RU2392251C1 - Method for production of aluminosilicate propant and composition thereof - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: under the method for production of alumosilicate ceramic propant involving thermal treatment of refractory raw material components, fine grounding of the mixture, granulation, drying and granulate baking, thermal treatment of refractory clayey raw material in the form of a briquette is performed at a temperature of 950°C, preparation of raw material components is performed by way of separate dry grinding of the alumina admixture for the average particle size to be 1-2 mcm and baked refractory clayey raw material in a mixture with a coagulating additive for the average particle size to be 2-5 mcm, the mixture granulation is performed for the granules bulk density to be minimum 1.0 g/cm³ while the granules baking is performed at a temperature of 1450°C. The composition for production of alumosilicate ceramic propant contains, wt %: baked clayey raw material - refined kaolin or refractory clay containing at least 80% of clayey minerals including at least 70% of kaolinite, free quartz - no more than 5%; alkaline oxides - no more than 1.0-1.2% 73.0-84.0, technical alumina 9.0-18.5, ferrioxide additives - sulphur wastes or ferric ore containing FeO+Fe₂O₃ in an amount of at least 65% 6.5-8.5.

EFFECT: reduction of the granulated material baking temperature for production of high-strength alumosilicate propants.

2 cl, 3 tbl, 1 ex

Description

The invention relates to the production of granular ceramic materials intended for use in various industries, for example, as proppants (proppants) in oil and gas production by hydraulic fracturing.

Existing proppants are distinguished by composition and by a number of properties, including density and strength, dividing into lightweight (bulk density not more than 1.57 g / cm ³ ) with medium strength and heavy (bulk density more than 1.57 g / cm ³ ) with high strength. The advantages of low-density proppants are tangible in a liquid medium of low and medium viscosity, easier to pass through the proppant layer. Such proppants are most effective in low and medium pressure wells and ineffective in high pressure wells. Therefore, the main problem in developing the technology of ceramic proppants is to ensure such mutually competing properties of the granular material as its high strength while maintaining low bulk density values.

A known method and composition of the mixture to obtain aluminosilicate propants, where kaolin containing 30.0-42.5 wt.% Al ₂ O ₃ / Simanovsky B.A .; Rozanov O.M .; Mozherin V.A. and others. A method of processing aluminum-silicon raw materials. RF patent for the invention No. 2140874. Claim 02/10/1998, publ. 11/10/1999 /. The disadvantage is the high bulk density of the proppants (more than 1.62-1.80 g / cm ³ ), limiting the scope of its application, since when carrying out hydraulic fracturing of an oil and gas formation with similar heavy proppants, it is necessary to use more viscous and expensive fluids. The high temperature of firing proppants (1450 ° C) leads to additional energy consumption.

The known composition of the proppant containing ceramic spherical granules from sintered raw materials - kaolin clay, including oxides of aluminum, silicon, iron and titanium, where enriched kaolin clay of the following composition is used as feedstock, wt.%: Aluminum oxide - 41-43; silicon oxide - 45-50; iron oxide - not more than 1.2 / Pyastolov A.M., Milenin S.I. Proppant. RF patent for the invention No. 2166079. Claim 12/23/1999. Publ. 04/27/2001 /. The disadvantage is the narrow range of ratios of aluminum and silicon oxides and strict restrictions on the content of impurity iron and titanium oxides in the initial clay raw materials, which makes it impossible to use clays of many deposits for this purpose, since most of the enriched kaolinite clays have a wider range of contents of these oxides (for calcined substance): aluminum oxide - 33-45 wt.%; silicon oxide - 51-60 wt.%. The content of iron oxide often reaches 2-3 wt.%, And titanium oxide - up to 1-1.5 wt.%.

A known composition of aluminosilicate mixture for the production of granules, including 70-99.5 wt.% Calcined kaolin with a content of 30-45% Al ₂ O ₃ and 0.5-30 wt.% Reinforcing additives containing the following substances or mixtures thereof: alumina dust baddeleyite, calcined at a temperature of 800-1100 ° С zirconium concentrate and unburnt bauxite / Simanovsky B.A .; Rozanov O.M .; Mozherin V.A. and others. Aluminum-silicon mixture for the production of granules. RF patent for invention 2140875. 02/10/1998, publ. 10/11/1999 /. The disadvantage of the mixture of this composition, as in previous cases, is a high bulk density (1.67-1.89 g / cm ³ ) and a high firing temperature of the granules (1450 ° C or more). In addition, the low values of sphericity and roundness of proppants (on average 0.8) adversely affect the wear of oil equipment.

The known composition of the charge and a method for producing lightweight high-strength ceramic proppants, including heat treatment of the initial aluminosilicate raw materials, which include kaolin, grinding the processed raw materials, screening of fractions having sizes different from the specified ones, with their subsequent return to the grinding stage, granulation of the heat-treated aluminosilicate raw materials with constant mixing of the mass and its moistening, drying and preliminary sieving of the obtained granules with return to the grinding of granules that differ from adannogo size, final calcining granules and sieving the fired pellets. In this case, before granulating the heat-treated aluminosilicate raw material (kaolin), a mineralizer is introduced into it in an amount of 2 to 5% and a dispersion of 10 μm of the following chemical composition (wt.%): 31 TiO ₂ in the form of rutile; 27 FeO; 13 SiO ₂ ; 3.8 MnO; 1.7 Cr ₂ O ₃ ; 1.1 MgO, and the heat treatment of the feedstock is carried out at a temperature of 1025 to 1145 ° C, providing complete decomposition of kaolinite, the beginning of the formation of mullite crystals and the isolation and modification of the glass phase / Ipatov SA, Potapov MA A method of obtaining a lightweight high-strength ceramic proppants. RF patent for the invention No. 2203248. Claim 06/14/2002, publ. 04/27/2003 /. The disadvantage of this method is the need for preliminary high-temperature heat treatment of kaolin in the temperature range from 1025 to 1145 ° C and stringent requirements to ensure the particle size distribution of crushed kaolin with a mass fraction of particles less than 2 microns - 20%, less than 5 microns - 45%, less than 10 microns - 60 %, less than 50 microns - 85%. This reduces the reliability of the performance of the specified process parameters and may cause instability of the characteristics of the finished product.

Closest to the proposed is a method for producing refractory high-strength ceramic proppants, according to which kaolin and bauxite are pre-fired, and for the production of granules, a mixture of co-grinding fired kaolin and bauxite is used in the ratio, wt.%: Fired kaolin 33-67; calcined bauxite - the rest, while the ratio of Al ₂ O ₃ : SiO ₂ in the mixture is 1: 1. Preliminary firing of kaolin, which contains 40-45% Al ₂ O ₃ and not more than 5% of free quartz, is carried out at a temperature of 1400-1500 ° C until water absorption of not more than 5% (preferably not more than 4%). The temperature of preliminary firing of bauxite depends on the content of Al ₂ O ₃ : 1500-1700 ° C (preferably 1600-1650 ° C) to a water absorption of not more than 5% with an Al ₂ O ₃ content _of 60-65%; 1100-1400 ° C (preferably 1250-1300 ° C) to a water absorption of 20-35% with an Al ₂ O ₃ content _of more than 65%. After preliminary firing, bauxite and kaolin are subjected to dry joint fine grinding to an average particle size of less than 10 microns (preferably less than 5 microns). The co-grinding mixture is granulated, the obtained granules are dried, dispersed to isolate the desired fraction, after which it is calcined at a temperature of 1500-1600 ° C (preferably 1550-1600 ° C) and the calcined granules are secondly dispersed to isolate a marketable product / Mozherin V.A .; Migal V.P .; Sakulin V.Ya. and others. The mixture for the manufacture of refractory high-strength spherical granules and the method of their production. RF patent for the invention No. 2211198. Claim 11/13/2001, publ. 08/27/2003 /.

The disadvantage of this method is the high firing temperatures of both components of the charge (kaolin and bauxite), which determines the high energy intensity of the process of obtaining proppant.

The task of the invention is to reduce the firing temperature of granular material to obtain high-strength lightweight aluminosilicate propants.

The invention consists in activating the sintering process of aluminosilicate ceramic mass through the use of sintering additives.

The task is ensured by a set of operations, including heat treatment of refractory clay raw materials at a temperature of 950 ° C, preparation of raw materials by separate dry grinding of alumina additives to sizes of 1-2 microns and calcined refractory clay raw materials in the form of crushed briquette in a mixture with sintering additive to sizes 2- 5 μm, granulating the mixture to a bulk density of granules of at least 1.0 g / cm ³ and firing the granules at a temperature of 1450 ° C.

At the same time, enriched kaolin or refractory clay with a clay mineral content of at least 80%, including kaolinite at least 70%, free quartz no more than 5% is used as refractory clay raw material; alkaline oxides not more than 1.0-1.5%, compressive strength in the sintered state - not less than 100 MPa, technical alumina as an alumina additive, iron oxide additive from the group: pyrite cinders or iron ore containing FeO + Fe ₂ O ₃ not less than 65% when their ratio in the ceramic mass of the composition (wt.%): Calcined refractory clay raw materials (refractory clay or enriched kaolin) - 73.0-84.0, technical alumina - 9.0- 18.5, iron oxide additive (iron ore or pyrite cinder) - 6.5-8.5.

The use of enriched kaolin or refractory clay with a clay mineral content of at least 80%, including kaolinite of at least 70%, is necessary to ensure maximum yield of the main crystalline phase (mullite), which determines the strength properties of aluminosilicate ceramics.

A content of more than 1.5% alkaline oxides in refractory clay or kaolin enriched kaolin leads to the formation of an increased amount of glass phase, which reduces the mechanical strength of the ceramic structure.

The use of refractory clay or enriched kaolin with a free quartz content of more than 5% is due to the softening effect of quartz as a result of its modification transformations during firing, occurring with a change (increase) in volume.

The use of an alumina additive in the form of technical alumina is necessary to increase the strength of the proppant due to the synthesis of secondary mullite as a result of the reaction of alumina binding to silica released from the structure of kaolinite during its destruction during heating.

The use of iron oxide additives from the group of pyrite cinder or iron ore with a content of FeO + Fe ₂ O _{3 of} at least 65% as a sintering additive is due to the need to reduce the temperature of firing of proppant due to the activation of the sintering process of aluminosilicate ceramic mass.

Example

As a refractory clay raw material according to the present method, enriched kaolin of the "Crane Log" deposit is used.

As an alumina additive, technical grade alumina of the brand G _{oo is used} .

Pyrite cinder in the form of a technical product or iron ore of the Bakcharsky deposit of the Tomsk region is used as a sintering additive.

The characteristics of the raw materials in chemical composition are shown in table 1.

The composition of the mixture for the production of proppants is shown in table 2.

Refractory raw materials (kaolin) are pre-compacted by briquetting and fired at a temperature of 950 ° C in order to dehydrate the main clay mineral (kaolinite).

The calcined kaolin briquette is crushed to a particle size of 2-3 mm, mixed with a sintering additive in the form of iron ore or pyrite cinder and crushed by a dry method in a ball mill to a particle size of 2-3 microns. Fine grinding of alumina additives is carried out in a ball mill by dry method to a particle size of 1-2 microns. To prevent the buildup of material on the walls of the mill and the aggregation of particles of finely ground material, a surfactant additive (oleic acid) is used in an amount of 0.5 wt.%.

The granulation of the raw material mixture is carried out in a turbopaste mixer to a bulk density of at least 1 g / cm ³ (in dry condition) using a clay slip with a density of 1.15-1.20 g / cm ³ or 0.3% as a moisturizing and plasticizing additive - solution of an organic binder (carboxymethyl cellulose), in an amount providing a moisture content of the mixture 16-18%.

In order to prevent baking during firing, freshly formed granules are dusted with technical alumina or kaolin, dried to an air-dry state and burned at a temperature of 1450 ° C in an electric furnace, after which they are cooled and dispersed into the necessary fractions.

On fired granules with a fraction of 20/40 (0.4-0.8 mm), which are commercial aluminosilicate proppants, the compressive strength, bulk density, true density, sphericity and roundness of the granules are determined (table 3).

The use of iron oxide additives from the group of pyrite cinders or iron ore with a content of FeO + Fe ₂ O _{3 of} not less than 65% as a strengthening additive ensures a reduction in the temperature of firing of proppant due to the activation of the sintering process of aluminosilicate ceramic mass.

A method of producing aluminosilicate propant and its composition

Table 1 The chemical composition of raw materials Raw material component The content of oxides, wt.% SiO ₂ Al ₂ O ₃ + TiO ₂ Fe ₂ O ₃ MgO Cao R ₂ O + P ₂ O ₅ + V ₂ O ₅ Δm _PPH. Kaolin of the Crane Log field 47.46 36.50 1.01 0.20 0.80 1,02 13.01 Pyrite cinder 13.56 2.08 74.58 1,53 2.05 next 6.20 Iron ore of the Bakcharsky deposit 11.20 5.01 67.06 0.50 1.40 3,58 11.25 Technical alumina G _oo 0.02 99.81 0,03 0.06 0.08

table 2 Component compositions of ceramic masses Components Prototype The content of components in the compositions, wt.% one 2 3 four 5 6 Outlawing compositions BUT B Calcined kaolin of the Crane Log field 67 84.0 82.6 75.0 73.0 84.0 82.5 90,4 72 Technical alumina G _oo - 9.5 9.0 18.5 18.5 9.5 9.2 4.8 eighteen Pyrite cinder - 6.5 8.5 6.5 8.5 - - 4.8 - Iron ore - - - - - 6.5 8.3 - 10 Burnt bauxite 33 - - - - - - - -

METHOD FOR PRODUCING ALUMINOSILICATE PROPANET AND ITS COMPOSITION

Table 3 The influence of technological parameters on the properties of aluminosilicate propant Parameters and properties Prototype Composition code one 2 3 four 5 6 Outlawing compositions BUT B The processing temperature of kaolin, ° C 1400-1500 950 950 950 950 950 950 950 950 Bauxite processing temperature, ° С 1600 - - - - - - - - Proppant firing temperature 1500-1600 1450 1450 1450 1450 1450 1450 1450 1450 Sphericity 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 Roundness 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 Bulk density, g / cm ³ 1,58 1,59 1,57 1,58 1,58 1,59 1,58 1,62 1.68 True density, g / cm ³ 2.62 2.62 2.61 2.62 2.61 2.62 2.62 2.66 2.72 Strength at 70 MPa,% of destroyed granules 11.9 9,4 11,4 11.3 9.5 9.8 10.9 15,5 13.7

Claims (2)

1. A method of producing aluminosilicate ceramic proppant, including heat treatment of refractory raw materials, fine grinding of the mixture, granulation, drying and firing of granulate, characterized in that the heat treatment of refractory clay raw materials in the form of a briquette is carried out at a temperature of 950 ° C, the preparation of raw materials is carried out separately dry grinding alumina additives to an average particle size of 1-2 microns and calcined refractory clay raw materials in a mixture with a sintering additive to an average particle size of 2-5 microns, gr the mixture is canceled to a bulk density of granules of at least 1.0 g / cm ³ and the granules are fired at a temperature of 1450 ° C. 2. Composition for producing aluminosilicate ceramic proppant, including refractory clay raw materials and alumina additive, characterized in that refractory clay or enriched kaolin with clay minerals content of at least 80%, including kaolinite of at least 70%, are used as clay raw materials quartz no more than 5%; alkaline oxides of not more than 1.0-1.2%, compressive strength in the sintered state of not less than 100 MPa, technical alumina is used as an alumina additive, iron oxide additive from the pyrite cinder group or iron ore with FeO + content is used as a sintering additive Fe ₂ O ₃ not less than 65% in the following ratio of components, wt.%:
burnt clay raw materials (enriched kaolin or refractory clay) 73.0-84.0 industrial alumina 9.0-18.5 iron oxide additive 6.5-8.5