Corrosion-resistant expansion agent for oil well cement and method for preparing the same

Abstract

The application discloses an oil well cement corrosion-resistant expanding agent and a preparation method thereof. The preparation method of the oil well cement corrosion-resistant expanding agent comprises the following steps: S1, mixing a jade processing waste powder after ball milling with hydrochloric acid, stirring and filtering to obtain a filtrate; S2, adjusting the pH value of the filtrate and heating to no precipitation, and separating by suction filtration to obtain a purified liquid; S3, adding ammonium bicarbonate into the purified liquid, drying after heating and separating by suction filtration to obtain basic magnesium carbonate; S4, mixing the basic magnesium carbonate with the jade processing waste powder and ball milling to obtain a powder; and S5, high-temperature calcining the powder, and rapidly cooling the obtained powder. The cooling mode of the method adopts a liquid nitrogen rapid cooling process, which can not only promote the internal stress of the CO2 corrosion-resistant material to be sufficient, but also achieve the purposes that the surface of the CO2 corrosion-resistant material is spherical, a large number of cracks are formed on the surface, and the particle size of the product is controllable.

Description

TECHNICAL FIELD

[0001] The present application relates to an oil well cement corrosion-resistant expanding agent and a preparation method thereof, and belongs to the field of oil and gas well cementing cement slurry additive. BACKGROUND

[0002] Well cementing is an indispensable part of drilling operation, and the main process includes casing and cementing, the purpose of which is to seal the casing and the annular space of the well wall to form a cement ring with high compressive strength and high cementing capacity to prevent underground fluid from channeling along the cement ring. During the cementing process, the invasion of high-pressure gas in the formation into the cement slurry column will cause gas channeling, which will cause pollution and loss of oil and gas resources, and is one of the major problems that have not been completely solved in cementing operations at home and abroad. When gas channeling is serious, the oil and gas well may even be unable to put into production. The commonly used cement in well cementing is Portland cement, and the water-binder ratio of the cement slurry is large, and the service temperature and pressure are high, so the cement often has a large shrinkage rate in use, which is the main reason for annular channeling, easy shrinkage and cracking of the cement ring, and unqualified well cementing quality.

[0003] Moreover, at present, the cement used in well cementing is mostly Portland cement system. In recent years, the CO2 corrosion problem of well cementing Portland cement stone has attracted much attention. This is because the source of high-concentration CO2 in the formation is no longer just the associated gas of oil and gas, but also the large amount of CO2 injected by CO2 flooding and CO2 storage technologies, which greatly increases the concentration of CO2 in the formation. Under the high temperature, high pressure and humid environment downhole, high-concentration CO2 will cause serious corrosion to Portland cement stone in a short time, which will increase the permeability of the cement stone and reduce the strength of the cement stone, etc., so that the cement stone loses the sealing performance, the sealing performance of the sealing system fails, and then leads to the decrease of oil and gas recovery and the failure of CO2 storage, etc. Therefore, ordinary Portland cement stone cannot meet the requirements of long-term sealing of oil and gas wells in high-concentration CO2 formations, and new anti-CO2 corrosion materials need to be researched to improve the CO2 corrosion resistance of well cementing cement stone and ensure the successful application of high-CO2 oil and gas reservoir development, CO2 flooding and CO2 storage technologies.

[0004] The use of oil well cement expanding agent is an important means to prevent gas channeling and avoid shrinkage and cracking of the oil well cement ring, and the purpose is to compensate for the volume shrinkage of the cement and make it slightly expand. However, the existing expanding agent has a single gain effect, which can only compensate for the shrinkage, and the corrosion resistance is not significant. Therefore, the present application is proposed. SUMMARY

[0005] The purpose of the present application is to provide an oil well cement corrosion-resistant expanding agent, which uses the waste powder of jade processing with serpentine as the main component as the raw material to prepare magnesium oxide and forsterite, reduces the volume shrinkage during the cement hydration process, improves the corrosion resistance of the well cement ring, prevents channeling from occurring, and ensures that the well cement ring has good integrity.

[0006] The application provides a preparation method of the oil well cement corrosion-resistant expanding agent.

[0007] S1, mixing the jade processing waste powder after ball milling with hydrochloric acid, stirring, filtering to obtain a filtrate;

[0008] S2, adjusting the pH value of the filtrate and heating to no precipitation, separating by suction filtration to obtain a purified liquid;

[0009] S3, adding ammonium bicarbonate to the purified liquid, drying after heating and suction filtration to obtain basic magnesium carbonate;

[0010] S4, mixing the basic magnesium carbonate with the jade processing waste powder and ball milling to obtain a powder;

[0011] S5, the powder is calcined at high temperature, and the obtained powder is rapidly cooled.

[0012] In the preparation method, the average particle size of the jade processing waste powder after ball milling in step S1 is 200-300 mesh;

[0013] The jade processing waste powder used in the application is mainly composed of serpentine;

[0014] The solid-liquid ratio of the jade processing waste powder and the hydrochloric acid is 60-120 g / L;

[0015] The stirring time is 30-90 min;

[0016] The concentration of the hydrochloric acid is 8 mol / L.

[0017] In the preparation method, the pH value of the filtrate is adjusted to 7.0-7.5 by using the ammonium bicarbonate solution in step S2;

[0018] The heating condition is water bath heating to 55-60 DEG C.

[0019] In the preparation method, the solid-liquid ratio of the ammonium bicarbonate and the purified liquid is 60-120 g / L in step S3;

[0020] The heating condition is water bath heating to 55-60 DEG C;

[0021] The drying condition is constant temperature drying at 105-110 DEG C.

[0022] In the preparation method, the average particle size of the basic magnesium carbonate and the jade processing waste powder after ball milling in step S4 is 100-200 mesh;

[0023] The mass ratio of the basic magnesium carbonate to the jade processing waste powder is 30-50:70-50.

[0024] In the preparation method, in step S5, the high-temperature calcination is performed in a muffle furnace at a temperature of 1100-1200 DEG C.

[0025] The holding time is 40-60 min.

[0026] The cooling method is liquid nitrogen quenching.

[0027] In the preparation method, in step S5, the expanded agent block obtained by quenching is further ball milled to obtain a powder with a particle size of 1500-3200 mesh.

[0028] On the basis of the oil well cement corrosion-resistant expanding agent, the application further provides a gas channeling prevention and corrosion-resistant well cementing cement, which comprises oil well cement and the oil well cement corrosion-resistant expanding agent.

[0029] The mass percentage of the oil well cement corrosion-resistant expanding agent is 4-5%.

[0030] The oil well cement is G-grade oil well cement or Portland cement, both of which are the most commonly used cements in oil and gas well cementing construction.

[0031] In the preparation of the well cementing cement, conventional admixtures and external additives, such as dispersants, fluid loss reducers and defoamers, are further added, and the specific requirements are determined according to the specific needs.

[0032] The well cementing cement added with the expanding agent of the application is particularly suitable for well cementing operations with high requirements for corrosion resistance and crack resistance, and can improve the crack resistance of the cement stone and the corrosion resistance of the cement sheath, prevent channeling, and ensure the good integrity of the cement sheath.

[0033] Compared with the prior art, the application has the following beneficial effects:

[0034] (1) The cooling method of the application adopts liquid nitrogen quenching process, which can promote the internal stress of the CO2 corrosion-resistant material, make the surface of the CO2 corrosion-resistant material spherical, and have a large number of cracks and controllable product particle size.

[0035] (2) The expanding agent of the application has a slow hydration reaction process, which can make the cement further hydrate in the later period, control the expansion time of MgO, make it react at the required time, and achieve the purpose of preventing channeling and resisting cracks in the later period.

[0036] (3) The expanding agent is involved in the hydration reaction with the cement slurry, and first, cement clinker is hydrated to generate Ca(OH)2 and Mg(OH)2, and then the generated Ca(OH)2 and Mg(OH)2 react with active components such as active silicon dioxide and active aluminum oxide in forsterite to generate reaction products such as hydrated calcium silicate, hydrated magnesium silicate, hydrated calcium aluminate or hydrated magnesium aluminate, and the two reactions are alternately carried out, so that the microstructure of the cement can be improved, and the strength of the cement can be improved.

[0037] (4) The preparation method technology is reliable in technology, high in yield, and low in quality requirement for raw materials; the prepared product is high in uniformity, good in chemical stability, and strong in hydration capacity, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a linear volume expansion rate diagram of the cement stones of Examples 1-3 and Comparative Examples 1-3 of the present application.

[0039] Figure 2 is a compressive strength diagram of the cement stones of Examples 1-3 and Comparative Examples 1-3 of the present application. DETAILED DESCRIPTION

[0040] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0041] The materials, reagents and the like used in the following examples can be obtained from commercial channels unless otherwise specified.

[0042] Example 1, One,

[0044] 1. The jade processing waste powder is ground to 200 mesh by a ball mill, mixed with hydrochloric acid (solid-liquid ratio is 80 g / L), the concentration of hydrochloric acid is 8 mol / L, stirred for 60 min, and a solid-liquid mixed system is obtained.

[0045] 2. The solid-liquid mixed system is filtered, the precipitate is washed, the washing liquid is mixed with the filtrate, ammonium bicarbonate solution is added to adjust the pH value to about 7, heated to 60℃ in a water bath, and after no precipitate is generated, the purified liquid is separated by suction filtration.

[0046] 3. The ammonium bicarbonate is mixed with the purified liquid (solid-liquid ratio is 100 g / L), heated to 60℃ in a water bath, and after no precipitate is generated, the basic magnesium carbonate is separated by suction filtration. Two,

[0048] 1. The basic magnesium carbonate is placed in a constant temperature drying oven, the drying temperature is 105℃, and the drying time is 90 min.

[0049] 2, the dry basic magnesium carbonate and jade processing waste powder mixed (weight ratio is 30:70), the mixed powder is ground to 200 mesh by ball mill.

[0050] 3, the mixed powder is placed in a muffle furnace for calcination (the temperature rising and holding process is: room temperature ~ 650℃, the temperature rising time is 45 min; 650℃, the holding time is 15 min; 650~800℃, the temperature rising time is 30 min; 800~900℃, the temperature rising time is 30 min, the holding time is 40 min), the calcined powder is rapidly cooled by liquid nitrogen and then ground to 1000 mesh by ball mill, to obtain a cement corrosion-resistant expansion material.

[0051] Example 2, One,

[0053] 1, the jade processing waste powder is ground to 200 mesh by ball mill and then mixed with hydrochloric acid (solid-liquid ratio is 80g / L), after stirring for 60 min, a solid-liquid mixed system is obtained.

[0054] 2, filter the solid-liquid mixed system, wash the precipitate, mix the washing liquid with the filtrate, add ammonium bicarbonate solution to adjust the pH value to about 7, heat in water bath to 60℃, after no precipitate is generated, separate by suction filtration to obtain a purified liquid.

[0055] 3, mix the ammonium bicarbonate with the purified liquid (solid-liquid ratio is 100g / L), heat in water bath to 60℃, after no precipitate is generated, separate by suction filtration to obtain the basic magnesium carbonate. Two,

[0057] 1, the basic magnesium carbonate is placed in a constant temperature drying oven, the drying temperature is 105℃, and the drying time is 90 min.

[0058] 2, the dry basic magnesium carbonate is mixed with the jade processing waste powder (weight ratio is 40:60), the mixed powder is ground to 200 mesh by ball mill.

[0059] 3, the mixed powder is placed in a muffle furnace for calcination (the temperature rising and holding process is: room temperature ~ 650℃, the temperature rising time is 45 min; 650℃, the holding time is 15 min; 650~800℃, the temperature rising time is 30 min; 800~900℃, the temperature rising time is 30 min, the holding time is 40 min), the calcined powder is rapidly cooled by liquid nitrogen and then ground to 1000 mesh by ball mill, to obtain a cement corrosion-resistant expansion material.

[0060] Example 3, One,

[0062] 1, the jade processing waste powder is ground to 200 mesh by ball mill and then mixed with hydrochloric acid (solid-liquid ratio is 80g / L), after stirring for 60 min, a solid-liquid mixed system is obtained.

[0063] 2, filter the solid-liquid mixture, wash the precipitate, mix the washing liquid with the filtrate, add ammonium bicarbonate solution to adjust the pH value to about 7, heat in water bath to 60°C, after no precipitate is generated, separate by suction filtration to obtain purified liquid.

[0064] 3, mix ammonium bicarbonate with the purified liquid (solid-liquid ratio is 100 g / L), heat in water bath to 60°C, after no precipitate is generated, separate by suction filtration to obtain basic magnesium carbonate. II,

[0066] 1, place the basic magnesium carbonate into a constant temperature drying oven, the drying temperature is 105°C, and the drying time is 90 min.

[0067] 2, mix the dried basic magnesium carbonate with jade processing waste powder (weight ratio is 50:50), and grind the obtained mixed powder to 200 mesh by a ball mill.

[0068] 3, place the mixed powder in a muffle furnace for calcination (the temperature rising and holding process is: room temperature-650°C, temperature rising time is 45 min; 650°C, holding time is 15 min; 650-800°C, temperature rising time is 30 min; 800-900°C, temperature rising time is 30 min, and holding time is 40 min), after the calcined powder is rapidly cooled by liquid nitrogen, grind it to 1000 mesh by a ball mill to obtain the cement corrosion-resistant expansion material.

[0069] Comparative Example 1, I,

[0071] 1, after the jade processing waste powder is ground to 200 mesh by a ball mill, mix it with hydrochloric acid (solid-liquid ratio is 80 g / L), the concentration of hydrochloric acid is 8 mol / L, after stirring for 60 min, a solid-liquid mixture is obtained.

[0072] 2, filter the solid-liquid mixture, wash the precipitate, mix the washing liquid with the filtrate, add ammonium bicarbonate solution to adjust the pH value to about 7, heat in water bath to 60°C, after no precipitate is generated, separate by suction filtration to obtain purified liquid.

[0073] 3, mix ammonium bicarbonate with the purified liquid (solid-liquid ratio is 100 g / L), heat in water bath to 60°C, after no precipitate is generated, separate by suction filtration to obtain basic magnesium carbonate. II,

[0075] 1, place the basic magnesium carbonate into a constant temperature drying oven, the drying temperature is 105°C, and the drying time is 90 min.

[0076] 2, mix the dried basic magnesium carbonate with jade processing waste powder (weight ratio is 30:70), and grind the obtained mixed powder to 200 mesh by a ball mill.

[0077] 3. Put the mixed powder into a muffle furnace for calcination (the temperature rising and holding process is as follows: room temperature ~ 650°C, temperature rising time is 45 min; 650°C, holding time is 15 min; 650 ~ 800°C, temperature rising time is 30 min; 800 ~ 900°C, temperature rising time is 30 min, holding time is 40 min), and then put the calcined powder into a ball mill for grinding to 1000 mesh after natural cooling to obtain the cement corrosion-resistant expansion material.

[0078] Comparative Example 2, I,

[0080] 1. Put the jade processing waste powder after grinding to 200 mesh by a ball mill into hydrochloric acid (the solid-liquid ratio is 80 g / L), and then stir for 60 min to obtain a solid-liquid mixed system.

[0081] 2. Filter the solid-liquid mixed system, wash the precipitate, mix the washing liquid with the filtrate, add ammonium bicarbonate solution to adjust the pH value to about 7, heat in a water bath to 60°C, and then separate the purified liquid by suction filtration after no precipitate is generated.

[0082] 3. Mix the ammonium bicarbonate with the purified liquid (the solid-liquid ratio is 100 g / L), heat in a water bath to 60°C, and then separate the basic magnesium carbonate by suction filtration after no precipitate is generated. II,

[0084] 1. Put the basic magnesium carbonate into a constant temperature drying oven, dry at 105°C for 90 min.

[0085] 2. Mix the dried basic magnesium carbonate with the jade processing waste powder (the weight ratio is 40:60), and then grind the obtained mixed powder to 200 mesh by a ball mill.

[0086] 3. Put the mixed powder into a muffle furnace for calcination (the temperature rising and holding process is as follows: room temperature ~ 650°C, temperature rising time is 45 min; 650°C, holding time is 15 min; 650 ~ 800°C, temperature rising time is 30 min; 800 ~ 900°C, temperature rising time is 30 min, holding time is 40 min), and then put the calcined powder into a ball mill for grinding to 1000 mesh after natural cooling to obtain the cement corrosion-resistant expansion material.

[0087] Comparative Example 3, I,

[0089] 1. Put the jade processing waste powder after grinding to 200 mesh by a ball mill into hydrochloric acid (the solid-liquid ratio is 80 g / L), and then stir for 60 min to obtain a solid-liquid mixed system.

[0090] 2. Filter the solid-liquid mixture, wash the precipitated residue, mix the washing liquid with the filtrate, add ammonium bicarbonate solution to adjust the pH value to about 7, heat in water bath to 60°C, and after no precipitate is formed, separate the purified liquid by suction filtration.

[0091] 3. Mix ammonium bicarbonate with the purified liquid (solid-liquid ratio is 100 g / L), heat in water bath to 60°C, and after no precipitate is formed, separate the basic magnesium carbonate by suction filtration. Two,

[0093] 1. Put the basic magnesium carbonate into a constant temperature drying oven, the drying temperature is 105°C, and the drying time is 90 min.

[0094] 2. Mix the dried basic magnesium carbonate with jade processing waste powder (weight ratio is 50:50), and grind the obtained mixed powder to 200 mesh by a ball mill.

[0095] 3. Place the mixed powder in a muffle furnace for calcination (the temperature rising and holding process is: room temperature ~ 650°C, temperature rising time is 45 min; 650°C, holding time is 15 min; 650 ~ 800°C, temperature rising time is 30 min; 800 ~ 900°C, temperature rising time is 30 min, and holding time is 40 min), grind the calcined powder to 1000 mesh by a ball mill after natural cooling, and obtain the cement corrosion-resistant expansion material.

[0096] The cooling method of the corrosion-resistant expansion materials obtained in Examples 1, 2 and 3 is liquid nitrogen quenching, and the cooling method of the corrosion-resistant expansion materials obtained in Comparative Examples 1, 2 and 3 is natural cooling. The volume shrinkage of the cement stone will lead to the decrease of the cementing quality of the well cementing I-II interface, and form micro annular space and micro cracks at the interface, thereby providing a channel for gas channeling, resulting in gas channeling. The greater the volume shrinkage rate, the greater the possibility of micro annular space and micro cracks and gas channeling. It can be known from the experiment that the volume shrinkage rate of the cement stone without adding expansion agent is 0.60178%, according to Table 1, the volume expansion rates of the cement stone added with the corrosion-resistant expansion materials of Examples 1, 2 and 3 obtained by liquid nitrogen quenching are 0.2512%, 0.5628% and 0.9031% respectively; the volume expansion rates of the cement stone added with the corrosion-resistant expansion materials of Examples 4, 5 and 6 obtained by natural cooling are 0.2409%, 0.5498% and 0.8746% respectively, and whether or not the liquid nitrogen quenching has little effect on the expansion rate of the cement stone.

[0097] Table 1: Test parameters and results of cement stone volume expansion

[0098]

[0099] The formula of the above cement slurry is: 100 parts by weight of G oil well cement, 0.5 parts by weight of dispersant USZ (Henan Weihui Chemical Co., Ltd.), 2 parts by weight of fluid loss additive G33S (Henan Weihui Chemical Co., Ltd.), 0.01 parts by weight of oil well cement defoamer XP-I (Henan Weihui Chemical Co., Ltd.), 4 parts by weight of corrosion-resistant expansive agent material, and 44 parts by weight of water. The cement slurry and the cured cement stone are prepared according to GB / T 33293-2016 “Determination of shrinkage and expansion of oil well cement under normal pressure”.

[0100] The linear volume expansion graph of the cement stone added with the expansive agent of Examples 1-3 and Comparative Examples 1-3 is shown in Figure 1 .

[0101] Through analysis of the experimental results, Figure 1 it can be known that the well cementing cement stone added with the expansive agent material of the application has no volume shrinkage after being cured at 60℃ (CO2) for 7d, and can expand the cement stone, which shows that the volume shrinkage of the well cementing cement stone is compensated by adding the expansive agent, the crack resistance of the well cementing cement stone is ensured, and whether being rapidly cooled by liquid nitrogen has little effect on the expansion rate of the cement stone.

[0102] The prepared cement slurry is poured into a cylindrical metal mold, and the compressive strength thereof is measured. The experimental parameters and experimental results are shown in Table 2.

[0103] Table 2: Compressive strength test parameters and results of cement stone

[0104]

[0105]

[0106] The formula of the above cement slurry is: 100 parts by weight of G oil well cement, 0.5 parts by weight of dispersant USZ (Henan Weihui Chemical Co., Ltd.), 2 parts by weight of fluid loss additive G33S (Henan Weihui Chemical Co., Ltd.), 0.01 parts by weight of oil well cement defoamer XP-I (Henan Weihui Chemical Co., Ltd.), 4 parts by weight of corrosion-resistant expansive agent material, and 44 parts by weight of water. The cement slurry and the cured cement stone are prepared according to GB / T 33293-2016 “Determination of shrinkage and expansion of oil well cement under normal pressure”.

[0107] The compressive strength graph of the cement stone added with the expansive agent of Examples 1-3 and Comparative Examples 1-3 is shown in Figure 2 .

[0108] Through analysis of the experimental results, Figure 2The experimental results show that: after the cement stone with the anticorrosion expansion material obtained by liquid nitrogen quenching is cured at 60℃(CO2) for 7d, the compressive strength of the cement stone is greatly improved compared with the pure cement stone sample, which shows that the cement stone can resist CO2 corrosion after adding the anticorrosion expansion agent, and the anticorrosion expansion agent ensures the CO2 corrosion resistance of the cement stone for well cementing; after the cement stone with the anticorrosion expansion material obtained by natural cooling is cured at 60℃(CO2) for 7d, the compressive strength of the cement stone is not obviously improved compared with the pure cement stone sample, which shows that liquid nitrogen quenching can promote the internal stress of the anticorrosion expansion agent material to resist CO2 corrosion.

Claims

1. A method for preparing an oil well cement corrosion-resistant expanding agent, comprising the following steps: S1. mixing a jade processing waste powder with hydrochloric acid after ball milling, stirring, and filtering to obtain a filtrate; the jade processing waste powder is a jade processing waste powder with serpentine as the main component; S2. adjusting the pH value of the filtrate and heating to no precipitation, and separating by suction filtration to obtain a purified liquid; S3. adding ammonium bicarbonate to the purified liquid, drying after heating and suction filtration to obtain basic magnesium carbonate; S4. mixing the basic magnesium carbonate with the jade processing waste powder and ball milling to obtain a powder; S5. high-temperature calcining the powder, and obtaining the product after quenching.

2. The method of claim 1, wherein: In step S1, the average particle size of the jade processing waste powder after ball milling is 200-300 mesh; the solid-liquid ratio of the jade processing waste powder to the hydrochloric acid is 60-120 g / L; the stirring time is 30-90 min.

3. The production method according to claim 1 or 2, characterized by: In step S2, the pH value of the filtrate is adjusted to 7.0-7.5 using an ammonium bicarbonate solution; the heating condition is water bath heating to 55-60℃.

4. The production method according to claim 1 or 2, characterized by: In step S3, the solid-liquid ratio of the ammonium bicarbonate to the purified liquid is 60-120 g / L; the heating condition is water bath heating to 55-60℃; the drying condition is constant temperature drying at 105-110℃.

5. The production method according to claim 1 or 2, characterized by: In step S4, the average particle size of the mixture of the basic magnesium carbonate and the jade processing waste powder after ball milling is 100-200 mesh.

6. The production method according to claim 1 or 2, characterized by: In step S5, the high-temperature calcining condition is calcining in a muffle furnace at a temperature of 850-1000℃; the holding time is 40-60 min; the quenching uses liquid nitrogen.

7. The production method according to claim 1 or 2, characterized by: In step S5, the step of ball milling the expanding agent block obtained by quenching to obtain a powder with a particle size of 1500-3200 mesh is further included.

8. The oil well cement corrosion-resistant expanding agent prepared by the method of any one of claims 1-7.

9. A cementing cement with anti-gas channeling and corrosion-resistant performance, comprising an oil well cement and the oil well cement corrosion-resistant expanding agent of claim 8; the mass percentage content of the oil well cement corrosion-resistant expanding agent is 4-5%.

10. The use of the oil well cement corrosion-resistant expanding agent of claim 8 or the cementing cement of claim 9 in cementing; the oil well cement corrosion-resistant expanding agent or the cementing cement has the functions of anti-channeling and anti-carbon dioxide corrosion.

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