JPH0340757B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses muddy water mainly composed of bentonite suspended water to excavate geological formations in drilling work for drilling oil, natural gas, geothermal wells, etc., or in civil engineering foundation work such as continuous wall construction method and shield construction method. The present invention relates to an agent that prevents mud from escaping from an excavated area in a construction method, the so-called mud construction method. When drilling geological formations, it transports cuttings to the surface, cools and lubricates bits, drill collars, and drill strings, prevents the eruption of underground oil, gas, water, etc. during drilling, and stabilizes the excavation wall surface. The so-called muddy water construction method, which uses muddy water for such purposes, is widely used in the above-mentioned construction works. However, the muddy water method is applied to coarse-grained, permeable strata such as gravel layers, strata with cracks such as carbonate rocks and volcanic rocks, or hollow strata found in coal rock and dolomite layers. This method has the problem that, in certain geological formations, a so-called sludge phenomenon occurs in which muddy water is lost into the geological formations. Various countermeasures have been taken since ancient times to deal with such sludge phenomena, and various methods have been considered depending on the degree of sludge and the type of strata in which it occurs. Examples of methods for preventing lost sludge that have been proposed so far include walnut grains, mica chips,
There are methods such as adding sludge prevention agents such as cotton seed slag and fiber substances to the muddy water to plug cracks and gaps in the strata, and methods such as cement flashing and cement squeezing. However, in order to increase the sludge prevention effect, it is necessary to prepare various types of sludge inhibitors with different particle sizes and shapes depending on the sludge situation. Depending on the degree of slippage, it may be difficult to completely prevent this. On the other hand, cement flats and cement squeeze are commonly used to remove mud from large cracks and from geothermal development wells because the materials are easily available and inexpensive. The bits have to be removed during the process; the cement slurry has a high specific gravity; Therefore, it has many disadvantages, such as being easily lost in the geological formations, and furthermore, if muddy water is mixed into the cement slurry, the hardening of the cement will be poor, and in some cases, it will not harden at all. Therefore, there is currently no effective countermeasure against any type of sludge, and there is a strong need for an excellent sludge prevention agent. The present inventors completed the present invention after conducting various studies in order to solve the current problems as described above and obtain an excellent anti-sludge agent. That is, the present invention relates to an anti-sludge agent for muddy water construction methods, which is characterized by comprising a monomer whose main component is a metal salt of α,β-monoethylenically unsaturated carboxylic acid and a polymerization catalyst thereof. be. It has been discovered that the sludge prevention agent of the present invention polymerizes and hardens after being injected into cracks and gaps in the strata, becomes a water-containing elastic body, and blocks and fills these gaps to prevent sludge. It was discovered that the method of preventing slippage of sludge using a chemical agent is an extremely economical method, and this led to the completion of the present invention. The cured sludge prevention agent of the present invention exhibits no syneresis phenomenon of water from the cured product, and is a flexible, water-impermeable, hydrated elastic material with excellent heat resistance and adhesion properties, making it an excellent material. Produces mud prevention effect. In addition, the sludge prevention agent of the present invention has a low viscosity and good permeability into pores, and the curing time depends on the amount of polymerization catalyst added, the type of sludge stratum, the depth, the underground temperature, etc. It has the advantage of being able to be set at any time depending on the wellbore conditions. Furthermore, depending on the working method when injecting the sludge prevention agent of the present invention into the pit,
Another advantage is that pouring work can be carried out with the excavation structure intact, without having to remove the bits as in the conventional method. The invention will be described in further detail below. As described above, the anti-sludge agent of the present invention is composed of a monomer whose main component is a metal salt of α,β-monoethylenically unsaturated carboxylic acid and a polymerization catalyst thereof. Metal salts of α,β-monoethylenically unsaturated carboxylic acids include calcium salts, magnesium salts, hyperlead salts, aluminum salts, etc. of acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, etc. Preferred in the present invention are calcium salts, magnesium salts, zinc salts, and aluminum salts of acrylic acid or methacrylic acid, and particularly preferred are acrylic salts that have good adhesion to sand particles, rock, etc. Magnesium salt of acid or methacrylic acid. The sludge prevention agent of the present invention is injected into the stratum, polymerizes and hardens, and becomes a water-containing elastic body to prevent sludge. Metal salts of α,β-monoethylenically unsaturated carboxylic acids (hereinafter referred to as monomer a) are used to prevent the syneresis phenomenon caused by syneresis and to improve adhesion, especially at high temperatures of about 50 to 100°C.
Preferable in the present invention is an anti-sludge agent in which an α,β-monoethylenically unsaturated carboxylic acid ester (hereinafter referred to as monomer b) having a hydroxy group or an alkoxy group is used in combination. Specific compounds of monomer b include acrylic acid,
An ester having a hydrophilic group such as methacrylic acid, maleic acid, itaconic acid, crotonic acid, etc., such as hydroxyethyl, hydroxypropyl, methoxyethyl, ethoxyethyl, butoxyethyl, etc., and is compatible or soluble with water, and is preferable for the present invention. are esters of acrylic acid or methacrylic acid, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate,
Particular preference is given to -hydroxyethyl methacrylate, methoxyethyl acrylate and ethoxyethyl acrylate. In the present invention, when monomer a and monomer b are used together, the desired effect of the present invention is well expressed, but in order to obtain the best effect, the following combination ratio should be used. It is preferable to take That is, when the total monomer is 100 parts by weight,
70 to 98 parts by weight of monomer a, more preferably 70 to 94 parts by weight
parts by weight, 2 to 30 parts by weight of monomer b, preferably 6 parts by weight
-30 parts by weight, the effect of the present invention is well expressed, and also for monomer b, a monomer having a hydroxy group and a monomer having an alkoxy group are used together, and the ratio in that case is 70 to 98 parts by weight of monomer a, more preferably 70 to 94 parts by weight, 1 to 25 parts by weight of a monomer having a hydroxy group such as 2-hydroxyethyl acrylate among monomer b, more preferably 5 to 25 parts by weight The best effect is obtained when the amount is 1 to 5 parts by weight of a monomer having an alkoxy group such as methoxyethyl acrylate. If the unsaturated carboxylic acid salt of monomer a is less than 70 parts by weight, the strength of the cured product will be insufficient, and if the unsaturated carboxylic acid ester of monomer b is less than 2 parts by weight, the hydration effect will be reduced. As it becomes insufficient, a syneresis phenomenon occurs from the cured product, and the adhesion properties also become insufficient. Further, by using two types of monomer b in combination as described above, even better fixing properties can be provided. The method of using the sludge prevention agent of the present invention is as follows:
The sludge prevention agent contains a polymerization catalyst because it is infiltrated into the sludge stratum using a pump, etc., and then the monomers mentioned above are polymerized and hardened to form a hardened product, thereby preventing sludge sludge. It is necessary. Catalysts suitable for the anti-sludge agent of the present invention include water-soluble oxygen-containing catalysts such as persulfates, hydrogen peroxide, perchlorates, etc., and redox-type catalysts such as persulfate as the oxidizing component. , perchloric acid, perboric acid and permanganic acid, any water-soluble peroxidation catalyst derived from peracids and their salts, such as ammonium persulfate, potassium peroxide, hydrogen peroxide,
Ammonium perchlorate and various reducing components as reducing agents, such as sulfurous acid, hyposulfite, thiosulfuric acid, erythorbic acid or its alkali metal salts, copper powder, iron powder, and their chlorides and sulfates are used in combination. Examples of suitable redox catalysts include ammonium persulfate - sodium thiosulfate, potassium persulfate -
Examples include sodium thiosulfate and hydrogen peroxide-acidic sodium sulfite. The amount of the polymerization catalyst used in the present invention is determined depending on the formation rate of the hardened material, which is determined by the type of the stratum where the sludge is occurring, the depth of the stratum, the temperature inside the well, and other well conditions. However, it is generally determined in the range of 0.05 to 20 parts by weight per 100 parts by weight of the monomer. Furthermore, in order to adjust the curing time, it is also possible to add a polymerization modifier such as red blood salt (potassium ferricyanide) to these. You can now set the curing time. The amount of polymerization regulator added is generally 100% of the monomer.
It is 0.003 to 0.7 parts by weight. When using the anti-sludge agent of the present invention, monomer a or monomer a and monomer b are generally selected from the viewpoint of workability during injection, curing time, and properties required for the cured product. is used as a 10-50% aqueous solution. Further, the polymerization catalyst is used by being added to this aqueous monomer solution immediately before injection. When using the anti-sludge agent of the present invention, in addition to using it alone, other anti-penetration agents may be added to prevent the fluid from penetrating into the stratum halfway to the target depth.
Inorganic substances such as cement, slag, bentonite, fly ash, and gypsum are added to this fluid to increase its viscosity and reduce its penetration rate before hardening, thereby reducing costs or increasing the strength of the hardened product. Addition of hollow microvitreous spheres, pearlite, gilsonite, or other lightweight materials to reduce the specific gravity of the fluid, reduce its penetration into the formation, or otherwise impair the properties of the process of the invention. It is also possible to add various additives, such as mixing a third substance within a range that does not contain the additives, to impart properties accordingly. The present invention will be further explained below with reference to Examples and Reference Examples. Example 1 To 100 c.c. of a 30% aqueous solution of a monomer mixture consisting of 80 parts by weight of magnesium acrylate, 18 parts by weight of hydroxyethyl acrylate, and 2 parts by weight of methoxyethyl acrylate, a 20% aqueous solution of ammonium persulfate as a polymerization catalyst was added. A 10% sodium thiosulfate aqueous solution and a 10% red blood salt aqueous solution as a polymerization regulator were added in the amounts shown in Table 1, and mixed well to obtain a sludge prevention agent. When the curing times were measured at 20°C, 40°C and 60°C, the values shown in Table 1 were obtained.

[Table] Example 2 A model of the ground was made by packing glass beads with various particle sizes listed in Table 2 into a filter cylinder, and then 80 parts by weight of magnesium acrylate, 18 parts by weight of hydroxyethyl acrylate, and 2 parts by weight of methoxyethyl acrylate.
A 30% aqueous solution of a monomer mixture consisting of parts by weight
Add 12 c.c. of an aqueous solution of 20% ammonium persulfate and 1 aqueous solution of 10% sodium thiosulfate as polymerization catalysts to 100 c.c.
cc, and 0.3 cc of a 10% red blood salt aqueous solution as a polymerization modifier were added and mixed well to obtain an anti-sludge agent. After this inhibitor was left at 20°C for 50 minutes, it was allowed to naturally permeate from the top of the ground model. After about 5 minutes, a temperature rise was observed, confirming the progress of the polymerization reaction of the aqueous monomer solution.
This seepage-hardened ground model was filled with muddy water and pressurized at a pressure of 7 kg/cm ³ . The amount of sludge water observed at that time was measured and compared with the case where no sludge prevention agent was used.

【table】

[Table] Example 3 Same as Example 2, 85 parts by weight of magnesium acrylate, 13 parts by weight of hydroxyethyl methacrylate,
To 100 c.c. of a 30% aqueous solution of a monomer mixture consisting of 2 parts by weight of ethoxyethyl acrylate, add a 10% aqueous solution of 20% ammonium persulfate in the amount shown in Table 3.
A red blood salt aqueous solution was added and mixed well to obtain a sludge prevention agent. This inhibitor was naturally infiltrated from the top of a ground model maintained at 40℃, 60℃, and 80℃. Under each condition, a temperature increase was observed, confirming the progress of the polymerization reaction. Then, the amount of sludge water was measured in the same manner as in Example 2.

[Table] Example 4 During on-site boring of a small hole diameter well A (hole diameter 5 7/8 inches), a sludge layer was encountered at a depth of 520 M (bottom circulation temperature 38°C). In order to prevent this slippage, 30% of the monomer mixture consisting of 85 parts by weight of magnesium acrylate, 13 parts by weight of hydroxyethyl methacrylate, and 2 parts by weight of ethoxyel acrylate was used.
20% ammonium persulfate 100% in aqueous solution 2000%
10% red blood salt 2.0 was added and stirred thoroughly to form an anti-sludge agent, and this was injected to the target depth. The filling amount at this time was 1740. Thereafter, it was left to stand still for 4 hours, and circulation of muddy water was started again. The amount of sludge water before injection of the above sludge prevention agent is 2260/
However, it was 40/hour after injection, and the effect of preventing sludge loss was extremely excellent. Example 5 During on-site boring of a small borehole diameter B well (hole diameter 5 7/8 inches), a sludge layer was encountered at a depth of 970M (bottomhole circulation temperature 69°C). In order to prevent this slippage,
200% ammonium persulfate was added to 2000 ml of a 30% aqueous solution of a monomer mixture consisting of 85 parts by weight of magnesium acrylate, 13 parts by weight of hydroxyethyl methacrylate, and 2 parts by weight of ethoxyethyl acrylate.
50 and 10% red blood salt 6.0 were added and mixed thoroughly, and the mixture was injected to the desired depth as an anti-sludge agent. The filling amount at this time was 1.820. After that, it was left to stand still for 4 hours and 30 minutes, and circulation of muddy water was started again. The amount of sludge water before using the sludge prevention agent of the present invention is:
It was 2710/hour, but after use it was 70/hour.
/ time, and the effect of preventing slippage was very excellent. Example 6 A ground model was made in the same manner as in Example 2 using glass beads with a diameter of 0.8 mm, and the amount of sludge water was measured in the same manner as in Example 2 using a sludge prevention agent with the composition listed in Table 4. As shown in Table 4, all of them had excellent sludge prevention effects.

【table】

【table】

Claims (1)

[Claims] 1. An anti-sludge agent for use in muddy water construction, characterized by comprising a monomer whose main component is a metal salt of α,β-monoethylenically unsaturated carboxylic acid and a polymerization catalyst thereof.