JP2000192026A - Additive for excavation slurry and excavation slurry composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive used for an excavation slurry and having excellent performances and excellent biodegradability and to provide an excavation slurry composition containing the same. SOLUTION: This additive comprises a water-soluble copolymer having a number-average molecular weight of 1,000-50,000 and derived from 30-95 mol% (a) at least one unsaturated monocarboxylic acid monomer selected from among acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts of these acids, 5-70 mol% (b) maleic acid (anhydride), fumaric acid, citraconic acid (anhydride), and alkali metal salts, alkaline earth metal salts, ammonium salts, and organic amide salts of these acids, and 0.5-15 mol%, based on 100 mol% of the total amount of the unsaturated carboxylic acid monomers, (c) quinone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling mud additive and a drilling mud composition, and more particularly to a biodegradable additive for drilling mud used in excavating ground and the additive. And a drilling mud composition containing:

[0002]

2. Description of the Related Art Conventionally, foundation work for civil engineering work, absorption of frictional heat generated during excavation of the ground such as bowling of oil wells and geothermal wells, removal of excavated waste from the bottom of a pit to the ground, maintenance of a pit wall, In order to prevent collapse of the collapsed stratum, a mud composition prepared on the ground is continuously and cyclically injected into a digging site. The mud composition is usually prepared using inorganic mud such as bentonite, attapulgite, serinite, hydrous magnesium silicate, water for use, and a drilling mud additive for stabilizing the mud. Among the conventionally used additives for drilling mud, as inorganic compounds, condensed phosphates such as sodium tripolyphosphate and sodium hexametaphosphate, alkali metal salts such as sodium carbonate and potassium carbonate, sodium aluminate, aluminate Examples thereof include aluminates such as potassium. As organic compounds, humates, ligninsulfonates, carboxymethylcellulose (CM
C), hydroxyethylcellulose (HEC), polyvinyl alcohol (PVA), phosphonate and the like, but each has problems.

For example, condensed phosphate is diffused from the ground when used for a long period of time, and when it flows into the sea, lake, etc., it becomes a causative substance such as water bloom and red tide. The muddy water using CMC has a serious drawback that it easily rots. Alkali metal carbonate, aluminate, HE
C, PVA, humates, lignin sulfonic acids, phosphonates and the like have poor performance. Recently, acrylic acid-based polymers have been proposed to solve these problems. For example, JP-A-2-185588 discloses a copolymer of an unsaturated monocarboxylic acid such as acrylic acid and an unsaturated dicarboxylic acid such as maleic acid, but is poor in biodegradability and remains in nature. Therefore, there is a problem in terms of environmental protection.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above, and provides a drilling mud additive having excellent performance and excellent biodegradability, and a drilling mud composition containing the additive. It is intended to do so.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a novel terpolymer derived from unsaturated monocarboxylic acid monomers, unsaturated dicarboxylic acid monomers and quinones. It has been found that the object of the present invention can be effectively achieved by using the present invention, and the present invention has been completed.

That is, the present invention relates to (a) acrylic acid,
One or two or more unsaturated monocarboxylic acid monomers selected from methacrylic acid and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids.
5 mol%, (b) one or more selected from maleic acid (anhydride), fumaric acid, citraconic acid (anhydride) and alkali metal salts, alkaline earth salts, ammonium salts and organic amine salts of these acids A monomer comprising 5-70 mol% of an unsaturated dicarboxylic acid monomer and (c) 0.5 to 15 mol% of a quinone based on 100 mol% of the total amount of the unsaturated carboxylic acid monomer. It is an object of the present invention to provide a drilling mud additive comprising a water-soluble copolymer having a number average molecular weight derived from components of 1,000 to 50,000, and a drilling mud composition containing the additive.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As the unsaturated monocarboxylic acid monomer of the component (a) used in the present invention, acrylic acid, methacrylic acid or a partially neutralized product of these acids with a monovalent metal, a divalent metal, ammonia, an organic amine or A completely neutralized product or a mixture thereof can be mentioned. Na, K as a monovalent metal, Mg, Ca, Ba as a divalent metal,
Zn can be mentioned. As organic amines, monomethylamine, dimethylamine, trimethylamine,
Examples thereof include alkylamines such as monoethylamine, diethylamine, and triethylamine; alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, and dimethylethanolamine; and pyridines.
Among them, acrylic acid and salts of acrylic acid are preferable, and particularly, partially neutralized or completely neutralized acrylic acid and a monovalent metal of acrylic acid are preferable.

The unsaturated monocarboxylic acid monomer of the component (b) includes maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride or a monovalent metal or a divalent metal of these acids. , Ammonia, a partially neutralized product or a completely neutralized product with an organic amine, or a mixture thereof. Na and K as monovalent metals,
Examples of the divalent metal include Mg, Ca, Ba, and Zn. In addition, monomethylamine,
Alkylamines such as dimethylamine, trimethylamine, monoethylamine, diethylamine and triethylamine, monoethanolamine, diethanolamine,
Triethanolamine, monoisopropanolamine,
Alkanolamines such as dimethylethanolamine,
Pyridines and the like can be mentioned. Among them, maleic anhydride and salts of maleic anhydride are preferred, and particularly, maleic anhydride and maleic anhydride are partially or completely neutralized with monovalent metals.

The quinones of the component (c) include p-hydroxyphenol, o-hydroxyphenol, m-hydroxyphenol, 2-methoxyhydroquinone, tetramethylhydroquinone, p-benzoquinone, o-benzoquinone, tolquinone, naphthoquinone and anthraquinone. ,
Methoquinone or a mixture thereof can be mentioned. Among these, p-hydroxyphenol (hydroquinone) or p-benzoquinone is preferable.

The water-soluble copolymer used in the present invention comprises:
(A) the unsaturated monocarboxylic acid monomer 30-
95 mol% (preferably 40 to 90 mol%), 5 to 70 mol% of the unsaturated dicarboxylic acid-based monomer of the component (b)
(10 to 60 mol%) and 0.5 to 15 mol% based on 100 mol% of the total amount of the unsaturated carboxylic acid monomer.
(Preferably 2 to 10 mol%) derived from a monomer component composed of the quinone component (c), and having a number average molecular weight of 1,000 to 50,000 (preferably 1,500 to
000).

Regarding the composition of the monomer, the component (a)
When the amount is less than 0 mol%, that is, when the amount of the component (b) exceeds 70 mol%, the biodegradability decreases, and the amount of the
Is exceeded, that is, when the component (b) is less than 5 mol%,
Biodegradability and performance as an additive for drilling mud are reduced.
If the component (c) is less than 0.5 mol% with respect to the unsaturated carboxylic acid monomer, a copolymer having sufficiently high biodegradability cannot be obtained, and if it exceeds 15 mol%. The performance as an additive for drilling mud drops. As for the number average molecular weight of this polymer, the number average molecular weight was 1,0.
If it is less than 00, the ability as an additive for drilling mud will not be sufficiently obtained, while if it exceeds 50,000, the biodegradability will decrease.

Next, in order to obtain the water-soluble copolymer used in the present invention, the monomer components comprising the components (a) to (c) may be copolymerized in the presence of a polymerization initiator. . As the polymerization initiator, for example, a combination of hydrogen peroxide and a reducing agent, a percarboxylic acid, a permaleic acid, and the like are used. As the reducing agent used here, iron ion, copper ion, zinc ion, nickel ion, ascorbic acid, saccharin and the like are preferable. The use ratio of these polymerization initiators is 0.1 to 30 with respect to the total amount of the raw material monomers.
% By weight, preferably 0.5 to 20% by weight.

As the polymerization initiator, azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, tetramethylthiuram disulfide and the like may be used.
The use ratio of these azo polymerization initiators is 0.1 to 10% by weight, preferably 0.5 to 10% by weight, based on the total amount of the raw material monomers.
5% by weight. If the use ratio of these polymerization initiators is less than the above range, a polymer having a sufficiently high molecular weight may not be obtained, and if it exceeds the above range, the effect corresponding thereto cannot be obtained.

In producing the water-soluble copolymer,
Usually, no solvent or aqueous solvent is used. A non-aqueous solvent may be used as the solvent. As the non-aqueous solvent, acetone, dimethylformamide, dimethylacetamide, ethyl acetate, N-methylpyrrolidone, benzene, toluene, xylene, dioxane and the like are used. In this reaction, polymerization is preferably performed in an aqueous solvent, but when a non-aqueous solvent is used, acetone is preferable.

The reaction conditions for this polymerization reaction are from atmospheric pressure to 1 M
Pa, preferably at atmospheric pressure to 0.5 MPa, 30
To 150 ° C, preferably 50 to 120 ° C. The polymerization time depends on the type of the raw material compound and the polymerization temperature, but is usually 10 minutes to 20 hours, preferably 1 to 4 hours. The water-soluble copolymer obtained as described above has the following formulas (1) and (2)
It is presumed to have a repeating unit represented by (3).

[0016]

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(Where X is a hydrogen atom, a monovalent metal atom, 2
It represents a valent metal atom, an ammonium group or an organic amine group, and R ¹ represents a hydrogen atom or a methyl group. )

[0018]

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(Wherein, X is the same as described above, and R ² represents a hydrogen atom or a methyl group.)

[0020]

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(Where Y is a hydrogen atom, a monovalent metal atom, 2
It represents a valent metal atom, an ammonium group or an organic amine group. A drilling mud composition can be obtained by using the thus obtained water-soluble copolymer-forming additive for drilling mud in combination with inorganic mud and water. Bentonite, attapulgite, serinite, hydrous magnesium silicate and the like can be mentioned as the inorganic mud, but bentonite is preferable in terms of effect. The mixing ratio of the excavating mud additive and the inorganic mud in this excavating mud composition was 1 to 10 based on the total amount of the composition.
% By weight, inorganic mud 0.05 to 0.5% by weight, with the balance being service water.

[0022]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. REFERENCE EXAMPLE 1 11.0 g of maleic anhydride and 30 ml of water were placed in a 300-ml separable flask equipped with a stirrer, a thermocouple and a reflux condenser, and 24.0 g of sodium hydroxide was added thereto while cooling. Twenty milliliters of the dissolved aqueous solution was gradually added. Then
In this separable flask, 34.6 g of acrylic acid and p
1.62 g of benzoquinone and 90 mg of ferrous chloride tetrahydrate as a reducing agent used in combination with hydrogen peroxide
And heated and stirred in an oil bath at 80 ° C. Next, 17.0 g of a 60% by weight hydrogen peroxide solution was added dropwise to the separable flask over 1 hour.
For 3 hours with stirring. After completion of the reaction, the reaction product was freeze-dried to obtain a water-soluble copolymer (1).
The resulting water-soluble copolymer, acrylic acid / maleic acid = 80/20 (molar ratio), had a number average molecular weight of 4,
500. Reference Examples 2 to 5 and Comparative Reference Examples 1 to 5 According to the method of Reference Example 1, water-soluble copolymers (2) to (5) and comparative water-soluble (co) polymers (1) to (5) I got The number average molecular weights are shown in Tables 1 and 2.

[Example 1] Inner diameter 90 mmφ, height 160
In a SUS304 mm tank, 100 g of deionized water, 6 g of bentonite and 0.2 g of the water-soluble copolymer obtained in Reference Example 1 as an additive for drilling mud were taken, and a dissolver stirring blade (vane diameter: 40 mmφ) was used. 000rpm
For 15 minutes to obtain a drilling muddy water composition (1). The funnel viscosity (FV) (* Note 1), gel strength (10 Gel) (* Note 2), and water absorption (* Note 3) of the obtained drilling mud composition (1) were measured. The result is
It is shown in the table. * Note 1: Measured with a 500 milliliter funnel viscometer. Unit: seconds * Note 2: Measured with a fan VG meter. The unit is Pascal * Note 3: 3 kg / cm ² using a filter according to API standards
The amount of dehydration 30 minutes after the pressure was measured. The unit is milliliter. Then, the drilling mud composition (1) is subjected to physical properties and cement resistance test, seawater resistance test and biodegradability test for water-soluble copolymer (1) as follows. went. Table 1 shows the results. Cement resistance test 5 g of cement was mixed with the above drilling muddy fluid composition (1), and the funnel viscosity (FV) of the muddy water left for 1 day, 10 minutes gel strength (10 Gel) and water absorption were measured. Table 1 shows the results. Seawater resistance test 4 g of Aquamarine S (manufactured by Yasu Pharmaceutical Co., Ltd.) was mixed with the above drilling muddy water composition (1) and the funnel viscosity (FV) of the muddy water left for one day, 10 minutes gel strength (10 Gel) and water absorption Was measured. Table 1 shows the results. Biodegradability test The polymer obtained in Reference Example 1 was subjected to JIS K6
The biodegradation rate was measured according to 950. The biodegradation rate is T
It was calculated from OC (total organic carbon content). Table 1 shows the results.

Examples 2 to 5 Water-soluble copolymers (2) to (5) obtained in Reference Examples 2 to 5 as additives for drilling mud
Except for the use of, the drilling mud compositions (2) to (5) were obtained in the same manner as in Example 1, and their physical properties, cement resistance, seawater resistance, and biodegradability test of the water-soluble copolymer were performed. Was. Table 1 shows the results. [Comparative Examples 1 to 5] Comparative Reference Example 1 as an additive for drilling mud
Comparative water-soluble (co) polymers (1) to (5)
Comparative Example 1 (Comparative composition (1))
To (5) were obtained and subjected to biodegradability tests of their physical properties, cement resistance, seawater resistance and water-soluble (co) polymer. Table 2 shows the results.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

According to the present invention, it is possible to provide a drilling fluid additive excellent in performance and excellent in biodegradability, and a drilling fluid composition containing the additive.

Claims (6)

[Claims] 1. (a) one or more unsaturated monocarboxylic acid monomers selected from acrylic acid, methacrylic acid and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids; (B) (anhydride) maleic acid, fumaric acid, (anhydrous) citraconic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids Or 5 to 70 mol% of two or more unsaturated dicarboxylic acid monomers and (c) 0.5 to 15 mol% of quinones based on 100 mol% of the total amount of the unsaturated carboxylic acid monomers. A drilling mud additive comprising a water-soluble copolymer having a number average molecular weight of 1,000 to 50,000 derived from a monomer component consisting of 2. The water-soluble copolymer comprises (a) 40 to 90 mol% of an unsaturated monocarboxylic acid monomer, (b) 10 to 60 mol% of an unsaturated dicarboxylic acid monomer and (c) 0.5 to 1 based on the total amount of the unsaturated carboxylic acid monomer
The additive for drilling mud according to claim 1, which is derived from a monomer component composed of 5 mol% of quinones. 3. The additive for drilling mud according to claim 1, wherein (a) the unsaturated monocarboxylic acid-based monomer is acrylic acid or a salt thereof. 4. The method according to claim 1, wherein (b) the unsaturated dicarboxylic acid monomer is
The additive for drilling mud according to any one of claims 1 to 3, which is (anhydrous) maleic acid or a salt thereof. 5. The additive for drilling mud according to claim 1, wherein the drilling mud is bentonite mud. 6. A drilling mud composition comprising the drilling mud additive according to any one of claims 1 to 5.