JPH048470B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to an additive for drilling mud. <Conventional technology and problems> Conventionally, muddy water such as bentonite muddy water or polymer muddy water has been used in ground excavation methods, but it is known that the performance of muddy water deteriorates due to seawater, cement, and other electrolytes. There is. For this reason, polyacrylic acid monovalent salt and cellulose sodium glycolate (CMC) with a degree of polymerization below 5000
(Japanese Patent Publication No. 49-46763) has been proposed. However, there was a problem in that it was not sufficient to prevent deterioration of muddy water performance due to contamination with salt water, cement, etc., and rot and deterioration caused by bacteria occurred. <Means for Solving the Problems> The present inventors have made extensive studies to solve these problems, and as a result, have arrived at the present invention. That is, the present invention provides an acrylic acid and/or methacrylic acid (co)polymer having a degree of polymerization of 5000 or less [(co) means a homopolymer or a copolymer, the same applies hereinafter. ] This is an additive for drilling mud consisting of a monovalent salt (a) and a monovalent salt of aluminate (b). In the monovalent salt (a) of acrylic acid and/or methacrylic acid (co)polymer having a degree of polymerization of 5000 or less in the present invention, the acrylic acid and/or methacrylic acid (co)polymer is acrylic acid-methacrylic acid. Examples include copolymers, acrylic acid polymers and methacrylic acid polymers. The amount of acrylic acid in the acrylic acid-methacrylic acid copolymer is not particularly limited. Examples of monovalent salts include alkali metal salts (sodium salts, potassium salts, etc.), ammonium salts, and amine salts (monoethanolamine, diethanolamine, triethanolamine, alkyl (C ₁ - C ₄ ) amine salts, etc.). It will be done. Preferred are sodium and potassium salts. Acrylic acid and/or methacrylic acid (co)
The degree of polymerization of the polymer is preferably 50 to 2,500.
When the degree of polymerization exceeds 5000, the flocculating action becomes stronger, making it easier to flocculate soil and cement, and when heavy metal ions are mixed in, they tend to become insoluble materials, making the drilling mud gel-like and deteriorating the performance of the mud. As the monovalent salt (b) of aluminic acid, an alkali metal salt of hydrated metaaluminate [M ¹ AlO ₂ .mH ₂ O (M ¹ represents an alkali metal), for example, NaAlO ₂ .5/
4H ₂ O, NaAlO ₂・3H ₂ O and KAlO ₂・3/
2H ₂ O], alkali metal aluminate anhydrides [M ¹ AlO ₂ such as NaAlO ₂ and KAlO ₂ ; and sodium orthoaluminates such as Na ₃ AlO ₃ ].
can be mentioned. In the alkali metal salt of aluminate, the molar ratio (x) of M ¹ ₂ O to Al ₂ O ₃ is:
It is usually 1.0 to 2.5, preferably 1.0 to 1.5.
Among these alkali metal salts, sodium salts are preferred. Sodium aluminate is generally obtained by mixing alumina hydrate and caustic soda, heating, stirring, and reacting them. For example, it can be obtained by reacting alumina trihydrate and caustic soda at a temperature of about 100 to 150°C and crystallizing it, but there are no particular restrictions on the manufacturing method, and any method can be used. It may depend on If necessary, an alkali metal carbonate containing potassium carbonate can be used together with the monovalent salt of aluminate (b). Among the alkali metal carbonate salts containing potassium carbonate, potassium carbonate includes anhydrous salts, monohydrates, dihydrates, and pentahydrates. Most preferred of these are anhydrous salts. In addition to potassium carbonate, it may contain other alkali metal carbonate salts, and examples of other alkali metal carbonate salts include sodium carbonate. Examples of the sodium carbonate salt include anhydrous salt (soda ash), monohydrate salt, and decahydrate salt, but soda ash is preferred. The pure amount of (a) in the additive for drilling mud is usually 15 to 85% by weight, preferably 30 to 70% by weight, based on the total weight of pure components of (a) and (b). If it is less than 15% by weight, gelation will occur when cement is mixed in, and if it exceeds 85% by weight, gelation will occur when seawater is mixed, and in both cases, muddy water performance will deteriorate. The pure amount of aluminic acid monovalent salt (b) in additives for drilling mud is usually 15 to 15% relative to the total weight of pure portions of (a) and (b).
85% by weight, preferably 30-70% by weight. If it is less than 15% by weight, gelation will occur when seawater is mixed in, and if it exceeds 85% by weight, gelation will occur when cement is mixed, and in either case, the performance in muddy water will deteriorate. The weight ratio of the monovalent salt of aluminate (b) and the alkali metal carbonate containing potassium carbonate is not particularly limited, but is usually 1:0 to 100. Examples of the drilling mud to which the additive of the present invention is added include inorganic clay mud such as bentonite, attapulgite, and sericite, and polymer mud having a water-soluble polymer skeleton. Among these, bentonite mud is preferred. The amount (pure amount) of the additive for drilling mud added to the drilling mud is usually 0.01 to 5% by weight, preferably
It is 0.05 to 3% by weight. If it is less than 0.01% by weight, it cannot be expected to be effective in preventing deterioration of muddy water performance due to seawater, cement, or other electrolytes, and if it exceeds 5% by weight, the effect of adding it cannot be expected and is economically disadvantageous. When adding the additive for drilling mud of the present invention to drilling mud, the following method can be mentioned as the addition method. (1) A method in which (a) and (b) are mixed in advance and added. (2) A method of adding (a) and (b) separately; this includes, for example, the following two methods. Method of adding (b) next to (a). Method of adding (a) and (b) at the same time. Among these addition methods, method (2) is preferred. The additive for drilling mud of the present invention is preferably added while stirring the mud. The mud composition for ground drilling obtained in this way usually has a specific gravity of 1.02 to 1.35 and a funnel viscosity of 21.
Maintains physical properties such as gel strength of ~45 seconds and 10 minutes of less than 2 Pascals and dehydration amount of less than 25 m. In an embodiment of performing ground excavation using a mud water composition, first, the additive for drilling mud of the present invention, an inorganic clay water-soluble polymer, etc. are added to water to prepare a mud water composition. Next, the ground is excavated using an excavator while circulating this muddy water composition to the excavation part. In this case, the mud composition always fills the inside of the excavation area, absorbs frictional heat, radiates heat, lubricates, etc., and carries the excavated soil to the ground to advance the excavation and form an impermeable mud wall. This prevents the borehole wall from collapsing. After the prescribed excavation is completed in this manner, a reinforced framework is appropriately installed, concrete is poured from the bottom, and while muddy water overflows from the top, the excavation is filled with concrete to construct a pile or wall. The muddy water that replaced the concrete is returned to the tank and reused. The additive of the present invention contains (a) and (b), but it also contains a solubility promoter (e.g., ethylene glycol, diethylene glycol, polyethylene glycol, etc.), a dispersing peptizer (e.g., sodium nitrofumate, tannins, lignin, etc.). sulfonate, condensed phosphate, etc.) may be used in combination as appropriate. <Example> The present invention will be described below with reference to Examples, but the present invention is not limited thereto. Parts in the examples are by weight. In addition, the mud water temperature is 20±3℃
It is. The test methods in Examples and Comparative Examples are as follows. (1) Funnel viscosity (FV): Measured using a 500 c.c. funnel viscometer. The unit is seconds. (2) 10 minute gel strength (10Gel): Measured with a Huang VG meter. The unit is pascal (Pa). (3) Amount of dehydration: Using filtration according to the APT standard, the amount of dehydration was measured after 30 minutes under a pressure of 3 Kg/cm ² . The unit is ml. (4) Stability against cement mixing: 1 to 3 parts of Portland cement was added to 100 parts of muddy water, and after 1 day had passed after mixing thoroughly, the above
The muddy water performance of (1) to (3) was measured. (5) Stability against seawater contamination: Add 1 and 3 parts of "Aquamarine S" [artificial seawater manufactured by Yashu Yakuhin Co., Ltd., 25 times concentrated product] to 100 parts of muddy water, mix well, and leave to stand. After one day had passed, the muddy water performance of (1) to (3) above was measured. Examples 1 to 5 and Comparative Examples 1 to 4 Table 1 shows the compositions of the drilling mud additives (Examples 1 to 5) and comparative additives (Comparative Examples 1 to 4) of the present invention.

[Table] The same applies below.

[Table] 100 parts of fresh water and 6 parts of bentonite (Kunigel, manufactured by Kunimine Kogyo Co., Ltd.) were placed in a Juicer mixer and stirred for 2 minutes. Next, the additive for drilling mud of the present invention and a comparative product shown in Table 1 were added, and the mixture was further stirred for 2 minutes to obtain a mud composition. Table 2 shows the results of investigating the muddy water performance.

【table】

【table】

[Table] The muddy water performance of the additive of the present invention was good. In addition, it was confirmed that the muddy water of Comparative Example 2 developed a putrid odor after being left for one week, and its viscosity was significantly reduced. <Effects of the Invention> The additive for drilling mud of the present invention has the following effects. (1) In the composition using the additive of the present invention, the physical properties of mud (dispersion stability, amount of water removed, etc.) do not change significantly even when seawater or salt water flows in during excavation. (2) In the composition using the additive of the present invention, the physical properties of mud (dispersion stability, amount of water removed, etc.) hardly change even if cement or the like is mixed. Therefore, it can be used repeatedly. (3) Since the composition using the additive of the present invention does not contain substances that are easily biodegradable such as CMC,
Not easy to rot. (4) A composition using the additive of the present invention has excellent dispersion stability of inorganic clays such as bentonite. (5) A composition using the additive of the present invention has a small amount of water dehydration and is excellent in mud wall forming property, that is, in preventing collapse of a drilled hole.

Claims (1)

[Claims] 1. A monovalent salt of an acrylic acid and/or methacrylic acid (co)polymer with a degree of polymerization of 5000 or less [(co)polymer means a homopolymer or a copolymer]
Additive for drilling mud consisting of (a) and monovalent salt of aluminate (b). 2 The pure amount of (a) relative to the total weight of pure components of (a) and (b) is
Additive according to claim 1, in an amount of 15 to 85% by weight. 3 The total weight of pure components (a) and (b) in drilling mud is 0.01 to 5.
Claim 1 or 2 added by weight%
Additives listed in section. 4. The additive according to any one of claims 1 to 3, wherein the drilling mud is bentonite mud. 5. The additive according to any one of claims 1 to 4, wherein the monovalent salt is a salt selected from the group consisting of alkali metal salts, ammonium salts, and amine salts.