mixed at a rotational speed of about 100 rpm for 45 minutes. Methyl acrylate resin was added here, after the temperature was lowered to 150 °C, a curing agent was added, and the resultant was sand mixed for an additional hour at a rotation speed of 70 rpm, and then the temperature was lowered to 50 °C. And the resultant was taken out to obtain coated propant 4.

Example 5

Aggregate 5 with a weight of 210, methyl acrylate resin with a weight of 18, and a curing agent with a weight of 4 were weighed. The aggregate was placed in a sand mixing kettle and heated to 200 °C, then sand mixed at a rotational speed of about 100 rpm for 45 minutes. Methyl acrylate resin was added here, after the temperature was lowered to 150 °C, a curing agent was added, and the resultant was sand mixed for an additional hour at a rotation speed of 70 rpm, and then the temperature was lowered to 50 °C. And the resultant was taken out to obtain coated propant 5.

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

Acid solubility
（%） Bulk density
(g/cm3) 52MPa
Destruction rate
（%） Turbidity (FTU) Example 1 2.64 1.41 2.68 ≤50 Example 2 2.76 1.42 2.71 ≤50 Example 3 3.02 1.4 3.12 ≤50 Example 4 2.09 1.33 2.16 ≤50 Example 5 2.62 1.38 2 51 ≤50 Commercially available coated proppant 3.32 1.59 3.97 ≤50

As can be seen from the data in Table 1, by coating a methyl acrylate resin film on the surface of the ceramsite proppant aggregate at the ratio shown in the present invention, the coated proppant of the present invention is a conventional coated proppant. And compared with the uncoated aggregate, while further reducing the density, it realizes higher strength and acid resistance.

Claims (6)

As a coated proppant comprising an aggregate having a weight part of 120 to 260 and a resin layer material having a weight part of 13 to 20 to coat the aggregate,
The aggregate is produced from the raw material bauxite tailing,
The resin layer material includes a methyl acrylate resin and a methyl acrylate resin curing agent,
The methyl acrylate resin curing agent is used in an amount of 20 to 35 wt% based on the total weight of the resin layer material,
Coated proppant. The method of claim 1,
The degree of functionality of the methyl acrylate resin curing agent is 2 or more, the coated proppant. The method of claim 1,
The particle size of the aggregate is 0.100mm to 2.800mm, the coated proppant. The method of claim 1,
The bauxite tailings have _{the main chemical composition of Al 2} O ₃ ≥55%, Fe ₂ O ₃ ≤3%, CaO≤2% and K ₂ O+Na ₂ O≤1%, the coated proppant. In the method for producing the coated proppant according to claim 1,
(a) feeding the aggregate into a sand mixer;
(b) mixing the methyl acrylate resin and the methyl acrylate resin curing agent, adding a solvent, and stirring evenly to completely dissolve to obtain a mixture;
(c) adding the mixture of the methyl acrylate resin and the methyl acrylate resin curing agent to the aggregate, stirring, and completely curing;
(d) air drying and uniformly spreading; And
(e) sieving and packaging; containing,
A method for producing the coated proppant. The method of claim 5,
In the method for producing the coated proppant,
(1) By weight, 40 to 75 of the bauxite tailings, 60 to 65 fly ash, 20 to 25 sintering aid, 5 to 10 quartz sand, 3 to 7 alumina Metering powder, 1 to 2 ball milling aids and 20 to 50 water;
(2) crushing the bauxite tailings and continuously dry grinding the crushed bauxite tailings;
(3) placing the result of step (2) in a ball mill together with the fly ash, the silica sand, and the ball milling aid, and adding water to obtain a mixed material by thoroughly mixing;
(4) drying the mixed material of step (3) and forming a pellet therefrom;
(5) adding the sintering aid and sintering at high temperature to obtain a ceramsite blank; And
(6) adding and polishing the alumina powder to the ceramsite blank, and removing the powder to obtain the aggregate;
Including a method for producing the coated proppant.