High-strength fracturing propping agent prepared from oily sludge and preparation method of high-strength fracturing propping agent

Abstract

The invention provides a high-strength fracturing propping agent prepared from oily sludge and a preparation method of the high-strength fracturing propping agent, and relates to the technical field of propping agents. The method comprises the following steps: deoiling and dewatering oily sludge to obtain dry-basis sludge; pre-burning the dry sludge to obtain cooked oil sludge; the pre-sintering temperature is 850 to 900 DEG C; mixing and grinding the cooked oil sludge and silica powder to obtain mixed micro powder; granulating the mixed micro powder into balls, and drying to obtain dried microspheres; and calcining the dried microspheres to obtain the high-strength fracturing propping agent. According to the invention, resource utilization of the oily sludge is realized, and the prepared fracturing propping agent has high strength. The prepared high-strength fracturing propping agent can completely replace a fracturing propping agent prepared from traditional bauxite, and the difficult problem that environment protection is difficult due to large-scale excavation of bauxite ore is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of proppants, and in particular to a high-strength fracturing proppant and a method for preparing the high-strength fracturing proppant by utilizing oil-containing sludge. Background Art

[0002] Oily sludge is a by-product of oil and gas field exploitation and one of the main sources of pollution in the oil industry. It has always been a "difficult" problem for the oil industry to deal with. With the continuous deepening of oil and gas field development, the total amount of oily sludge generated during oil and gas well production, well repair operations, crude oil stabilization and purification, and oil and gas pipeline leakage rescue has increased rapidly, and oily sludge has been clearly listed as hazardous solid waste by the national environmental authorities. The stockpile of this type of oily sludge continues to increase, causing increasingly serious environmental pollution and ecological damage to oil-producing areas. Although major oil and gas fields have successively carried out a series of measures in recent years, such as oily sludge reduction, resource utilization, oily sludge profile adjustment, fired brick cofferdams or mixed with asphalt for road construction, this bottleneck problem has not been perfectly solved due to technical routes, technical maturity, treatment process equipment or cost. These "solid hazardous wastes" generated by oil and gas field exploitation have no "way" to go, which has seriously affected the normal development of oil and gas fields. They must be harmlessly disposed of or resource-based and comprehensively utilized.

[0003] CN 115232613 A discloses a fracturing proppant and a method for preparing the fracturing proppant using oil sludge produced by oil and gas field exploitation. The patent uses the oil-containing sludge produced by the oil field as raw material, realizing the resource utilization of the oil-containing sludge. However, the crushing rate of the 40-70 mesh finished product and the 70-140 mesh finished product of the fracturing proppant prepared by the patent is only less than 9.0% under a closing pressure of 86 MPa, which is difficult to meet the high strength requirements. Summary of the invention

[0004] The purpose of the present invention is to provide a high-strength fracturing proppant and a method for preparing the high-strength fracturing proppant using oily sludge. The present invention not only realizes the resource utilization of oily sludge, but also the prepared fracturing proppant has high strength.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a high-strength fracturing proppant using oily sludge, comprising the following steps: deoiling and dehydrating the oily sludge to obtain dry sludge;

[0007] Pre-burning the dry sludge to obtain cooked oil sludge; the pre-burning temperature is 850-900°C;

[0008] The cooked oil mud and silica powder are mixed and ground to obtain mixed micro powder; the mass of the mixed micro powder remaining on a 600-mesh sieve is less than 3%;

[0009] Granulating the mixed micro powder into balls, and drying to obtain dried micro balls;

[0010] The dried microspheres are calcined to obtain a high-strength fracturing proppant; the calcination temperature is 1080-1150°C.

[0011] Preferably, the mass of the cooked oil mud is 50-60% of the total mass of the cooked oil mud and the silica powder.

[0012] Preferably, the calcination holding time is 2.5 to 3 hours.

[0013] Preferably, the calcination is performed under air atmosphere.

[0014] Preferably, the pre-burning holding time is 90 to 150 minutes.

[0015] Preferably, in terms of mass percentage, the content of silicon dioxide in the silica powder is 87-95%, the content of Al2O3 is 2.53-3.61%, and the content of Fe2O3 is 1.48-4.73%.

[0016] Preferably, the dry sludge has a water content of <20wt% and an oil content of <2wt%.

[0017] Preferably, the free water content of the dried microspheres is 0.01 to 1 wt %.

[0018] The present invention provides a high-strength fracturing proppant prepared by the method described in the above scheme, when the particle size of the high-strength fracturing proppant is 40-70 meshes, the crushing rate under the closing pressure of 86 MPa is ≤5.9%;

[0019] When the particle size of the high-strength fracturing proppant is 70-140 meshes, the crushing rate under a closing pressure of 103 MPa is ≤4.9%.

[0020] The invention provides a method for preparing a high-strength fracturing proppant by utilizing oily sludge, comprising the following steps: deoiling and dehydrating the oily sludge to obtain dry sludge; pre-burning the dry sludge to obtain cooked oil sludge; the pre-burning temperature is 850-900°C; mixing and grinding the cooked oil sludge with silica powder to obtain mixed micro-powder; the mass of the mixed micro-powder after 600 mesh sieve is less than 3%; granulating the mixed micro-powder into balls, drying to obtain dried micro-pellets; calcining the dried micro-pellets to obtain a high-strength fracturing proppant; the calcining temperature is 1080-1150°C.

[0021] The present invention uses oily sludge as raw material, and pre-burns at high temperature to completely remove the extremely small amount of organic matter or inorganic salts remaining therein and the chemical additives added in the production processes such as oil production, water injection, and gathering and transportation, so as to avoid the generation of pores during the calcination of micro-pellets and reduce the strength of the fracturing proppant. At the same time, pre-burning causes the mineral particles with low eutectic temperature to rearrange, so that part of the original phase is dissolved in the molten body, filling part of the pores and forming a new micro-mineral crystal growth stage. The micro-mineral crystals are not destroyed during grinding, so the density of the micro-pellets during balling is improved, and the strength of the fired fracturing proppant is increased.

[0022] The invention fills the gap that it is difficult to prepare high-strength petroleum fracturing proppants by using oil-containing sludge associated with oil and gas field exploitation as the main raw material without pre-burning. In addition, the preparation method of the invention is refined, and only silica powder is added, without adding other substances such as fly ash, bauxite, clay or manganese powder; the prepared high-strength fracturing proppants can not only completely replace the fracturing proppants prepared from traditional bauxite, eliminating the thorny problem of environmental protection difficulties in large-scale excavation of bauxite mines, but also allow solid hazardous waste materials from deep underground to return to the site where they were mined in the form of functional materials, realizing a truly environmentally friendly closed loop and green crude oil mining. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing a high-strength fracturing proppant using oily sludge, comprising the following steps: deoiling and dehydrating the oily sludge to obtain dry sludge;

[0024] Pre-burning the dry sludge to obtain cooked oil sludge; the pre-burning temperature is 850-900°C;

[0025] The cooked oil mud and silica powder are mixed and ground to obtain mixed micro powder; the mass of the mixed micro powder remaining on a 600-mesh sieve is less than 3%;

[0026] Granulating the mixed micro powder into balls, and drying to obtain dried micro balls;

[0027] The dried microspheres are calcined to obtain a high-strength fracturing proppant.

[0028] The invention removes oil and water from the oily sludge to obtain dry sludge; the calcination temperature is 1080-1150°C.

[0029] In the present invention, the oily sludge is preferably formed during the exploitation of oil and gas fields. Specifically, the oily sludge can be a mixture of one or more of the oily sludge from well repair operations, the oily sludge from tank cleaning at oil and gas gathering and transportation stations, and the oily sludge from oilfield pipeline leak rescue operations. In the present invention, the oil content of the oily sludge is preferably 10-15%, the solid (mud) content is preferably 10-30%, and the water content is preferably 60-80%, by mass percentage.

[0030] The present invention preferably adopts a thermochemical sedimentation dehydration and deoiling process for dehydration and deoiling. The present invention does not make special requirements on the specific implementation process of the thermochemical sedimentation dehydration and deoiling, which is well known in the art; in the present invention, the temperature of the deoiling and dehydration is preferably not more than 100° C. The present invention reduces the loss of petroleum hydrocarbon vapor volatilization by controlling the temperature of the deoiling and dehydration to not more than 100° C., thereby ensuring the nature of the crude oil and being economical, safe and environmentally friendly.

[0031] In the present invention, after deoiling and dehydration, the water content of the obtained dry sludge is preferably less than 20wt%, and the oil content is preferably less than 2wt%.

[0032] After obtaining the dry sludge, the present invention pre-burns the dry sludge to obtain cooked oil sludge.

[0033] In the present invention, the pre-calcination temperature is 850-900°C, preferably 860-890°C, more preferably 870-880°C; the pre-calcination holding time is preferably 90-150 min, more preferably 100-140 min, further preferably 120-130 min. In the present invention, the pre-calcination is preferably carried out in an air atmosphere.

[0034] The present invention removes all the very small amount of organic matter or inorganic salts remaining in the dry sludge and the chemical additives added in the production processes such as oil production, water injection, and gathering and transportation through pre-burning, thereby avoiding the generation of pores during the calcination of micro-pellets and reducing the strength of the fracturing proppant. At the same time, pre-burning causes the mineral particles with a low eutectic temperature to rearrange, so that part of the original phase is dissolved in the molten body, filling part of the pores to form new micro-mineral crystals. The micro-mineral crystals are not destroyed during grinding, thereby improving the density of the micro-pellets during balling and increasing the strength of the fired fracturing proppant.

[0035] After the cooked oil mud is obtained, the method mixes and grinds the cooked oil mud with silica powder to obtain mixed fine powder.

[0036] In the present invention, the silica powder is preferably quartz sand tailings; the content of silicon dioxide in the silica powder is preferably 87-95%, the content of Al2O3 is preferably 2.53-3.61%, and the content of Fe2O3 is preferably 1.48-4.73%.

[0037] In the present invention, the mass of the cooked oil sludge is preferably 50-60% of the total mass of the cooked oil sludge and silica powder, specifically 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60%.

[0038] The present invention has no special requirements for the mixed grinding process, as long as the 600-mesh sieve residue of the obtained mixed micropowder is less than 3%. The present invention controls the fineness and particle size distribution of the mixed micropowder to ensure that the product has a lower porosity, which is beneficial to improving the strength of the fracturing proppant.

[0039] After obtaining the mixed micro powder, the present invention granulates the mixed micro powder into balls, and dries the balls to obtain dried micro balls.

[0040] The present invention preferably uses water as a binder for granulation into balls. In the present invention, the size of the granulated balls is determined according to the size of the target product, for example, it can be 40-70 mesh, or 70-140 mesh, or other required sizes.

[0041] The present invention has no special requirements for the drying conditions, as long as the free water content of the dried microspheres is 0.01-1 wt%.

[0042] After obtaining the dried microspheres, the present invention calcines the dried microspheres to obtain high-strength fracturing proppants.

[0043] In the present invention, the calcination temperature is 1080-1150°C, preferably 1090-1140°C, and more preferably 1100-1130°C; the calcination holding time is preferably 2.5-3h. In the present invention, the calcination is preferably carried out in an air atmosphere.

[0044] In the present invention, the rate of heating to the calcination temperature is preferably 5°C / min. The present invention rearranges the particles of the mineral at high temperature through calcination, and part of the original phase is dissolved in the melt, filling part of the pores, forming a new microcrystalline mineral growth stage, and improving the density of the product.

[0045] After the calcination is completed, the present invention preferably cools the obtained calcined product and then sieves it through vibration to obtain a high-strength fracturing proppant.

[0046] In the present invention, 100% of the waste materials or waste products generated due to abnormal working conditions are returned to the mixed grinding step, forming a closed-loop cycle without solid waste discharge.

[0047] The present invention provides a high-strength fracturing proppant prepared by the method described in the above scheme. When the particle size of the high-strength fracturing proppant is 40-70 meshes, the crushing rate under a closing pressure of 86 MPa is ≤5.9%; when the particle size of the high-strength fracturing proppant is 70-140 meshes, the crushing rate under a closing pressure of 103 MPa is ≤4.9%.

[0048] In the present invention, the sphericity of the high-strength fracturing proppant is preferably ≥ 0.9, the acid solubility is preferably ≤ 6.8%, and the bulk density is preferably 1.40 to 1.51 g / cm 3 .

[0049] A high-strength fracturing proppant and a method for preparing a high-strength fracturing proppant using oily sludge provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] The compositions of the silica powder used in the following examples and comparative examples are shown in Table 1.

[0051] Table 1 Composition of silica powder (mass percentage)

[0052] <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO MgO NaO K LoI Silica powder 87～95 2.53～3.61 1.48～4.73 0.58～0.74 0.15～0.45 0.25 0.2 0.21

[0053] Example 1

[0054] This embodiment provides a method for preparing a high-strength fracturing proppant, and the raw materials used are shown in Table 2.

[0055] The preparation method is as follows:

[0056] (1) removing oil and water from oil-containing sludge associated with oil and gas field exploitation through a thermochemical sedimentation dehydration and deoiling process to obtain dry sludge (containing 15 wt% water and 0.35 wt% oil);

[0057] (2) pre-calcining the dry sludge at 850°C for 120 min and then naturally cooling it to room temperature to obtain cooked sludge;

[0058] (3) Mixing the cooked oil sludge with silica powder (quartz sand tailings) and grinding until the residue on a 600-mesh sieve is less than 1%, thereby obtaining a mixed fine powder;

[0059] (4) using water as a binder, the mixed micropowder is made into 40-70 mesh and 70-140 mesh microspheres, the microspheres are polished and ground for 80 minutes after being formed into balls for 45 minutes, and then dried to a free water content of 0.05 wt %, to obtain dried microspheres;

[0060] (5) calcining the dried microspheres to 1150°C at a temperature rise gradient of 5°C / min and then keeping the temperature for 2.5 hours;

[0061] (6) The calcined microspheres are cooled to about 60° C., and then subjected to oscillation screening, crushing rate detection, grading, and inspection to obtain a high-strength fracturing proppant with a crushing rate of 5.5% at a closure pressure of 86 MPa for 40-70 mesh and a crushing rate of 4.6% at a closure pressure of 103 MPa for 70-140 mesh.

[0062] During the preparation process, 100% of the waste or waste products generated due to abnormal operating conditions are returned to step (3), forming a closed-loop cycle with no solid waste discharge.

[0063] Example 2

[0064] This embodiment provides a method for preparing a fracturing proppant, and the raw materials used are shown in Table 2.

[0065] The preparation method comprises the following steps:

[0066] (1) removing oil and water from oil-containing sludge associated with oil and gas field exploitation through a thermochemical sedimentation dehydration and deoiling process to obtain dry sludge (containing 13 wt% water and 0.8 wt% oil);

[0067] (2) pre-burning the dry sludge at 890°C for 100 min to obtain cooked sludge;

[0068] (3) Mixing the cooked oil sludge with silica powder (quartz sand tailings) and grinding them until the residue on a 600-mesh sieve is less than 1.5%, thereby obtaining a mixed fine powder;

[0069] (4) using water as a binder to prepare the mixed micropowder into microspheres of 40 to 70 meshes, polishing and grinding for 70 minutes after 55 minutes of balling, and then drying to a free water content of 0.2 wt% to obtain dried microspheres;

[0070] (5) calcining the dried microspheres to 1140°C at a temperature rise gradient of 5°C / min and then keeping the temperature for 2.9 hours;

[0071] (6) The calcined microspheres are cooled to about 60° C., and then subjected to oscillation screening, crushing rate detection, classification, and inspection to obtain a high-strength fracturing proppant with a crushing rate of 5.7% at a closing pressure of 86 MPa and a 40-70 mesh size.

[0072] During the preparation process, 100% of the waste or waste products generated due to abnormal operating conditions are returned to step (3), forming a closed-loop cycle with no solid waste discharge.

[0073] Example 3

[0074] This embodiment provides a method for preparing a fracturing proppant, and the raw materials used are shown in Table 2.

[0075] The preparation method comprises the following steps:

[0076] (1) removing oil and water from the oily sludge associated with oil and gas field exploitation through a thermochemical sedimentation dehydration and deoiling process to obtain dry sludge (containing 10 wt% water and 0.6 wt% oil);

[0077] (2) pre-burning the dry sludge at 900°C for 150 min to obtain cooked sludge;

[0078] (3) Mixing the cooked oil sludge with silica powder (quartz sand tailings) and grinding until the residue on a 600-mesh sieve is less than 1.1%, thereby obtaining a mixed fine powder;

[0079] (4) using water as a binder to prepare the mixed micropowder into microspheres of 70 to 140 meshes, polishing and grinding for 60 minutes after forming into balls for 50 minutes, and then drying to a free water content of 0.09 wt % to obtain dried microspheres;

[0080] (5) calcining the dried microspheres to 1120°C at a temperature rise gradient of 5°C / min, and then keeping the temperature for 2.5 hours;

[0081] (6) The calcined microspheres are cooled to about 60° C., and then subjected to oscillation screening, crushing rate detection, grading, and inspection to obtain a high-strength fracturing proppant with a crushing rate of 4.1% at a closing pressure of 103 MPa and a 70-140 mesh size.

[0082] During the preparation process, 100% of the waste or waste products generated due to abnormal operating conditions are returned to step (3), forming a closed-loop cycle with no solid waste discharge.

[0083] Example 4

[0084] This embodiment provides a method for preparing a fracturing proppant, and the raw materials used are shown in Table 2.

[0085] The preparation method comprises the following steps:

[0086] (1) removing oil and water from the oily sludge associated with oil and gas field exploitation through a thermochemical sedimentation dehydration and deoiling process to obtain dry sludge (containing 11 wt% water and 1.5 wt% oil);

[0087] (2) pre-burning the dry sludge at 880°C for 90 minutes to obtain cooked sludge;

[0088] (3) Mixing the cooked oil sludge with silica powder (quartz sand tailings) and grinding until the residue on a 600-mesh sieve is less than 1.2%, thereby obtaining a mixed fine powder;

[0089] (4) using water as a binder to prepare the mixed micropowder into microspheres of 70 to 140 meshes, polishing and grinding for 65 minutes after forming into balls for 40 minutes, and then drying to a free water content of 0.03 wt % to obtain dried microspheres;

[0090] (5) calcining the dried microspheres to 1110°C at a temperature rise gradient of 5°C / min and then keeping the temperature for 2.4 hours;

[0091] (6) The calcined microspheres are cooled to about 60° C., and then subjected to oscillation screening, crushing rate detection, classification, and inspection to obtain a high-strength fracturing proppant with a crushing rate of 4.3% at a closing pressure of 103 MPa and a 70-140 mesh size.

[0092] During the preparation process, 100% of the waste or waste products generated due to abnormal operating conditions are returned to step (3), forming a closed-loop cycle with no solid waste discharge.

[0093] Comparative Example 1

[0094] A method for preparing a fracturing proppant, which differs from Example 1 only in the fineness of the grinding powder.

[0095] The specific steps are as follows:

[0096] (1) removing oil and water from oil-containing sludge associated with oil and gas field exploitation through a thermochemical sedimentation dehydration and deoiling process to obtain dry sludge (containing 15 wt% water and 0.35 wt% oil);

[0097] (2) pre-calcining the dry sludge at 850°C for 120 min and then naturally cooling it to room temperature to obtain cooked sludge;

[0098] (3) Mixing the cooked oil sludge with silica powder (quartz sand tailings) and grinding until the residue on a 500-mesh sieve is less than 1%, thereby obtaining a mixed fine powder;

[0099] (4) using water as a binder, the mixed micropowder is made into 40-70 mesh and 70-140 mesh microspheres, the microspheres are polished and ground for 80 minutes after being formed into balls for 45 minutes, and then dried to a free water content of 0.05 wt %, to obtain dried microspheres;

[0100] (5) calcining the dried microspheres to 1150°C at a temperature rise gradient of 5°C / min and then keeping the temperature for 2.5 hours;

[0101] (6) The calcined microspheres are cooled to about 60° C., and then sieved and classified by vibration to obtain 40-70 mesh fracturing proppants. The crushing rate is 11.8% at a closing pressure of 86 MPa, and the crushing rate is 9.4% at a closing pressure of 70-140 MPa.

[0102] Comparative Example 2

[0103] A method for preparing a fracturing proppant, which differs from Example 3 only in the calcination temperature. The specific steps are as follows:

[0104] (1) removing oil and water from the oily sludge associated with oil and gas field exploitation through a thermochemical sedimentation dehydration and deoiling process to obtain dry sludge (containing 10 wt% water and 0.6 wt% oil);

[0105] (2) pre-burning the dry sludge at 900°C for 150 min to obtain cooked sludge;

[0106] (3) Mixing the cooked oil sludge with silica powder (quartz sand tailings) and grinding until the residue on a 600-mesh sieve is less than 1.1%, thereby obtaining a mixed fine powder;

[0107] (4) using water as a binder to prepare the mixed micropowder into microspheres of 70 to 140 meshes, polishing and grinding for 60 minutes after forming into balls for 50 minutes, and then drying to a free water content of 0.09 wt % to obtain dried microspheres;

[0108] (5) calcining the dried microspheres to 1190°C at a temperature rise gradient of 5°C / min and then keeping the temperature for 2.5 hours;

[0109] (6) The calcined microspheres are cooled to about 60° C., and then sieved and classified by vibration to obtain 70-140 mesh ceramsite proppants. The crushing rate is 10.5% at a closing pressure of 103 MPa.

[0110] Comparative Example 3

[0111] A method for preparing a fracturing proppant, which differs from Example 3 only in that the dry sludge is not pre-burned at high temperature. The specific steps are as follows:

[0112] (3) removing oil and water from the oily sludge associated with oil and gas field exploitation through a thermochemical sedimentation dehydration and deoiling process to obtain dry sludge (containing 10 wt% water and 0.6 wt% oil);

[0113] (2) According to the ratio of dry sludge to silica powder, the dry sludge and silica powder (quartz sand tailings) are mixed and ground to a 600-mesh sieve residue of less than 1.1%, thereby obtaining a mixed fine powder;

[0114] (3) using water as a binder to prepare the mixed micropowder into microspheres of 70-140 meshes, polishing and grinding for 60 minutes after forming into balls for 50 minutes, and then drying to a free water content of 0.09 wt % to obtain dried microspheres;

[0115] (4) calcining the dried microspheres to 1190°C at a temperature rise gradient of 5°C / min and then keeping the temperature for 2 hours;

[0116] (5) The calcined microspheres are cooled to about 60° C., and then sieved and classified by vibration to obtain 70-140 mesh ceramsite proppants. The crushing rate is found to be 11.3% at a closing pressure of 103 MPa.

[0117] Table 2 Raw material dosage (mass percentage) of the embodiments and comparative examples

[0118] Cooked oil mud Silica powder Example 1 60％ 40％ Example 2 57％ 43％ Example 3 59％ 41％ Example 4 56％ 44％ Comparative Example 1 60％ 40％ Comparative Example 2 59％ 41％ Comparative Example 3 59％ 41％

[0119] The fracturing proppants obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were tested according to the standard SY / T5108-2014 "Proppant Performance Test Method for Hydraulic Fracturing and Gravel Packing Operations", and the test results are shown in Table 3.

[0120] Table 3 Test results

[0121]

[0122] It can be seen from Table 3 that the 86MPa and 103MPa high-strength fracturing proppants prepared in Examples 1-4 fully meet the requirements of the bidding standard SY / T5108-2014 "Proppant Performance Test Method for Hydraulic Fracturing and Gravel Packing Operations" for oil and gas field exploitation petroleum fracturing proppants; in addition, it can be seen from the results of Comparative Examples 1 and 2 that the different fineness of the grinding and the calcination temperature make the product have large pores and excessive melting, which has a great impact on the product quality. It can be seen from Comparative Example 3 that the crushing rate of raw sludge and cooked sludge is significantly increased under the same specifications and the same pressure level, and even fails to meet the bidding and procurement standard requirements.

[0123] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing high-strength fracturing proppant using oily sludge, characterized in that: The following steps are involved: Deoiling and dehydrating the oily sludge to obtain dry sludge; Pre-burning the dry sludge to obtain cooked oil sludge; the pre-burning temperature is 850-900°C; The cooked oil mud and silica powder are mixed and ground to obtain mixed micro powder; the mass of the mixed micro powder remaining on a 600-mesh sieve is less than 3%; Granulating the mixed micro powder into balls, and drying to obtain dried micro balls; The dried microspheres are calcined to obtain a high-strength fracturing proppant; the calcination temperature is 1080-1150°C.

2. The method according to claim 1, characterized in that The mass of the cooked oil mud is 50-60% of the total mass of the cooked oil mud and the silica powder.

3. The method according to claim 1, characterized in that The calcination holding time is 2.5 to 3 hours.

4. The method according to claim 1 or 3, characterized in that: The calcination is performed under air atmosphere.

5. The method according to claim 1, characterized in that The pre-burning heat preservation time is 90 to 150 minutes.

6. The method according to claim 1 or 2, characterized in that: Calculated by mass percentage, the content of silicon dioxide in the silica powder is 87-95%, the content of Al2O3 is 2.53-3.61%, and the content of Fe2O3 is 1.48-4.73%.

7. The method according to claim 1, characterized in that The dry sludge has a water content of less than 20 wt% and an oil content of less than 2 wt%.

8. The method according to claim 1, characterized in that The free water content of the dried microspheres is 0.01-1 wt %.

9. The high-strength fracturing proppant prepared by the method according to any one of claims 1 to 8, characterized in that: When the particle size of the high-strength fracturing proppant is 40-70 mesh, the crushing rate under the closing pressure of 86 MPa is ≤5.9%; When the particle size of the high-strength fracturing proppant is 70-140 meshes, the crushing rate under a closing pressure of 103 MPa is ≤4.9%.

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