Oil fracturing proppant with fly ash and its preparation method

Abstract

The application provides a petroleum fracturing proppant with fly ash and a preparation method thereof, and belongs to the technical field of fracturing proppants. The petroleum fracturing proppant with fly ash comprises the following raw materials in parts by weight: fly ash 10-20 parts, low-grade bauxite 50-60 parts, magnesite tailings 10-15 parts, phosphogypsum 5-10 parts, and fluxing agent 6-15 parts. The application utilizes fly ash and other solid wastes or hazardous wastes, and based on the complementary and synergistic effect of the components of the raw materials, the density of the ceramsite proppant is further reduced, the anti-crushing performance is improved, and the petroleum fracturing mining demand is better met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fracturing proppants, and particularly relates to a resourceful oil fracturing proppant of fly ash and a preparation method thereof. BACKGROUND

[0002] With the gradual depletion of world oil and gas resources, people have to develop low-permeability oil and gas reservoirs that are difficult to exploit. Because the permeability of oil and gas reservoirs is low, conventional means cannot be used for exploitation, and hydraulic fracturing technology must be used to obtain industrial production. In the process of fracturing, oil fracturing proppants are added to prevent hydraulic fractures from closing, so as to ensure the fracture conductivity.

[0003] Ceramic proppants belong to one kind of oil fracturing proppants, are solid particles with certain strength used to support fractures in the process of hydraulic fracturing, and are mainly applied to oil and gas hydraulic fracturing technology. The basic principle is that a high-pressure pump system on the ground is used to inject fracturing fluid containing certain proppant materials into an oil and gas layer, so that when the liquid pressure is much higher than the rock breaking pressure, the oil and gas layer will have fractures, and the proppants will enter the fractures to make the fractures continue to extend and remain open, so as to ensure that the oil and gas layer still has fractures with a certain length and width after the fracturing is completed and the fracturing fluid is discharged from the wellbore, thereby improving the permeability and increasing the yield.

[0004] Traditional ceramic proppants are high-strength and high-density dark spherical particles sintered from high-quality bauxite ore mixed with other minerals and additives, and the main component is Al2O3, and the common phases are corundum phase and mullite phase. The ceramic proppants have the advantages of high compressive strength, high sphericity, smooth surface and good corrosion resistance, so that the porosity formed by the accumulation of the proppants in the oil and gas rock layer gap is large, the oil and gas conductivity is enhanced, and the proppants are widely applied to deep well / low permeability oil and gas fields. However, the increasingly scarce bauxite resources cannot support the large consumption of aluminum ceramic proppants, so currently, low-cost minerals or solid waste are more used as main raw materials to prepare ceramic proppants with low density and environmental friendly characteristics.

[0005] Fly ash is a solid particulate matter (excluding fly ash produced by coal-fired power plants) in the flue gas ash after waste combustion, which belongs to hazardous waste. The main sources of fly ash are waste incineration and other hazardous waste incineration, and the fly ash produced by waste incineration accounts for 3%-5% of the total amount of waste. Waste incineration for power generation has become one of the important sources of fly ash. At present, there are studies that have disclosed the use of fly ash to make ceramsite proppant, for example: patent application document CN110590338A discloses a method for preparing fracturing sand by using fly ash from waste incineration, which comprises the following steps: fly ash from waste incineration, bauxite, and manganese ore powder are dried and treated, and are ground separately to pass through a 325 mesh standard sieve; the obtained raw materials are mixed uniformly in proportion, and are sprayed into balls in a disc granulator to obtain a fracturing proppant semi-finished product with a particle size of 20-40 mesh; the semi-finished product is placed in a porcelain square canister and dried in an oven; the dried semi-finished product is placed in a muffle furnace and sintered at 1200-1400°C for 1-3h, and is cooled to room temperature with the furnace, and is sieved to obtain a fracturing proppant product with a particle size of 20-40 mesh. Again, patent application document CN114292637A discloses a fly ash resource treatment method, which comprises the following steps: fly ash and graphite powder are dried and treated, and are ground separately to pass through a 200 mesh sieve; the fly ash and graphite powder that have passed through the 200 mesh sieve are mixed uniformly in proportion, and are sprayed with a water mist containing sodium sulfide in a disc granulator to obtain first pellets; the first pellets are mixed with a capturing agent in a stirrer, and are dried to obtain second pellets; lime slurry, quicklime, quartz fiber, bauxite, silicon carbide, and water are mixed uniformly in proportion to form a slurry, and the slurry covers the second pellets, and is dried to obtain third pellets; the third pellets are microwave sintered to obtain high-strength sand. However, the technology is complex, the use of sodium sulfide and the capturing agent may cause secondary pollution, graphite powder is a high-value industrial raw material, and the cost is high, so the economy is poor, and it is difficult to promote.

[0006] Therefore, the present application is proposed. SUMMARY

[0007] The present application solves the technical problem of the prior art, and provides a petroleum fracturing proppant that utilizes fly ash as a resource, which can reduce the density while improving the anti-breaking capacity of the petroleum fracturing proppant.

[0008] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a petroleum fracturing proppant that utilizes fly ash as a resource, which comprises the following raw materials in the following proportions by weight: fly ash 10-20 parts, low-grade bauxite 50-60 parts, magnesite tailings 10-15 parts, phosphogypsum 5-10 parts, and fluxing agent 6-15 parts.

[0009] Optionally, the fluxing agent comprises waste glass and boron mud, and the mass ratio of the waste glass to the boron mud is (5-10):(1-5).

[0010] Optionally, the fly ash contains SiO2 with a mass percentage of 30-50%, Al2O3 with a mass percentage of 15-30%, CaO with a mass percentage of 5-15%, and Fe2O3 with a mass percentage of 3-10%.

[0011] Optionally, the low-grade bauxite contains Al2O3 with a mass percentage of ≤45%, SiO2 with a mass percentage of 20-30%, Fe2O3 with a mass percentage of 5-15%, and TiO2 with a mass percentage of 1-3%.

[0012] Optionally, the magnesite tailings contain MgO with a mass percentage of 30-35%, CaO with a mass percentage of 5-10%, SiO2 with a mass percentage of 5-15%, Al2O3 with a mass percentage of 0.5-2%, and Fe2O3 with a mass percentage of ≤3%.

[0013] Optionally, the waste glass contains SiO2 with a mass percentage of 70-75%, Na2O with a mass percentage of 10-15%, CaO with a mass percentage of 5-10%, and Al2O3 with a mass percentage of 1-3%.

[0014] Optionally, the phosphogypsum contains CaSO4·2H2O ≥75%.

[0015] Optionally, the boron mud contains MgO with a mass percentage of 20-30%, SiO2 with a mass percentage of 15-20%, Fe2O3 with a mass percentage of ≤10%, and B2O3 with a mass percentage of ≤3%.

[0016] Optionally, the petroleum fracturing proppant for resource utilization of fly ash contains, by mass percentage, Al2O3 45-60%, SiO2 20-35%, MgO 1-5%, Fe2O3 3-8%, CaO 2-6%, B2O3 0.5-2%, and Na2O 1-3%.

[0017] Optionally, the fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum, and boron mud have a particle size of ≤100 mesh.

[0018] The application further provides a preparation method of the petroleum fracturing proppant for resource utilization of fly ash, which comprises the following steps: mixing fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum, and boron mud, stirring, granulating, sintering, cooling, and screening to obtain a product.

[0019] Optionally, the sintering process parameters include: pre-sintering at 300-500℃ for 1-2h; then heating at a rate of 2.5-3.2℃ / min to 1150-1250℃, and holding for 2-4h.

[0020] In the pre-sintering stage, pre-sintering at 300-500℃ for 1-2h can remove the residual organic matter, crystal water (dehydration of CaSO4·2H2O in phosphogypsum), and unburned carbon in fly ash, avoiding the collapse of the structure caused by the release of gas at high temperature; at the same time, Al2O3 and SiO2 in low-grade bauxite begin to form pre-mullite, and MgCO3 in magnesite tailings decomposes into active MgO, laying the foundation for subsequent high-temperature reactions. If the temperature is too low, the volatile components cannot be completely removed, and if it is too high, some components may sinter too early, inhibiting subsequent foaming. If the time is too short, volatile components will remain, and high-temperature foaming will be out of control; if the time is too long, energy consumption will increase and Fe2O3 may be generated excessively. In the high-temperature sintering stage, heating at a rate of 2.5-3.2℃ / min to 1150-1250℃, and holding for 2-4h, the waste glass and boron mud form a low-viscosity liquid phase, which encapsulates Al2O3-SiO2 particles and promotes densification. The decomposition of phosphogypsum (CaSO4→CaO+SO3↑) and the oxidation of unburned carbon in fly ash (C+O2→CO2↑) release gas, which is captured by the glass phase to form closed pores, reducing the density. At the same time, Al2O3 and SiO2 form mullite (3Al2O3·2SiO2), and MgO and Al2O3 form spinel (MgAl2O4), significantly improving the compressive strength and breaking resistance of the double-phase structure. If the rate is too slow, the glass phase will flow too early, gas will escape, and the open porosity will increase; if the rate is too fast, thermal stress cracks will be induced; if the holding time is too short, the crystal phase will not develop completely; and if the time is too long, the spinel grains will coarsen, increasing the brittleness.

[0021] Optionally, the cooling process parameters include: cooling the sintered product to 800-850℃ at a rate of 15-20℃ / min, then to 400-450℃ at a rate of 4-5℃ / min, and finally to room temperature at a rate of 12-17℃ / min.

[0022] In the cooling process, firstly, a rapid cooling stage (15-20 ℃ / min cooling to 800-850 ℃) is carried out, the closed pore structure is locked, and the pore wall softening collapse at high temperature is prevented; the spinel-mullite grain growth temperature zone is rapidly passed through, and the grain size is maintained; the cooling rate is too low, leading to excessive grain growth and strength reduction; the rate is too high, leading to thermal stress microcracks and weakening of the anti-crushing performance. Then, a medium-speed cooling stage (4-5 ℃ / min cooling to 400-450 ℃) is carried out, the internal residual stress of the glass phase is eliminated, and the spontaneous fracture in the later stage is avoided; the rate is too fast, leading to phase change stress concentration and increased open porosity; the rate is too slow, prolonging the production cycle and reducing the economy. Finally, rapid cooling to room temperature (12-17 ℃ / min) is carried out, the low-temperature crystallization zone is rapidly passed through, the borate or silicate secondary crystallization is prevented, the structural uniformity is ensured, and the stability of the pore structure and crystal phase distribution is ensured. The rate is too low, which may lead to local crystallization and reduce acid resistance; the rate is too high, which is harsh on equipment requirements and has no obvious performance gain.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The application utilizes fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud to prepare ceramsite proppants, and through the complementary and synergistic effect of the components of the raw materials, the density of the ceramsite proppants is further reduced, and the anti-crushing performance is improved, so that the ceramsite proppants better meet the needs of oil fracturing exploitation.

[0025] In the application, the fly ash is rich in SiO2 and Al2O3, and supplements the insufficient silicon and aluminum components in the low-grade bauxite, reacts with the bauxite to generate mullite at high temperature, and improves the high-temperature strength. The unburned carbon in the fly ash is oxidized to release CO2 during sintering, and cooperates with SO3 released by the phosphogypsum to form a composite closed pore structure; at the same time, the spherical particles in the fly ash combine with the waste glass melt, improve the particle packing density, and reduce the open porosity, thereby reducing the product density and improving the anti-crushing performance.

[0026] The low-grade bauxite is used as a main aluminum source (the Al2O3 content is preferably 40%-45%), provides a basic skeleton of the ceramsite proppants, reduces the raw material cost, forms corundum and mullite phases at high temperature to provide compressive strength, the Fe2O3 therein improves the toughness through solid solution strengthening, and the TiO2 promotes sintering densification. The MgO in the magnesite tailings reacts to generate spinel (MgAl2O4), and the Vickers hardness of the spinel is significantly higher than that of mullite, thereby improving the anti-crushing performance.

[0027] Magnesite tailings: Provide MgO, form magnesia-alumina spinel with Al2O3 and SiO2, the thermal expansion coefficient of which matches that of mullite, reducing the risk of thermal stress cracking and improving the high-temperature resistance and compressive strength of the ceramic proppant. The high melting point of MgO inhibits high-temperature deformation and reduces sintering shrinkage. Form borate magnesium glass phase with B2O3 in boron mud, fill grain boundary pores, and improve density.

[0028] ‌Waste glass: Provides SiO2 and Na2O, acts as a flux to reduce sintering temperature while reducing energy consumption; molten glass phase wraps around raw material particles, improving flowability and sphericity. Na + CaO from phosphogypsum decomposition 2+ Form calcium-sodium silicate to enhance the stability of closed pore structure.

[0029] ‌Phosphogypsum: Mainly contains CaSO4·2H2O, which decomposes into CaO and SO3 gas at high temperature, and CaO reacts with SiO2 / Al2O3 to form calcium silicate or calcium aluminate to enhance strength; gas is wrapped by glass phase to form closed pore structure, reducing density.

[0030] ‌Boron mud: Contains MgO and a small amount of B2O3, which acts as a flux to further reduce sintering temperature (about 100-150℃), promote densification and reduce porosity. Boron mud forms B2O3-SiO2 network with SiO2 in waste glass to improve temperature resistance.

[0031] The present application improves and optimizes the preparation process by combining the characteristics of raw materials, especially the sintering and cooling process, and through the synergistic effect of the above-mentioned raw materials, the balance between density and strength is achieved, the anti-crushing ability is effectively improved while the density is reduced, and the particle size specification of the obtained petroleum fracturing proppant is 20 / 40 mesh, the bulk density is ≤1.35 g / cm 3 , the 52MPa crushing rate is ≤4.0%, the sphericity and roundness are ≥0.80, the acid solubility is ≤4.0%, the raw material cost is reduced by more than 40%, it can replace traditional bauxite ceramic proppant, and has market competitiveness. The present application passes the leaching toxicity test (GB5085.3-2007), and the leaching concentrations of Pb and Cd meet the standard requirements. DETAILED DESCRIPTION

[0032] In order to better understand the present application, the content of the present application will be further clearly described below in conjunction with examples, but the protection content of the present application is not limited to the following examples. In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details.

[0033] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary, and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0034] All starting materials were obtained from commercial sources unless otherwise specified, and were used without further purification unless otherwise specified, and contain no components other than those not specifically named if not otherwise specified.

[0035] The chemical composition of each raw material in the following cases is as follows:

[0036] The fly ash contains 30-50% of SiO2 by mass, 15-30% of Al2O3 by mass, 5-15% of CaO by mass, and 3-10% of Fe2O3 by mass.

[0037] The low-grade bauxite contains 40-45% of Al2O3 by mass, 20-30% of SiO2 by mass, 5-15% of Fe2O3 by mass, and 1-3% of TiO2 by mass.

[0038] The magnesite tailings contain 30-35% of MgO by mass, 5-10% of CaO by mass, 5-15% of SiO2 by mass, 0.5-2% of Al2O3 by mass, and ≤3% of Fe2O3 by mass.

[0039] The waste glass contains 70-75% of SiO2 by mass, 10-15% of Na2O by mass, 5-10% of CaO by mass, and 1-3% of Al2O3 by mass.

[0040] The phosphogypsum contains ≥75% of CaSO4·2H2O.

[0041] The boron mud contains 20-30% of MgO by mass, 15-20% of SiO2 by mass, ≤10% of Fe2O3 by mass, and ≤3% of B2O3 by mass.

[0042] A resource utilization fly ash oil fracturing proppant, the effective chemical composition of which contains 45-60% of Al2O3 by mass, 20-35% of SiO2 by mass, 1-5% of MgO by mass, 3-8% of Fe2O3 by mass, 2-6% of CaO by mass, 0.5-2% of B2O3 by mass, 1-3% of Na2O by mass, and the balance being inevitable impurities.

[0043] Al2O3: as the aluminum source of mullite phase and corundum phase, provides compressive strength and high temperature stability, the crystal phase ratio is controlled reasonably to balance the bulk density and compressive strength. SiO2: forms a low viscosity melt with B2O3 and Na2O, wraps the crystal phase, and improves the toughness; high temperature molten state fills the opening, promotes the formation of closed pore structure. MgO: generates MgAl2O4 with Al2O3, improves the crushing resistance; Mg 2+ solid solution mullite lattice, reduces the thermal expansion coefficient, and reduces microcracks. Fe2O3: Fe 3+ substitutes A 3+ enter the mullite lattice, induce lattice distortion, and improve the compressive strength; generate low melting point ferrite, reduce the sintering temperature. CaO: reacts with SO3 decomposed by phosphogypsum to generate CaO-SiO2 glass phase, reduce the melt viscosity, and promote the closed pore; generate wollastonite, reduce acid erosion. B2O3: reduce the sintering temperature, promote densification; and form a B-O-Si three-dimensional network to resist acid erosion. Na2O: reduces the melt viscosity, improves the sphericity of the granulation; with B2O3, forms a Na2O-B2O3-SiO2 eutectic system to accelerate densification.

[0044] The particle size of fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud is 100 mesh.

[0045] In the following examples, a resource utilization of fly ash oil fracturing proppant is made from the following raw materials by weight: fly ash 10-20 parts, low-grade bauxite 50-60 parts, magnesite tailings 10-15 parts, phosphogypsum 5-10 parts, fluxing agent 6-15 parts.

[0046] Example 1: A resource utilization of fly ash oil fracturing proppant is made from the following raw materials by weight: fly ash 15 parts, low-grade bauxite 53 parts, magnesite tailings 12 parts, waste glass 8 parts, phosphogypsum 8 parts, boron mud 4 parts.

[0047] A resource utilization of fly ash oil fracturing proppant, the mass percentage of effective chemical components is: Al2O3 47.2%, SiO2 29.3%, MgO 4.2%, Fe2O3 7.8%, CaO 4.1%, B2O3 1.8%, Na2O 2.1%, and the rest is inevitable impurities.

[0048] A preparation method of a resource utilization of fly ash oil fracturing proppant, comprising:

[0049] The fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud are mixed, fully stirred, granulated by using a pair of roller granulator, the diameter is controlled to be 10-15mm, pre-sintered at 420℃ for 1.5h; then heated to 1230℃ at a rate of 2.7℃ / min, and kept for 2.5h; the sintered product is cooled to 832℃ at a rate of 17℃ / min, then cooled to 420℃ at a rate of 4.5℃ / min, and finally cooled to room temperature (25℃) at a rate of 15℃ / min; screened to obtain the product.

[0050] Example 2: A petroleum fracturing proppant recycling fly ash, which is made of the following raw materials by weight: fly ash 12 parts, low-grade bauxite 56 parts, magnesite tailings 13 parts, waste glass 9 parts, phosphogypsum 5 parts, and boron mud 5 parts.

[0051] A petroleum fracturing proppant recycling fly ash, the mass percentage of effective chemical components is: Al2O3 51.3%, SiO2 30.5%, MgO 3.4%, Fe2O3 5.2%, CaO 2.1%, B2O3 0.8%, Na2O 2.8%, and the rest is inevitable impurities.

[0052] A preparation method of a petroleum fracturing proppant recycling fly ash, comprising:

[0053] The fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud are mixed, fully stirred, granulated by using a pair of roller granulator, the diameter is controlled to be 10-15mm, pre-sintered at 420℃ for 1.5h; then heated to 1230℃ at a rate of 2.7℃ / min, and kept for 2.5h; the sintered product is cooled to 832℃ at a rate of 17℃ / min, then cooled to 420℃ at a rate of 4.5℃ / min, and finally cooled to room temperature (25℃) at a rate of 15℃ / min; screened to obtain the product.

[0054] Example 3: A petroleum fracturing proppant recycling fly ash, which is made of the following raw materials by weight: fly ash 17 parts, low-grade bauxite 53 parts, magnesite tailings 10 parts, waste glass 6 parts, phosphogypsum 10 parts, and boron mud 4 parts.

[0055] A petroleum fracturing proppant recycling fly ash, the mass percentage of effective chemical components is: Al2O3 50.5%, SiO2 32.4%, MgO 5.0%, Fe2O3 3.2%, CaO 2.6%, B2O3 1.1%, Na2O 1.2%, and the rest is inevitable impurities.

[0056] A preparation method of a petroleum fracturing proppant recycling fly ash, comprising:

[0057] The fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud are mixed, fully stirred, granulated by a pair of roller granulator, the diameter is controlled to be 10-15mm, pre-sintered at 500℃ for 1h; then heated to 1250℃ at a rate of 3.2℃ / min, and kept for 2h; the sintered product is cooled to 800℃ at a rate of 15℃ / min, then cooled to 450℃ at a rate of 5℃ / min, and finally cooled to room temperature at a rate of 17℃ / min; screened to obtain the product.

[0058] Example 4: A petroleum fracturing proppant recycling fly ash, which is made of the following raw materials by weight: fly ash 10 parts, low-grade bauxite 60 parts, magnesite tailings 14 parts, waste glass 5 parts, phosphogypsum 6 parts, and boron mud 5 parts.

[0059] A petroleum fracturing proppant recycling fly ash, the mass percentage of effective chemical components is: Al2O3 59.3%, SiO2 22.3%, MgO 1.1%, Fe2O3 4.6%, CaO 6.0%, B2O3 2.0%, Na2O 1.5%, and the rest is inevitable impurities.

[0060] A preparation method of a petroleum fracturing proppant recycling fly ash, comprising:

[0061] The fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud are mixed, fully stirred, granulated by a pair of roller granulator, the diameter is controlled to be 10-15mm, pre-sintered at 350℃ for 2h; then heated to 1210℃ at a rate of 3.0℃ / min, and kept for 3.5h; the sintered product is cooled to 820℃ at a rate of 16℃ / min, then cooled to 420℃ at a rate of 4.3℃ / min, and finally cooled to room temperature at a rate of 13℃ / min; screened to obtain the product.

[0062] The preparation methods of the following examples 5-8 refer to example 1 and will not be repeated.

[0063] Example 5: A petroleum fracturing proppant recycling fly ash, which is made of the following raw materials by weight: fly ash 11 parts, low-grade bauxite 54 parts, magnesite tailings 13 parts, waste glass 10 parts, phosphogypsum 9 parts, and boron mud 3 parts.

[0064] A petroleum fracturing proppant recycling fly ash, the mass percentage of effective chemical components is: Al2O3 49.5%, SiO2 25.6%, MgO 4.2%, Fe2O3 8.0%, CaO 5.1%, B2O3 1.3%, Na2O 3.0%, and the rest is inevitable impurities.

[0065] Example 6: A petroleum fracturing proppant resourcefully utilizing fly ash, which is made of raw materials in parts by weight as follows: fly ash 20 parts, low-grade bauxite 50 parts, magnesite tailings 11 parts, waste glass 7 parts, phosphogypsum 7 parts, boron mud 5 parts.

[0066] A petroleum fracturing proppant resourcefully utilizing fly ash, the mass percentage of effective chemical components of which is: Al2O3 45.2%, SiO2 34.3%, MgO 3.1%, Fe2O3 7.1%, CaO 4.5%, B2O3 1.5%, Na2O 1.1%, and the balance is inevitable impurities.

[0067] Example 7: A petroleum fracturing proppant resourcefully utilizing fly ash, which is made of raw materials in parts by weight as follows: fly ash 18 parts, low-grade bauxite 58 parts, magnesite tailings 13 parts, waste glass 5 parts, phosphogypsum 5 parts, boron mud 1 part.

[0068] A petroleum fracturing proppant resourcefully utilizing fly ash, the mass percentage of effective chemical components of which is: Al2O3 52.3%, SiO2 31.2%, MgO 2.1%, Fe2O3 6.3%, CaO 3.0%, B2O3 0.5%, Na2O 1.3%, and the balance is inevitable impurities.

[0069] Example 8: A petroleum fracturing proppant resourcefully utilizing fly ash, which is made of raw materials in parts by weight as follows: fly ash 15 parts, low-grade bauxite 55 parts, magnesite tailings 15 parts, waste glass 6 parts, phosphogypsum 7 parts, boron mud 2 parts.

[0070] A petroleum fracturing proppant resourcefully utilizing fly ash, the mass percentage of effective chemical components of which is: Al2O3 46.8%, SiO2 27.5%, MgO 3.5%, Fe2O3 7.5%, CaO 5.5%, B2O3 1.7%, Na2O 2.7%, and the balance is inevitable impurities.

[0071] Comparative Example 1: A petroleum fracturing proppant, which differs from Example 1 in that the waste glass is omitted from the raw materials, and the corresponding preparation method omits the addition of waste glass.

[0072] Comparative Example 2: A petroleum fracturing proppant, which differs from Example 1 in that the boron mud is omitted from the raw materials, and the corresponding preparation method omits the addition of boron mud.

[0073] Comparative Example 3: A petroleum fracturing proppant, which is made of raw materials in parts by weight as follows: fly ash 10 parts, low-grade bauxite 60 parts, magnesite tailings 20 parts, waste glass 5 parts, phosphogypsum 5 parts, boron mud 10 parts.

[0074] Comparative Example 4: A petroleum fracturing proppant was prepared from the following raw materials in parts by weight: fly ash 10 parts, low-grade bauxite 70 parts, and magnesite tailings 20 parts.

[0075] Comparative Example 5: Different from Example 1, in the preparation method, pre-sintering was performed at 350℃ for 3h; then the temperature was increased to 1130℃ at a rate of 2℃ / min, and the temperature was maintained for 3h.

[0076] Comparative Example 6: Different from Example 1, in the preparation method, the sintered product was cooled to room temperature (25℃) at a rate of 10℃ / min.

[0077] Next, the content of the evaluation test is described.

[0078] The petroleum fracturing proppants prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to performance testing according to the relevant provisions of the standard SY / T5108-2014 Performance Test Method for Proppants Used in Hydraulic Fracturing and Gravel Packing Operations, and the leaching toxicity was tested according to GB5085.3-2007. The test results are shown in Table 1 below.

[0079] Table 1 Performance Test Results

[0080]

[0081] The above results show that the petroleum fracturing proppant obtained by the present application has a bulk density ≤1.35g / cm 3 , a crushing rate ≤4.0% at 52MPa, a sphericity and roundness ≥0.80, and an acid solubility ≤4.0%; the leaching concentrations of Pb and Cd meet the standard requirements. The results of Comparative Example 1 show that omitting the addition of waste glass has a significant effect on the bulk density, sphericity and roundness of the product; the results of Comparative Example 2 show that omitting the boron mud has a significant effect on the acid solubility of the product; the results of Comparative Example 3 show that the ratio of the raw materials has a significant effect on the bulk density and crushing rate of the product; the results of Comparative Example 4 show that the raw materials and their ratio have a significant effect on the various properties of the product; and Comparative Examples 5 and 6 show that the preparation steps and process parameters have a significant effect on the properties of the petroleum fracturing proppant.

[0082] It can be seen that the raw materials and their ratio of the fracturing proppant of the present application are scientific and reasonable, and the properties of the prepared product meet the relevant standard requirements, especially the bulk density and the crushing rate, which achieve a better balance and can better meet the needs of petroleum fracturing operations.

[0083] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting, and other modifications or equivalent replacements to the technical solutions of the present application made by those of ordinary skill in the art should be covered within the scope of the claims of the present application, as long as they do not deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A resourceful oil fracturing proppant utilizing fly ash, characterized in that: The raw materials include fly ash 10-20 parts, low-grade bauxite 50-60 parts, magnesite tailings 10-15 parts, phosphogypsum 5-10 parts, and fluxing agent 6-15 parts; the fluxing agent includes waste glass and boron mud, and the mass ratio of the waste glass to the boron mud is (5-10):(1-5); The effective chemical components of the petroleum fracturing proppant include Al2O3 45-60%, SiO2 20-35%, MgO 1-5%, Fe2O3 3-8%, CaO 2-6%, B2O3 0.5-2%, and Na2O 1-3%; The preparation method of the petroleum fracturing proppant includes mixing fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud, stirring, granulating, sintering, cooling, and screening to obtain the product; the sintering process parameters include pre-sintering at 300-500 DEG C for 1-2 h, then heating to 1150-1250 DEG C at a rate of 2.5-3.2 DEG C / min and keeping for 2-4 h; the cooling process parameters include cooling the sintered product to 800-850 DEG C at a rate of 15-20 DEG C / min, then to 400-450 DEG C at a rate of 4-5 DEG C / min, and finally to room temperature at a rate of 12-17 DEG C / min.

2. A resource utilization oil fracturing proppant using fly ash according to claim 1, characterized by: The low-grade bauxite contains Al2O3 with a mass percentage of ≤45%, SiO2 with a mass percentage of 20%-30%, Fe2O3 with a mass percentage of 5%-15%, and TiO2 with a mass percentage of 1%-3%.

3. A resource utilization oil fracturing proppant using fly ash according to claim 2, characterized by: The particle size of the fly ash, low-grade bauxite, magnesite tailings, waste glass, phosphogypsum and boron mud is ≤100 mesh.

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