JP2002194341A - Method for improving wall-forming property of drilling mud - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively recycle a deteriorated drilling mud without carrying out disposal of the deteriorated drilling mud. SOLUTION: This method for improving wall-forming properties of drilling mud comprises adding a mud film-forming agent for the drilling mud consisting essentially of (x) a copolymer comprising (a) an unsaturated carboxylic acid and/or its salt and (b) a monoester of (b1) an unsaturated carboxylic acid and (b2) a hydroxy group-containing compound represented by R(OA)nOH (R denotes hydrogen or a 1-12C hydrocarbon group; A denotes a 2-4C alkylene group; and n denotes an integer of 1-100) as constituent units to the deteriorated drilling mud produced by a mud drilling method such as an underground continuous wall making technique or a mud water shielding technique in a method for improving the wall-forming properties of the drilling mud.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the wall-forming properties of drilling mud used in a muddy construction method such as a muddy shield method and an underground continuous wall method.

[0002]

2. Description of the Related Art In a muddy water method such as a muddy water shield method and an underground continuous wall method, a so-called excavation mud is used. Is basically required, and it is desirable that low viscosity is maintained within a range in which liquid leakage is prevented in view of slurry transportation and the like. Also,
The underground diaphragm wall method is also required to have cement resistance.

In order to satisfy such a function, conventionally, drilling mud using a bentonite, a CMC, a dispersant, a polymer agent or the like as a mud making material has been widely used. Such mud for drilling, because bentonite and the like are well dispersed in the muddy water,
While the low viscosity is maintained, the dispersed bentonite and the like form a good mud cake on the face and the groove wall, and the mud cake makes it possible to secure the water stopping property and thus the stability of the face and the groove wall.

[0004]

However, during the repetitive use of such drilling mud, the fine particles of the excavated soil that cannot be separated even by using a sediment separator are removed into the mud by the excavation. It gradually remains, and the specific gravity of the muddy water increases, and the concentration and function of bentonite, polymer, and the like relatively decrease, and as a result, the wall-forming property decreases.

[0005] Therefore, for the so-called degradation mud concrete wall of which it was lowered, but reuse by adding bentonite and polymers can be achieved, since the mud is greatly thickened as the amount of addition increases, the deterioration mud There is an inevitable limit to reusing, and eventually there is a problem that a large amount of degraded mud must be disposed of and a new mud must be produced using the above-mentioned mud-making material and replenished as needed. .

The present invention has been made in view of the above circumstances, and has as its object to provide a method of improving the wall forming property of drilling mud which can be effectively regenerated without discarding the degraded mud.

[0007]

In order to achieve the above-mentioned object, a method for improving the wall-forming properties of a drilling mud according to the present invention is characterized in that an unsaturated carboxylic acid and / or a salt thereof (a a) an unsaturated carboxylic acid (b1) and the following general formula _{(1) R (OA) n} OH (1) R; hydrocarbon group hydrogen or 1 to 12 carbon atoms a; alkylene group having 2 to 4 carbon atoms n A mud film forming agent for drilling mud containing a copolymer (x) having a monoester (b) of a hydroxyl group-containing compound (b2) represented by an integer of 1 to 100 as a constitutional unit as an essential component; To be added to

Further, in the method for improving the wall-forming property of muddy water for drilling according to the present invention, the monoester (b) constituting the copolymer (x) is preferably 1 to 40% by mass, The number average molecular weight of the polymer (x) is 5,000 to 100,000.

Further, in the method for improving the wall-forming properties of drilling mud according to the present invention, the unsaturated carboxylic acid and / or its salt (a) may contain acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, At least one selected from the group consisting of alkali metal salts and ammonium salts, wherein the unsaturated carboxylic acid (b1) is acrylic acid,
It is at least one selected from the group consisting of methacrylic acid, itaconic acid, maleic acid and fumaric acid.

Further, the method for improving the wall-forming properties of drilling mud according to the present invention is directed to a polyacrylate, a polymethacrylate or a copolymer thereof, the weight average molecular weight of which is Mw.
And at least one of sodium carbonate and a dispersant for drilling mud, wherein the water content is 10,000 to 14,000.

Further, according to the present invention, the method for improving the wall-forming properties of drilling mud according to the present invention is characterized in that an unsaturated carboxylic acid and / or its salt (a) is used as a main constituent unit. Excavating, characterized in that a mud film forming agent for excavating mud is added to the degraded mud, which is composed of coalesced (x ') and whose (co) polymer (x') has a weight average molecular weight Mw of 200,000 to 3,000,000. For improving muddy wall formation.

Further, in the method for improving wall-forming properties of drilling mud according to the present invention, the unsaturated carboxylic acid and / or its salt (a) may contain acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, One or more selected from the group consisting of these alkali metal salts and ammonium salts.

Further, the method for improving the wall forming properties of drilling mud according to the present invention is directed to a polyacrylate, a polymethacrylate or a copolymer thereof, the weight average molecular weight of which is Mw.
And at least one of sodium carbonate and a dispersant for drilling mud, wherein the water content is 10,000 to 14,000.

In a muddy water excavation method such as an underground continuous wall method or a muddy water shield method, muddy water for excavation is used to stabilize a trench wall or the like. And the specific gravity of the muddy water increases, and the wall-forming properties deteriorate.

The so-called degraded mud having deteriorated wall-forming properties has been conventionally recycled by adding bentonite or a polymer. However, as the amount of addition increases, the mud drastically increases in viscosity.

On the other hand, in the method for improving wall-forming properties of muddy water for drilling according to claims 1 to 4, the deteriorated muddy water contains an unsaturated carboxylic acid and / or a salt thereof (a) and an unsaturated carboxylic acid. A mud film forming agent for drilling mud is added, which contains, as an essential component, a copolymer (x) having (b1) and a monoester (b) of a hydroxyl group-containing compound (b2) as a constituent unit.

In this way, the deteriorated mud not only improves the wall-forming properties but also suppresses the increase in viscosity, and the deteriorated mud is regenerated as new mud for excavation.

In producing the copolymer (x),
It may be performed by a known production method, for example, a solution polymerization method. That is, an unsaturated carboxylic acid and / or a salt thereof (a) and a monoester (b) are added to a predetermined solvent as two kinds of monomers, and then these are added at 50 to 150 ° C. under normal pressure or The polymerization may be performed under pressure.

As the solvent, for example, water, isopropyl alcohol, toluene, ethylene dichloride, methyl ethyl ketone or a mixture thereof can be used.

In the polymerization, a radical polymerization initiator is used in an amount of 0.1 to 15% by mass relative to the total mass of the unsaturated carboxylic acid and / or its salt (a) and the monoester (b). A transfer agent may be used as needed.

Here, as the radical polymerization initiator, persulfates such as potassium persulfate, azo compounds such as azobisisobutyronitrile, and peroxides such as benzoyl peroxide and dicumyl peroxide may be used. it is possible, as the chain transfer agent, it is possible to use lauryl mercaptan, thioglycolic acid, a sulfur-containing compound such as mercaptoethanol.

When a part or all of the unsaturated carboxylic acid and / or its salt (a) is an unsaturated carboxylic acid salt, the unsaturated carboxylic acid or its anhydride or its carbon number as a precursor thereof is used. The lower alkyl esters of 1 to 4 may be neutralized before polymerization, or the copolymer may be neutralized after polymerization. Examples of the neutralizing agent, for example potassium hydroxide, including alkali metal hydroxides such as sodium hydroxide, ammonium hydroxide, ammonia, or the like is used.

Further, the copolymer (x) is not necessarily, an unsaturated carboxylic acid (b1) and the hydroxyl group-containing compound (b
Not limited to the use of the monoester (b) with 2) as a monomer for copolymerization with the unsaturated carboxylic acid and / or its salt (a), but a precursor of the monoester (b), That is, the unsaturated carboxylic acid (b1) or its anhydride or a lower alkyl ester having 1 to 4 carbon atoms is copolymerized as a monomer with the unsaturated carboxylic acid and / or its salt (a), and then the hydroxyl group The copolymer (x) may be produced by reacting with the containing compound (b2).

Unsaturated carboxylic acid and / or its salt (a)
Is composed of any substance, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid and can be appropriately selected from the group consisting of alkali metal salts and ammonium salts thereof. .
The unsaturated carboxylic acid (b1) is also optional, but can be appropriately selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid.

In the monoester (b), R is a hydrogen or an alkylene group in the general formula (1).
2, and more preferably an alkylene group having 1 to 6 carbon atoms. R represents an alkyl group (eg, methyl group, octyl group), a cycloalkyl group (eg, cyclohexyl group), an aryl group (eg, phenyl group), an alkylaryl group (eg, ethylphenyl group), an aralkyl group (eg, benzyl group). it may be either.

[0026] As for the n in the general formula (1), usually averaged to ensure good concrete walled 1-10
0, and an integer having an average of 2 to 90 is preferable.

(B2) is an aliphatic dihydric alcohol having 2 to 4 carbon atoms or 1 to 1 carbon atoms represented by ROH.
Those obtained by adding an alkylene oxide having 2 to 4 carbon atoms to a 2 aliphatic alcohol, a phenol or an araliphatic alcohol are preferred.

The aliphatic dihydric alcohol having 2 to 4 carbon atoms includes ethylene glycol, propylene glycol,
1,4-butanediol and the like can be mentioned.

The aliphatic alcohol having 1 to 12 carbon atoms may be a natural alcohol or a synthetic alcohol (Ziegler alcohol, oxo alcohol, etc.). Specific examples include linear or branched saturated aliphatic alcohols such as methyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, lauryl alcohol, isobutyl alcohol, tert-butyl alcohol, and 2-ethylhexyl alcohol, cyclohexyl alcohol, and ethylcyclohexyl alcohol. And the like.

Examples of phenols include phenol and ethyl phenol. Examples of the araliphatic alcohol include benzyl alcohol.

As the alkylene oxide having 2 to 4 carbon atoms, ethylene oxide (hereinafter abbreviated as EO) alone; EO and another alkylene oxide [propylene oxide (abbreviated as PO hereinafter), 1,2-butylene oxide; , Tetrahydrofuran, substituted alkylene oxide (epichlorohydrin), etc.];
Mixtures of more than one species. Particularly preferred among the exemplified ones are a combination of EO and EO / PO.
When using another alkylene oxide together with EO, the addition mode may be random addition or block addition,
There is no particular limitation.

The mass ratio of the monoester (b) constituting the copolymer (x) and the number average molecular weight of the copolymer (x) are arbitrary, but the above-mentioned monomer constituting the copolymer (x) is optional. Mass% of the ester (b) is 1 to 40%,
And the number average molecular weight of the copolymer (x) is 5,000 to 1,
When it is 00000, high wall-forming properties and low viscosity can be obtained.

[0033] Here, polyacrylates, polymethacrylates or the deterioration of at least one of their copolymers in a dispersed agent or sodium carbonate for drilling fluid to the weight average molecular weight Mw 10000 to 14000 When added to muddy water, the decrease in dispersibility in the muddy water for excavation due to the chemical action of calcium ions eluted from concrete is suppressed, and the wall-forming properties and low viscosity are maintained well. It exerts particularly excellent effects on the degraded muddy water generated in the above.

[0034] polyacrylate, polymethacrylates or a weight-average molecular weight a copolymer thereof M
The dispersing agent for drilling mud and sodium carbonate having w of 10,000 to 14000 may be used in combination with only the dispersing agent for drilling mud and sodium carbonate with the mud film forming agent for drilling mud, or both. You may make it use together. When the dispersant for drilling mud and sodium carbonate are used in combination with the mud film forming agent for drilling mud, sodium carbonate may be mixed in advance with the dispersing agent for drilling mud to form a single agent, or at the site. You may mix.

The copolymer (x) comprises (a) and (b)
In addition to the above, another monomer (c) can be used as a structural unit. (C) is not particularly limited as long as it can be copolymerized, and examples thereof include the following (c1) to (c5).

(C1) Amide group-containing ethylenically unsaturated monomer: (meth) acrylamide, N-methylol (meth) acrylamide, etc.

(C2) (meth) acrylic acid alkyl esters (alkyl group having 1 to 12 carbon atoms): methyl (meth) acrylate, butyl (meth) acrylate, etc.

(C3) Ethylenically unsaturated monomer having a hydroxyl group: hydroxyalkyl (having 1 to 1 carbon atoms)
4) (meth) acrylate [for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, etc.]

(C4) Ethylenically unsaturated monomers having a polyalkylene glycol chain other than (b): polyethylene glycol (number average molecular weight: 120 to 600) mono (meth) acrylate, polypropylene glycol (number average molecular weight: 150 to 450) ) mono (meth) acrylate, methyl alcohol ethylene oxide 1-4 moles adducts (meth) acrylate, etc.

(C5) Quaternary ammonium group-containing ethylenically unsaturated monomer: (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, etc.

Among these (c1) to (c5), preferred are (c2) to (c4).

Further, copolymers other monomers constituting (X) (c) mass% of units usually 30% or less, preferably 2
0% or less.

On the other hand, in the method for improving the wall-forming properties of muddy water for drilling according to claims 5 to 7, the (co) polymer having unsaturated carboxylic acid and / or its salt (a) as a main constituent unit ( x '), and a mud film forming agent for drilling mud is added to the degraded mud with the (co) polymer (x') having a weight average molecular weight Mw of 200,000 to 3,000,000.

[0044] In this case, the degraded muddy water is charged in the first aspect.
Similar to the fourth aspect, not only the wall forming property is improved,
The increase in viscosity is also suppressed, and the degraded mud is regenerated as new drilling mud.

The production of the (co) polymer (x ') may be carried out by a known production method, for example, a solution polymerization method as in the case of the polymer (x). That is, the unsaturated carboxylic acid and / or
Or adding the salt (a) thereof as a monomer to a predetermined solvent,
Next, this is polymerized at 50 to 150 ° C. under normal pressure or under pressure, or an unsaturated carboxylic acid and / or a salt thereof (a)
And another monomer may be added to a predetermined solvent and then copolymerized at 50 to 150 ° C. under normal pressure or under pressure. That is, the (co) polymer (x ′) according to the present invention is
In which it subsumes two concepts of homopolymers and copolymers. However, it is desirable to be composed of a single polymer.

Type of solvent, method of homopolymerization or copolymerization,
The radical polymerization initiator and the neutralization process are the same as those of the method for improving the wall-forming property of the muddy water for drilling according to claims 1 to 4, and thus the description thereof is omitted here.

Unsaturated carboxylic acid and / or its salt (a)
Is composed of any substance, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid and can be appropriately selected from the group consisting of alkali metal salts and ammonium salts thereof. .
Here, the alkali metal salt includes a sodium salt, a potassium salt and the like.

Here, at least one of a polyacrylate, a polymethacrylate, or a copolymer thereof and a dispersant for drilling mud or a sodium carbonate having a weight average molecular weight Mw of 10,000 to 14,000 or sodium carbonate is used. When added to muddy water, the decrease in dispersibility in the muddy water for excavation due to the chemical action of calcium ions eluted from concrete is suppressed, and the wall-forming properties and low viscosity are maintained well. It exerts particularly excellent effects on the degraded muddy water generated in the above.

Here, the salt referred to as polyacrylate or polymethacrylate includes at least an alkali metal salt such as a sodium salt and a potassium salt or an ammonium salt. In addition, the weight average molecular weight Mw is determined by gel permeation chromatography.

Polyacrylate, polymethacrylate or a copolymer thereof, having a weight average molecular weight M
The dispersing agent for drilling mud and sodium carbonate having w of 10,000 to 14000 may be used in combination with only the dispersing agent for drilling mud and sodium carbonate with the mud film forming agent for drilling mud, or both. For example, if the mass ratio is 9
You may make it use together so that it may become 9: 1 to 1:99. In addition, when the dispersant for drilling mud and sodium carbonate are used in combination with the mud film forming agent for drilling mud, sodium carbonate is
It may be mixed in advance with the dispersant for drilling mud and made into one agent, or may be mixed at the site.

The (co) polymer (x ') may be a single polymer containing only (a) as a monomer as described above, or (a) may be a main structural unit (70% by mass or more). age,
5. Other monomers other than (a), for example, claims 1 to 4.
In addition to the monoester (b), which is a monomer of the above, other monomers (c) may be used as a constitutional unit. (C) is not particularly limited as long as it can be copolymerized, and examples thereof include (c1), (c2) and (c5).

Among these, preferred is (c2).

The mass% of the other monomer (b) constituting the (co) polymer (x ') is usually less than 1%, preferably 0.9% or less, and The mass% is usually 30
%, Preferably 20% or less.

The mud film forming agent for drilling mud according to any one of claims 5 to 7 may be mixed with the mud forming agent for drilling mud according to claims 1 to 4 at an arbitrary ratio (for example, a mass ratio of 99: 1
１ ： 1: 99).

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the method for improving the wall forming properties of muddy water for excavation according to the present invention will be described below with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.

(First Embodiment)

In the method for improving the wall-forming properties of the drilling mud according to the present embodiment, the unsaturated carboxylic acid and / or a salt thereof is added to the degraded mud generated by the mud drilling method such as the underground continuous wall method or the mud shield method. a) and an unsaturated carboxylic acid (b)
1) and the following general formula (1) R (OA) _n OH (1) R; hydrogen or a hydrocarbon group having 1 to 12 carbon atoms A; an alkylene group having 2 to 4 carbon atoms n; an integer of 1 to 100 And a mud film forming agent for drilling mud which contains a copolymer (x) having a monoester (b) of a hydroxyl group-containing compound (b2) as a constituent unit as an essential component,
Dilute with water as needed.

Here, the mass ratio of the monoester (b) to the copolymer (x) is preferably 1% to 40%. This is because when the mass% of the monoester (b) with respect to the copolymer (x) is less than 1%, the wall-forming property is reduced irrespective of the addition amount of the mud film forming agent for drilling mud, and when it exceeds 40%. If the addition amount of the mud film forming agent for drilling mud is low, agglomeration may occur and the wall forming property may be reduced.

The number average molecular weight of the copolymer (x) is
It is good to be 5000-100,000. This is the number the average molecular weight is below 5000, forming wall may be lowered regardless amount of drilling mud for mud film forming agent, exceeds 100,000, when a low amount of drilling mud for mud film forming agent This is because there is a possibility that agglomeration occurs and the wall forming property is reduced.

The number average molecular weight is measured by gel permeation chromatography.

FIG. 1 is a chemical structural formula (chemical formula) showing an example of the above-mentioned mud film forming agent for drilling mud, in which unsaturated carboxylic acid and / or its salt (a) is converted to sodium methacrylate sodium salt 2, The monoester (b) is shown as a mud film forming agent 1 for drilling mud, comprising methoxypolyethylene glycol methacrylate 3.

When the above-mentioned mud-forming agent for excavated mud is added to the degraded mud generated by the mud drilling method such as the underground continuous wall method or the mud shield method, the degraded mud only improves the wall forming property. In addition, the increase in viscosity is also suppressed, and the deteriorated mud is regenerated as new mud for excavation.

As described above, according to the method for improving the wall-forming properties of the drilling mud according to the present embodiment, the fine particles in the muddy water are dispersed by the dispersing action of the mud film forming agent for the drilling mud added to the degraded muddy water. The components are dispersed in the degraded muddy water to maintain the viscosity or to further reduce the viscosity, and also, by the wall-building action, a state in which a high-quality mud cake can be formed on the inner surface of the face or the groove wall.

That is, by adding the above-mentioned mud film forming agent for excavated muddy water to the deteriorated muddy water generated by the muddy water excavation method, it is possible to improve the wall forming property while suppressing the thickening of the deteriorated muddy water. Thus, the degraded muddy water can be regenerated as new drilling muddy water.

Therefore, it is possible to reuse the degraded mud which had to be discarded in the past as new mud for excavation, not only to reduce the excavation cost but also to be industrial waste. Degraded mud can also be reduced in volume.

Needless to say, the necessary mud-making material can be saved with the reuse of the degraded mud.

Further, according to the method for improving the wall-forming properties of drilling mud according to the present embodiment, the above-mentioned mud film forming agent for drilling mud can be used as an aqueous solution, which was conventionally required. Starting with that mixers for mixing the bentonite or CMC becomes unnecessary, it becomes possible to significantly reduce or omit the plant or stockyards for performing their storage or stirring, for restoring a deteriorated mud Time can be greatly reduced.

According to the method for improving the wall forming property of the muddy water for excavation according to the present embodiment, not only the wall forming property is improved,
The viscosity may be lowered, it becomes advantageous for pumping and sediment separation, drilling efficiency is improved.

Although not particularly mentioned in the present embodiment, it is a polyacrylate, a polymethacrylate, or a copolymer thereof having a weight average molecular weight Mw of 10,000.
At least one of a dispersing agent for drilling mud and sodium carbonate of 1 to 14000 may be added together with the above-mentioned mud film forming agent for drilling mud.

According to such a configuration, a decrease in the dispersibility in the mud for excavation due to the chemical action of calcium ions eluted from the concrete is suppressed, and the wall-forming property and low viscosity are maintained satisfactorily. to deterioration mud generated in the continuous wall method, it exhibits particularly excellent effects and advantages.

[0071] Here, polyacrylates, polymethacrylates or dispersing agent or sodium carbonate for drilling muds and the weight average molecular weight Mw 10,000 or 14000 a copolymer thereof, the dispersing them drilling mud Only one of the agent and sodium carbonate may be used in combination with the above-mentioned mud film forming agent for drilling muddy water, or both may be used in combination. When the dispersant for drilling mud and sodium carbonate are used in combination with the mud film forming agent for drilling mud, sodium carbonate may be mixed in advance with the dispersing agent for drilling mud to form a single agent, or at the site. You may mix.

In this embodiment, since a remarkable effect was confirmed by experiments, the mass% of the monoester (b) constituting the copolymer (x) was 1 to 40%, and the copolymer (x)
The number average molecular weight of 5,000 to 100,000 was used, but the mud film forming agent for drilling mud used in the present invention is not limited to such a range, and even outside the range described in the embodiment, a certain effect can be obtained. It is possible to get.

[0073]

Next, the mud film forming agent for drilling mud used in the method for improving the wall forming property of drilling mud according to this embodiment will be described more specifically. Unless otherwise specified, parts and% indicate parts by mass and% by mass, respectively.

First, as the unsaturated carboxylic acid and / or its salt (a) constituting the mud film forming agent for drilling mud, sodium methacrylate (hereinafter a-1) and sodium acrylate (hereinafter a-2) ) Were used in the experiment. As the unsaturated carboxylic acid ester (b), 10 kinds of unsaturated carboxylic acid esters are used, and the unsaturated carboxylic acid esters (hereinafter, b-1 to b-10) constituting the 10 kinds of unsaturated carboxylic acid esters are used. Table 1 shows the composition of the carboxylic acid (b1) and the hydroxyl group-containing compound (b2). In the table, EO and PO represent ethylene oxide and propylene oxide, respectively.

[0075]

[Table 1]

Next, the aforementioned sodium methacrylate (a
-1) and sodium acrylate (a-2) in combination with 10 types of unsaturated carboxylic esters (b-1 to b-10) (x) (hereinafter, Examples 1 to 16) Table 2 shows the composition ratio, the monoester content ratio (%), and the number average molecular weight at the time of the production of The conditions for measuring the number average molecular weight are shown below.

GPC system manufactured by Waters (pump: model 510, detector: waters410) Eluent: type water / methanol (70/30) + CH ₃
COONa (0.5%) Flow rate 1.0 (ml / min) Column; TSKgel G3000PWXL + TSKgel G5000PWXL 7.8m
l ID × 30 cm

[0078]

[Table 2]

The copolymers (x) of Examples 1 to 16 described above
First, water 363 is placed in a reaction vessel.
And 196 parts of isopropyl alcohol, and after purging with nitrogen, the temperature was raised to 80 ° C., and 151 parts (1.757 mol) of methacrylic acid, 48 parts of methoxypolyethylene glycol (the number of moles of ethylene oxide added: 28) were stirred. (0.036 mol), and
39.8 parts of a 5% aqueous solution of sodium persulfate (0.008 mol of sodium persulfate) were simultaneously added dropwise over 3 hours to react. Furthermore, after aging for 2 hours at the same temperature, removed by distillation isopropyl alcohol, sodium hydroxide 4
After neutralization with 146 parts of an 8% aqueous solution (1.757 mol of sodium hydroxide), water was added in such an amount that the solid content became 30% to obtain a copolymer having a number average molecular weight of 42,800 (Example 1). Further, Examples 2 to 16 were obtained in the same manner as in Example 1 except that the monomer composition was changed so as to have the structural units shown in Table 2.

The mud film forming agent for drilling mud made of the copolymers (x) of Examples 1 to 16 produced in this way was added to mud to make mud for excavation, and the wall forming property and viscosity of mud were examined. (Table 3).

Here, the muddy water before adding the mud film forming agent for drilling muddy water has a fine particle content of 75 μm or less and a specific gravity of 1.0 μm.
It was prepared by adjusting the concentration to be 05. By the way, the viscosity at that time was 11.1 mPa · s. The muddy water viscosity was measured with a B-type viscometer.

The wall-forming property in the table is slightly different from the index in the API standard. In order to accelerate the drainage process and shorten the experiment time, the lower wall of the filter paper was depressurized. It was measured as the amount of drainage, and 5
A value of not more than ml is a measure of good wall-forming properties. In addition, the case where CMC was used is also shown as Comparative Example 1 for comparison with the prior art.

[0083]

[Table 3]

As can be seen from the table, Examples 1 to 6, 11
Regarding to No. 16, regardless of the addition amount, the wall-forming properties are 5 ml or less, which are all good, and the viscosity of the muddy water is also low, in other words, the good dispersibility is maintained. In Examples 7 to 10, it can be seen that the wall-forming properties are reduced when the added amount is small.

By the way, in Comparative Example 1 using CMC,
Although the wall-forming property can be secured, the result confirms the problem that the viscosity is increased.

Next, the above-mentioned mud film forming agent for drilling mud according to Example 11 was added to the degraded mud, and the wall-forming properties and changes in mud viscosity were examined. In addition, the wall-forming property and the funnel viscosity of the degraded muddy water before adding the muddy film forming agent for drilling mud according to Example 11 are read as values when the addition amount of the muddy film forming agent for drilling muddy water is 0, respectively. Can be.

First, FIG. 2 shows the wall-forming properties and the funnel viscosity when the muddy water specific gravity is 1.05. In the same figure, the sample indicated as Sample A is the mud film forming agent for drilling mud water according to Example 11, and the case where CMC was added is also shown for comparison.

As can be seen from this figure, with this specific gravity, the wall-forming properties are about 0.1% or more for the mud film forming agent for drilling mud according to Example 11, and about 0.04% for CMC. While improvement is recognized in the above range, the funnel viscosity is
The mud film forming agent for drilling mud water according to Example 11 did not show a tendency to increase the viscosity regardless of the addition amount, and it can be seen that the addition amount of the CMC was acceptable if the addition amount was small.

Next, the wall forming property and the funnel viscosity when the muddy water specific gravity is 1.085 are shown in FIG.

As can be seen from FIG.
The wall-forming property was improved in the range of about 0.25% or more in the mud film forming agent for drilling mud and the CMC in the range of 0.06% or more in the eleventh example. It can be seen that the thickening tendency of the mud film forming agent for drilling mud is not recognized irrespective of the addition amount, whereas the thickening tendency is clearly recognized as the addition amount increases in CMC.

FIG. 4 shows the wall-forming properties and funnel viscosities when the specific gravity of the muddy water is 1.10.

As can be seen from the figure, when the specific gravity is increased to this level, the wall-forming property is about 0.2% or more in the mud film forming agent for drilling mud according to Example 11, and 0.04% in CMC.
Although the improvement was observed in the above range, the viscosity of the funnel was not increased regardless of the addition amount of the mud film forming agent for drilling mud according to Example 11, whereas the CMC
So it can be seen that the thickening tendency is remarkably observed as the amount added increases.

(Second Embodiment)

Next, a second embodiment will be described.

In the method for improving the wall-forming properties of the drilling mud according to the present embodiment, the unsaturated carboxylic acid and / or a salt thereof is added to the degraded mud generated by the mud drilling method such as the underground continuous wall method or the mud shield method. a) as the main structural unit (co)
A mud film forming agent for drilling mud, which is composed of a single polymer as the polymer (x ') and has a weight average molecular weight Mw of 200,000 to 3,000,000, is added with water as needed. Dilute.

The homopolymer as the (co) polymer (x ') has a weight average molecular weight Mw of 200,000 to 3 as described above.
And the weight average molecular weight Mw is 2
If it is less than 100,000, the amount of drainage, which is an index of wall formation, slightly exceeds 5 ml, and if it exceeds 3 million, the amount of drainage greatly exceeds 5 ml.

[0097] Here, the drainage amount is slightly different from the index in the API standard, and is measured with the lower side of the filter paper under reduced pressure in order to accelerate the drainage process and shorten the experiment time. 5 ml or less is a measure of good wall-forming properties.

FIG. 5 is a chemical structural formula (chemical formula) showing an example of the above-mentioned mud film forming agent for drilling muddy water. The unsaturated carboxylic acid and / or its salt (a) is obtained by polymerizing sodium acrylate 12. This is shown as a mud film forming agent 11 for drilling mud.

The lower limit and the upper limit of the weight average molecular weight Mw were determined by forming a curve approximating the result obtained in an experiment described later, and as an intersection between the curve and a line having a drainage rate of 5 ml, 200,000 and 300, respectively. Although it is determined to be 10,000, the range of the weight average molecular weight Mw is desirably 500,000 to 2.5 million in consideration of an empirical safety factor in consideration of experimental errors and the like.

On the other hand, the mud film forming agent 11 for drilling mud is preferably used by adding it to the mud having a concentration of 20 to 30% by mass. In this concentration range, the weight average molecular weight Mw is 1,000,000. If it exceeds, high viscosity of syrup (about 100
MPa · s), which is not necessarily excellent in workability when added to muddy water.

Therefore, from the viewpoint of such addition workability, it is desirable that the weight average molecular weight Mw of the mud film forming agent 11 for drilling muddy water is 500,000 to 1,000,000. Furthermore, to reliably increase the added work of the mud is cleared with a margin drainage amount upper limit, it is optimal for the weight average molecular weight Mw of drilling mud for mud film forming agent 11 and 600,000 to 800,000.

When the above-described mud film forming agent for drilling mud is added to the degraded mud generated by the mud drilling method such as the underground continuous wall method or the mud shield method, the degraded mud only improves the wall forming property. In addition, the increase in viscosity is also suppressed, and the deteriorated mud is regenerated as new mud for excavation.

As described above, according to the method for improving the wall-forming properties of the drilling mud according to the present embodiment, fine particles in the muddy water are dispersed by the dispersing action of the excavated muddy mud film forming agent added to the degraded muddy water. The components are dispersed in the degraded muddy water to maintain the viscosity or to further reduce the viscosity, and also, by the wall-building action, a state in which a high-quality mud cake can be formed on the inner surface of the face or the groove wall.

That is, by adding the above-mentioned mud film forming agent for excavated muddy water to the degraded muddy water generated by the muddy water excavation method, it is possible to improve the wall forming property while suppressing the thickening of the deteriorated muddy water. Thus, the degraded muddy water can be regenerated as new drilling muddy water.

Therefore, it is possible to reuse the degraded mud which had to be discarded in the past as new mud for excavation, thereby not only reducing the excavation cost but also industrial waste. Degraded mud can also be reduced in volume.

Needless to say, the necessary sludge material can be saved with the reuse of the degraded mud.

Further, according to the method for improving the wall forming property of drilling mud according to the present embodiment, the above-mentioned mud film forming agent for drilling mud can be used as an aqueous solution. In addition to eliminating the need for a mixer for kneading bentonite and CMC, it is possible to significantly reduce or omit plants and stockyards for storing and stirring them, and to regenerate degraded muddy water. Time can be greatly reduced.

Further, according to the method for improving the wall forming property of the muddy water for excavation according to the present embodiment, not only the wall forming property is improved,
Since the viscosity can be reduced, it is advantageous for pumping and sediment separation, and the excavation efficiency is also improved.

[0109] Although not particularly mentioned in the present embodiment, polyacrylate, a poly methacrylate or a copolymer thereof of a weight average molecular weight Mw 10000
At least one of a drilling mud dispersant and sodium carbonate having a size of 1 to 14000 may be added together with the drilling mud mud film forming agent described above.

According to this configuration, a decrease in the dispersibility in the mud for excavation due to the chemical action of calcium ions eluted from the concrete is suppressed, and the wall-forming property and low viscosity are maintained satisfactorily. It exerts particularly excellent effects on degraded muddy water generated by the continuous wall method.

The dispersing agent for drilling mud or sodium carbonate, which is a polyacrylate, polymethacrylate or a copolymer thereof and whose weight average molecular weight Mw is 10,000 to 14000, is used for dispersing the drilling mud. Only one of the agent and sodium carbonate may be used in combination with the above-mentioned mud film forming agent for drilling muddy water, or both may be used in combination. When the dispersant for drilling mud and sodium carbonate are used in combination with the mud film forming agent for drilling mud, sodium carbonate may be mixed in advance with the dispersing agent for drilling mud to form a single agent, or at the site. it may be mixed.

[0112]

Next, the mud film forming agent for excavated mud used in the method for improving the wall forming property of excavated mud according to this embodiment will be described more specifically. Unless otherwise specified, parts and% indicate parts by mass and% by mass, respectively.

First, as described in the above embodiment, the unsaturated carboxylic acid and / or its salt (a) was sodium acrylate, which was polymerized to produce a mud film forming agent 11 for drilling muddy water. .

Table 4 shows the wall-forming properties (ml), viscosity (concentration: 25% by mass) of the mud film forming agent for drilling mud 11 when the weight average molecular weight Mw was changed, and the viscosity of mud when mixed with mud. (MPa · s).

Here, the weight average molecular weight Mw was measured by gel permeation chromatography under the same measurement conditions as the number average molecular weight in the first embodiment.

However, the following columns are used. Column: TSKgel α-3000 + TSKgel α-6000

The standard substance was polyoxyethylene glycol (manufactured by Tosoh Corporation; TSKSTANDARD POLYETHYLE).
NE OXIDE), and the same reference material was used in the first embodiment.

The muddy water before the addition of the mud film forming agent 11 for excavated muddy water was prepared by adjusting the concentration so that the fine particles were 75 μm or less and the specific gravity was 1.05. The muddy water viscosity was measured with a B-type viscometer. The amount of addition to muddy water was 5 kg / m ³ .

[0119]

[Table 4]

[0120] In the table, blanks indicate the case of mud only, and those of Examples 1 'to 9' indicate the wall-forming index of the mud film forming agent 11 for drilling mud. In the case where the drainage amount is 5 ml or less, and Comparative Examples 1 'to 3', the mud film forming agent for drilling mud water 1
In case 1, the amount of drainage exceeded 5 ml. For comparison with the prior art, the case using CMC is also shown as Comparative Example 4 '.

FIG. 6 is a graph obtained by plotting the results with the weight-average molecular weight Mw plotted on the horizontal axis (logarithmic axis) and the wall-forming property (ml) plotted on the vertical axis. Those corresponding to Comparative Examples 1 'and 2' and indicated by white circles correspond to Examples 1 'to 9'. Comparative Example 3 'is not plotted on the same graph because the wall forming property is extremely poor.

As can be seen from these charts, the weight average molecular weights Mw of Examples 1 'to 9' in which the drainage amount, which is an index of wall forming property, was 5 ml or less were in the range of 200,000 to 3,000,000. It can be seen that Comparative Examples 1 'to 3' exceed the drainage amount. Comparative Example 4 '
Indicates that the muddy water viscosity is equal to that of Example 1 '
And much higher than Example 9 ', indicating that the viscosity is too high as the mud for drilling.

The production process of the mud film forming agent 11 for excavated muddy water is specifically described in the case of the above-mentioned Example 1 '. First, 440.7 parts of water is charged into a reaction vessel, and the reaction vessel is purged with nitrogen. MadeNoboru was raised, with stirring, acrylic acid 23
8.5 parts and 100 parts of a 2.0% aqueous solution of sodium persulfate were simultaneously dropped and reacted over 3 hours. After further aging at the same temperature for 2 hours, isopropyl alcohol was removed by distillation and neutralized with 220.8 parts of a 48% aqueous sodium hydroxide solution.

Next, the muddy film forming agent 11 for drilling muddy water according to Example 5 'described above was added to the degraded muddy water, and the wall-forming properties and changes in the muddy water viscosity were examined. Note that the wall-forming properties and the funnel viscosity of the degraded mud before adding the mud-forming agent for drilling mud according to Example 5 ′ are 0% when the amount of the mud-forming agent for drilling mud is not added.
Can be read as the value when.

First, FIG. 7 shows wall-forming properties and funnel viscosities when the specific gravity of the muddy water is 1.05. In the figure, the sample A 'is the mud film forming agent for drilling mud according to Example 5', and also shows the case where CMC is added for comparison.

As can be seen from the figure, with this specific gravity, the wall-forming properties are about 0.13% or more for the mud film forming agent for drilling mud according to Example 5 'and 0.07% for CMC. The improvement is recognized in the range of about or more, and the funnel viscosity is almost not increased regardless of the addition amount in the mud film forming agent for drilling mud according to Example 5 '. It turns out that it is an allowable range.

Next, FIG. 8 shows wall-forming properties and funnel viscosities when the muddy water specific gravity is 1.085.

As can be seen from the figure, when this specific gravity is reached,
The wall-forming properties were improved in the range of about 0.1% or more by the mud film forming agent for drilling mud according to Example 5 'and 0.05% or more by CMC. It can be seen that the thickening tendency of the mud film forming agent for drilling mud according to ′ is not recognized regardless of the added amount, whereas the thickening tendency is clearly recognized in the CMC as the added amount increases.

[0129] Next, a concrete wall properties and the funnel viscosity when mud a specific gravity of 1.11 is shown in FIG.

As can be seen from the figure, when the specific gravity is increased to this level, the wall-forming property is about 0.1% or more in the excavated mud film forming agent according to Example 5 'and 0.05% in the CMC.
Although the improvement was observed in the above range, the viscosity of the funnel was not increased regardless of the addition amount of the mud film forming agent for drilling mud according to Example 5 '.
It can be seen that the tendency of thickening is remarkably recognized as the addition amount increases.

[0131]

As described above, according to the method for improving the wall-forming property of muddy water for excavation according to the present invention, it is possible to improve the wall-forming property of the muddy water while suppressing the thickening of the degraded muddy water. , it is possible to reproduce the deterioration mud as new drilling mud.

Therefore, it is possible to reuse the degraded mud which had to be discarded in the past as new mud for excavation, not only to reduce the excavation cost but also to be industrial waste. Degraded mud can also be reduced in volume.

[0133]

[Brief description of the drawings]

FIG. 1 is a chemical structural formula showing a mud film forming agent for drilling mud used in the method for improving wall formation properties of drilling mud according to the present embodiment.

FIG. 2 is a graph showing an experimental result of a method for improving the wall forming property of muddy water for excavation according to the embodiment.

FIG. 3 is a graph showing an experimental result of the method for improving the wall forming property of the mud for excavation according to the embodiment.

Figure 4 is a graph showing the experimental results of forming walls improving method of drilling mud according to the present embodiment.

FIG. 5 is a chemical structural formula showing a mud film forming agent for excavated mud used in the method for improving the wall forming property of excavated mud according to the second embodiment.

FIG. 6 is a diagram illustrating a weight average molecular weight Mw of a mud film forming agent for drilling mud used in the method for improving wall formation property of drilling mud according to the second embodiment.
Graph showing the relationship between the Zokabe properties (freeness amount).

FIG. 7 is a graph showing an experimental result of the method for improving the wall forming property of the muddy water for excavation according to the second embodiment.

FIG. 8 is a graph showing an experimental result of the method for improving the wall forming property of the mud for excavation according to the second embodiment.

FIG. 9 is a graph showing experimental results of the method for improving the wall-forming properties of muddy water for excavation according to the second embodiment.

[Explanation of symbols]

1, 11 Mud film forming agent for drilling mud 2 Sodium methacrylate (unsaturated carboxylate (a)) 3 Methoxy polyethylene glycol methacrylate (monoester (b)) 12 Sodium acrylate (unsaturated carboxylate (a)) )

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuji Sato 4-640 Shimoseito, Kiyose-shi, Tokyo Inside the Obayashi-gumi Technical Research Institute Co., Ltd. (72) Inventor Yoshio Tanimizu, Sanyo Chemical Industry Co., Ltd., 1-11, Hitotsubashi Nohonmachi, Higashiyama-ku, Kyoto, Kyoto Prefecture (72) Inventor Kaoru Yamazaki, 1-11, Hitotsubashi Nohonmachi, Higashiyama-ku, Kyoto, Kyoto, Japan (72) Inventor Tomokazu Shimizu 1-1-1, Hitotsubashi-Honcho, Higashiyama-ku, Kyoto City, Kyoto Prefecture F-term in Sanyo Chemical Industries Co., Ltd. 4H026 CB08 CC06

Claims (7)

[Claims] 1. An unsaturated carboxylic acid and / or a salt thereof (a), an unsaturated carboxylic acid (b1) and the following general formula (1): R (OA) _n OH (1) R; alkylene group n of 2 to 4 carbon atoms; hydrocarbon group a of 12 copolymer and monoester (b) and a structural unit of a hydroxyl group-containing compound represented by integers of 1~100 (b2) (x A method for improving the wall-forming properties of muddy water for drilling, characterized by adding a mud film forming agent for drilling mud containing essential component (1) to degraded muddy water. 2. The mass% of the monoester (b) constituting the copolymer (x) is 1 to 40%, and the number average molecular weight of the copolymer (x) is 5,000 to 10,000.
The method for improving the wall forming properties of muddy water for drilling according to claim 1, wherein the value is 0. 3. The unsaturated carboxylic acid and / or its salt (a) is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, and alkali metal salts and ammonium salts thereof. At least one kind of the unsaturated carboxylic acid (b1) is acrylic acid,
The method for improving the wall-forming properties of drilling mud according to claim 1 or 2, wherein the method is at least one selected from the group consisting of methacrylic acid, itaconic acid, maleic acid and fumaric acid. 4. A degraded mud comprising a polyacrylate, a polymethacrylate or a copolymer thereof, wherein the weight average molecular weight Mw is 10,000 to 14,000 and at least one of a dispersant for drilling mud and sodium carbonate is used as the degraded mud. Concrete walls improving method of drilling mud of claim 1 wherein the added. 5. A (co) polymer (x ′) having an unsaturated carboxylic acid and / or a salt thereof (a) as a main structural unit, and a weight average molecular weight Mw of the (co) polymer (x ′). 2
A method for improving the wall-forming properties of muddy water for excavation, characterized by adding a mud film forming agent for excavated muddy water of from 0,000 to 3,000,000 to deteriorated muddy water. 6. The unsaturated carboxylic acid and / or its salt (a) is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid and their alkali metal salts and ammonium salts. The method for improving the wall-forming properties of drilling mud according to claim 5, which is at least one kind. 7. polyacrylates, polymethacrylates or copolymers thereof in a by the deterioration mud at least one of the dispersing agent or sodium carbonate for drilling fluid to the weight average molecular weight Mw 10000 to 14000 Concrete walls improving method of drilling mud of claim 5 wherein the added.