阅读说明：本技术 一种用于超高温深井的固井水泥及其制备方法和应用 (Well cementation cement for ultra-high temperature deep well and preparation method and application thereof ) 是由 滕学清 艾正青 李鹏晓 张峰 曾建国 袁中涛 刘爱萍 王银东 徐力群 熊钰丹 石 于 2018-06-05 设计创作，主要内容包括：本发明提供一种用于超高温深井的固井水泥及其制备方法和应用。该用于超高温深井的固井水泥,包括如下重量份的组分：油井水泥：100份、第一抗强度衰退剂：40～80份、第二抗强度衰退剂：3～10份、填充剂：5～10份,其中：第一抗强度衰退剂为硅粉,第二抗强度衰退剂选自三氧化二铝、氢氧化铝、氧化锌、氢氧化锌和氯化锶中的一种或多种。本发明所提供的用于超高温深井的固井水泥,能够解决现有固井水泥石在200℃～240℃的超高温深井水热环境下长期强度发生严重衰退的问题,从而有效提高了高温下井身质量,实现层间有效封隔,确保井筒水泥环长期密封完整性,延长油井寿命。并且还具有制备工艺简单、施工作业方便的优点。(The invention provides well cementation cement for an ultrahigh temperature deep well as a preparation method and application thereof. The well cementation cement for the ultrahigh-temperature deep well comprises the following components in parts by weight: oil well cement: 100 parts of a first anti-strength-decay agent: 40-80 parts of a second anti-strength-fading agent: 3-10 parts of filler: 5-10 parts, wherein: the first strength deterioration resistant agent is silicon powder, and the second strength deterioration resistant agent is selected from one or more of aluminum oxide, aluminum hydroxide, zinc oxide, zinc hydroxide and strontium chloride. The well cementation cement for the ultra-high temperature deep well provided by the invention can solve the problem that the long-term strength of the existing well cementation set cement seriously declines in the ultra-high temperature deep well hydrothermal environment of 200-240 ℃, so that the well quality under high temperature is effectively improved, effective interlayer packing is realized, the long-term sealing integrity of a shaft cement sheath is ensured, and the service life of an oil well is prolonged. And also has the advantages of simple preparation process and convenient construction operation.)

1. The well cementation cement for the ultra-high temperature deep well is characterized by comprising the following components in parts by weight:

Oil well cement: 100 parts of a first anti-strength-decay agent: 40-80 parts of a second anti-strength-fading agent: 3-10 parts of filler: 5 to 10 parts by weight of a surfactant,

Wherein: the first strength deterioration resistant agent is silicon powder, and the second strength deterioration resistant agent is selected from one or more of aluminum oxide, aluminum hydroxide, zinc oxide, zinc hydroxide and strontium chloride.

2. The cementing cement for ultra-high temperature deep wells according to claim 1, wherein the oil well cement is a G-grade oil well cement.

3. The well cementation cement for ultra-high temperature deep wells according to claim 1, wherein the first strength decay resistant agent comprises silica in an amount of more than 96% by mass.

4. A well cementation cement for an ultrahigh temperature deep well according to claim 1 or 3, wherein in the first strength deterioration resisting agent, the mass content of 500-600 mesh silicon powder particles is more than 50%, the mass content of 200-300 mesh silicon powder particles is more than 30%, and the mass content of silicon powder particles below 200 mesh is less than 20%.

5. A well cementation cement for an ultra high temperature deep well according to any one of claims 1 to 4, wherein the first strength decay resisting agent is in an amount of 55 to 75 parts by weight.

6. A well cement for a ultra high temperature deep well according to any one of claims 1 to 5, wherein the D50 particle size of the second anti-strength decay agent is not more than 5 μm.

7. A cement for cementing a deep well at ultrahigh temperature according to claim 1, wherein the filler is selected from at least one of nano silica, nano calcium carbonate and nano magnesium oxide.

8. A well cementing cement for ultra high temperature deep wells according to any one of the claims 1 to 7, wherein the D50 particle size of the filler is not more than 200 nm.

9. the method for preparing a cement for cementing a well with a ultra-high temperature deep well according to any one of claims 1 to 8, comprising:

And mixing the oil well cement, the first anti-strength recession agent, the second anti-strength recession agent and the filler in proportion to obtain the well cementation cement for the ultra-high temperature deep well.

10. Use of a cement according to any one of claims 1 to 8 for cementing ultra high temperature deep wells in ultra high temperature deep wells.

Technical Field

The invention belongs to the technical field of petroleum drilling, and particularly relates to well cementation cement for an ultrahigh-temperature deep well as a preparation method and application thereof.

Background

The well cementation is a process of injecting cement into an annular space between a casing and a stratum and forming a cement sheath after solidification, and aims to realize effective interlayer packing, supporting and protecting the casing by utilizing the cementing action and hardness of the cement sheath, thereby ensuring the long-term sealing integrity of a shaft and prolonging the service life of an oil well.

The good long-term integrity of the shaft has important significance for normal production and continuous stable production of the oil well. Along with the deep progress of oil and gas exploration, the drilling quantity of complex oil and gas reservoirs such as deep wells, ultra-deep wells and the like is increasing day by day, and ultra-high temperature deep wells with the bottom temperature higher than 200 ℃ are continuously generated. The strength of well cementation set cement is easy to rapidly decline in an ultrahigh temperature environment, so that interlayer packing is ineffective, the long-term integrity of a high-temperature deep well shaft is seriously influenced, and the service life of an oil well is shortened.

Aiming at the problem of long-term strength decline of the set cement at high temperature, a great deal of research is carried out at home and abroad. The general method is that silicon materials such as silicon powder and micro silicon are added into cement under the condition that the temperature is higher than 110 DEG CThe main principle of the strength stabilizer is as follows: when the temperature is higher than 110 ℃, the CSH gel structure of the main hydration product of the cement is unstable and gradually transformed into alpha-C with loose structure and lower strength₂SH crystal phase, resulting in decreased cement strength and increased permeability; after silicon materials such as silicon powder and micro-silicon are added, the ratio of calcium to silicon in the cement is reduced to 1: 1 or so, thereby generating tobermorite (C) with compact structure and high strength₅S₆H₅) And the like, thereby ensuring the long-term strength stability of the set cement.

The addition amount of the strength stabilizer such as silicon powder is different according to different temperature intervals, and generally, the higher the temperature is, the addition amount of the silicon powder is correspondingly increased. For example, under the high-temperature environment below 110-150 ℃, the reasonable mixing amount of the silicon powder is about 30 percent; under the high temperature environment of 150-180 ℃, 35-40% of silicon powder is generally required to be added; when the temperature exceeds 180 ℃, more than 40 percent of fine silicon powder or more coarser silicon powder needs to be added.

At present, research on ultra-high temperature cement at home and abroad mainly focuses on the field of heavy oil thermal production wells. The thermal recovery environment temperature of the thickened oil thermal recovery well is higher (the highest temperature can reach more than 300 ℃), and a large number of researches show that the high-temperature-resistant well cementation set cement of the thermal recovery well doped with 40-60% coarse silica powder can keep basic stability in long-term strength in the environment higher than 300 ℃, and meet the well cementation requirement of the thickened oil thermal recovery well.

the research on the set cement of the ultra-high temperature deep well (a well with the bottom hole resting temperature higher than 200 ℃ and the well depth of more than 4500m according to the common concept of the international and domestic petroleum industry) is mostly limited to short-term strength research within 7 days, and the research on long-term strength decline is relatively less. Research shows that 40-60% of silica powder is added as a strength stabilizer, the short-term strength does not change obviously within 7 days, but the long-term strength of the set cement often declines to a greater extent within 28 days, the decline rate can reach more than 60% at most, and the long-term sealing performance of the shaft cement sheath is directly influenced.

The ultra-high temperature deep well is different from a thick oil thermal production well, the high temperature resistant set cement of the thick oil thermal production well adopts a mode of high temperature maintenance after low temperature (about 50 ℃) forming, and the high temperature resistant set cement of the ultra-high temperature deep well directly simulates the actual temperature (generally 200 ℃ -240 ℃) in the well for maintenance, so the high temperature hydration process of the ultra-high temperature resistant set cement and the high temperature resistant set cement has obvious difference, the formula of the high temperature resistant set cement meeting the thermal production well (the thermal production steam injection temperature is more than 300 ℃) is caused, and the high temperature resistant set cement obviously declines in the environment of the ultra-high temperature deep well (200 ℃ -240.

Generally, for the high-temperature resistant set cement of the ultra-high temperature deep well, how to effectively inhibit the long-term excessive strength from declining is lack of an effective coping means at present. Therefore, the formula and the matched preparation process of the well cementation cement for the ultra-high temperature deep well are provided, the long-term strength of the well cementation cement stone in the ultra-high temperature deep well hydrothermal environment of 200-240 ℃ is prevented from seriously declining, and the formula and the matched preparation process have very practical significance for improving the cementing capacity of the high temperature deep well cement stone interface, reducing the risk of annular gas channeling, ensuring the long-term sealing integrity of a shaft cement sheath and prolonging the service life of an oil well.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the well cementation cement for the ultra-high temperature deep well, which can solve the problem that the long-term strength of the existing well cementation set cement is seriously degraded in the ultra-high temperature deep well hydrothermal environment of 200-240 ℃.

The invention also provides a preparation method of the well cementation cement for the ultra-high temperature deep well, which has the characteristics of simple process and feasible production.

The invention also provides application of the well cementation cement for the ultra-high temperature deep well in the ultra-high temperature deep well. The long-term strength of the well cementation cement stone formed by the well cementation cement can not be obviously declined in the ultrahigh-temperature deep well hydrothermal environment of 200-240 ℃.

In order to achieve the purpose, the invention firstly provides a well cementation cement for an ultrahigh temperature deep well, which comprises the following components in parts by weight:

Oil well cement: 100 parts of a first anti-strength-decay agent: 40-80 parts of a second anti-strength-fading agent: 3-10 parts of filler: 5 to 10 parts by weight of a surfactant,

Wherein: the first strength deterioration resistant agent is silicon powder, and the second strength deterioration resistant agent is selected from one or more of aluminum oxide, aluminum hydroxide, zinc oxide, zinc hydroxide and strontium chloride.

According to the technical scheme of the invention, the first anti-strength recession agent, the second anti-strength recession agent and the filling agent are reasonably configured and cooperate with oil well cement, so that the long-term strength of the cement stone formed during final well cementation can be kept in a stable state, and the requirement of the ultra-high temperature deep well at 200-240 ℃ is met.

The inventor analyzes possible reasons by combining practical effects that the well cementation set formed by the well cementation cement with the formula can be quickly hydrated to generate hydration products with high thermal stability at high temperature such as tobermorite and xonotlite and effectively inhibit alpha-C under the environment of the ultra-high temperature deep well of 200-240 DEG C₂The generation of SH harmful crystal phase enables the long-term strength of well cementation set cement to be kept in a stable state, and well meets the requirement of an ultra-high temperature deep well at 200-240 ℃, so that the well quality at high temperature can be effectively improved, effective interlayer packing is realized, the long-term sealing integrity of a shaft cement sheath is ensured, and the service life of an oil well is prolonged.

The oil well cement is cement specially used for well cementing engineering of oil wells and gas wells. In the practice of the present invention, the oil well cement used is specifically a grade G oil well cement.

The G-grade oil well cement is a cement material which is most commonly applied to oil and gas well cementing construction, and comprises the following main components in percentage by weight: 62 to 67 parts of SiO₂: 20 to 24 parts of Al₂O₃: 3 to 7 parts of Fe₂O₃: 2-6 parts. As the main component of well cementing cement, under the high-temperature hydrothermal environment, G-grade oil well cement can generate hydration reaction with water and other components to generate cement stone which is stable at high temperature. In particular, grade G well cement is commercially available.

According to the technical scheme of the invention, the first anti-strength deterioration agent and the second anti-strength deterioration agent are jointly used as a high-temperature strength stabilizer of the well cementation cement. In principle, the proportion of the mass of the second strength deterioration agent to the mass of the first strength deterioration agent is controlled to be 10-20%, and the second strength deterioration agent and the first strength deterioration agent can be reasonably adjusted according to conditions such as actual curing temperature and the like, so that the second strength deterioration agent and the first strength deterioration agent can play the optimal strength stabilizing role.

The silicon powder is used as a first strength recession resistant agent as a main component of the high-temperature strength stabilizer, and the main component of the silicon powder is crystalline alpha-quartz. In the silicon powder, the mass content of the silicon dioxide is more than 96%.

The particle size composition of the first anti-strength-recession agent is reasonably controlled, and the effect of the first anti-strength-recession agent is better played. In the specific implementation process of the invention, in the used silicon powder, the mass content of 500-600-mesh silicon powder particles is more than 50%, the mass content of 200-300-mesh silicon powder particles is more than 30%, and the mass content of silicon powder particles below 200 meshes is less than 20%.

In the specific implementation process of the invention, the used silicon powder is purchased from Kuerle Zhengyu petroleum materials Co., Ltd, the product model is SY-6, and the particle size distribution of the silicon powder meets the requirements.

The silica powder meeting the requirement of the particle size distribution is used as a main component of the high-temperature strength stabilizer, so that the silica powder can rapidly participate in hydration reaction in an ultrahigh-temperature environment, can react with oil well cement more sufficiently, generates more hydration products with good thermal stability and high strength, and prevents the early strength of well cementation set cement from being excessively weakened; on the other hand, sufficient silica powder participates in the reaction in the later stage, so that the long-term strength stability of the well cementation set cement is ensured.

The addition amount of the first anti-strength-recession agent is further controlled, and the effect of the strength stabilizer is further exerted. In the specific implementation process of the present invention, the weight part of the first strength deterioration resistant agent may be 45 to 80 parts, such as 45 to 75 parts, and further such as 55 to 75 parts.

As an auxiliary component of the high-temperature strength stabilizer, in the present invention, the second anti-strength-degrading agent may be one selected from aluminum oxide, aluminum hydroxide, zinc oxide, zinc hydroxide, strontium chloride, etc., or a mixture of two or more of the above components, for example, a mixture of aluminum oxide and zinc oxide is selected as the second anti-strength-degrading agent; for another example, a mixture of aluminum oxide, zinc oxide and strontium chloride is selected as the second anti-strength-degrading agent. Wherein the specific crystal form of the aluminum oxide is gamma-Al₂O₃。

The strength recession resistant agent is an auxiliary high-temperature strength stabilizer, can participate in high-temperature hydration reaction of set cement, and is prepared by introducing Al into a hydration product³⁺、Zn²⁺、Sr²⁺And the crystal phase structure of the main hydration product is improved, and the generated crystal form of the main hydration product is more stable at a high temperature for a long time, so that the long-term strength of the set cement is kept stable. In the specific implementation process of the invention, the second anti-strength decay agent is generally 5-10 parts by weight.

all the components constituting the second anti-strength-degrading agent can be obtained commercially, and generally industrial-grade products are selected, such as industrial-grade aluminum oxide products, industrial-grade aluminum hydroxide products, industrial-grade zinc oxide products, industrial-grade zinc hydroxide products and industrial-grade strontium chloride products.

When the second anti-strength deterioration agent is obtained by compounding the two or more components, the proportion of the components is not particularly limited, for example, a mixture of aluminum oxide and zinc oxide is selected as the second anti-strength deterioration agent, and the mass ratio of the aluminum oxide to the zinc oxide can be 3: 2, or 5: 3; for another example, a mixture of aluminum oxide, zinc oxide and strontium chloride is selected as a second anti-strength-degrading agent, and the mass ratio of the aluminum oxide to the zinc oxide to the strontium chloride can be 5: 3: 2, or 4: 2: 4, and may also be 3: 2: 5.

The particle size composition of the second anti-strength deterioration agent is reasonably controlled, and the auxiliary effect of the second anti-strength deterioration agent is better exerted. The particle size of the D50 particle of the second anti-strength-degrading agent is generally controlled to be less than or equal to 5 μm. In the specific implementation process of the invention, the D50 particle size of the second anti-intensity decay agent is less than or equal to 5 microns, and the D90 particle size is less than or equal to 10 microns.

In the invention, the D50 particle size refers to the corresponding particle size when the cumulative particle size distribution percentage of the sample reaches 50%; accordingly, the D90 particle size refers to the particle size corresponding to 90% of the cumulative percent particle size distribution of the sample.

According to the technical scheme of the invention, the used filler is one or a mixture of more of nano silicon dioxide, nano calcium carbonate, nano magnesium oxide and the like. In the specific implementation process of the invention, the mixture of nano-silica and nano-magnesia is used as the filler.

When the filler is a mixture of the above components, the ratio of the components is not particularly limited in the present invention.

specifically, the D50 particle size of the filler particles is generally controlled to be less than or equal to 200 nm; in the specific implementation process of the invention, the D50 particle size of the used filler is less than or equal to 200nm, and the D90 particle size is less than or equal to 10 μm. Through the compact packing design, on one hand, the filler is filled in the pores of large particles through the particle grading effect, so that the compactness of a particle system is improved; on the other hand, through chemical reaction with cement hydration products, a crystalline mineralogy enhancement effect is generated, and the porosity of the set cement is reduced, so that the permeability of the set cement is reduced.

The invention also provides a preparation method of the well cementation cement for the ultrahigh temperature deep well, which comprises the following steps: and mixing the oil well cement, the first anti-strength recession agent, the second anti-strength recession agent and the filler in proportion to obtain the well cementation cement for the ultra-high temperature deep well.

Specifically, the oil well cement, the first anti-strength recession agent, the second anti-strength recession agent and the filler can be added into the ash mixing equipment according to a proportion and mixed uniformly to obtain the well cementation cement for the ultrahigh-temperature deep well, and the well cementation cement can be used for field construction.

The configuration process is very simple, and is beneficial to actual large-scale popularization and application. In addition, the well cementation cement for the ultra-high temperature deep well can be configured on site during well cementation construction, and can also be transported to a well cementation construction site after being configured in advance, so that the well cementation cement has the advantage of convenience in construction operation.

The invention also provides application of the well cementation cement for the ultra-high temperature deep well in the ultra-high temperature deep well.

Unless otherwise stated, the definition of the ultra-high temperature deep well in the invention follows the common concept in international and domestic petroleum industry, namely the well with the bottom hole resting temperature higher than 200 ℃ and the well depth more than 4500 m.

The concrete process for injecting the well cementation cement into the annular space between the casing and the stratum and forming the cement sheath is not particularly limited, and the construction process aiming at the ultrahigh temperature deep well can be adopted, so that the process is not repeated.

The inventor researches and discovers that the decrease rate of the 28-day strength to the 2-day strength of the cement stone formed by the well cementation cement for the ultra-high temperature deep well provided by the invention is not more than 15% under the hydrothermal environment of the ultra-high temperature deep well at 200-240 ℃, which shows that the long-term strength of 28 days does not obviously decline and the requirement of the ultra-high temperature deep well at 200-240 ℃ can be well met.

In addition, the well cementation cement for the ultra-high temperature deep well provided by the invention has good compatibility with oil well cement additives and has no adverse effect on the comprehensive performance of cement paste.

According to the well cementation cement for the ultra-high temperature deep well, the first anti-strength recession agent, the second anti-strength recession agent and the filling agent are reasonably configured and cooperate with the oil well cement, so that well cementation set cement formed by the well cementation cement has very good thermal stability, especially for the ultra-high temperature deep well environment of 200-240 ℃, the long-term strength keeps basically stable, the 28-day long-term strength attenuation amplitude is less than 15%, the well quality at high temperature is effectively improved, effective interlayer isolation is realized, the long-term sealing integrity of a shaft cement ring is ensured, and the service life of an oil well is prolonged.

In addition, the well cementation cement for the ultra-high temperature deep well has good compatibility with oil well cement additives and has no adverse effect on the comprehensive performance of cement paste.

The preparation method of the well cementation cement for the ultra-high temperature deep well provided by the invention can be used for on-site construction only by uniformly mixing the oil well cement, the strength recession resistant agent and the filler in proportion, so that the preparation method has the advantages of simplicity, flexibility and convenience in construction operation.

Drawings

FIG. 1 is a development curve (200 ℃) of compressive strength of well-cementing cement paste in example 1 of the present invention and comparative examples 1 to 3;

FIG. 2 is a graph showing the development curve of compressive strength of well-cementing cement set (210 ℃ -240 ℃) in examples 2-5 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following examples and comparative examples, the silica powder (SY-6 type, Kuerle Zhengyu Petroleum materials Co., Ltd.) used had a D50 particle size of 26 μm; the alumina is industrial grade alumina, and the D50 grain diameter thereof is 6.5 μm; the zinc oxide is industrial grade zinc oxide, and the D50 particle size is 4.3 mu m; the strontium chloride is industrial grade strontium chloride, and the D50 particle size is 3.6 mu m; the D50 particle size of the nano silicon dioxide is 120 nm; the D50 particle size of the nano-magnesia is 231 nm.