CN108037273A - Sial white bind ceramic fine bead prepares the well cementation test block performance test of oil well anti-gas-leak - Google Patents

Abstract

The present invention provides a kind of sial white bind ceramic fine bead and prepares the well cementation test block performance test of oil well anti-gas-leak,By G grades of 40~50 wt% of oil-well cement,10~15 wt% of superfine cement,Particle diameter is hollow 25~35 wt% of sial white bind ceramic fine bead of 50~250 μm of closed pores,5~7 wt% of flyash of loss on ignition 1.1%,Purity 99.9%,1.5~2 wt% of calcium oxide,1~5wt% of 0.5~1.0wt% of sodium sulphate and silica flour,Obtain mixture,The sum of percentage by weight of above component is 100%,Mixture is stirred evenly,Sized mixing with 0.5~0.7 ratio of mud,Add the aluminium foaming agent that mixture gross weight is 0.2~0.5%,It is prepared into dilatant slurry,Carry out the density of dilatant slurry,Acid-base value measures,Uniformity test,Rate of change of the density is tested and anti-gas-leak performance test.

Description

Performance test of oil well anti-leakage gas cementing test block prepared by silica-alumina shale soil ceramic microbeads

technical field

The invention relates to performance testing of an oil well anti-leakage gas cementing test block prepared by silicon-aluminum shale soil ceramic microbeads, and belongs to the field of material technology.

Background technique

At present, in oil well cementing at home and abroad, ultra-low density cement is used for high-temperature and high-pressure oil wells, but fly ash floating beads are used, which has low compressive strength and a large change rate of cement slurry density. After the cement slurry is statically solidified, air leakage, In addition, the proportion of lightening agents such as fly ash floating beads must be controlled within 40%, otherwise, the lightening agent will affect the compressive strength of the cement test block, and the density of the cement test block is less than 40%. Above 1.2g/cm ³ , it is not feasible to reduce the density of the cement test block only by increasing the proportion of lightening agent.

Contents of the invention

Modified silica-alumina shale soil ceramic material is used as a lightening agent, and the modified silica-alumina shale soil ceramic material is used to improve the performance of compression resistance, flexural resistance, high temperature resistance and corrosion resistance of the cementing test block. Foaming agent is added to the cement to form an expanded slurry, which reduces the density of the slurry and the pressure at the bottom of the well. During the hydration process, a gel-like substance is formed, and the pores of the matrix structure of the cement slurry become smaller, forming a high air resistance cementing test. block, which reduces the permeability of the cementing test block and increases the pore flow resistance of the cementing test block.

Prevent the slurry from leaking due to weight loss in the cementing process, and reduce the compressive capacity.

Its technical solution is:

The performance test of the oil well anti-leakage gas cementing test block prepared by silica-alumina shale ceramic microbeads includes the following steps:

A. Preparation of closed-cell hollow silica-alumina shale ceramic microspheres:

The first step, the preparation of the base material: shale soil powder with a particle size of 20-50 µm, silica powder with a particle size of 10-50 µm, and alumina powder with a particle size of 10-50 µm in a weight ratio: 70-85wt%: 10-20wt%: 10-30wt% sampling to obtain mixed powder, the sum of the weight percentages of the above components is 100%;

The second step, the modified firing of the base material: After the first step is mixed and stirred evenly, then add 5-8wt% of the total weight of the mixed powder to reduce the resin, stir evenly in the mixer, and press it into a billet with a compactor. Dry at 100-300°C for 6-12 hours, heat-preserve and fire in a reduction electric furnace at 1500-1650°C for 2-4 hours, and obtain modified silicon-aluminum shale ceramic blocks through displacement reaction. Shale soil has strong hygroscopicity and Expansibility, the modified silicon-aluminum shale soil has stable physical and chemical properties, high-temperature resistance of alumina, strong compressive and flexural properties of silica, and the modified silicon-aluminum shale soil is resistant to compression, flexural, and Erosion, anti-aging, acid and alkali resistance, high temperature resistance are improved;

Step 3: Preparation of modified solid silica-alumina shale ceramic microbeads: process the silica-alumina shale ceramic block obtained in the second step on a spheroidizer to make solid silica-alumina sheets with a particle size of 5-50 μm Geotechnical ceramic microbeads, the spheroidization process is that the fan blows up the materials, and the rotating motion between the materials rubs against each other to form spherical particles with uniform wall thickness. The spherical particles have uniform stress distribution at each particle point and high compressive strength;

The fourth step, preparation of modified silica-alumina shale soil ceramic slurry: the percentage composition of silica-alumina shale soil slurry is: 65-70 wt% of solid silica-alumina shale soil ceramic microbeads with a particle size of 5-50 μm: water 30-35 wt%;

The fifth step, adding foaming agent: add urea to the silica-alumina shale soil ceramic slurry prepared in the fourth step, the concentration is 1-3g/L, use N ₂ H ₄ CO as the foaming agent, when the temperature in the furnace When the temperature rises to 135°C, CO ₂ and NH ₃ are generated by decomposition, which increases the volume of silica-alumina shale ceramic microbeads;

The sixth step, the preparation of modified closed-cell hollow silica-alumina shale soil ceramic microspheres: fully stir and filter the mixed slurry in the fifth step, and use high-pressure spraying and high-speed centrifugal rotary spraying method to form microspheres, which are separately controlled vertically in multiple areas After dehydration, expansion, high-temperature sintering, surface melting and vitrification, and ball formation in the oxygen-enriched combustion furnace, the closed-cell hollow silicon-aluminum shale ceramic microspheres with a wall thickness of 15-50 µm and a particle size of 50-250 µm are obtained through wind cleaning and classification , The wall thickness of floating beads made of inorganic mineral materials is artificially controllable, the compressive strength is 120-250MPa, and the closed-pore hollow silicon-aluminum shale-soil composite ceramic beads have high compressive strength;

B. Modified closed-pore hollow silicon-aluminum shale soil ceramic microbeads to prepare oil well anti-leakage gas cementing test block:

The first step, the ingredients of the anti-leakage gas cementing test block: 40-50wt% of G-grade oil well cement, 10-15wt% of ultra-fine cement, and closed-cell hollow silica-aluminum shale soil ceramic microbeads with a particle size of 50-250μm 25 ~35wt%, 1.1% loss on ignition of fly ash 5~7wt%, pure 99.9% calcium oxide 1.5~2wt%, sodium sulfate 0.5~1.0wt% and silicon powder 1~5wt%, to obtain the mixture, the above combination The sum of the percentages by weight is 100%. Fly ash with an ignition loss of 1.1% is used. According to the accumulation principle, the fly ash mainly fills the two materials of G-grade oil well cement and closed-cell hollow silica-alumina shale ceramic microbeads. The gap between particle sizes, when two particles with different particle sizes are tangent to each other, the gap between the tangent circles is filled with fly ash, so that the G-grade oil well cement and glass micro-beads are closely combined, but the usage amount should be controlled within a certain amount. within the range of 5% to 7% of the total weight, otherwise, it will affect the strength of the high temperature and high pressure test block, followed by the fly ash generated by high temperature sintering, which is active and can significantly increase the hydration rate of the slurry. Fly ash with low loss requires a small water-cement ratio, which is helpful for the early strength of the cementing test block. The purity of calcium hydroxide is 99.9%. The higher the purity of calcium oxide, the stronger the activity, the faster the hydration speed, and the formation of gel Calcium hydroxide is a substance that is beneficial to the early strength of the slurry. Temperature plays an important role in the early strength of the test block. Secondly, the calcium hydroxide formed after hydration is alkaline and can adjust the pH value of the slurry. Under weakly alkaline conditions It can improve the early strength of high temperature and high pressure oil well cement. Sodium sulfate is a water loss reducing agent with obvious effect of reducing water loss. The sodium ion in sodium sulfate has the function of reverse osmosis, and the diffusion speed is fast, so that the slurry can be solidified during solidification. Precipitate part of the water, how much sodium sulfate is used, plays an important role in reducing the water loss of the slurry, using active silicon, aluminum and G-grade oil well cement to react to form hydrated calcium silicate gel and other gels, increasing the voids in the cement slurry The flow resistance and the pressure of the voids reduce the voids of the particles in the cementing test block, improve the structure of the slurry, reduce the permeability of the cementing test block, and increase the compactness and compressive strength of the cementing test block;

The second step, the preparation of the expansion slurry of the anti-leakage test block: sample and mix according to the weight percentage of the first step to obtain the mixed powder, and stir the mixed material evenly, and adjust the slurry with a water-cement ratio of 0.5 to 0.7, wherein the ash is the mixed material , and then add an aluminum foaming agent with a total weight of 0.2-0.5% of the mixture. The aluminum foaming agent is one of aluminum powder paste, aluminum powder or aluminum compounds. The hydration reaction of the aluminum foaming agent generates bubbles. The expanded slurry is formed, the density of the slurry is reduced, and the pressure is correspondingly reduced. Active silicon and aluminum react with G-grade oil well cement to form calcium silicate hydrate gel-like substances and other gels, and the structural pores of the cement slurry become smaller. The pressure resistance is enhanced, the slurry is sucked by the liquid pump, and sprayed onto the outer surface of the high-speed rotating drum, and the centrifugal force is generated on the outer surface of the drum to sprinkle the slurry, so as to realize the spinning and stirring;

The third step, performance index test:

a. Determination of the density of the expansion slurry: take the expansion slurry prepared in the second step, pour it into a slurry density meter to measure the density, the density of the expansion slurry is between 0.8 and 1.2g/ ^cm3 , and the density of this slurry is called ultra-low Density, the compressive strength of the test block is high, and the modified silica-alumina shale soil ceramic material is used to improve the compressive, flexural, erosion-resistant and anti-aging properties of the closed-cell hollow ceramic microspheres of the silica-alumina shale soil, which has good performance. Excellent heat insulation, elasticity, willfulness, acid resistance, alkali resistance and pressure resistance, anti-aging and oxidation resistance.

b. Determination of the pH of the expansion slurry: take the expansion slurry prepared in the second step, pour it into a pH value tester, and display the pH value. The pH value of the expansion slurry is between 9.0 and 10.5;

c. Uniformity test of the slurry: Take the expansion slurry prepared in the second step and pour it into the settling cylinder. Observe the uniformity and stability after 0.5 hours. The property is no longer floating up and down, and the microbeads are evenly distributed in the expansion slurry;

d. Density change rate test of the test block: prepare the slurry in the second step, pour it into a group of three test molds whose length, width and height are 53mm*53mm*53mm respectively, and maintain them in a water bath curing box with a constant temperature of 52°C 24 hours, 48 hours, 96 hours, soak in cold water for 1 hour after demoulding, put the solidified test block into the press for density change rate test, the density change rate of the test block is less than 0.02%;

e. Anti-leakage performance test: Air leakage occurs during the solidification process of the slurry, that is, in the process of changing from a plastic state to a solid state. Take the expanded slurry prepared in the second step and pour it into the air leakage simulation experimental device. The air leakage simulation experiment The device includes a bracket, a remote control electric digital display tilt angle regulator, a central tube, an outer tube, a pressure hole, a pressure measurement hole, an upper sealing cover, a lower sealing cover, a filter screen, and the central tube runs through the outer tube. The diameter of the central tube is as large as different specifications, the inner diameter is between 10 and 200 cm, an annular space is formed between the central pipe and the outer pipe, and there are micro-holes on the central pipe and the outer pipe. The annular space is the wellbore annular space, and the expanded slurry is injected into it. The components are installed on the bracket, and the influence of the tilt angle of the bracket from 0 to 90° on the air leakage, the effect of the gap between the central tube and the outer tube on the slurry solidification time and air leakage, the effect of the amount of water loss on the air leakage, The influence of the density of the slurry on the air leakage, the influence of the weight loss of the slurry on the air leakage, the excessive water loss in the hydration reaction, resulting in excessive volume shrinkage, the pressure is proportional to the depth, pressurization from the pressure hole, the pressure range is from 1 to 350MPa, the pressure measuring hole is connected to a digital pressure sensor to measure the static pressure of the annular expansion slurry, and the filter net is equipped with a filter hole to measure the amount of water loss. The water loss should be 10-50mL/30min. The influence of inclination angle and pressure on water loss, the influence of multi-factor density, inclination angle and pressure combined measurement on water loss, the amount of water loss is directly related to air leakage, and record the measured test value, excessive water loss The gaps and cracks in the test block are caused to prevent the grout from losing weight during solidification. One of the reasons for the air leakage of the cementing test block is that the greater the density of the cementing test block, the greater the pressure per unit area. With the deepening of the cementing depth, the bottom The greater the pressure, the subsidence occurs, and the expansion cement is used to reduce the density of the slurry, thereby reducing the pressure at the bottom of the well. During the hydration process, a gel-like substance is formed, and the pores of the matrix structure of the cement slurry become smaller, forming a high air resistance cementing test. block, which reduces the permeability of the cementing test block and increases the pore flow resistance of the cementing test block.

The present invention has the following advantages.

1. After the replacement reaction of thermal reduction, a modified ceramic material is produced to improve the performance of compression resistance, bending resistance, erosion resistance and aging resistance of the closed-pore hollow ceramic microspheres of silica-alumina shale soil.

2. The expanded slurry is used to reduce the density of the slurry, thereby reducing the pressure at the bottom of the well.

3. Active silicon, aluminum and G-grade oil well cement react to form hydrated calcium silicate gel-like substances and other gels, and the matrix structure pores of the cement slurry become smaller, forming a high air resistance cementing test block, which reduces the cementing effect. The permeability of the test block improves the pore flow resistance of the cementing test block.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the test bench for the air leakage performance test of the embodiment of the present invention.

In the figure 1, bracket 2, remote control electric digital display tilt angle regulator 3, lower sealing cover 4, beaker 5, filter screen 6, outer tube 7, center tube 8, upper sealing cover 9, pressure measuring hole 10, plus Pressure hole 11, pressure pump 12, digital pressure sensor.

Detailed ways

Example 1.

The performance test of the oil well anti-leakage gas cementing test block prepared by silica-alumina shale ceramic microbeads includes the following steps:

A. Preparation of closed-cell hollow ceramic microspheres in silica-alumina shale soil:

The first step, the preparation of the base material: the silicon-aluminum shale soil powder with a particle size of 25 µm, the silica powder with a particle size of 40 µm, and the alumina powder with a particle size of 30 µm are sampled according to the weight ratio: 70wt%: 15wt%: 15wt% to obtain a mixed powder;

The second step, the modified firing of the base material: After the first step is mixed and stirred evenly, add 5wt% of the total weight of the mixed powder and reduce the resin, stir evenly in the mixer, and press it into a billet with a compactor, at 150 ° C Dry for 10 hours, heat-preserve and fire in a reduction electric furnace at 1500°C for 4 hours, and obtain a modified silica-alumina shale ceramic block through a displacement reaction. The chemical composition of the modified silica-alumina shale soil changes, and alumina makes the silica-alumina shale The temperature resistance of rock and soil is improved, the attraction of molecular bonds is increased, and the performance of compression resistance, flexural resistance, erosion resistance, aging resistance, acid and alkali resistance, and high temperature resistance is improved;

The third step, preparation of modified solid silica-alumina shale soil ceramic microbeads: process the silica-alumina shale soil blocks obtained in the second step on a spheroidizer to make solid silica-alumina shale soil ceramics with a particle size of 30 μm microbeads.

The fourth step, preparation of the silica-alumina shale soil ceramic slurry: The percentage composition of the silica-alumina shale soil slurry is: 70wt% of solid silica-alumina shale soil ceramic beads with a particle size of 30 μm: 30wt% of water.

The fifth step, adding foaming agent: add urea to the silica-aluminum shale soil ceramic slurry prepared in the fourth step, the concentration is 2.5g/L, use N ₂ H ₄ CO as the foaming agent, when the temperature in the furnace When the temperature rises to 135°C, it decomposes to generate CO ₂ and NH ₃ , which increases the volume of ceramic microbeads.

Step 6. Preparation of modified closed-cell hollow silica-alumina shale ceramic microspheres: fully stir and filter the mixed slurry in step 5, and use high-pressure spraying and high-speed centrifugal rotary spraying method to form microspheres. After dehydration, expansion, high-temperature sintering, surface melting and vitrification, and ball formation in the combustion furnace, 200 μm closed-pore hollow silica-alumina shale soil ceramic microbeads are obtained through wind cleaning and grading. The thickness is 25µm, which is larger than the wall thickness of other floating beads, and the compressive strength is 200MPa.

B. Modified closed-pore hollow silicon-aluminum shale soil ceramic microspheres to prepare oil well anti-leakage test blocks.

The first step, the ingredients of the anti-leakage test block: take G grade oil well cement 45wt%, ultra-fine cement 15wt%, silica-alumina shale soil with a particle size of 200μm 30wt% closed-cell hollow ceramic microbeads, and ignition loss 1.1% 5wt% fly ash with a particle size of 20µm, 2.0wt% calcium hydroxide with a purity of 99.9%, 1.0wt% sodium sulfate and 2wt% silicon powder with a particle size of 5µm to obtain a mixture.

The second step, the preparation of the expansion slurry of the anti-leakage test block: sample and mix the mixture according to the weight percentage of the first step, and stir the mixture evenly, adjust the slurry with a water-cement ratio of 0.55, and then add aluminum powder paste, aluminum The hydration reaction of the powder paste generates bubbles, forms an expanded slurry, and reduces the density of the slurry. Active silicon, aluminum and G oil well cement react to form calcium silicate hydrate gel-like substances and other gels, and the matrix structure of the cement slurry becomes porous. Small, the slurry is sucked by the liquid pump, sprayed onto the outer surface of the high-speed rotating drum, and the centrifugal force is generated on the outer surface of the drum to sprinkle the slurry to realize the spinning and stirring.

The third step, performance index test:

a. Determination of the density of the expanded slurry: take the second step to prepare the slurry, pour it into a slurry density meter and weigh the density, the density of the expanded slurry is between 0.9g/cm ³ , the density of this slurry is called ultra-low density, test block The compressive strength is high, and the modified silica-alumina shale soil ceramic material is used to improve the compressive, flexural, erosion-resistant and anti-aging properties of the closed-pore hollow ceramic microspheres of the silica-alumina shale soil.

b. Determination of the pH of the expansion slurry: Take the second step to prepare the slurry, pour it into a pH value tester, and display the pH value. The pH value of the expansion slurry is 9.5.

c. Uniformity test of the slurry: Take the expansion slurry prepared in the second step and pour it into the settling cylinder. Observe the uniformity and stability after 0.5 hours. The property is no longer floating up and down, and the microbeads are evenly distributed in the expanded slurry.

d. Density change rate test of the test block: prepare the slurry in the second step, pour the stirred slurry into a group of two test molds with length, width and height of 53mm*53mm*53mm respectively, and maintain in a water bath with a constant temperature of 52°C Cured in the box for 24 hours, 48 hours, and 96 hours respectively, soaked in cold water for 1 hour after demoulding, and put the solidified test block into a press to test the density change rate of the test block.

e. Performance test of gas leakage prevention cementing test block: Take the expansion slurry prepared in the second step and pour it into the air leakage simulation experimental device. The air leakage simulation experimental device includes bracket 1, remote control electric digital display tilt angle regulator 2, Center tube 7, outer tube 6, pressurization hole 10, pressure measuring hole 9, upper sealing cover 8, lower sealing cover 3, filter screen 5, wherein, the central tube 7 runs through the outer tube 6, the central tube 7 can be replaced, and the central tube An annular space is formed between 7 and the outer tube 6, and the expanded slurry is injected into it, and other components are installed on the bracket 1, and the inclination angle regulator 2 with remote control electric digital display makes the inclination angle of the bracket 1 60°, and the central tube 7 and the outer tube 7 The gap between the tubes 6 is 40 cm. The influence of the measurement angle on the solidification of the slurry, the influence of the amount of dehydration on the air leakage, and the influence of the density of the slurry on the air leakage are due to the gaps and cracks in the test block. Loss of weight leads to a decrease in compressive strength, and the pressure is proportional to the depth. Use a pressure pump 11 to pressurize from the pressure hole 10 to 300MPa. The digital pressure sensor 12 measures the static pressure of the slurry in the annular space. The filter screen 5 is equipped with The fluid loss hole measures the amount of water loss. The water loss in the beaker 4 is 25mL/30min. The water loss per unit time meets the cementing requirements. The influence of density, inclination angle, and pressure on the water loss is measured by single factor. In turn, it will affect the gas leakage of the oil well. The combined measurement of multi-factor density, inclination angle and pressure will affect the water loss reduction. The amount of water loss reduction is directly related to the gas leakage. As the cementing depth deepens, the bottom pressure increases and subsidence occurs. Modified closed-cell hollow silica-zirconia ceramic beads and expanded slurry are used to reduce the density of the slurry, solve the weight loss phenomenon of the slurry, and reduce the pressure at the bottom of the well. , during the hydration process, a gel-like substance is formed, and the pores of the matrix structure of the cement slurry become smaller, forming a high air resistance cementing test block, which improves the pore flow resistance of the cementing test block and reduces the permeability of the cementing test block , improving the pore flow resistance of the cementing test block.

Claims (1)

1. Performance test of oil well anti-leakage gas cementing test block prepared by silica-alumina shale soil ceramic microbeads, including the following steps: The first step, the ingredients of the anti-leakage gas cementing test block: G-grade oil well cement 40-50wt%, ultra-fine cement 10-15wt%, particle size 50-250μm closed-pore hollow silica-aluminum shale soil ceramic microbeads 25 ～35wt% and 1.1% loss on ignition of fly ash 5～7wt%, purity 99.9% calcium oxide 1.5～2wt%, sodium sulfate 0.5～1.0wt% and silicon powder 1～5wt% were sampled to obtain the mixture. The sum of weight percentages of points is 100%; The second step, the preparation of the expansion slurry of the anti-leakage gas cementing test block: take a sample according to the weight percentage of the first step to obtain the mixture, stir the mixture evenly, and adjust the slurry with a water-cement ratio of 0.5-0.7, wherein the ash is the mixture , and then add an aluminum foaming agent with a total weight of 0.2-0.5% of the mixture. The hydration reaction of the aluminum foaming agent generates bubbles, forming an expanded slurry, reducing the density of the slurry, and reactive silicon and aluminum react with G-grade oil well cement to form Calcium silicate hydrate gel-like substances and other gels increase the flow resistance and void pressure of cement slurry voids, reduce the voids of particles in the cementing test block, improve the structure of the slurry, and reduce the penetration of the cementing test block Higher rate, which improves the compactness and compressive strength of the cementing test block. The slurry is sucked by the liquid pump and sprayed onto the outer surface of the high-speed rotating drum, and the centrifugal force is generated on the outer surface of the drum to sprinkle the slurry to realize the spinning and stirring; The third step, the performance test of the anti-leakage gas-leakage cementing test block: take the expansion slurry produced in the second step and pour it into the air leakage simulation experimental device. Regulator (2), center tube (7), outer tube (6), pressurization hole (10), pressure measurement hole (9), upper sealing cover (8), lower sealing cover (3), filter screen (5 ), wherein the center pipe (7) runs through the outer pipe (6), and the diameter of the center pipe (7) has various specifications, an annular space is formed between the center pipe (7) and the outer pipe (6), and the expanded slurry is injected into it, Other components are installed on the bracket (1), and there is a keyboard on the control cabinet. The rotation angle of the servo motor can be changed by inputting parameters, and then the tilt angle of the bracket (1) can be changed to test the influence of different tilt angles of the bracket (1) on air leakage. , The effect of the gap between the center pipe (7) and the outer pipe (6) on the solidification time of the slurry and air leakage, the effect of the amount of water loss on the air leakage, the effect of the density of the slurry on the air leakage, the effect of the weight loss of the slurry on the air leakage Influence, use the pressure pump (11) to pressurize from the pressure hole (10), connect the pressure measurement hole (9) to the digital pressure sensor (12), measure the static pressure of the slurry in the annular space, simulate the pressure values at different depths, filter The net (5) is equipped with filtration holes to measure the amount of water loss, and the water loss enters the beaker (4), and the single factor measures the influence of density, inclination angle and pressure on the water loss, and the multi-factor density, inclination angle , The impact of pressure combination measurement on water loss reduction, the amount of water loss reduction is directly related to air leakage, and record the measured test values. The greater the density of the cementing test block, the greater the pressure per unit area. With the deepening of the cementing depth, The greater the pressure at the bottom, the subsidence occurs. The modified closed-pore hollow silica-alumina shale soil microbeads and expanded slurry reduce the density of the slurry, reduce the pressure at the bottom of the well, and generate a gel-like substance during the hydration process. The pores of the matrix structure of the cement slurry become smaller, forming a high air resistance cementing test block, which reduces the permeability of the cementing test block and increases the pore flow resistance of the cementing test block.