JPS5815048A - Cement composition for high temperature - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to compositions suitable for use under high temperature conditions. More specifically, the present invention aims to strengthen steel pipes in wells with the main purpose of reinforcing casing pipes (-pipe) inserted into the wells when drilling wells such as oil wells or geothermal wells under high temperature conditions. It concerns the Shichimen) IIi compound that was injected into the shoulder and left to the samurai to break the hardening.

When drilling a geothermal well inside an oil well, a long steel pipe (called a casinder pipe) is inserted to prevent the collapse of the oil well carved by drilling. Cement is filled with cement for the purpose of fixing and reinforcing the surface of the steel pipe.In general, a predetermined amount of slurry soaked cement is pumped into the inside of the steel pipe from the ground surface to the mouth, and then it is filled with cement. Boosting mud water is injected later and the slurry cement is transferred to the lower end of the steel pipe and transferred to the shoulder (outside) of the steel pipe.Finally, the cement that has migrated to the shoulder of the steel pipe is hardened. A method is used that consists of the steps of allowing the product to stand until

Naturally, the requirements for cement used for the above purposes are different from those for cement for general construction. Physical properties that are a problem in terms of strength include setting time (also referred to as sintering time) and strength development. The setting time is an important item that affects workability when pumping cementis slurry to a predetermined depth.If the setting time is too short, it will harden before reaching the predetermined depth, causing practical problems; If the setting time is long, the hardening process after moving around the steel pipe will take a long time, so in practice, the same layer will be formed.On the other hand, after cement has hardened, light beams are used to reinforce the casing pipe. It requires strength.

Oil wells, geothermal wells, etc. are sometimes exposed to far more severe conditions than general structures, that is, high pressure and high temperature conditions for long periods of time, so durability of strength under such conditions is particularly required. .

Conventionally, most of the construction work was carried out under high temperature conditions of about 250C or less, and the cement used for reinforcing casing pipes under such conditions was difficult to set. Since the speed is relatively slow, cement slurry, which is made by adding a setting retarder and a specific gravity adjusting agent to cement, is often used. For example, among the various oil well cements specified by the standards of the American Petroleum Insulators (API), examples of cements with such a slow solidification rate include Class G cement, 30a (mainly containing 1,810 g and other cements). 3CaO-me 120., β-1ICa 0
・8102 * 4 Ca O-A 1203 ・F
Cement containing e. It is used with the addition of a setting retarder or specific gravity adjusting agent.

On the other hand, in recent years, temperature conditions have increased to about 250C or higher, for example 5
Many oil wells and geothermal wells are being drilled that reach SOC9, and conventional cement compositions such as those mentioned above are suitable for casing pipe reinforcement construction (cementing construction) using cement under these high-temperature conditions. When this is used, various types of bulges occur.

For example, a cement composition made by adding a silicic acid substance to class G cement for the purpose of high temperature resistance, deterioration resistance, etc.
Furthermore, when a setting retarder is added to extend the setting time, the setting time varies significantly depending on the amount of the setting retarder added, making it difficult to obtain a cement composition that exhibits the desired setting time. In addition, since the setting time varies greatly depending on slight variations in the amount added, a stable and high-quality product can be obtained industrially, and the same as No. 11 can be obtained.

Regarding Krasuf cement, both companies report that a large amount of setting retarder is required to slow down the setting time at high temperatures, and furthermore, the addition of such a large amount of setting retarder makes the addition of such a large amount of setting retarder difficult. Poor curing and significant foaming phenomena may also occur.
This has the disadvantage of reducing the strength development of the cement composition.

The purpose of the present invention is to provide a cement material that can be used for reinforcing casing pipes under particularly high-temperature excavation conditions, and has the following configuration. .

(1) ICab-81019 linker-140-80
Weight S (ratio to the entire cement composition) (2)
A cement slurry for high temperatures, characterized in that it contains a siliceous material, 7 to 45% by weight (as above) and (2) blast furnace slag, 3 to 35% by weight (as above).

Next, the present invention will be explained in detail.

Aya's 2CaO-8101 clinker is generally made from limestone, silica, clay, iron concentrate, etc.
It is obtained by a method such as firing at a temperature of 11' or higher, and is well known as a type of cement F mineral, as it is also used as the main component of conventional grains, such as clasfuse minerals. lCaO-8102 Talincar (
lCaO-8i in (hereinafter simply abbreviated as talincar)
The content of 02 is usually 80% by weight or more, and for the purpose of the present invention, it is particularly preferable that the content is within the range of 85 to 9% by weight. These 2CaO・Sin
Various forms of the crystal thick part g are known, such as α', β, r, etc.9, and any form is effective for the purpose of the present invention. However, particularly preferred forms are α' and β forms. The clinker usually has a plain specific surface area of 2,000 to 400,051"/l, preferably 2,500
It is preferable that it is contained in the cement composition in a pulverized form so as to have a particle size of 300,051 mm.

As the (to) siliceous substance, crystalline siliceous substances such as silica stone and silica sand, and those containing a relatively large amount of silicic acid (8102) such as amorphous silica are preferable. These siliceous materials usually have a plain specific surface area of 200,001 s or more, preferably 2 s OO~
It is preferable that the cement composition is pulverized to 4000 am''/y.

A typical example of blast furnace slag is blast furnace cement)
Blast furnace water slag used for illumination (basicity 14
0 or more).

In the present invention, blast furnace slag is 2CaO・5102 (
By adding it to the clinker) and siliceous material, it was possible to delay the setting of the mixture and improve the strength development properties. For this reason, even when a setting retarder is added as in the case of cement compositions for oil wells/geothermal valves in the prior art,
The amount added can be reduced, and therefore the occurrence of partial curing failure or foaming phenomenon can be significantly suppressed. Blast furnace slag usually has a plain specific surface area of 1800
512 mm or more, preferably 2,300 to 300,051 mm
The cement composition of the present invention is preferably contained in the cement composition in the form of (1) 2 Cao-8i.
Oz clinker, (to) siliceous material, and (2)
It must contain blast furnace slag at least 1 [* min.]
In order to achieve the object of the present invention, each of these components must be present in the cement composition in proportions within a certain range. That is, in the composition of the present invention, (1) is ・4
It is necessary to contain 0 to 80 weight groups, (total) 7 to 45 weight groups, and work to 3 to 35 weight groups. Cement compositions containing components in amounts that clearly deviate from these ranges are not suitable because they are unsuitable for the purpose of the present invention in terms of various properties such as setting time, strength development, and workability. In addition, each component in the composition of the present invention has (1) 45 to 75 weight units, (2) 10 to 40 weight units, and (2) 5 to 3 weight units.
Preferably, it is present in a content of 0% by weight (particularly preferably 10-20%).

Note that the 2CaO.5102 clinker used in the present invention has poor pulverizability, and it is often difficult to grind it alone to the desired fineness. Therefore, it is desirable to add and mix one or more of gypsum, calcareous material, and ply ash to the clinker before performing the pulverization operation.

These additive ingredients for auxiliary grinding such as gypsum (grinding piece material)
It is not preferable that the amount added exceeds 5 parts by weight to the cement composition to be prepared. The addition of these additive components improves the pulverizability of the clinker (e.g., the time required for pulverization) as described above, but the addition effect also improves the physical properties of the cement composition (e.g., setting time and/or strength). This extends to improvements in expressivity. Therefore, a mixture of one or more of gypsum, calcareous material, and fly ash is added to the cement F composition by 0.5 to 5 times (preferably 2 to 4.5 times by weight, both based on the total amount of the composition). (weight calculation) s is a preferred embodiment.

The cement composition of the present invention can be prepared, for example, by separately pulverizing predetermined amounts of clinker (with addition of pulverizing aids such as gypsum as necessary), siliceous material, and blast furnace slag, and then mixing them (separation pulverization). Alternatively, the mixture may be prepared by simultaneously grinding each component (mixed grinding) to obtain a mixture having an appropriate powder degree. In addition, if necessary, a setting retarder and/or a setting retarder may be added to the thus obtained friend cement composition.
Alternatively, a specific gravity adjusting material can also be added and mixed. This set retarder may be added during grinding of the clinker.

As the setting retarder, for example, a ligninsulfonic acid salt compound is used, and this ligninsulfonic acid #1 compound is preferably used in combination with a boron compound. Examples of suitable boron compounds include borates such as potassium borate, sodium borate, calcium borate, and boric acid. The combined ratio (blending ratio) of lignin sulfonate compound and boron compound is 1:10
It is preferable that the ratio is within the range of ~5:1 (former:latter, weight basis). The amount of setting retarder added to the cement composition is appropriately determined depending on the construction conditions (temperature, pressure, etc.). (amount relative to the cement composition). When a lignin sulfonate compound (preferably used in combination with a boron compound≠) is added as a setting retarder to the cement composition of the present invention, an effective setting retarding effect appears even when the amount added is relatively low. ,
Furthermore, since the setting time shows a proportional relationship between the amount of the setting retarder added and the amount of rut, there is an advantage that a cement composition having a desired setting time can be easily obtained.

As the specific gravity adjusting material, inorganic lightweight substances such as perlite, fly ash, diatomaceous earth, and microsilica can be used. The amount of the specific gravity adjusting agent added will naturally vary depending on the type of specific gravity adjusting agent, the concentration of the slurry, and the desired specific gravity. For example, the well temperature is about 250-400C
In order to obtain a low specific gravity cement slurry (specific gravity L3-1.7) suitable for use in oil/geothermal wells under the conditions of
It is usually added to the cement composition in an amount of 3 to 30% by weight. In addition, in order to prevent the above-mentioned specific gravity adjusting material from floating and separating after preparing the cement slurry, bentonite is added at the same time as the specific gravity adjusting material by 2 or more weights (preferably 3 to 8% by weight relative to the cement composition). It is preferable.

The cement composition of the present invention as described above has the following advantages over cement compositions conventionally used for reinforcing casing pipes of oil wells or geothermal wells.

It is particularly suitable for use in oil/geothermal wells under high temperature conditions with wellbore temperatures of about 250-400C. In other words, it shows an appropriate condensation time even under such high temperature conditions,
It also has excellent strength development.

(To) Mainly because the addition of blast furnace slag increases the setting time of the paper, the present invention uses a setting retarder that is generally added to extend the setting time of cement compositions for reinforcing casing pipes. Even when added to a cement F composition, the amount required is low. For this reason, the partial curing failure or foaming phenomenon that tends to occur when a large amount of setting retarder is added does not occur, and the strength development property is also improved.

(To) The above-mentioned effects, which are mainly caused by the addition of blast furnace slag, are enhanced by the further addition of components such as gypsum, calcareous substances, and fly ash, and these additional components also improve the pulverizability of tallinker. GC & valid.

(2) When a setting retarder is added to the cement composition of the present invention, the amount added and the setting time show a nearly proportional relationship, making it easy to prepare a cement composition having a desired setting time.

(5) Since geothermal layers are generally unstable and prone to collapse, low specific gravity cement is often required, but by adding a specific gravity adjusting agent to the cement composition of the present invention, the above temperature conditions can be achieved A low specific gravity slurry (specific gravity, about 1.3 to 1.7) that can be used even under such severe conditions can be easily obtained.

In explaining the present invention, up until now, oil wells and geothermal wells under high temperature conditions have been described as objects to be constructed.
It goes without saying that it can also be used for construction on other objects under similar harsh conditions.

Examples and comparative examples of the present invention are shown below.

The data in Table 1 shows the types and contents of typical chemical components in the test samples.

Table 1 Chemical composition of test samples (wt%) [Example G] and Comparative Example 1-4] A cement composition containing various amounts of 2CaO0Si02 clinker, silica stone, and blast furnace slag was used. On the other hand, a set retarder (2 parts by weight of a set retarder mainly composed of calcium lignin sulfonate and 2 B, 0 □) in potassium borate.

A slurry was prepared by adding 7.5% by weight of 11H20 (a mixture with 1 part by weight of a setting retarder) and 44% by weight of water, and the slurry was prepared under 350C construction conditions according to the test method prescribed by the American Petroleum Institute. Assuming that.

A setting test and a strength test were conducted. The setting test was performed using a thickening time tester specified by the American Petroleum Institute under the conditions of 300C1700kyf/llI''.On the other hand, the strength test was conducted using a thickening time tester specified by the American Petroleum Institute under the condition of 350C1211k)f. After curing under /l♂ conditions for 24 hours and 7 days, the cured products were subjected to a stiffness test.The results are shown in Table 2.

#! Table 2 Note: The setting time is calculated from the time when the viscosity is 100% after slurry preparation.
The cement compositions of Examples 1 to 5 have a long setting time and are excellent in stiffness, as shown by the time taken to reach 1111 degrees. On the other hand, the cement F compositions of Comparative Examples 1 to 4 either have a short setting time or are inferior in enjoyment.

[Example 6-12 and Comparative Example 5-7] 2CaO810
21 linker with gypsum (Example 6) and limestone (Example 7)
), fly ash (Example 8), also gypsum and limestone (Example 9), gypsum and fly ash (Example 10), limestone and fly ash (Example 11)
, gypsum, limestone and fly ash (Example 12)
Iron l-lumil (φ4
0X403) was conducted. In this case, 1
The amount of sample per batch 9 was kept constant at 5 k), and the time required to grind it to a Blaine specific surface area of 3000 ff'' was calculated.Additionally, 100 parts by weight of silica stone and 15 parts by weight of blast furnace slag were added to these pulverized products. A setting test and a strength test were carried out under the same test conditions as in Example 1 above. In the test, gypsum (Comparative Example 5
), limestone (Comparative Example 6) and ply ash (Comparative Example 7) were added in an amount of 10% by weight, and the same test was conducted.

These results are shown in Table 3. The results of Example 4 above for a composition with the same composition but without the addition of a grinding aid are also shown.

Table 3 As can be seen from Table 3, the addition of gypsum, limestone and fly ash, singly or in combination, during the pulverization of 2CaO-8i02 clinker shortens the paper-grinding time. In this case, the amount of grinding aid added is 5
It is preferable that the amount is t by weight (relative to the cement composition), and if it is added in a large amount beyond that limit, the grinding time will become longer.
Otherwise, the quality will deteriorate.

[Example 13-14 and Comparative Example 8-9] Using the cement compositions of Example 2 and Comparative Example 1 - Required to obtain a setting time of about 200 minutes for each of the 12 types of setting retarders added The required amount of setting retarder was determined. The setting retarder used in this was mainly composed of the above-mentioned setting retarder M and B (2 parts by weight of a setting retarder mainly composed of calcium lignin sulfonate, potassium borate, and B2O).4H20. (a mixture with 1 part by weight of a set retarder). The test conditions in this case were 350C, the same temperature as in Example 1.
The measurements were taken as follows. These results are shown in Table 4.

Table 4 As can be seen from Table 4, the cement composition of the present invention requires a small amount of setting retarder, and as a result, partial curing defects and foaming phenomena are improved. It also showed favorable results in terms of strength development.

[Examples 15-16 and Comparative Examples io-i2] The cement composition of Example 2 and two of this composition
A setting test was carried out on cement compositions in which the amount of setting retarder A added was changed, using the cement compositions obtained when the CaO-8i02 clinker was used with the Tallin force for class G cement specified by the American Petroleum Metal Regulations. and strength tests were conducted. The test conditions were the same as in Example 1, and the results are shown in Table 5.

Table 5 Note) Compound layer of class G clinker*: 3CaO・
5to2sss, 2CaO・510218%, 3CaO
-mu'2031%, 4CaO-AjL203 Fe2O
315% (all percentages by weight) As shown in Table 5, the cement composition of the present invention (2
The setting time of (using CaO-8i02 clinker) is highly proportional to the amount of setting retarder added, and it is extremely easy to prepare a cement composition having a desired setting time.

[Example 17-19] Using the cement composition of Example 2 and adding a setting retarder to it, the cement composition was tested at a temperature of 250 to 400C (well temperature ) were subjected to setting and strength tests. In this case, the condensation test was conducted at a temperature 50C lower than the wellbore temperature (circulation temperature), and the curing temperature for the strength test was conducted under the same conditions as the wellbore temperature (standing temperature). These results are shown in Table 6.

Table 6 From the results in Table 6, it can be seen that as the well temperature increases, the amount of setting retarder required generally increases, and there is also a tendency for strength development to decrease.
It can be seen that it can be used satisfactorily in wells under temperature conditions of 0 to 400C.

[Example 2O-22] The cement composition of Example 2 was mixed with setting retarder A, and further pearlite (specific gravity adjusting material) and bentonite, and this cement mixture was used to adjust the concentration condition to 350 C&:
A setting test and a strength test were conducted in the same manner. In addition, the amount of kneading water is based on the external ratio weight to the cement mixture, and is 6.
0% (Example 20), 65 whispers (Example 21) and 68
% (Example 22). These results tt171
! Shown below.

The results of Example 13 above, in which the same mixture was tested with a kneading water amount of 44%, are also shown.

Table 7 It is seen that by blending an appropriate amount of specific gravity adjusting material, a low specific gravity slurry (specific gravity 1.3 to 1.9) that can be used in papermaking and high temperature conditions can be obtained.

Patent applicant: Ube Industries Co., Ltd.

Claims (1)

[Claims] In a tm product, a lCaO. Characteristic high temperature cement composition. 2. I
．． 5~S weight-Claims of Claims■ The high-temperature cement composition as described in item 1.