CN115872649A - Oil and gas well cementing anti-corrosion admixture and multi-component composite anti-corrosion cement slurry system for ultra-high temperature sour gas wells - Google Patents

Abstract

The application discloses a well cementation anticorrosion additive for an oil and gas well and a multi-component composite anticorrosion cement slurry system for an ultrahigh-temperature acid gas well, wherein the well cementation anticorrosion additive for the oil and gas well adopts the combination of two or more of blast furnace slag, metakaolin, biological ash, hydroxyapatite and basic zinc carbonate; the multi-element composite anti-corrosion cement paste system comprises the following components in parts by weight: 90-110 parts of Jiahua G-grade oil well cement, 30-40 parts of high-temperature stabilizer, 5-7 parts of functional composite emulsion, 4-6 parts of fluid loss additive, 3-5 parts of high-efficiency dispersant, 1-15 parts of oil and gas well cementing anticorrosion additive and 0.5-1.5 parts of expanding agent. The well cementation cement slurry system with the functions of resisting 220 ℃ ultrahigh temperature, resisting gas channeling and resisting CO2 corrosion can effectively meet the long-term sealing of an abnormal high-temperature acidic corrosion gas well, reduce the energy consumption requirement and provide guarantee for exploration and development, efficient production and environmental protection.

Description

Oil and gas well cementing anti-corrosion admixture and multi-component composite anti-corrosion additive for ultra-high temperature sour gas wells Corrosion cement slurry system

technical field

The invention relates to the technical field of oil and gas well cementing, in particular to an oil and gas well cementing anti-corrosion additive and a multi-component composite anti-corrosion cement slurry system for ultra-high temperature acid gas wells.

Background technique

In the cementing operation of ultra-high temperature sour gas wells, the cement sheath is usually affected by acid corrosion, which hinders oil and gas production. On the one hand, the corrosive medium will destroy the bond between the cement sheath and the formation, resulting in interlayer interflow; Perforation even leads to the scrapping of the whole well. If this problem cannot be effectively controlled, it will lead to blowout or the scrapping of the whole well, resulting in major safety accidents. Therefore, on the basis of ensuring that the basic properties of oil well cement stone meet the requirements of conventional cementing operations, conducting research on cement stone anti-corrosion and anti-gas channeling is the key to improving the quality of this type of complex cementing, and is also the key to ensuring long-term and stable production of ultra-high temperature sour gas wells. premise.

Scholars at home and abroad have done a lot of research on improving the corrosion resistance of cement stone. Yuan B et al. used the film-forming and filling effects of nano-silica gel (NL) to reduce the original permeability and average pore size of cement stone by 3.35 times and 35.38%, respectively. In addition, NL also reacted with Ca(OH) ₂ to generate tobermullite with a low Ca/Si ratio, which lowered the pH of the cement. Rooby D et al. studied the influence of nano-CaCO ₃ (CFC), nano-SiO ₂ (CFS) and nano-ZrO ₂ (CFZ) on the corrosion performance of fly ash (CF) cement stone, and found that nano-materials can inhibit the corrosion of cement stone. Cracking, corrosion resistance has been significantly enhanced. Krivenko P et al. used surfactants and Na ₃ PO ₄ to modify soluble sodium silicate (SSS), and then explored its effect on slag-based cement. The results show that the matrix density of slag-based cement stone can be significantly improved by using modified SSS, and the mechanical properties and corrosion resistance can be enhanced. Using sodium styrene sulfonate (SSS) and nano-SiO ₂ as emulsifiers, Zhang B et al prepared soap-free emulsion (PSAC) by soap-free emulsion polymerization, and studied the carbonization of PSAC cement at 90 °C and 3 MPa CO ₂ Performance was evaluated. It was found that PSAC has a typical core-shell structure and good heat resistance. After 60 days of corrosion, the corrosion depth of PSAC cement stone is only 2.16mm, the permeability is 0.0018mD, and the compressive strength drops by 6.65%. Xu B et al. constructed a composite anti-corrosion additive (CRA) composed of amorphous nano-silica, latex and resin, and studied the corrosion performance of CRA cement stone at 150 °C. It is found that the original permeability of CRA cement stone is reduced, and the CH phase in cement stone is reduced, the hydration product Ca/Si is reduced, and the corrosion resistance of cement stone is enhanced. Zuo J et al. explored the effect of epoxy resin emulsion and metakaolin (MK) on the corrosion performance of cement stone, and found that after adding MK, the water absorption rate and chloride ion diffusion coefficient of epoxy resin emulsion cement stone were significantly reduced. In particular, the maximum decrease in chloride ion diffusion coefficient of 1250 mesh MK is 73.1%.

However, there are still many problems in the above-mentioned anti-corrosion additives. Conventional polymers and resin materials have obvious performance degradation under high temperature and ultra-high temperature conditions, and have a great impact on the thickening process of cement slurry; acid-resistant particles have a large particle size. It has good slurry fluidity, but poor sedimentation stability, and when the particle size is small, it will reduce the slurry fluidity and increase the difficulty of pumping; most inorganic mineral powders have good compatibility with cement slurry, but will greatly Reduce the early compressive strength of cement stone. In addition, these cement slurry systems use a single material, which cannot meet the complex actual working conditions, and are mostly used in medium and low temperature environments, and there are very few cases involving ultra-high temperature corrosion research.

Contents of the invention

The purpose of the present invention is to provide an oil and gas well cementing anti-corrosion additive to solve the problem of poor anti-corrosion performance of the cement slurry system.

In order to achieve the above object, the present invention provides an anti-corrosion admixture for oil and gas well cementing, which is characterized in that it is made of two combinations of blast furnace slag, metakaolin, biological ash, hydroxyapatite and basic zinc carbonate. Divided or mixed with two or more components.

Further, it is composed of 9-11 parts of blast furnace slag, 4-6 parts of metakaolin, 4-6 parts of biological ash and 4-6 parts of hydroxyapatite according to the weight ratio.

A multi-component composite anti-corrosion cement slurry system for ultra-high-temperature acid gas wells, comprising: 90-110 parts of Jiahua G-grade oil well cement, 30-40 parts of high-temperature stabilizer, and 5-5 parts of functional composite emulsion. 7 parts, 4-6 parts of fluid loss reducer, 3-5 parts of high-efficiency dispersant, 1-15 parts of the oil and gas well cementing anti-corrosion additive, and 0.5-1.5 parts of expansion agent.

In order to improve the compactness of the cement stone matrix, the functional composite emulsion is a mixture of modified polystyrene emulsion, nano liquid silicon, lye and amine polymer.

Further, the mass ratio of the modified polystyrene emulsion, nano liquid silicon, lye and amine polymer is 7:6:0.2:9.

In order to improve the fluidity of the cement slurry, the dispersant is at least two combinations of sulfonated formaldehyde-acetone polycondensate, naphthalene sulfonate and polycarboxylic acid dispersant, and the dispersant can be used to avoid excessive viscosity due to consistency. As a result, it is difficult to pump and reduce the engineering cost. The dispersant combination is selected based on the combination of temperature resistance, dispersion effect and mixing ability.

Preferably, the content of the sulfonated formaldehyde-acetone polycondensate is greater than 70% of the total content of the dispersant.

In order to suppress the α-C ₂ SH phase, the high temperature stabilizer is 200-250 mesh silica sand and/or nano liquid silicon emulsion.

In order to improve the high-temperature stability of cement stone, the _SiO2 content in the Jiahua G grade oil well cement is ≥ 20%, and the CaO content is ≥ 61%. The cement slurry under this ratio has better basic properties and a certain Ca content, Facilitate the pozzolanic reaction with high temperature stabilizers.

Preferably, the multi-component composite anti-corrosion cement slurry system includes: 100 parts of Jiahua G grade oil well cement, 35 parts of high temperature stabilizer, 6 parts of functional composite emulsion, 4.8 parts of fluid loss reducer, 3.4 parts of high-efficiency dispersant, 10-15 parts of the oil and gas well cementing anticorrosion additive, and 0.8 parts of expansion agent.

Beneficial effect:

1. The inorganic powder in the anti-corrosion admixture mainly has two forms: pore filling and alkaline excitation secondary cementation. Among them, the pore filling mainly uses the dense calcium carbonate layer formed by the anti-corrosion admixture and cement stone carbonization to prevent the infiltration of acidic corrosion medium. In addition, the protective layer can also reduce the Ca ²⁺ loss rate under high temperature and pressure, thereby slowing down the corrosion of Ca(OH) ₂ and CSH phase. Another part of the anti-corrosion admixture can show gelatinity under certain excitation, thereby effectively reducing the micropores of cement stone and improving the corrosion resistance of cement stone;

2. The functional compound emulsion can effectively reduce the primary pores inside the cement stone, thereby significantly improving the compactness of the cement stone matrix, and the emulsion can effectively reduce the water loss of the cement slurry at high temperature, and avoid the weight loss of the cement slurry due to water loss And gas channeling and other issues. In addition, the alkaline particles in the composite emulsion can excite the inorganic mineral powder to form a crystalline phase, thereby improving the matrix compactness of cement stone; There is a good interaction, the formed accumulation pores are smaller, and can maintain a high suspension, and it is not easy to form a concentrated area of silica fume, which is beneficial to the suppression of α-C ₂ SH phase; 4. A cement for oil and gas wells The well multi-component composite anti-corrosion cement slurry system has a cementing slurry system that is resistant to 220°C ultra-high temperature, gas channeling, and CO ₂ corrosion. development, efficient production and environmental protection.

Description of drawings

Fig. 1 is the comparison chart of the corrosion age of the present embodiment 1-4;

Fig. 2 is the microstructure of the corrosion area of multi-component composite anti-corrosion cement stone (the combined addition of anti-corrosion additives is 10%);

Figure 3 is the microstructure of the non-corroded area of multi-component composite anti-corrosion cement stone.

Detailed ways

The present invention will be described in further detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto. By combining the following examples, the present invention is further illustrated, and the present invention includes but is not limited to the content of the following examples. Jiahua G-grade oil well cement is provided by Jiahua Special Cement Co., Ltd., 300/800 mesh silica fume and expansion agent are commercially available products, anti-corrosion additive combination, functional compound emulsion, defoamer, fluid loss reducer, dispersant The agent was provided by Jingzhou Jiahua Technology Co., Ltd. No special instructions in the examples, all are percentages by weight.

Example 1

A multi-component composite anti-corrosion cement slurry system suitable for ultra-high temperature acid gas wells, related to the field of oil and gas well cementing technology, using Jiahua G grade oil well cement, high temperature stabilizer, expansion agent as the main gray matter components, and functional composite emulsion as the Microporous filler and anti-channeling agent, the specific composition is as follows:

Among them, the _SiO2 content in Jiahua G grade oil well cement is 21%, and the CaO content is 70%; the functional composite emulsion is a mixture of modified polystyrene emulsion, nano liquid silicon, lye and amine polymer; high temperature stability The agent is 300 mesh silica sand, the dispersant is a combination of 7 parts of sulfonated formaldehyde-acetone polycondensate and 3 parts of naphthalene sulfonate; the functional composite emulsion is (6 parts of modified heat-resistant latex + 1 part of stabilizer) + 6 parts Nano liquid silicon + 0.2 parts of NaOH solid phase particles + 9 parts of amine polymer.

Weigh the raw materials according to the specific composition ratio in the above table, mix them, and prepare cement slurry according to SY/T5546-92, named as 0% BFs.

Example 2

In this embodiment, on the basis of Embodiment 1, two or more of blast furnace slag, metakaolin, biological ash, hydroxyapatite, basic zinc carbonate and inorganic powder are used as anti-corrosion additives, and the specific composition is as follows:

The anti-corrosion admixture is composed of 10 parts of blast furnace slag, 5 parts of metakaolin, 5 parts of biological ash and 5 parts of hydroxyapatite in terms of weight ratio.

Weigh the raw materials according to the specific composition ratio in the above table, mix them, prepare cement slurry according to SY/T5546-92, and name it as 5% BFs.

Example 3

On the basis of Example 2, this embodiment continues to increase the proportion of anti-corrosion additives, and the specific composition is as follows:

Weigh the raw materials according to the specific composition ratio in the above table, mix them, and prepare cement slurry according to SY/T5546-92, named as 10% BFs.

Example 4

On the basis of Example 2, this embodiment continues to increase the proportion of anti-corrosion additives, and the specific composition is as follows:

Weigh the raw materials according to the specific composition ratio in the above table, mix them, prepare cement slurry according to SY/T5546-92, and name it as 15% BFs.

For the test of the corrosion depth of cement stones in ultra-high temperature oil wells, it is mainly distinguished with the naked eye and combined with a microscope for auxiliary observation. By splitting the cement stones under a constant corrosion age at the center line, and selecting four corrosion thicknesses on the side of the corrosion layer to record, and then Calculate the mean value to obtain the corrosion depth value. Based on this method, examples 1-4 are tested, and the results are as shown in the accompanying drawings.

It can be seen from Figure 1 that within the age range of 60 days, the corrosion depth of multi-component composite anti-corrosion cement stones changes regularly with the growth of corrosion curing age, which is consistent with the development law of corrosion depth of conventional cement pastes. y=A+B*sqrt(x) fits the relational expression. With the increase of the amount of anti-corrosion admixture, the corrosion depth of cement stone gradually decreases, and the corrosion depth of cement stone under 10% and 15% anti-corrosion admixture is relatively close, so when the amount of anti-corrosion admixture is controlled to about 10%, the A more effective anti-corrosion effect can be obtained.

For the compressive strength test method of the corrosion experiment, the compressive strength of the cement stone before and after corrosion was measured according to the national standard GB//T199139-2012 "Cement Stone Test Method", and the compressive strength decline rate was calculated. The results are shown in Table 1.

Table 1 Decline rate of compressive strength

It can be seen from the table that with the increasing amount of anti-corrosion admixture, the initial compressive strength of multi-component composite anti-corrosion cement stone decreases first and then increases, while the change rate of compressive strength after 60 days of corrosion gradually decreases. When the additives are 10% and 15%, respectively, the compressive strength of the multi-component composite anti-corrosion cement stone at 60 days is within ±4.5% compared with that before corrosion, which shows that in the multi-component composite anti-corrosion cement stone, When the amount of anti-corrosion admixture is 10% or more, relatively stable corrosion performance can be obtained.

According to the multi-component composite anti-corrosion cement stone, according to the American Petroleum Institute standard (API RP-40), the permeability of the cement stone sample was measured by HKY-200 pulse decay gas permeability tester. The test results are shown in Table 2.

Table 2 Permeability measurement results

It can be seen from the table that with the increasing amount of anti-corrosion admixture, the change rate of permeability of multi-component composite anti-corrosion cement stone after 60 days of corrosion gradually decreases. When the addition of anti-corrosion additives is 10% and 15% Compared with the pre-corrosion, the permeability of the stone at 60 days fluctuates within ±3.5%, which also shows relatively stable corrosion performance.

In order to analyze the reasons for the influence of multi-component composite anti-corrosion cement on the corrosion performance, a scanning electron microscope was used to observe the cross-section of multi-component composite anti-corrosion cement stone when the amount of anti-corrosion admixture was 10%, and the corrosion was 28 days, to judge the corrosion layer of multi-component composite anti-corrosion cement stone Changes in the microstructure, the results are shown in Figure 2.

It can be seen from Figure 2 that there are a small amount of scattered CaCO ₃ crystalline phases in the multi-component composite anti-corrosion cement stone corrosion layer, most of the CaCO ₃ crystalline phases exist in the form of aggregates, and a small amount of polymer coating layer can be seen, no xonotlite, Ca (OH) ₂ , the profile shows good structural integrity. This is because in the multi-component composite anti-corrosion cement stone, the alkali-induced mineral recrystallization cements and fills the original pore structure of the hydration product, which effectively improves the compactness of the cement stone matrix and expands the coverage of the cement. Cooperate with anti-corrosion additives and polymers to further improve the structural integrity of the section.

The microstructure of the non-corroded area inside the multi-component composite anti-corrosion cement stone is shown in Figure 3.

It can be seen from Figure 3 that the non-corroded area of the multi-component composite anti-corrosion cement stone contains a large amount of alkali-activated minerals, which has a high structural integrity, and a large amount of needle-shaped tobermullite and a small amount of long-flaky anti-corrosion materials can be seen. In addition, the matrix filling in the cross-section of the multi-component composite anti-corrosion cement stone sample has a larger coverage area, and a higher degree of integrity and compactness, which increases the difficulty of intrusion of acidic corrosive media.

Claims (10)

1. A kind of oil and gas well cementing anticorrosion admixture is characterized in that: it is to adopt two kinds of components or more than two kinds of components in blast furnace slag, metakaolin, biological ash, hydroxyapatite and basic zinc carbonate to mix made. 2. The anticorrosion additive for oil and gas well cementing according to claim 1, characterized in that: it is composed of 9-11 parts of blast furnace slag, 4-6 parts of metakaolin, and 4-6 parts of biological ash according to the weight ratio. It is composed of 4-6 parts of hydroxyapatite. 3. A multi-component composite anti-corrosion cement slurry system for ultra-high temperature sour gas wells employing the anti-corrosion additive described in claim 1 or 2, characterized in that, the multi-component composite anti-corrosion cement slurry system includes: Calculated: 90-110 parts of Jiahua G grade oil well cement, 30-40 parts of high temperature stabilizer, 5-7 parts of functional compound emulsion, 4-6 parts of fluid loss reducer, 3-5 parts of high-efficiency dispersant, Oil and gas well cementing anti-corrosion admixture 1-15 parts, expansion agent 0.5-1.5 parts. 4. The multi-component composite anti-corrosion cement slurry system according to claim 3, characterized in that: the functional composite emulsion is a mixture of modified polystyrene emulsion, nano liquid silicon, lye and amine polymer. 5. multivariate composite anti-corrosion cement slurry system according to claim 4, is characterized in that: the mass ratio of described modified polystyrene emulsion, nano liquid silicon, lye and amine polymer is 7:6: 0.2:9. 6. The multi-component composite anti-corrosion cement slurry system according to any one of claims 3-5, characterized in that: the dispersant is sulfonated formaldehyde-acetone condensation polymer, naphthalene sulfonate and polycarboxylic acid dispersion A combination of at least two of the agents. 7. The multi-component composite anti-corrosion cement slurry system according to claim 6, characterized in that the content of the sulfonated formaldehyde-acetone polycondensate is greater than 70% of the total content of the dispersant. 8. The multi-component composite anti-corrosion cement slurry system according to any one of claims 3-7, characterized in that: the high-temperature stabilizer is 200-250 mesh silica sand and/or nano liquid silicon emulsion. 9. The multi-component composite anti-corrosion cement slurry system according to any one of claims 3-7, characterized in that: the _SiO2 content in the Jiahua G grade oil well cement is ≥ 20%, and the CaO content is ≥ 61%. 10. The multi-component composite anti-corrosion cement slurry system according to claim 9, characterized in that, the multi-component composite anti-corrosion cement slurry system includes: 100 parts of Jiahua G grade oil well cement, high temperature stable 35 parts of agent, 6 parts of functional composite emulsion, 4.8 parts of fluid loss reducer, 3.4 parts of high-efficiency dispersant, 10-15 parts of the oil and gas well cementing anti-corrosion additive, and 0.8 part of expansion agent.

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