CN106701055A - Preparation method of lightweight and high-strength fracturing propping agent - Google Patents

Abstract

The invention discloses a preparation method of a lightweight high-strength fracturing proppant, which belongs to the technical field of proppant preparation. In the present invention, the silicon dioxide produced by calcination is used as the core, and the surface is coated with hydroxyapatite and alumina produced by calcination. At a high temperature, a part of the silicon dioxide reacts with carbon to form silicon carbide, while the other part of the silicon dioxide reacts with the evaporated The sodium carbonate produced by crystallization reacts at high temperature to form sodium silicate, and then dissolves and removes sodium silicate by washing with water to form a hollow structure. The invention makes full use of the hollow microspheres formed by silicon carbide, alumina and hydroxyapatite to achieve light weight High-strength effect, the density is more than 10% lower than that of conventional ceramsite-type fracturing proppants, which effectively solves the problem of high density of traditional ceramsite-type fracturing proppants, which is easy to cause loss of fracturing equipment.

Description

A kind of preparation method of light-weight high-strength fracturing proppant

technical field

The invention discloses a preparation method of a lightweight high-strength fracturing proppant, which belongs to the technical field of proppant preparation.

Background technique

Fracturing proppant is a special material that is pumped into formation fractures together with fracturing fluid to support fractures and increase oil and gas conductivity during hydraulic fracturing in the oil and gas industry. Compared with quartz sand and resin-coated sand, ceramsite fracturing proppant has the characteristics of low fragmentation rate, corrosion resistance, good flow conductivity and high cost performance, and has been adopted by more and more oil fields.

Since hydraulic fracturing was successfully tested in the United States in 1947, it has become a mature mining technology and has been widely used in oil and gas fields around the world. In the total cost of hydraulic fracturing, the cost of fracturing proppant accounts for a large proportion of the entire operation cost, which not only represents a large part of the initial cost of oil and gas wells, but also determines the economic life of oil and gas wells or oil fields; the success or failure of hydraulic fracturing effects , the validity period mainly depends on the quality of the proppant. At present, there are three main types of proppant: ceramsite, quartz sand and resin coated sand. The strength of quartz sand is low and the broken debris will block the cracks, reduce the conductivity, and cannot meet the requirements of deep well mining; various resin-coated sands solve the problem of low strength of quartz sand, but the production cost is high and the process is complicated; sintered ceramics Granules have been widely used in more and more oil fields due to their high strength, good chemical stability, and superior cost performance, but their high density can easily cause damage to fracturing equipment. The development of my country's ceramsite proppant began in the 1980s. The earliest product was the sprayed bauxite high-strength proppant. It has been developed for more than 30 years, and the products of some domestic enterprises or scientific research institutions have caught up with the world's advanced level. , Some product performance even exceeds the world advanced level. As society's demand for oil and gas continues to increase, the depth of oil and gas wells increases year by year. How to reduce the density of ceramsite proppant and explore new ceramsite proppant under the premise of maintaining high strength has become a research field in the field of inorganic materials or oil and gas exploration. One of the hot spots.

Contents of the invention

The technical problem mainly solved by the present invention is: aiming at the problem that the density of the traditional sintered ceramsite type fracturing proppant is too high, it is easy to cause damage to the fracturing equipment during use and affect the exploitation of oil and natural gas, and provides a silicic acid The white precipitate produced by the reaction of sodium and hydrochloric acid is the inner core, and the surface is covered with a layer of calcium hydroxyphosphate, and the aluminum hydroxide precipitate is produced by the reaction of aluminum nitrate with uric acid, ammonia water, etc., and mixed with carbon black, under the protection of argon It is calcined, mixed with sodium carbonate solution, evaporated and crystallized, calcined again, and finally washed and dried with water to obtain a light-weight high-strength fracturing proppant. In the present invention, the silicon dioxide produced by calcination is used as the core, and the surface is coated with hydroxyapatite and alumina produced by calcination. At a high temperature, a part of the silicon dioxide reacts with carbon to form silicon carbide, while the other part of the silicon dioxide reacts with the evaporated The sodium carbonate produced by crystallization reacts at high temperature to form sodium silicate, and then dissolves and removes sodium silicate by washing with water to form a hollow structure. The invention makes full use of the hollow microspheres formed by silicon carbide, alumina and hydroxyapatite to achieve light weight High-strength effect, the density is more than 10% lower than that of conventional ceramsite-type fracturing proppants, which effectively solves the problem of high density of traditional ceramsite-type fracturing proppants, which is easy to cause loss of fracturing equipment.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

(1) Measure 150-200mL of 10% sodium silicate solution, pour it into a three-necked flask with a dropping funnel, and then place the three-necked flask in a digital speed measuring constant temperature magnetic stirrer at a temperature of 55-60 ℃, and the rotation speed is 300-500r/min, add 120-160mL hydrochloric acid with a concentration of 2mol/L into the three-necked flask through the dropping funnel, and control the drop within 30-45min. ~45min, a white suspension was obtained;

(2) Mix the white suspension obtained above with 280-380mL mass fraction of 8-10% aluminum nitrate solution, pour it into a three-necked flask, then add 20-40g urea, 30-40g nanometer calcium hydroxyphosphate, 40 ～60mL diethanolamine, then put the three-necked flask in a digital speed measuring and constant temperature magnetic stirrer, under the condition of temperature 65～70℃, rotation speed 400～600r/min, stir at constant temperature for 15～20min, then through the dropping funnel to Add 400-500mL ammonia water with a mass fraction of 15% into the three-necked flask, and continue to stir and react at a constant temperature for 45-60min;

(3) After the reaction is finished, filter, collect the filter cake, and wash the filter cake with deionized water until the washing liquid is neutral, then transfer the washed filter cake into an oven, and dry it at a temperature of 105 to 110°C until Constant weight, then mix the dried filter cake with 3-5g of carbon black crushed to 325-500 mesh evenly, and transfer to the muffle furnace, and pass argon gas into the furnace at a rate of 3-5mL/min. In the protected state, the temperature is programmed at a rate of 6-8 °C/min to 680-700 °C, and after 20-30 min of heat preservation and calcination, the temperature is programmed to 1100-1200 °C at a rate of 10-15 °C/min, and the heat-retaining calcination is performed for 45-60 min. Cool down to room temperature with the furnace, discharge the material, and obtain calcined mixed powder;

(4) Pour the calcined mixed powder obtained above into an evaporating dish containing 400-600 mL of a sodium carbonate solution with a mass fraction of 10-15%, stir and mix with a glass rod for 10-15 minutes, heat and evaporate to dryness, and then place the evaporating dish The material in the tube type resistance furnace is transferred to the tube type resistance furnace, and calcined at a temperature of 1100~1200°C for 30~45min. Stir and mix with a glass rod for 15-20 minutes, filter, collect the filter cake, put the obtained filter cake in an oven, and dry it to constant weight at a temperature of 105-110°C to obtain a light-weight high-strength fracturing proppant.

The properties of the fracturing proppant prepared by using the present invention are as follows: the bulk density is 0.9-1.6 g/cm ³ , the apparent density is 2.0-2.2 g/cm ³ , the roundness and sphericity are 0.7-0.9, and the turbidity is 25-30 FTU , the broken rate of 20/40 mesh products under 48MPa pressure is less than 10%, and the apparent density can reach 2.2g/cm ³ , which is far lower than the apparent density of the current sintered bauxite proppant (2.6～3.5g/cm ³ ).

The beneficial effects of the present invention are:

(1) The light-weight high-strength fracturing proppant obtained in the present invention has low density, is not easy to settle during use, is convenient for pumping, reduces the requirement on the viscosity of fracturing fluid, reduces the damage to the pump, and effectively reduces the difficulty and cost of construction ;

(2) The light-weight high-strength fracturing proppant obtained in the present invention has high strength, low breakage rate during use, can effectively maintain the conductivity of fracturing fluid, is suitable for deep well fracturing, and has broad market prospects.

detailed description

Measure 150-200mL of 10% sodium silicate solution by mass fraction, pour it into a three-necked flask with a dropping funnel, and then place the three-necked flask in a magnetic stirrer with a digital speed measurement and constant temperature, at a temperature of 55-60°C and a speed of Under the condition of 300-500r/min, add 120-160mL hydrochloric acid with a concentration of 2mol/L into the three-necked flask through the dropping funnel, and control the dropping within 30-45min. Obtain a white suspension; mix the white suspension obtained above with 280-380mL of 8-10% aluminum nitrate solution with a mass fraction of 8-10%, pour it into a three-necked flask, then add 20-40g of urea, 30-40g of nano-hydroxy phosphoric acid Calcium, 40-60mL diethanolamine, and then put the three-neck flask in a digital speed measuring and constant-temperature magnetic stirrer, at a temperature of 65-70°C and a speed of 400-600r/min, stir at a constant temperature for 15-20min, and then drop Add 400 to 500 mL of ammonia water with a mass fraction of 15% into the three-necked flask through the liquid funnel, and continue to stir and react at a constant temperature for 45 to 60 minutes; Transfer the washed filter cake to an oven and dry it to a constant weight at a temperature of 105-110°C, then mix the dried filter cake with 3-5g of carbon black crushed to 325-500 mesh evenly, and transfer to In the muffle furnace, argon gas is introduced into the furnace at a rate of 3-5mL/min, and the temperature is programmed to rise to 680-700 °C at a rate of 6-8 °C/min under the protection of argon, and after 20-30 minutes of heat preservation and calcination, continue Programmable heating at a rate of 10-15°C/min to 1100-1200°C, heat-retaining and calcining for 45-60 minutes, cooling to room temperature with the furnace, and discharging to obtain calcined mixed powder; pour the calcined mixed powder obtained above into a container containing 400-600 mL In an evaporating dish with a fraction of 10-15% sodium carbonate solution, stir and mix with a glass rod for 10-15 minutes, heat and evaporate to dryness, and then transfer the material in the evaporating dish to a tube-type resistance furnace at a temperature of 1100-1200°C Calcined for 30 to 45 minutes under the same conditions, after cooling to room temperature with the furnace, pour the material in the tubular resistance furnace into a beaker filled with 1 to 2 L of water, stir and mix with a glass rod for 15 to 20 minutes, filter, collect the filter cake, and The resulting filter cake is placed in an oven, and dried at a temperature of 105-110°C until it reaches a constant weight to obtain a lightweight high-strength fracturing proppant.

Example 1

Measure 150mL of sodium silicate solution with a mass fraction of 10%, pour it into a three-necked flask with a dropping funnel, and then place the three-necked flask in a digital speed measuring constant temperature magnetic stirrer at a temperature of 55°C and a speed of 300r/min Under certain conditions, add 120 mL of hydrochloric acid with a concentration of 2 mol/L to the three-necked flask through the dropping funnel, and control the dropping within 30 minutes. After mixing evenly with 280mL of 8% aluminum nitrate solution, pour it into a three-necked flask, then add 20g of urea, 30g of nano-calcium hydroxyphosphate, and 40mL of diethanolamine, and then place the three-necked flask in a digital speed measuring constant temperature magnetic stirrer , at a temperature of 65°C and a rotation speed of 400r/min, stir at a constant temperature for 15min, then add 400mL of ammonia water with a mass fraction of 15% into the three-necked flask through a dropping funnel, and continue stirring at a constant temperature for 45min; when the reaction is complete, filter and collect filter cake, and wash the filter cake with deionized water until the washing liquid is neutral, then transfer the washed filter cake to an oven, and dry it to a constant weight at a temperature of 105°C, then mix the dried filter cake with 3g Grind the carbon black to 325 mesh and mix it evenly, and transfer it to a muffle furnace, feed argon gas into the furnace at a rate of 3mL/min, under the protection of argon, program the temperature to 680 °C at a rate of 6 °C/min, and heat-preserve and calcinate After 20 minutes, continue to heat up to 1100°C at a rate of 10°C/min, heat-preserve and calcinate for 45min, cool to room temperature with the furnace, and discharge to obtain calcined mixed powder; In the evaporating dish of sodium carbonate solution, stir and mix with a glass rod for 10 minutes, heat and evaporate to dryness, then transfer the material in the evaporating dish to a tubular resistance furnace, and calcinate for 30 minutes at a temperature of 1100 ° C, and wait to be cooled with the furnace to At room temperature, pour the material in the tubular resistance furnace into a beaker filled with 1L of water, stir and mix with a glass rod for 15 minutes, filter, collect the filter cake, and put the obtained filter cake in an oven at a temperature of 105°C Dry to constant weight to obtain a lightweight high-strength fracturing proppant.

The performance of the fracturing proppant prepared by using the present invention is as follows: the bulk density is 0.9g/cm ³ , the apparent density is 2.0g/cm ³ , the roundness and sphericity are 0.7, the turbidity is 25FTU, and the 20/40 mesh product is at 48MPa The fracture rate under pressure is 9%, and the apparent density is much lower than that of the current sintered bauxite proppant.

Example 2

Measure 180mL of sodium silicate solution with a mass fraction of 10%, pour it into a three-necked flask with a dropping funnel, and then place the three-necked flask in a digital speed measuring constant temperature magnetic stirrer at a temperature of 58°C and a speed of 400r/min Under certain conditions, add 140 mL of hydrochloric acid with a concentration of 2 mol/L to the three-necked flask through the dropping funnel, and control the dropping within 40 minutes. After mixing evenly with 320mL of 9% aluminum nitrate solution, pour it into a three-necked flask, then add 30g of urea, 35g of nano-calcium hydroxyphosphate, and 50mL of diethanolamine, and then place the three-necked flask in a magnetic stirrer with digital display speed measurement and constant temperature , at a temperature of 68°C and a rotation speed of 500r/min, stir at a constant temperature for 18min, then add 450mL of ammonia water with a mass fraction of 15% into the three-necked flask through a dropping funnel, and continue stirring at a constant temperature for 50min; when the reaction is complete, filter and collect filter cake, and wash the filter cake with deionized water until the washing liquid is neutral, then transfer the washed filter cake to an oven, and dry it to a constant weight at a temperature of 108°C, then mix the dried filter cake with 4g Grind the carbon black to 400 meshes and mix it evenly, and transfer it to a muffle furnace. Introduce argon gas into the furnace at a rate of 4 mL/min. Under the protection of argon gas, program the temperature to 690 °C at a rate of 7 °C/min, and heat-preserve and calcinate After 25 minutes, continue to program the temperature up to 1150°C at a rate of 12°C/min, heat-preserve and calcinate for 50min, cool to room temperature with the furnace, and discharge to obtain a calcined mixed powder; pour the calcined mixed powder obtained above into a container containing 500 mL of In the evaporating dish of sodium carbonate solution, stir and mix with a glass rod for 12 minutes, heat and evaporate to dryness, then transfer the material in the evaporating dish to a tubular resistance furnace, and calcinate for 40 minutes at a temperature of 1150 ° C, and wait to be cooled with the furnace to At room temperature, pour the material in the tubular resistance furnace into a beaker filled with 1L of water, stir and mix with a glass rod for 18 minutes, filter, collect the filter cake, and put the obtained filter cake in an oven at a temperature of 108°C Dry to constant weight to obtain a lightweight high-strength fracturing proppant.

The performance of the fracturing proppant prepared by using the present invention is as follows: the bulk density is 1.2g/cm ³ , the apparent density is 2.1g/cm ³ , the roundness and sphericity are 0.8, the turbidity is 28FTU, and the 20/40 mesh product is at 48MPa The fracture rate under pressure is 8%, and the apparent density is much lower than that of the current sintered bauxite proppant.

Example 3

Measure 200mL of sodium silicate solution with a mass fraction of 10%, pour it into a three-necked flask with a dropping funnel, and then place the three-necked flask in a digital speed measuring constant temperature magnetic stirrer at a temperature of 60°C and a speed of 500r/min Under certain conditions, add 160 mL of hydrochloric acid with a concentration of 2 mol/L to the three-necked flask through the dropping funnel, and control the dropping within 45 minutes. After mixing evenly with 380mL of 10% aluminum nitrate solution, pour it into a three-necked flask, then add 40g of urea, 40g of nano-calcium hydroxyphosphate, and 60mL of diethanolamine, and then place the three-necked flask in a digital speed measuring constant temperature magnetic stirrer , at a temperature of 70°C and a rotation speed of 600r/min, stir at a constant temperature for 20min, then add 500mL of ammonia water with a mass fraction of 15% into a three-neck flask through a dropping funnel, and continue stirring at a constant temperature for 60min; when the reaction is complete, filter and collect filter cake, and wash the filter cake with deionized water until the washing liquid is neutral, then transfer the washed filter cake to an oven, and dry it to a constant weight at a temperature of 110°C, then mix the dried filter cake with 5g Grind the carbon black to 500 meshes and mix it evenly, and transfer it to a muffle furnace. Introduce argon gas into the furnace at a rate of 5 mL/min. Under the protection of argon, program the temperature to 700 °C at a rate of 8 °C/min, and heat-preserve and calcinate After 30 minutes, continue to heat up to 1200°C at a rate of 15°C/min, heat-preserve and calcinate for 60min, cool to room temperature with the furnace, and discharge to obtain calcined mixed powder; pour the calcined mixed powder obtained above into a container with a mass fraction of 15% In the evaporating dish of sodium carbonate solution, stir and mix with a glass rod for 15 minutes, then heat and evaporate to dryness, then transfer the material in the evaporating dish to a tubular resistance furnace, and calcinate for 45 minutes at a temperature of 1200 ° C, and wait to be cooled with the furnace to At room temperature, pour the material in the tubular resistance furnace into a beaker filled with 2L of water, stir and mix with a glass rod for 20 minutes, filter, collect the filter cake, and put the obtained filter cake in an oven at a temperature of 110°C Dry to constant weight to obtain a lightweight high-strength fracturing proppant.

The performance of the fracturing proppant prepared by using the present invention is as follows: the bulk density is 1.6g/cm ³ , the apparent density is 2.2g/cm ³ , the roundness and sphericity are 0.9, the turbidity is 30FTU, and the 20/40 mesh product is at 48MPa The fracture rate under pressure is less than 10%, and the apparent density is much lower than that of the current sintered bauxite proppant.

Claims (1)

1. a kind of preparation method of high-strength light fracturing propping agents, it is characterised in that specific preparation process is：

(1) 150~200mL mass fractions are measured for 10% sodium silicate solution, is poured into the there-necked flask with dropping funel, then will There-necked flask is placed in digital display and tests the speed in constant temperature blender with magnetic force, is 55~60 DEG C in temperature, and rotating speed is 300~500r/min conditions Under, by dropping funel to adding 120~160mL concentration for 2mol/L hydrochloric acid in there-necked flask, control is dripped in 30~45min It is complete, completion of dropping is treated, continue constant temperature 30~45min of stirring reaction, obtain white suspension；

(2) after above-mentioned gained white suspension is well mixed with 280~380mL mass fractions for 8~10% aluminum nitrate solutions, Pour into there-necked flask, add 20~40g urea, 30~40g nano-hydroxy phosphoric acid calcium, 40~60mL diethanol amine, then There-necked flask is placed in into digital display to test the speed in constant temperature blender with magnetic force, is 65~70 DEG C in temperature, rotating speed is 400~600r/min bars Under part, constant temperature stirs 15~20min, is to addition 400~500mL mass fractions in there-necked flask by dropping funel then 15% ammoniacal liquor, continues 45~60min of constant temperature stirring reaction；

(3) question response terminates, filtering, collects filter cake, and filter cake is washed with deionized up to cleaning solution is in neutrality, then will washing Filter cake afterwards is transferred in baking oven, is dried to constant weight under the conditions of being 105~110 DEG C in temperature, then by dried filter cake and 3~5g The carbon black for being crushed to 325~500 mesh is well mixed, and is transferred to Muffle furnace, with 3~5mL/min speed to being passed through argon gas in stove, Under argon gas guard mode, 680~700 DEG C are warming up to 6~8 DEG C/min rate programs, after 20~30min of insulation calcining, continued 1100~1200 DEG C are warming up to 10~15 DEG C/min rate programs, insulation 45~60min of calcining cools to room temperature with the furnace, goes out Material, obtains calcined mixed powder；

(4) it is 10~15% sodium carbonate liquors to pour into above-mentioned gained calcined mixed powder and fill 400~600mL mass fractions In evaporating dish, after stirring 10~15min of mixing with glass bar, material in evaporating dish is then transferred to tubular type by heating evaporation to dry In resistance furnace, 30~45min, room temperature to be cooled to the furnace, by tubular electric resistance are calcined under the conditions of being 1100~1200 DEG C in temperature Material is poured into the beaker for filling 1~2L water in stove, and after stirring 15~20min of mixing with glass bar, filter cake is collected in filtering, and Gained filter cake is placed in baking oven, is dried to constant weight under the conditions of being 105~110 DEG C in temperature, obtain final product the support of high-strength light pressure break Agent.