JP6566157B2 - How to wash wells - Google Patents

Description

  The present invention relates to a well cleaning method.

In the production field of water-soluble natural gas and iodine, a well (production well) for pumping up formation water (brine) in which natural gas and iodine are dissolved, and pressure is applied to the pumped brine to return it to the formation again (reduction) Wells (reduction wells) are provided for injection. In these wells, during use, dirt adheres to the inner wall of the well, and clogging occurs in a plurality of strainer holes and the formation connecting the inside and outside of the well. As a result, the flow path of the brine is blocked, and the pumping capacity and reduction press-fitting capacity of the well are reduced.

These clogging are particularly noticeable in the reduction well. In areas where ground subsidence due to the pumping of formation water is significant, there may be restrictions on the amount of water pumped from production wells and the amount of water that is reduced and injected into the formation. When the amount of water to be pumped is the same as the amount of water to be reduced and injected,
Since the amount of water to be pumped must be reduced as the amount of water that is reduced and injected is reduced,
The reduction in the capacity of the reduction well has a significant impact on the production capacity. Here, the dirt and clogging are caused by suspended solids in the brine and the accumulation of slime generated by the propagation of bacteria, and the slime must be removed to restore the well's ability.

Slime is mainly composed of biofilms formed by bacteria and minerals such as iron and silicon, and is sticky and strongly sticks in strainer holes and formations. Therefore, it cannot be removed unless a certain level of impact is applied. However, in order to remove slime by only mechanical cleaning or physical cleaning, equipment and work become large and there is a possibility that a sufficient cleaning effect cannot be obtained.

As conventional techniques for alleviating these problems, Patent Document 1 and Patent Document 2 disclose cleaning means using both physical cleaning and chemical cleaning.

In Patent Document 1, a cleaning agent containing a peroxide and a plurality of other compounds is introduced into a well, and a strainer and a gravel layer are formed in a deep underground by introducing a foaming aid or pressurizing the well with a pressure pump. A cleaning means for performing slime removal is disclosed.

Patent Document 2 discloses removal of deposits from wells and aquifers by injecting carbon dioxide and chemicals as energy for removing deposits into the wells and then pumping water back from the wells to reverse flow. A cleaning means for performing is disclosed.

JP 1987-182327 A Japanese Patent No. 4996808

In the cleaning means of Patent Document 1, it is necessary to prepare a plurality of compounds, and it is necessary to add a chemical directly into the well in order to avoid hydrolysis of peroxide. However, it is usually not easy to open a well that is sealed under pressure and to directly add a drug because it takes time and effort.

Further, in the cleaning method of Patent Document 2, the cleaning equipment must be newly installed in the well. However, in the case where the structure of the well does not correspond to the new cleaning equipment, or because the site around the well is small and large materials including the cleaning equipment cannot be installed, the cleaning method of Patent Document 2 is already installed. May not be applicable to wells. Furthermore, since it takes time and expense to install the cleaning equipment, it cannot be implemented in a short period of time and easily.

The present invention has been made in view of such problems, and an object of the present invention is to provide a well cleaning apparatus and method that can be implemented easily and efficiently.

  That is, the present invention is as follows.

[1] A well cleaning method comprising: a chemical injection step of introducing a chemical into a well; and a backwashing step of discharging water in the formation and the well to the ground.
[2] The well cleaning method according to [1], wherein the well is a well that conducts water containing one or both of water-soluble natural gas and iodine.
[3] The well cleaning method according to [1], wherein the well is a well that press-fits water containing one or both of water-soluble natural gas and iodine into the formation.
[4] The drug used in the drug charging step includes, as an active ingredient, an isothiazolone compound represented by the general formula (1), a halogenated aliphatic nitroalcohol represented by the general formula (2),
It contains at least one selected from the group consisting of a triazine compound represented by the general formula (3), hydrazine, triethanolamine, hydrogen peroxide, sodium hydroxide, and potassium hydroxide [ The well cleaning method according to any one of [1] to [3].
(Wherein, R ₁ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group or an aralkyl group, and X ₁ and X ₂ represent the same or different hydrogen atoms or halogen atoms)
(Wherein R ₂ represents a hydrogen atom, a halogen atom, a lower alkyl group, or a hydroxy lower alkyl group, R ₃ represents a hydrogen atom or a lower alkyl group, and X ₃ represents a halogen atom)
(In the formula, R ₄ and R ₅ represent the same or different ethyl group or isopropyl group)
[5] The isothiazolone compound represented by the general formula (1) is 5-chloro-2-methyl-4
-The well cleaning method according to any one of [1] to [4], which is isothiazoline-3-one.
[6] Any of [1] to [4], wherein the backwashing step sends compressed air from the compressor to the water in the well, causes the water in the formation to flow into the well, and discharges it to the ground. The method for cleaning wells according to the above.

Examples of the isothiazolone compound represented by the general formula (1) in the present invention include 2
-Methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 4,5-dichloro-
Examples include 2-octyl-4-isothiazolin-3-one and 1,2-benzisothiazolin-3-one.

Examples of the halogenated aliphatic nitroalcohol represented by the general formula (2) include 2-chloro-2
-Nitroethanol, 1-chloro-1-nitropropanol-2, 3-chloro-3-nitrobutanol-2, 2-chloro-3-nitrobutanediol (1,3), 1-chloro-1
-Nitrobutanol-2, 2-chloro-2-nitrobutanol, 2-chloro-2-nitropentanol-3, 2,2-dichloro-2-nitroethanol, 2-chloro-2-bromo-2-nitroethanol, 3-chloro-3-nitropentanediol (2,4), 4-chloro-4-nitrohexanol-3, 2-bromo-2-nitroethanol, 2-bromo-
2-nitropropanol, 2-bromo-2-nitropropanediol (1,3), 2-bromo-2-nitrobutanediol (1,3), 3-bromo-3-nitropentanediol (2,4), 2,2-dibromo-2-nitroethanol and the like can be mentioned.

Examples of the triazine compound represented by the general formula (3) include 2-methylthio-4-ethylamino-6-isopropylamino-s-triazine, 2-methylthio-4,6-bisethylamino-s-triazine, 2 -Methylthio-4,6-bisisopropylamino-s-triazine and the like.

  According to the present invention, a well cleaning method that can be easily and efficiently performed is obtained.

It is a block diagram which shows embodiment of this invention roughly, and is a figure explaining the washing | cleaning method of the well used in Example 8 and Comparative Example 4. FIG. It is a figure explaining the washing | cleaning apparatus of the evaluation 2. 10 is a flowchart showing a cleaning method used in Example 8. It is a figure explaining the washing | cleaning method of the well used in the comparative example 3. 10 is a flowchart showing a cleaning method used in Comparative Example 3. 10 is a flowchart showing a cleaning method used in Comparative Example 4. It is a graph which shows transition of the reducing capability of the well which implemented the washing | cleaning method used in Example 8, Comparative Example 3, and Comparative Example 4. FIG.

DESCRIPTION OF SYMBOLS 1 Reduction well 2 Casing pipe 2a Strainer part 3a 1st control valve (opening-closing means)
3b Second control valve (opening / closing means)
4 well entrance (ground side opening)
5 Pipeline 6 Press-in pump 6 'Temporary press-in pump 7 Lift pipe 8 High-pressure hose 9 Cleaning device 10 Slime input part 11 Filling part 12 Valve (opening / closing means)
13 Water reservoir 14 Temporary press-fitting line 15 Temporary waste liquid discharge line 16 Tubing steel pipe 17 Compressor 18 Existing sedimentation tank 19 Existing drainage tank B1 Gravel layer B2 Gravel layer B3 Gravel layer B'1 Contaminated part B'2 Contaminated part B'3 Part where dirt is accumulated

Hereinafter, although embodiment of this invention is described, this invention is not limited to this. FIG. 1 shows a schematic diagram of the reduction well 1 and the cleaning device 9 that perform cleaning according to the present embodiment. The reduction well 1 includes a casing pipe 2 made of a cylindrical steel pipe, and the casing pipe 2 includes a strainer portion 2a provided in a tip region. The strainer portion 2a includes a plurality of holes that penetrate the casing pipe 2 in the radial direction and connect the inner periphery and the outer periphery. The reduction well 1 is a well that injects water containing either or both of water-soluble natural gas and iodine into the formation.

The cleaning device 9 includes a lift pipe 7, a high-pressure hose 8, a compressor 17, an existing sedimentation tank 18, a press-fitting pump 6, a pipeline 5, a first control valve 3 a, a second control valve 3 b, and an existing drainage tank 19. Is mainly provided. The lift pipe 7, the high-pressure hose 8, and the compressor 17 are
This equipment is used for daily cleaning work.

The lift pipe 7 is made of a cylindrical steel pipe or synthetic resin, and is inserted by a predetermined length from the well port (ground side opening) 4 of the casing pipe 2 toward the ground. The well opening 4 of the casing pipe 2 is closed while maintaining airtightness with the lift pipe 7. The high pressure hose 8
It is attached to the well opening 4 of the lift pipe 7 while maintaining airtightness. Compressor 1
7 is connected to the end of the high-pressure hose 8 opposite to the end attached to the lift pipe 7, and feeds compressed air to the high-pressure hose 8. The compressed air flows into the lift pipe 7 through the high-pressure hose 8 and is discharged from the tip of the lift pipe 7 into the casing pipe 2.

The existing sand basin 18 has two roles. One is the role of temporarily storing water-soluble natural gas and brackish water pumped from a production well (not shown) and separated into gas and liquid in a collection tank (not shown), and the other is provided near the reduction well 1 It is the role which settles and removes the solid substance contained in brine. The brine pumped up from the production well is called production brine. The production brine is temporarily stored in the existing sedimentation tank 18. The inflow amount of the production brine and the liquid feed flow rate of the press-fitting pump 6 are controlled so that the liquid level in the existing sand basin 18 is kept constant. The press-fitting pump 6 press-fits the brine stored in the existing sedimentation tank 18 into the casing pipe 2 through the pipeline. As described above, the well port 4 of the casing pipe 2 is sealed while maintaining airtightness.
Brine water does not leak from the well 4 of the casing pipe 2. The first control valve 3a includes a flow meter (not shown), is provided on the pipeline between the press-fitting pump 6 and the casing pipe 2, and controls the inflow of brine into the casing pipe 2 by opening and closing, The amount of irrigation water flowing into the casing pipe 2 is measured. An existing drainage tank 19 is connected to the casing pipe 2 via a pipeline and the second control valve 3b. Second control valve 3
By opening and closing b, it is possible to control that the brine discharged in the backwashing step described later or the brine containing the chemical flows into the existing drainage tank 19. The existing drainage tank 19 temporarily stores brine. In addition, the existing sand settling tank 18, the press-fitting pump 6, the pipeline 5, the first control valve 3a, and the second control valve 3b allow the brine to flow into the reduction layer through the reduction well 1 during normal operation. Can also be used when As described above, since pressure is applied to the brine in the casing pipe 2 by the press-fitting pump 6, during normal operation so that the brine does not flow into the existing drainage tank 19 through the pipeline due to this pressure, The control valve 3b is closed.

The formation in which the reduction well 1 is provided will be described. In the illustrated example, the gravel layer B (B1
-B3) is the main reducing layer, and the other part is a layer with low water permeability, such as a mud layer, which is difficult for brine to flow. As shown in the figure, the strainer portion 2a of the reduction well 1 has a gravel layer B (B
1 to B3) is installed at a depth position, and dirt adheres to the strainer portion 2a and the gravel layer B ′ (B′1 to B′3) in the vicinity of the reduction well 1 and is clogged. The depth of the gravel layer B is referred to as well reduction depth.

A method for cleaning the reduction well 1 using the cleaning device 9 will be described. First, a chemical | medical agent is injected | thrown-in to the brine which press-fits in the reduction well 1, and is mixed (chemical | medical agent injection | pouring process). The method of introducing the chemical is not limited, for example, it is introduced into a sand settling tank installed on the ground or pumped to the middle of the press-fitting line. The drugs to be added are, as active ingredients, isothiazolone compounds represented by the general formula (1), halogenated aliphatic nitro alcohols represented by the general formula (2), triazine compounds represented by the general formula (3) , Hydrazine, triethanolamine, hydrogen peroxide, sodium hydroxide, potassium hydroxide as long as it is a drug containing one or more, but for the isothiazolone compound represented by the general formula (1), 5-chloro-2-methyl-4-
Those containing isothiazoline-3-one are more preferred. The concentration of the isothiazolone compound represented by the general formula (1) is 0.01 to 3.0% by weight, and the concentration of the halogenated aliphatic nitroalcohol represented by the general formula (2) is 0.1 to 1.3. % By weight, the concentration of the triazine compound represented by the general formula (3) is 0.05 to 0.1% by weight, and the concentration of hydrazine is 0.8.
1-3.0 wt%, triethanolamine concentration 0.01-0.1 wt%, hydrogen peroxide concentration 0.5-2.5 wt%, and sodium hydroxide and potassium hydroxide concentrations Is preferably 0.05 to 0.5% by weight, but may be other values. In addition, the density | concentration here shows the active ingredient density | concentration in the brine after adding a chemical | medical agent to a brine.

Next, with the lift pipe 7 in the reduction well 1, the valve 3a is opened and the valve 3b is closed. As a result, the brine containing the drug can be reduced and injected into the reduction well 1 without opening the well 4. Thereafter, the brine mixed with the medicine is injected into the reduction well 1 using the injection pump 6. This press-fitting operation may be performed while the drug is being added, or may be resumed after the press-fitting is temporarily stopped and the drug is poured into the brine to finish mixing. The injection pump 6 is stopped when a predetermined amount of irrigation water is injected after the chemical is introduced, the valve 3a is closed, and the reducing well 1 is sealed.

Next, the high-pressure hose 8 and the lift pipe 7 are connected, compressed air is sent from the compressor 17 into the reducing well 1, the valve 3b is opened, and the reaction mixture in the formation and reducing well 1 is mixed with the brine solution. Discharge to the ground drainage tank (back washing process). This is called backwashing work, and by this operation, dirt and clogging in the gravel layer B, the strainer portion 2a, and the reduction well 1 are removed along with the flow of water and discharged to a ground drainage tank.

  Hereinafter, the present invention will be described by way of examples, but this does not limit the present invention.

<< Evaluation 1: Slime embrittlement experiment >>
First, the slime embrittlement effect of the drug was evaluated. The evaluation method is as follows. In addition, although the evaluation method using the chemical | medical agent of Example 1 is shown here, other Examples 2-4, 6 and 7 , Comparative Examples 1-2 , and the reference example were also evaluated on the same conditions.

[Evaluation method]
The slime was collected from the reduction well 1 and the equipment attached thereto and used. A slime solution prepared by adding 4 g of slime, which was centrifuged twice at a rotational speed of 2000 rpm for 5 minutes, into a screw-tube bottle, diluting 0.05 g of Conlime C-3 with 50 g of brine and adjusting the drug concentration to 0.1% by weight. The whole amount was added until it soaked. At this time, the slime was a lump of about 2 cm in diameter. This was allowed to stand in a thermostat at 30 ° C. for 48 hours, and then evaluated as follows from the slime shape and the slime sedimentation speed after the screw tube bottle was turned upside down 10 times. In the case of evaluation C at a drug concentration of 0.1% by weight, the drug concentration was increased and the evaluation was performed again. The pH of the brine used was 7.40.
Evaluation A: Applicable to any of the following (1) to (2) (1) There is no bulky slime before stirring, and the sedimentation rate is the sedimentation rate of slime that has been subjected to the above operation without adding a chemical (hereinafter referred to as “slime”). , Blank), pH after treatment is 6.0 to 8.5 and no generation of oxygen gas (2) The sedimentation rate is the sedimentation rate of slime (hereinafter referred to as blank) after the above operation without adding a chemical. ) Slower, pH after treatment of 6.0 to 8.5 and no generation of oxygen gas Evaluation B: Applicable to any of the following (3) to (5) (3) Bulk slime before stirring No, but after treatment the pH falls outside the range of 6.0 to 8.5 or oxygen gas is generated (4) There is no bulky slime before stirring, but the sedimentation rate is faster or the same as blank ( 5) Sedimentation rate is slower than blank, but after treatment What H is the occurrence of outside or oxygen gas in the range of 6.0 to 8.5

Evaluation C: There is a massive slime before stirring, and the sedimentation speed is faster than or the same as blank

<< Evaluation 2: Cleaning experiment >>
Subsequently, the slime cleaning effect was evaluated. The specifications of the device and the evaluation method are as follows.
[Device specifications]
Referring to FIG. 2, the apparatus used in evaluation 2 mainly includes a water reservoir 13, a slime charging unit 10, a filling unit 11, and a valve 12. Each component of the device is made of vinyl chloride and is connected to each other by flange fastening. The filling portion 11 is filled with a filler made of φ5 mm alumina balls at a filling rate of 65.2% (in-container porosity 34.8%). The slime input part 10 has a dimension of 2
The dimension of 5A × 535 mm and the filling portion 11 is 25A × 585 mm. The alumina ball filling rate was set equal to the formation porosity around the reduction well 1.
[Evaluation method]
The slime was collected from the reduction well 1 and the equipment attached thereto and used. 100 g of slime, which was centrifuged twice at a rotational speed of 2000 rpm for 5 minutes, was charged into the slime charging unit 10 and an aqueous solution prepared to the same drug concentration as in Evaluation 1 was added so that the total amount of slime was immersed. This was allowed to stand in a room at 20 ° C. for 48 hours, and then the valve 12 was opened and the water stuck in the water reservoir 13 was allowed to flow, and the flow rate of water discharged through the filling portion 11 was measured. At this time, the water surface of the water reservoir 13 was kept constant, and the water head pressure was kept constant. The water head pressure here is the slime input part 1
This is the water pressure at the upper surface of 0, in other words, at the boundary between the water reservoir 13 and the slime charging unit 10.

Table 1 shows the results of Evaluation 1 and Evaluation 2. Table 1 shows the drug names, active ingredients, and slime embrittlement experimental results of various drugs related to Evaluation 1, with respect to Examples 1 to 4, 6 and 7, Comparative Examples 1 to 2 and Reference Examples, and Evaluation 2 The result of the chemical | medical agent evaluated in Example 1 regarding (cleaning simulation experiment) and the result when a chemical | medical agent is not added (comparative example 3) are shown. It turns out that the chemical | medical agent containing the active ingredient in this invention is excellent in the embrittlement effect of slime. Moreover, since the discharge | emission flow volume when water head pressure is made constant is large, it turns out that slime was removed and the resistance at the time of water supply became small.

<< Evaluation 3: Reduction well cleaning experiment >>
The cleaning method according to the present invention using the drug of Example 1 is set as Example 8, the drug cleaning method for a general well using the drug of Comparative Example 1 is set as Comparative Example 3, and the reverse that has been carried out on a daily basis in the past. A cleaning method using only washing was applied as a comparative example 4 to the reducing well 1 shown below.
Reduction well 1: Average amount of reduced water 30m ³ / h, reduction depth 518-544m, bore diameter 210mm

(Example 8)
A method for cleaning the reduction well 1 according to Example 8 will be described with reference to FIGS.

First, the valve 3a was opened, the valve 3b was closed, and it was confirmed again that the normal operation state in which the press-fitting pump 6 was operating, and work was started. In step S31, a predetermined amount of chemical was put into the existing sand settling tank 18. At this time, since the production brine is constantly supplied to the existing sand basin 18, the brine and chemicals in the existing sand basin 18 are diluted by mixing. At the same time, the injection of the irrigation water into the reduction well 1 by the injection pump 6 is continued, but the irrigation water containing the chemical, that is, the chemical liquid does not reach the injection pump suction port immediately. The concentration of was adjusted. The amount of chemicals to be charged is calculated in consideration of the point corresponding to 1000 ppm with respect to the volume of the reduction well 1 and the amount of water extending from the outer circumference of the reduction well 1 to the outside 2 m and the dilution in the existing sand settling tank 18. It was done. Here, the volume of the reduction well 1 was calculated based on the diameter and length of the reduction well 1. In addition, the amount of water that spreads from the entire outer periphery of the reduction well 1 to the outer side 2 m was calculated based on the surface area where the strainer and the formation were in contact.

The chemical | medical agent thrown into the existing sand settling tank 18 in step S31 reached | attained the suction port of the reduction pump with progress of time, and moved to step S32 automatically. The chemical solution was pumped into the casing pipe 2 by the press-fitting pump 6. Further, as time elapses, step S is automatically performed.
33, the chemical solution reached the well reduction depth, filled the inside of the reduction well 1, and penetrated into the gravel layer B through the strainer part 2a.

Next, in step S34, it was determined whether or not a predetermined amount of brine was injected by using a flow meter provided in the first control valve 3a. If not press-fitted, the process returns to step S32, and steps S32 to S34 are repeated. On the other hand, when press-fitting, the process has proceeded to step S35.

In step S35, the press-fitting pump 6 was stopped, the injection of the chemical solution was stopped, and left for a predetermined time. At this time, the valve 3a was closed. Further, since the valve 3b is kept closed from the start of work, the reduction well 1 is in a sealed state. Thereby, since the chemical | medical solution was left still in the state which osmose | permeated the inside of the gravel layer B and the strainer part 2a, the adhering slime became embrittled.

In the next step S <b> 36, the compressed air generated by the compressor 17 was sent into the reduction well 1 through the lift pipe 7. This is called lift air supply. Thereby, the density of the brine in the casing pipe 2 falls, and becomes lower than the density of the brine in the gravel layer B. Due to the difference in density between the brine in the casing pipe 2 and the brine in the gravel layer B, the brine in the gravel layer B flows into the casing pipe 2. Here, by the processing in step S35,
The slime adhering to the gravel layer B and the strainer portion 2a is embrittled. Therefore, the slime adhering to the gravel layer B and the strainer portion 2a peels off and flows into the casing pipe 2 due to the water flow of the brine flowing into the casing pipe 2. The slime then lifts the casing pipe 2 with the brine by the pressure of the lift air supply,
It flows into the existing drainage tank 19 through the second control valve 3b.

In step S <b> 37, the brine containing the slime was collected through the existing drainage tank 19.
The recovered brine was called recovered liquid and met the drainage standards for general wastewater. Therefore, it was able to drain into rivers etc. as general waste water without chemical treatment. Step S
If the process by 37 is continued, the ratio of slime and chemicals in the recovered liquid will be reduced.
Most of the recovered liquid became brine, sand, and slime in the formation.

Then, after the ratio of slime and chemical solution in the recovered liquid is reduced, and most of the water becomes brine, sand and slime in the formation, in step S38, the lift air supply is continued and the drainage by lift cleaning is predetermined. Went for a period. After a predetermined period, lift air supply was stopped and the process was terminated. After the processing was completed, the first control valve 3a was opened, the second control valve 3b was closed, and the press-fitting pump 6 was started to resume the reduction, and returned to the normal operation state.
(Comparative Example 3)

  A cleaning method for the reduction well 1 according to Comparative Example 3 will be described with reference to FIGS.

The cleaning method of the reduction well 1 according to the comparative example 3 cannot be performed with the equipment during normal operation shown in FIG. For this reason, first, in step S501, jigs and large materials dedicated to this cleaning method were installed, and a vehicle for transporting and lifting materials and the like was mobilized. Next, in step S502, after stopping the press-fitting pump 6 (not shown), the valves 3a and 3b were closed.
Further, the well 4 was opened, the reduction well 1 was opened, and a lift pipe (not shown) permanently installed in the reduction well 1 was pulled up.

Next, the tubing steel pipe 16 was lowered to the reduction depth of the reduction well 1 in step S503. The length of the tubing steel pipe 16 is generally about 9 to 10 m per piece, and both ends have a screwed structure so that they can be connected together. The operation of joining the tubing steel pipes 16 and the descending work of the tubing steel pipes 16 were repeated, and the tubing steel pipes 16 were lowered to the reduction depth. At this time, the tip 23 of the high-pressure hose 8 was connected in the middle of the tubing steel pipe 16. The position of the connecting portion between the tubing steel pipe 16 and the tip 23 was changed according to the situation.

Next, in step S504, the stock solution of the drug was diluted with brine in a temporary working solution tank 21 on the ground to prepare a drug solution with a predetermined concentration. In step S505, the chemical solution is supplied to the temporary press-fitting line 1 connected to the ground portion of the tubing steel pipe 16 by the temporary press-fitting pump 6 ′.
4 was sent to the reduction well 1. In step S506, the chemical solution reached the well reduction depth, filled the inside of the reduction well 1, and penetrated into the gravel layer B through the strainer portion 2a. Next, in step S507, it was determined whether or not a predetermined amount of chemical solution was fed using a flow meter (not shown) provided in the temporary press-fitting line 14. If not, the process returns to step S504, and steps S504 to S507 are repeated. On the other hand, when liquid feeding is in progress, the process proceeds to step S508.

In step S508, the temporary press-fit pump 6 ′ was stopped and the temporary press-fit line 14 was removed. At this time, since the tubing steel pipe 16 and the high-pressure hose 8 are installed in the reduction well 1, a special jig is attached to the well 4 to seal the reduction well 1. In this state, the reducing well 1 was allowed to stand for a predetermined period. The predetermined period was at least one night.

In the next step S509, the chemical solution that has permeated into the reduction well 1 and the surrounding formation was recovered from the tubing steel pipe 16 via the temporary waste liquid discharge line 15 to the temporary waste liquid tank. More specifically, the tubing steel pipe 16 and the temporary waste liquid discharge line 15 are connected, and the end of the high-pressure hose 8 that is not connected to the tubing steel pipe 16 is connected to the compressor 17.
The compressed air from the compressor 17 was sent into the tubing steel pipe 16, and the compressed air was fed from the tip 23 into the tubing steel pipe 16 (tubing lift process).
. In the tubing lift process, the chemical density in the upper part of the tubing steel pipe 16 out of the chemical liquid filling the tubing steel pipe 16 was reduced, and the chemical liquid was discharged from the temporary waste liquid discharge line 15 to the temporary waste liquid tank 22. Further, by continuing the tubing lift process, the amount of water equivalent to the amount of water discharged from the temporary waste liquid discharge line 15 is continuously increased from the formations B1 to B3 or the formations B′1 to B′3. 2 is continuously fed into the tube 2 and then flows into the tubing 16. This is called a tubing lift effect. By repeating the above continuously, the chemical solution in the tubing steel pipe 16 and the casing pipe 2 and the chemical solution that has penetrated into the formation B are transferred from the tubing steel pipe 16 via the temporary waste liquid discharge line 15 to the temporary waste liquid tank. 22 recovered. The chemical solution collected in the temporary waste liquid tank 22 is referred to as a discharged liquid. In addition, the amount of the discharged chemical solution was measured using a flow meter (not shown) provided in the temporary waste liquid discharge line 15. By sending compressed air into the tubing steel tube 16,
The chemical solution inside the casing pipe 2 and the chemical solution that has penetrated into the formation B are the tubing steel pipe 16.
It is called lift effect that it is discharged from.

In step S510, it is determined whether the temporary waste liquid tank 22 is filled with the discharged liquid,
If not satisfied, the process executes step S509 again, and if satisfied, the process proceeds to step S511. In step S511, the effluent was treated as industrial waste.

In the next step S512, it was determined whether or not the discharged liquid of substantially the same amount as the delivered chemical was collected. If not collected, the process re-executes steps S509 to S512, and if collected, the process proceeds to step S513.

In step S513, the composition of the discharged liquid was inspected to determine whether or not the obtained composition was substantially the same as the composition of the brine before work. If they are not substantially the same, the process proceeds from step S509 to S513.
If the process is substantially the same, the process proceeds to step S514, where it is determined that all of the chemicals that have been sent are collected on the ground, and that all the interior of the reduction well 1 has been replaced with brine. After confirming that all of the injected chemicals were discharged and that all of the reducing well 1 was replaced with brine, all the discharged liquid in the temporary waste liquid tank 22 was treated as industrial waste, and the discharge work was completed. .

In the next step S515, the temporary waste liquid discharge line 15 was disconnected, and the tubing steel pipe 16 and the high-pressure hose 8 installed in the reduction well 1 were lifted from the reduction well 1. And in step S517, after performing the restoration work in the vicinity of the reduction well 1 and the reduction well 1, the well 4 was sealed and the temporary equipment was removed. Then, the process was finished. After the processing is finished, the second control valve 3
In the closed state b, the first control valve 3a was opened and the press-fitting pump 6 (not shown) was started to return to the normal operating state.
(Comparative Example 4)

  A cleaning method for the reduction well 1 according to Comparative Example 4 will be described with reference to FIGS.

First, in step S61, the press-fitting pump 6 was stopped, the first control valve 3a was closed, the reducing well 1 was sealed, and the high-pressure hose 8 and the lift pipe 7 were combined. Thereafter, the first control valve 3
Open b.
In the next step S62, compressed air was sent from the compressor 17 into the reducing well 1, and the gravel layer B and the brine in the reducing well 1 were collected in the existing drainage tank 19 on the ground. Here, the recovered liquid in the existing drainage tank 19, that is, the wastewater drained in the backwashing step is referred to as backwashing water. Backwash water has confirmed that it meets the drainage standards for general wastewater based on previous knowledge. Therefore, in step S63, the recovered liquid was drained as general waste water without being chemically treated. When draining backwash water as general waste water, it is necessary to perform a predetermined water quality analysis. Therefore, in step S64, the water quality analysis of the waste water was performed at a predetermined location and time. In step S65, lift cleaning in the backwashing process was continued, and after a predetermined period, lift air supply was stopped and the process was terminated. After the processing is completed, the second control valve 3b is closed, and the first control valve 3
A was opened, and the press-fitting pump 6 (not shown) was started to return to a normal operation state.

Table 2 shows the workload of Comparative Example 3 and Example 8. The cleaning of Comparative Example 3 requires a large scale and cost because it requires the preparation of dedicated jigs and large materials, and the use of tubing steel pipes. On the other hand, the cleaning of Example 8 according to the present invention does not require these facilities and operations, and can be performed using facilities used in daily cleaning operations. The amount of work can be greatly reduced. In addition, the expense of Table 2 displayed the washing expense of Example 8 as 1.

Furthermore, the effluent in Comparative Example 3 must be effluent treated as industrial waste by law. In the drainage process, the processing amount is determined by the capacity of the processing equipment. On the other hand, since the volume of the temporary waste liquid tank 22 is restricted due to restrictions such as the area of the work site, there is a limit to the storage amount of the discharged liquid. Therefore, when the amount of drainage collected in the temporary waste liquid tank 22 exceeds the drainage processing amount, there is a possibility that the drainage cannot be continuously collected. On the other hand, the effluent in Example 8 is
Since the wastewater standards for general wastewater were met, washing could be continued continuously without being limited by the amount of drainage.

FIG. 7 shows the reducing ability before and after cleaning in Example 8, Comparative Example 3, and Comparative Example 4. The reducing ability here is represented by the ratio between the flow rate when water is injected into the gravel layer B and the wellhead pressure, and the larger the value, the higher the ability. Here, the wellhead pressure is the pressure of the wellhead 4. The wellhead pressure in the reduction well 1 is indicated by the differential pressure between (failure around the reduction well 1 + formation pressure) and (pressure-injection pump discharge pressure + head pressure in the reduction well 1). Represents difficulty in handling. Here, the formation pressure is the pressure of the gravel layer B, the head pressure is the water pressure at the water surface in the reduction well 1, and is in a stationary state, that is, when the press-in pump 6 is not moved, and no lift air is supplied. When the water level in the reduction well 1 does not change, formation pressure and head pressure are kept equal. The pressure of the press-fit pump that is reduced to the reduction well 1 is kept substantially constant as long as the mechanical operating conditions are not changed. Moreover, the water head pressure and the formation pressure in the reduction well 1 are the original characteristics of the reduction well 1, and the change is minute. That is, when there are many obstacles around the reduction well 1 and it is difficult to reduce, the apparent wellhead pressure is greatly indicated. On the contrary, the clogging in the strainer part 2a and the gravel layer B is removed, and the easier the reduction, the smaller the wellhead pressure is indicated. In other words, even if the flow rate at the time of reduction is equal, the smaller the wellhead pressure, the higher the reduction ability.

In the cleaning according to Example 8, it can be seen that the reducing ability of the reducing well 1 is greatly recovered as compared with Comparative Example 3 and Comparative Example 4. Moreover, the high capability is maintained even after several months of cleaning, and it can be seen that the cleaning effect is persistent.

As described above, in the cleaning method according to the present invention, as an active ingredient, an isothiazolone compound represented by the general formula (1), a halogenated aliphatic nitroalcohol represented by the general formula (2), and a general formula (3) By using a chemical containing one or more of the triazine compounds represented by the formula, hydrazine, triethanolamine, hydrogen peroxide, sodium hydroxide and potassium hydroxide, the slime fixed on the inner wall of the well and in the formation It becomes easy to peel off, and a sufficient cleaning effect can be obtained with only energy for discharging the water in the formation and well to the ground.

According to the present invention, it is possible to carry out cleaning of the formation and the well interior more easily and with higher efficiency than before.

An isothiazolone compound represented by the general formula (1), a halogenated aliphatic nitro alcohol represented by the general formula (2), a triazine compound represented by the general formula (3), hydrazine, triethanolamine, peroxide A medicine containing one or more of hydrogen, sodium hydroxide, and potassium hydroxide has a bactericidal and algaecic action and is widely used as a bactericidal agent for cooling water.
Examples of commercially available fungicides include Contelim C-3 (Diaqua Solutions), Olgard T-819K (Organo), Takurin OSR (Kurita Industry), and the like. In the present invention, these chemicals are used to sterilize microorganisms in the slime and destroy the biofilm, thereby facilitating peeling of the slime fixed on the inner wall of the well or in the formation. Also,
Since chemicals are not easily decomposed in water, it is not necessary to put them directly into the well, and they can be put into the normal production or press-fitting line and sent into the well, thus eliminating the need to open the well.

Furthermore, in the backwash process, a large cleaning effect can be obtained only with the energy that drains the water in the formation and well to the ground, so there is no need to lift a lift pipe or install large-scale equipment in a short period of time. Can be cleaned. In addition, it is not necessary to install equipment necessary for cleaning in the well, and cleaning of the existing well can be easily started.

According to the present invention, cleaning of a well can be easily performed with high efficiency, clogging in a strainer hole and a formation is eliminated, and an improvement in well capacity can be obtained.

In addition, although this embodiment demonstrated using the reduction well 1, this invention may be applied not to the reduction well 1 but to a production well. The production well is a well that conducts water containing either or both of water-soluble natural gas and iodine. In step S35, the reducing well 1 is allowed to stand at least overnight. However, the standing period is not limited to one night, and may be a period sufficient for the chemical liquid to embrittle the slime.

The reducing layer is not limited to the gravel layer. Moreover, the arrangement of the gravel layer described in FIGS. 1 and 4 is merely an example, and the present invention can be applied to other formations.

The size of each member shown in the present specification and the drawings is an example, and is not limited to these sizes. Moreover, the material of each member is an illustration, Comprising: It is not limited to these materials. While embodiments of the present invention have been described with reference to the accompanying drawings, it will be understood by those skilled in the art that modifications may be made to the structure and structure of each part without departing from the scope and spirit of the described invention. It is self explanatory.

Claims (5)

Including a chemical injection step of introducing a chemical into the well and a backwashing step of discharging the water in the formation and well to the ground,
The chemical used in the chemical injection step is an isothiazolone compound represented by general formula (1), a halogenated aliphatic nitroalcohol represented by general formula (2), or a general formula (3) as an active ingredient. A well cleaning method comprising one or more selected from the group consisting of a triazine compound, hydrazine, triethanolamine, sodium hydroxide, and potassium hydroxide .
(Wherein, R ₁ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group or an aralkyl group, and X ₁ and X ₂ represent the same or different hydrogen atoms or halogen atoms)
(Wherein R ₂ represents a hydrogen atom, a halogen atom, a lower alkyl group, or a hydroxy lower alkyl group, R ₃ represents a hydrogen atom or a lower alkyl group, and X ₃ represents a halogen atom)
(In the formula, R ₄ and R ₅ represent the same or different ethyl group or isopropyl group)   The well cleaning method according to claim 1, wherein the well is a well that conducts water containing one or both of water-soluble natural gas and iodine.   The well cleaning method according to claim 1, wherein the well is a well that press-fits water containing one or both of water-soluble natural gas and iodine into the formation. Well cleaning method according to any one of claims 1 to 3, isothiazolone compound represented by general formula (1) is characterized in that it is a 5-chloro-2-methyl-4-isothiazolin-3-one . The well according to any one of claims 1 to 4 , wherein the backwashing step sends compressed air from the compressor to the water in the well, causes the water in the formation to flow into the well, and discharges it to the ground. Cleaning method.