JP2001020653A - Casing patching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which the casing leakage of a deep well or the like can be repaired in a short time without reducing a casing diameter as a pipe-in-pipe in the repair of the casing leakage. SOLUTION: In the casing pating method, a packer 1 in which a mold- releasing film layer is formed onto the outer circumferential surface of the expanded rubber element of the packer 1 and a glass mat-roving cloth 3 layer impregnated with an underwater curable resin is formed onto the mold-releasing film layer is lowered to the position 14 of casing leakage in a well previously investigated and confirmed by a high-pressure hose 5, the expanded rubber element 2 of the packer 1 is expanded through the high-pressure hose, controlling pressure to a gas cylinder, the underwater curable resin is cured, the expanded rubber element 2 is shrunk by degassing, only the packer body is pulled up, and cured glass mat-roving cloth 3 impregnated with the underwater curable resin is stuck at the position of the casing leakage and the casing leakage is repaired.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water well, a gas well,
Casing patch for hot spring wells, reduction wells, etc., that is, when a hole that causes leakage of water, earth and sand, etc. occurs in part of the buried pipe of a vertically buried water well, etc., this hole is quickly closed. Concerning the construction method.

[0002]

2. Description of the Related Art According to Japanese Unexamined Patent Publication No. 4-353190, the packer method is a method in which a chemical solution such as mortar is injected under pressure into the ground to block the backflow of the chemical solution in order to prevent backflow of the chemical solution. It is described that a packer device is used in a general term of the methods.

[0003] Steel materials such as iron pipes and resin products such as FRP are generally used as construction materials for water wells and the like.
Due to long-term use of these construction materials, holes with a diameter of several millimeters or tens of millimeters or cracks with a length are generated, causing a large amount of water to flow into water wells, inflow of sediment, and the original mission of the well. May significantly inhibit.

Conventionally, companies and municipalities that own water wells or the like have to perform interior piping work to repair casing leaks in such a case, and inevitably install a slightly smaller pump to continue operation. Is the actual situation.
For example, in order to repair a casing leak, if a slightly smaller interior pipe is to be constructed, it will require several millions of construction costs depending on the depth, but it will require negative costs due to a decrease in the capacity such as pumping capacity. The effect is great.

[0005] As a rehabilitation technique for sewer pipe drainage buried underground, an EPR method using an EPR method repair material (a composite material based on an epoxy resin) was approved in 1993 as a sewerage technology / technical examination certificate No. 0503. ing. In this method, a composite material impregnated with EPR No. 2 resin in a reinforced material is wound around the outer circumference of a foil tube, sent laterally to a culvert repair site, compressed by air pressure, and after the composite material is cured, the foil tube is removed and removed. Things.

The casing patch method of the present invention differs from the above-mentioned method in that it must be carried out under a high water pressure of several hundred meters below the surface of the water, so that a glass mat roving using a vertical packer is required. The problem of drop-off prevention when the cloth descends and the detachment of the packer after the underwater-curable resin is cured, and also the problems of heavy-duty packers and suspension facilities and the pressurized system facilities of the expanding rubber element, and the target depth of the packer There are many problems related to the improvement of suspension accuracy.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned situation of repair of casing leaks in water wells and the like, the present inventors have significantly reduced the construction cost of new interior pipe work and reduced the initial facility capacity. As a result of an effort to create a casing patch method that can be repaired without lowering, it has been found that the above object can be achieved by some improvements in the use of a water-curable resin.

[0008]

That is, the present invention provides a glass mat / roving cloth layer in which a release film layer is formed on the outer peripheral surface of an expanded rubber element of a packer, and a water-curable resin is impregnated on the release film layer. The packer formed is lowered by a high-pressure hose to a casing leak position in the well which has been checked and checked in advance, and the expansion rubber element of the packer is controlled via the high-pressure hose while controlling the gas cylinder pressure or the water pumping pressure. After the underwater-curable resin is cured, the expanded rubber element is contracted by degassing or dewatering, the packer body alone is pulled up, and the underwater-curable resin-impregnated cured glass mat / roving cloth is leaked from the casing. Casing patch that is attached to a location and repairs casing leaks It is intended to provide the law.

In the present invention described above, it is preferable to apply a water-curable resin liquid mixed with a thickener on a release film.

Preferably, the underwater curable resin is an epoxy resin or a urea resin.

Preferably, the water-curable resin is an epoxy resin and the thickener is sepiolite.

The length of the glass mat / roving cloth layer is preferably 2000 mm or less and 500 mm or more.

The glass mat / roving cloth has a glass mat layer and a roving cloth layer alternately formed,
The three glass mat layers and the two roving cloth layers make the total basis weight of the glass mat layers 300 to 900.
g / m ² , total weight of roving cloth layer 500
９００900 g / m ² , and the total basis weight is 800-18.
It is preferably 00 g / m ² .

It is preferable that rubber guides are attached to the upper and lower sides of the packer.

It is preferable that the high-pressure hose serves to support the packer body, move the packer up and down, and supply nitrogen gas to the packer.

Preferably, the release film layer is a polyolefin film or a vinyl chloride film, and the polyolefin film is a polyethylene film.

Preferably, the gas in the gas cylinder is selected from the group consisting of nitrogen gas, helium gas, argon gas, oxygen and air.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the general shape of a packer used in the present invention will be described. The packer shown below is an example for illustrating the technical idea of the present invention, and can be appropriately changed according to the scale of a water well or the like.

FIG. 1 shows an outer diameter of 178 mm and a length of 2470 m.
FIG. 4 is a diagram showing the outer diameter of a single packer having a length of 2700 kgf / cm ² when an internal pressure of ² to 8 kgf / cm ² is applied to a certain type of expanded rubber element (length: 1700 mm). It is attached. In this example, the outer diameter of the expansion rubber element 2 is 2 kg.
This indicates that the gas expands to 200 mm at a gas pressure of f / cm ² and 300 mm at 8 kgf / cm ² .

FIG. 2 also shows that an expanded rubber element having a length of 1700 mm is reduced to about 1670 mm at a gas pressure of ² kgf / cm ² and 1570 m at 8 kgf / cm ² with expansion.
It is shown to shrink to about m. In this single packer 1, an expansion rubber element is fixed at a fixing point 3.

In the packer employed in the present invention,
A release film layer is formed on the outer peripheral surface of the expanded rubber element. The release film layer is a glass mat / roving cloth impregnated with a water-curable resin described below formed on the release film layer, and after the water-curable resin is cured, the gas is released to shrink the expanded rubber element. This is for releasing the cured underwater-curable resin-impregnated glass mat / roving cloth using this layer as an interface.

As the film suitable for such a purpose of use, any material can be used as long as it satisfies the purpose of use. For example, a polyolefin-based film and a vinyl chloride-based film are preferred. For example, a material having a thickness of 30 to 100 μm and suitable for the purpose of use of the above-described expanded rubber element is selected, and among them, a polyethylene film is generally used.

In the present invention, on the release film layer,
It is preferable that a thickener such as sepiolite is mixed with a water-curable resin such as an epoxy resin and applied, and this step will be described later.

The present invention is particularly characterized in that a glass mat / roving cloth impregnated with a water-curable resin is mounted on a release film layer.

As the former material of the above-mentioned glass mat and roving cloth, a chopped strand glass mat is preferably used. Strands cut to a predetermined length are dispersed in random directions and laminated to a uniform thickness. , Formed in a mat shape to maintain strength in all directions.

The roving cloth is, for example, a bundle of glass filaments having a diameter of 10 to 15 μm, which are bundled into strands, which are uniformly aligned so as to have a predetermined count. , To increase the strength in the horizontal direction.

The most preferred glass mat / roving cloth is formed by alternately forming a glass mat layer and a roving cloth layer. For example, three glass mat layers and two roving cloth layers form Generally, the basis weight is 300 to 900 g / m ² , the total weight of the roving cloth layer is 500 to 900 g / m ² , and the overall basis weight is 800 to 1800 g / m ² . Needless to say, it is changed depending on the scale, purpose, and repair specifications. The preferred glass mat and roving cloth described above are those of 3G2R in which three layers of glass mat (3G) and two layers of roving cloth (2G) are formed by alternately laminating glass mats and roving cloth. It is confirmed that the use of such a 3G2R glass mat / roving cloth is preferable. In the case of a 2G1R laminate using a two-layer glass mat and a one-layer roving cloth having the same basis weight, about 3 kgf / cm ^2. The liquid-containing epoxy resin leaks at a pressure of, while the 4G3R laminate similarly laminated, when the packer is erected, falls off due to its own weight even when the underwater curable resin mixed with the thickener is used. This is because there is a tendency. However, such 3G2
It goes without saying that the adoption of the R laminated body can be changed by changing the use of each constituent material.

The underwater curable resin for impregnating a glass mat or roving cloth is used for the purpose of the present invention.
Any composition that can be cured in water can be used, and is not specified.

However, bisphenol A
Suitable examples include an epoxy resin containing a modified epoxy resin as a main component and a modified polyamine and a modified aromatic polyamine as a curing agent, and a polyurea resin containing an aromatic polyamine as a main component and a hexamethylene diisocyanate as a curing agent.

The above-mentioned epoxy resin is generally used as a mixture of the main agent 2 and the curing agent 1 in a weight ratio. For the purpose of use, JWWA-K of the Japan Water Works Association is used.
It is necessary to clear the resin dissolution test of -135, and since the safety of the epoxy resin is proved, the casing patch method can be applied to wells for drinking water.
Such a resin is used in water, for example, at a water temperature of 14 ° C. and about 24 ° C.
It can be cured within hours.

As a curing agent for the epoxy resin, a modified polyamine, a modified aromatic polyamine or the like is usually used, and the curing is not accelerated by the addition of a usual additive such as an amine.

If necessary, a thickening agent is further added to the epoxy resin obtained by mixing the above-mentioned main ingredient and curing agent to prepare an impregnating composition of a water-curable resin, which will be described in detail later.

As the polyurea resin used as the underwater curable resin, a resin mainly containing an aromatic polyamine and a curing agent containing hexamethylene diisocyanate is generally used. Used.

As a method of forming the glass mat / roving cloth layer by impregnating the underwater curable resin, as described above, the glass mat layer and the roving cloth layer are alternately formed, and the underwater curing is usually performed for each layer. A method of impregnating a conductive resin is employed. That is, a glass mat or a roving cloth layer is impregnated with a water-curable resin, a roving cloth layer or a glass mat layer is formed thereon, and the water-curable resin is impregnated, and a similar layer formation and impregnation operation is performed. A predetermined layer is formed.

The total impregnation amount of the underwater curable resin in the underwater curable resin-impregnated glass mat / roving cloth layer formed as described above is 300 to 450 g / m ^2.
, And the total basis weight of the overall basis weight 800~1800g / m ² of the glass mat-roving cloth becomes 1100~2250g / m ^2.

Thus, in one example, the total weight of the underwater curable resin impregnated glass mat roving cloth layer is:
For example, it is about 3 to 5 kg per packer.

When the underwater curable resin glass mat / roving cloth having such a weight is directly wound on a release film formed on the outer peripheral surface of the expanded rubber element of the packer to form a glass mat / robink layer. Is often observed to fall off due to the weight of the formation layer.

Therefore, in the casing patch method of the present invention, for example, a thickener such as sepiolite is mixed with a liquid amount of about 1/10 of the underwater curable resin liquid for impregnation to increase the viscosity. It is preferable to apply a mucus on the release film, and then wind a glass mat / roving cloth impregnated with a water-curable resin.

A thickening agent such as sepiolite is added to a mixed composition of an epoxy resin, a polyurea resin, or the like obtained by mixing the above-described main agent and a curing agent with respect to 100 parts by weight of the mixed composition.
It is preferable to mix 5 to 40 parts by weight, preferably 30 to 35 parts by weight, and apply the mixture so that the surface of the glass mat / roving cloth does not protrude. Thus, the impregnated underwater curable resin is prevented from flowing out of the glass mat / roving cloth and the glass mat / roving cloth layer is prevented from falling off.

As a method for fixing the glass mat / roving cloth to the packer, other methods may be adopted, but it is not preferable to use a mechanical process method for removing the packer after curing of the underwater curable resin.

The underwater curable resin-impregnated glass mat / roving cloth prepared as described above is wound on a release film layer coated with an underwater curable resin liquid containing a thickener, and a masking tape is further applied. Wrap in a spiral and secure.

Above and below the packer adjusted as described above, when descending the packer, the underwater-curable resin-impregnated glass mat / roving cloth comes into direct contact with the unevenness, rust, deposits, etc. on the inner surface of the casing. So as not to be
It is preferable to attach a rubber guide (centralizer).

As an example, as a centralizer of φ178 mm packer, 45 mm width, 10 mm thickness, 59 mm
A method can be shown in which two rubber plates having a length of 0 mm are wound around both ends of the packer body and firmly fixed with vinyl tape.

The packer body prepared as described above is lowered by a high-pressure hose to a casing leak position in a vertical mine previously checked and confirmed. It is necessary to confirm with a television camera and to grasp the depth value accurately.

The high pressure hose employed in the present invention is:
It is unique in that it has the function of supporting the own weight of the packer body, for example, 125 kg, moving the packer up and down, and transmitting the pressure of a gas cylinder such as nitrogen gas into the expander rubber element of the packer through a high-pressure hose to expand the packer. is there. Due to such functional requirements, the maximum working pressure of the high pressure hose is 700 kg / cm ² , and the elongation rate belongs to the ultra high pressure hose of about 0.5% / 100 kg.

Further, the reason that these functions depend only on the high-pressure hose is that, according to the study of the present inventors, the function of suspending the packer and the function of supplying the gas from the gas cylinder are provided separately and the casing patch is provided. This is because, when the construction method is implemented, in a deep well environment of several hundred meters, for example, it has been recognized that a gas supply facility is entangled with a packer suspension facility and causes troubles such as cutting and falling.

The use of the above-described high-pressure hose is the most important study subject in the practice of the casing patch method of the present invention, and a hose having a tensile strength of about three times its own weight is not uncommon in a method of handling ultra-high pressure. However, the advantage of being able to bend is inextricably linked to the disadvantage of being stretched.When using an off-the-shelf hose, the one with excellent tensile strength has a large elongation due to its structure, the depth error becomes remarkable, and it falls into the deep well. It is dangerous to do so. Therefore, it is preferable to select a hose having a small elongation even if the strength is slightly sacrificed by repeating the tensile test.

The lowering of the casing leak by the high-pressure hose 5 to the position of the casing leak is usually performed by using a tripod 9, an upper sheave 7, and a lower sheave 8, as shown in FIG. The lowering is performed by the operation of the driving winch 13 or the electric winch, and the packer body is slowly lowered into the well.

A connection joint between the high-pressure hose 5 and the packer body is attached to the tip of the high-pressure hose 5, and a gas supply path for expanding the expandable rubber element of the packer, etc., and a flow of formation water flowing through the center pipe of the packer. A connection joint 4 having a path is connected as shown in FIG.

FIG. 4 (a) is a state diagram of the packer body during its descent. In the figure, reference numeral 14 denotes a casing leak point, for example, a hole. The descent of the packer body must lead accurately to the leak even at a depth of several hundred meters. It is not always easy to accurately match the depth measured in advance by the underwater camera with the descending depth of the high-pressure hose 5 by a mark every 10 m.

As the high-pressure hose expands and contracts, slack off (SLACKO) generated when gas is supplied to the inflatable rubber element.
It is necessary to correct the actual depth in consideration of a floating phenomenon called FF), for example, a floating phenomenon such as 7 cm at a depth of 300 m. That is, the drive winch 2 is stopped by lowering to the target depth + slack-off depth, and the winch is fixed by the fixing device.

Here, the slack-off phenomenon will be described a little. The slack-off is a summary of various error factors relating to the estimation of the descent position, which should be considered when the packer is operated, that is, when the inflatable rubber element is inflated, and the following factors are considered.

Piston effect: Effect of gas supply into high-pressure hose Deflection of high-pressure hose Effect of expansion of expanded rubber element Effect of temperature difference: Formation water 14 ° C. or more, for example, nitrogen gas 5-10 ° C. The following calculation formulas for correcting in consideration of such error factors are known, but the resolution of each factor is omitted.

Total slack off

[0055]

(Equation 1) The packer floats by the value obtained by the above equation, and the suspension position is corrected in consideration of the floating amount.

According to the experience of the present inventors, 300 m is set as the target depth, and the target depth (300 m) + the total slack off (0.0) is set.
7m), the patch central part was successfully bonded with an accuracy of 299.90m.

When the target depth is 300 m, the width of the underwater curable resin-impregnated glass mat / roving cloth at the casing leak position is preferably at least 1 m, as shown in FIG. It has been confirmed that it is preferable to increase the depth according to the target depth. However, the increase in the sticking width is limited by workability along with the increase in the weight of the inflatable rubber element.
The degree is regarded as a tentative limit.

Next, the patch operation will be described. FIG. 4B is a state diagram showing a state in which the inflatable rubber element is expanded by gas pressure, and is performed by the following procedure.

The inside diameter of the casing pipe to be patched is checked in advance, and the operating pressure of the packer is determined from the inflation data of the packer. Calculate the water column pressure at the target depth from the still water level confirmed by the underwater television camera.
The above inflation data (differential pressure)
To determine the packer operating pressure.

Based on the pressure data determined in this way, for example, the valve of the nitrogen cylinder shown in FIG. 3 is opened, and the nitrogen gas is supplied into the high-pressure hose 5 while the regulator of the collecting device 1 is adjusted. . When the gauge pressure at the regulator outlet reaches the predetermined packer operating pressure, close all high-pressure valves. Typical operating pressures are, for example, in the range of ² to 8 kgf / cm ² described above.

When repairing a well with a high formation pressure, the expansion rubber element of the packer can be expanded through a high-pressure hose while controlling the pumping pressure of water. At this time, the packer operation start pressure is 10 kgf /
It is preferable to use a high-pressure packer of cm ² or more.
Because, from the ground (0m) to the head in the well (tens of meters
This is because the water column pressure in the high pressure hose up to several hundred meters (deep) activates the packer during descent and patches the casing before reaching the target point.

The curing of the glass mat / roving cloth impregnated with the underwater curable resin used in the present invention is controlled by the blending ratio of the main agent and the curing agent and the like. In general, curing is completed in about 8 hours of curing time.

After the curing of the underwater curable resin is completed, the gas in the packer and the gas in the high pressure hose are released. FIG. 4 (c)
Is a state diagram showing a state in which gas is being discharged and the high-pressure hose 5 is being slowly wound up by, for example, a hydraulically driven winch operation.

Thus, the glass mat roving cloth impregnated and cured with the underwater curable resin has been attached to the casing leak position, and then the packer is pulled up to the ground, and the priming procedure of the casing patch method of the present invention is as follows. finish.

The above-described casing patch method of the present invention is applicable to water wells and the like having a pipe diameter of about 200 to 400 mm and various depths, and is generally applicable to a patch method having a depth of about 1000 m. By using a high-pressure gas cylinder, etc., it is expected that the casing patch method at a deeper depth can be put to practical use.

The above-mentioned casing patch method is a casing patch technique which can be inexpensively implemented by a combination of a packer and a special resin, and can be constructed by one engineer and two operators. The renovation period is generally only two days.

[0067]

EXAMPLES Hereinafter, one embodiment of the present invention will be described with reference to examples, but the present invention is not limited to these embodiments.

Example 1 A single packer having an outer diameter of 178 mm and a length of 2470 mm manufactured by PETRO METARIC was used with a packer of 125 kg in weight having an expanded rubber element of 1700 mm in length.

On the outer peripheral surface of the expanded rubber element, 50 μm
A 1 m wide polyethylene film (manufactured by Iwatani Materials Co., Ltd.) having a thickness of m was wound and sealed so that the ends overlapped.

The formation of the glass mat / Robink cloth layer impregnated with the underwater curable resin on the release film layer was carried out as follows.

The glass mat is formed by dispersing chopped strands cut to a predetermined length in a random direction and laminating them in a uniform thickness to form a mat having a thickness of 0.5 mm and a thickness of 36 mm.
MC-380A-104 of 0 g / m ² and 1040 mm width
SS (manufactured by Nitto Boseki Co., Ltd., trade name), Robink cloth bundles several hundreds of filaments of 10 to 15 μm into strands, and uniformly flattens them into a bundle of 0.5 mm in thickness of 588 g. / M ² , 1000 mm wide WR
All of -570C-100CS (manufactured by Nitto Boseki Co., Ltd., trade name) used JIS-compliant standard products.

As the underwater curable resin, a bisphenol A type epoxy resin SSJ-100B main agent (trade name, manufactured by Sotec Co., Ltd.) as a main agent, a modified polyamine as a curing agent, and an SSJ-100B curing agent using a modified aromatic polyamine (stock) (Trade name, manufactured by Sotec Co., Ltd.) at a ratio of 100: 55. This is JWWA of Japan Water Works Association
It is a product that has passed the resin dissolution test standard of K135.
The curing time at a water temperature of 14 ° C. is about 24 hours.

Three glass mats wound in a roll are cut. The cutting length is determined by calculating the circumference from the inner diameter of the casing pipe and multiplying the circumference by 1.27 times. Further, two roving cloths wound in a roll shape are cut. Similarly, the cutting width is a value obtained by multiplying the circumference by 1.27 times.

Insulation case of epoxy resin (20 ° C. or higher)
The epoxy resin was taken out from the above, and 2.0 L / m ² of the main agent and 1.
1 L / m ² of a curing agent was mixed, a blue sheet was spread on a workbench, a polyethylene sheet was stuck thereon, and
Place the first glass mat, mix the base resin and the curing agent, lightly apply epoxy resin to the entire mat with a roller, and defoam with a dedicated pig hair roller.

The first roving cloth is placed on a glass mat impregnated with epoxy resin, and impregnated with epoxy resin. Similarly, apply lightly on the entire mat with a roller,
Defoam with a dedicated pig hair roller.

Similarly, the second glass mat and the second roving cloth are similarly impregnated and defoamed in the same manner to complete an epoxy resin-impregnated mat in which three glass mats and two roving cloths are alternately combined.

Next, sepiolite and Milcon MS-2 (trade name, manufactured by Showa Mining Co., Ltd.) are added to the remaining epoxy resin, which accounts for 10% of the total amount, of 30 to 35 parts by weight based on 100 parts by weight of the epoxy resin. To increase the viscosity,
Epoxy resin containing sepiolite is applied to the polyethylene film surface of the expanded rubber element.

The center of the epoxy resin-impregnated glass mat / roving cloth obtained as described above was aligned with the center of the expanded rubber element of the packer, wound around the expanded rubber element, and fixed firmly with masking tape.

This state was maintained until one hour had passed since the mixing of the main component of the epoxy resin and the curing agent, and the next operation was carried out.

The inside of the casing 6 of the packer 1 (11-3 /
4 "CGS, inner diameter 279.4 mm, outer diameter 298.5 m
The following high-pressure hose 5 was used for suspension to m). High pressure hose JAS08 (Bridgestone Flowtech Co., Ltd., trade name), maximum working pressure 700 kgf /
cm ² , burst pressure 2000 kgf / cm ² , inner diameter 12.
8 mm, outer diameter 21.2 mm, weight 710 g / m.

A connection joint 4 for connecting to the packer 1 is connected to the tip of the high-pressure hose 5.

As the collecting device 11 shown in FIG. 3, six nitrogen cylinders 12 were used. Normally, three nitrogen cylinders are two
Since three casing patches are possible, the remaining three were used for backup. Specifications are 7000L type, filling pressure 1
50 ksc.

As the hydraulic drive winch 13, a band brake is used as a brake, and a device for stopping the rotation of the drum is separately provided on the side. This is to prevent the drum from rotating even if the band brake is loosened. A 740 m winding amount and a winding speed of 25.7 m / min from Maruma Heavy Vehicle Co., Ltd. were used.

As the tension meter 10, a load signal sent from the load cell is displayed on a tension meter in the body-mounted vehicle so as to inform the operator of the suspension load of the packer. Tension sensor model L
T-2TF (trade name, manufactured by Sosan Co., Ltd.) was used.

The procedure for suspending and removing the packer 1 was carried out as follows.

The load cell for the tension meter 10 is mounted on the tripod 9. Attach the upper sheave 7 for the high pressure hose 5 to the hook at the bottom of the load cell. Attach the lower sheave 8 for the high pressure hose to the lower part of the tripod.

A rubber plate is fixed to both upper and lower ends of the main body of the packer 5 with tape as a centralizer. Attach the connection fitting to the box of the center pipe above the packer. The connection joint 4 and the inflator (upper packer) are connected by a dedicated high-pressure line.

The high pressure hose 6 dropped from the upper sheave 7 is connected to the connection joint 4 at the end of the center pipe of the packer 1.

The hydraulic drive winch is operated, and the packer 1 is slowly lowered into the casing 6 while checking the operation state of the packer 1 with a tension meter.

The length of the high pressure hose is measured while lowering the packer body. The length is measured by marking each 10 m with a stainless steel tape measure and adding the marks. Lower the Packer 1 to the target depth. The target depth is the depth value of the hole (casing leak location) confirmed by the underwater TV camera the day before, and the depth is the counter value of 300 m mounted on the camera car
It was adopted. 6 kgf / cm of nitrogen gas in the packer body
^{When the} feeder was supplied so as to be ² , a lifting effect of the packer called slack off occurred.

The slack-off is calculated to be 0.07 m according to the above-mentioned generally used formula, whereby the packer body is lowered to the value of (target depth + all slack-off), the winch is stopped by the band brake, The winch was fixed with the fixing device (pin) in the above.

24 hours after the supply of the nitrogen gas,
The release valve of the collecting device was opened to release the nitrogen gas inside the packer and the high pressure hose. After confirming that the release of nitrogen gas from the release valve has been completed, start the engine of the body-mounted vehicle, put in PTO, operate the hydraulic system, and release the fixing device (pin) on the side of the hydraulic drive winch Then, the band brake of the hydraulic drive winch was released, the high pressure hose was slowly wound up, and the packer body was lifted to the ground.

When the packer was lifted, the work was performed while paying attention to the value of the tension meter, and the packer was lifted to the ground, and the casing patch work was completed.

After the completion of the casing patch construction, the state of the repaired portion was confirmed again by inserting a television camera, and it was confirmed that the epoxy resin-cured glass mat and the roving cloth were fixed in the entire repaired portion. In addition, it was recognized that the subsequent pumping volume recovered to the average value before the failure.

The following facts were confirmed by the above experiment.

1. It was confirmed that the accuracy of hanging the packer was 299.90 m as described above.

2. Epoxy resin impregnated cured glass mat
The strength of the roving cloth was compared with that of the ordinary hard PVC pipe and FRP casing pipe with the same specifications, and the results shown in the following table were obtained.

[Table 1] As described above, the sample of Example 1 has almost the same strength as the FRP casing pipe.

3. The following experimental facts were confirmed in underwater curing experiments on the ground.

That is, in a casing of φ300 mm,
Drill circular holes and short holes of φ65 mm, φ30 mm and 10 × 50 mm at intervals of 250 mm above and below, and drill φ65 mm, φ30 mm and 10 × 50 m in each hole.
The iron socket was welded, and the pressure resistance of the epoxy resin in-water cured glass mat / roving cloth layer was tested by the external pressure from the iron socket side, and the following pressure resistance was obtained.

[0100] From ^{φ65mm 11kgf / cm 2 φ30mm 19kgf /} cm 2 10 × 50mm 31kgf / cm 2 above results, it was shown that withstand the formation pressure to one minute.

[0101]

The so-called pipe-in-pipe method has been adopted for closing or repairing casing leaks in deep wells, etc., resulting in a casing that is one size smaller and has been forced to lower the pumping amount and other performance. It has been confirmed that the repair work can be completed within one day without reducing the casing diameter by adopting the casing patch method of the present invention, so this is a very useful casing patch method.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the gas pressure in an inflatable rubber element and the outer diameter of the inflatable rubber element.

FIG. 2 is a diagram showing the relationship between the gas pressure and the length of an expanded rubber element.

FIG. 3 is a diagram showing an example of a packer suspension device.

FIG. 4 is a diagram showing a state when the packer is suspended (a), when the expandable rubber element is inflated (b), and when repair and the packer are collected (c).

FIG. 5 is a diagram showing a relationship between hanging accuracy and a sticking width at a target depth of 300 m.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Packer 2 Inflatable rubber element 3 Epoxy resin impregnated glass mat / Robink cloth 4 Connection joint 5 High pressure hose 6 Casing 7 Upper sheave 8 Lower sheave 9 Tripod 10 Tension meter 11 Assembly device 12 Gas cylinder 13 Winch 14 Casing leak point (hole) 15 Centralizer

Claims (11)

[Claims] 1. A packer comprising a release film layer formed on the outer peripheral surface of an expanded rubber element of a packer, and a glass mat / roving cloth layer impregnated with an underwater curable resin formed on the release film layer, which is subjected to high pressure. The hose is lowered to the position of the casing leak in the well that has been checked and checked in advance, and the expandable rubber element of the packer is expanded through a high-pressure hose while controlling the pressure of the gas cylinder or the pumping pressure of water. After curing, degassing or dewatering to shrink the inflatable rubber element, pull up only the packer body, attach the impregnated cured glass mat / roving cloth of the underwater curable resin to the casing leak position, repair the casing leak The casing patch method characterized by doing. 2. The casing patch method according to claim 1, wherein an underwater curable resin solution mixed with a thickener is applied onto the release film. 3. The casing patch method according to claim 2, wherein the underwater curable resin is an epoxy resin or a urea resin. 4. The underwater-curable resin is an epoxy resin,
4. The thickener according to claim 3, wherein the thickener is sepiolite.
5. The casing patch method described in 1. 5. The casing patch method according to claim 1, wherein the length of the glass mat / roving cloth layer is 2,000 mm or less and 500 mm or more. 6. A glass mat / roving cloth, wherein a glass mat layer and a roving cloth layer are alternately formed, and three glass mat layers and two roving cloth layers form a total basis weight of 300 to 300 mm. 9
00 g / m ² , total weight of roving cloth layer 5
100 to 900 g / m ² , and the total basis weight is 800 to
The casing patch method according to claim 5, wherein the casing patch method is 1800 g / m ² . 7. The casing patch method according to claim 1, wherein rubber guides are attached to upper and lower sides of the packer. 8. The casing patch method according to claim 1, wherein the high-pressure hose serves to support the packer body, move the packer up and down, and supply nitrogen gas to the packer. 9. The casing patch method according to claim 1, wherein the release film layer is a polyolefin-based film or a vinyl chloride-based film. 10. The casing patch method according to claim 9, wherein the polyolefin-based film is a polyethylene film. 11. The casing patch method according to claim 1, wherein the gas in the gas cylinder is selected from the group consisting of nitrogen gas, helium gas, argon gas, oxygen and air.