WO2018198881A1

WO2018198881A1 - Well closing device and temporary well closing method

Info

Publication number: WO2018198881A1
Application number: PCT/JP2018/015857
Authority: WO
Inventors: 吉田　博明; 卓磨小林
Original assignee: 株式会社クレハ
Priority date: 2017-04-28
Filing date: 2018-04-17
Publication date: 2018-11-01
Also published as: GB201910253D0; CN110168190A; CN110924892A; GB202009313D0; CA3050226A1; GB2575557A; RU2020109744A; GB2575557B; RU2020109744A3; GB2584023B; CA3050226C; RU2717466C1; US20200149368A1; GB2584023A

Abstract

The present invention addresses the problem of providing a well closing device capable of reducing costs and shortening a process for boring a well, and a method for temporarily closing the well by using the well closing device. This well closing device includes: a down hole plug; a setting tool (2) for operating and installing the down hole plug; and an obstacle for closing the flow passage of the down hole plug, wherein the obstacle is included in the setting tool (2), and thus the flow passage of the down hole plug can be reliably closed in a short time after installing the down hole plug inside a well and removing the setting tool (2). In addition, by using this well closing device, the well can be temporarily closed reliably in a short time.

Description

Well closing device and well temporary closing method

The present invention relates to a well closing device used in a well recovery method (Enhanced Oil Recovery) performed to produce hydrocarbon resources such as oil or natural gas, and a method of temporary well blocking using the same.

The “fracturing method” or “hydraulic fracturing method” is one of the enhanced recovery methods for hydrocarbon resources. Depending on the hydraulic pressure of the fracturing fluid, a deep underground production layer (oil such as shale oil or natural gas such as shale gas) It is a method of generating cracks in the layer that produces hydrocarbon resources such as. Using this method, a predetermined section is partially closed sequentially from the tip of the well hole (down hole) drilled in the underground layer several thousand meters below, and the inside of the blocked section Fracturing fluid is fed into the production layer at a high pressure to cause cracks in the production layer. Next, fracturing is performed by closing the next predetermined section (usually, a section before the preceding section, that is, a section on the ground side). Thereafter, this process is repeated until the necessary sealing and fracturing are completed.

Various methods are known as methods for closing the borehole sequentially from the tip of the borehole. For example, downhole plugs (“flac plug”, “bridge plug”, “packer”, etc.) And a method using a downhole tool called). As downhole plugs, for example, Patent Documents 1 to 4 disclose downhole plugs capable of closing and fixing well holes.

Patent Document 1 discloses a downhole plug for well excavation (hereinafter, simply referred to as “plug”), specifically, a mandrel (main body) having a hollow portion in the axial direction, and Along the axial direction on the outer peripheral surface perpendicular to the axial direction of the mandrel, the ring or annular member (annular member), the first conical member (slip) and the slip are formed from an elastomer or rubber, etc. Disclosed is a plug comprising a malleable element, a second conical member and a slip, and an anti-rotation mechanism. The blocking of the well hole by the downhole plug for well drilling is as follows.

That is, by moving the mandrel in the axial direction, the gap between the ring or the annular member and the detent mechanism is reduced. Along with this, the slip comes into contact with the inclined surface of the conical member and advances along the conical member, and the slip expands radially outward and comes into contact with the inner wall of the well and is fixed to the well. . Further, the malleable element expands and deforms and abuts against the inner wall of the well hole to close the well hole, thereby blocking the well hole. The mandrel has a hollow portion in the axial direction, and a well or the like can be sealed by setting a ball or the like on the hollow portion.

Examples of the material for forming the plug include metal materials (aluminum, steel, stainless steel, etc.), fibers, wood, composite materials, plastics, and the like, preferably composite materials containing a reinforcing material such as carbon fiber, especially It is described that the composite material contains a polymer such as an epoxy resin or a phenol resin, and that the mandrel is formed of aluminum or a composite material. On the other hand, it is described that a material that decomposes by temperature, pressure, pH (acid, base) or the like can be used for the ball or the like in addition to the materials described above.

Patent Document 2 discloses a packer assembly for well excavation in which each packer is detachably connected to an adjacent packer.

In Patent Document 3, a mandrel having a hollow portion in the axial direction, and a slip, a slip wedge, and an elastic packer element along the axial direction on the outer peripheral surface orthogonal to the axial direction of the mandrel , And an extrusion limiter and the like are described.

Patent Document 3 discloses a disposable downhole tool (which means a downhole plug or the like) or a member thereof containing a degradable material that decomposes when exposed to an environment in a well. As degradable materials, degradable polymers such as aliphatic polyesters such as polylactic acid are disclosed. Further, in Patent Document 3, a cylindrical body part having a flow hole in the axial direction (tubular body) and a peripheral surface orthogonal to the axial direction of the cylindrical body part are provided along the axial direction. A combination of a packer element assembly consisting of an upper sealing element, a central sealing element and a lower sealing element, and a slip and a mechanical slip body is described. Further, it is disclosed that a flow of only one direction of fluid is allowed by setting a ball in the flow hole of the cylindrical main body part.

Patent Document 4 discloses a downhole plug having a flag plug, a mandrel that exists in the axial direction of the flag plug and has a hollow portion, and a setting rod that passes through the hollow portion of the mandrel. The setting rod disclosed in Patent Document 4 is connected to the front end of the downhole plug.

Generally, a downhole plug having an opening in the center and having a seat for receiving an obstacle is used. In particular, when using a ball as an obstacle, a downhole plug with a ball bowl seat is used. To close the borehole, use a setting tool to place the downhole plug in place. Activate the hole plug. Thereafter, an obstacle is supplied and arranged on the seat of the downhole plug to close the opening of the seat, thereby completing the closing of the well hole (for example, Patent Document 5).

However, when a ball is used as an obstacle, for example, a high pressure is required to supply and place a ball of a predetermined size from the ground to the ball seat of the downhole plug installed in the underground reaching a depth of 1000 to 5000 m. It is necessary to transport the ball over a certain amount of time due to the water flow. At this time, since the high-pressure water flow is used, the ball may be deformed due to collision with the well wall during transportation, or damage such as cracking or chipping may occur, thereby impairing the sealing performance.

On the other hand, Patent Document 6 discloses a mandrel that exists in the axial direction of the flack plug, and a cylindrical metallic sleeve installed inside the mandrel, and the metallic sleeve contains a ball. A downhole plug is described.

Also, the downhole plugs are sequentially arranged in the well until the well is completed, but it is necessary to remove these at the stage where the recovery of hydrocarbon resources is started. Plugs are usually not designed to be unblocked and recovered after use, so they can be removed by breaking or drilling, or breaking into small pieces, And it is necessary to spend a lot of money and time for drilling. There are also specially designed plugs that can be recovered after use (retrievable plug), but since the plugs are deep underground, it takes a lot of money and time to recover all of them. I need it.

Furthermore, under the increasingly severe and diverse mining conditions such as deepening, the ability to seat obstacles on the seats of the downhole plugs in a short time ensures that well drilling is possible. Therefore, it is required to provide a well closing device and a method for temporarily closing a well that can reduce the cost and shorten the process.

US Patent Application Publication No. 2011/0277789 US Patent Application Publication No. 2003/0183391 US Patent Application Publication No. 2005/0205266 US Patent Application Publication No. 2011/0277787 US Patent Application Publication No. 2015/0252643 US Patent Application Publication No. 2002/0189822

The problem of the present invention is that the mining conditions such as deepening are becoming increasingly severe and diverse, and an obstacle that blocks the flow path of the downhole plug can be reliably supplied in a short time. The object of the present invention is to provide a well closing device and a method for temporarily closing a well using the well closing device.

As a result of diligent research to solve the above-mentioned problems, the present inventors have included an obstacle that blocks the flow path of the downhole plug in the setting tool used for installing the downhole plug. The present invention has been completed by finding that the problem can be solved by providing an obstacle to the downhole plug in a short time and in a state in which the damage is suppressed without being thrown in.

That is, according to the present invention, a device for closing a well, which is a downhole plug, a setting tool that is disposed on the rear end side of the downhole plug, and operates and installs the downhole plug, One or more obstacles that block the flow path of the downhole plug, wherein the downhole plug includes a hollow mandrel that is open at least at a rear end, and the setting tool includes a front end of the mandrel. A setting rod connected directly or indirectly to the side, and a setting sleeve arranged to cover part or all of the setting rod and at least a part of the downhole plug. Insert the rod from the opening at the rear end of the mandrel into the hollow part of the mandrel. Are, the obstacles are contained in the space in the setting tool, wellbore closure device is provided.

The setting tool of the present invention itself or a part thereof may be called an adapter kit, and the adapter kit includes a setting rod and a setting sleeve.

Here, “front end” and “rear end” in this specification refer to the front and rear ends in the direction in which the downhole plug advances from the well entrance to the well. Further, “front end side” and “rear end side” refer to the front and rear of the midpoint of the length in the long axis direction.

A downhole plug; a setting tool disposed on a rear end side of the downhole plug for operating and installing the downhole plug; and one or more obstacles for closing the flow path of the downhole plug; The downhole plug includes a hollow mandrel having at least a rear end opened, and the setting tool is on a front end side of the mandrel. A setting rod that is directly or indirectly connected to the setting rod, and a setting sleeve that is shaped to cover part or all of the setting rod and at least a part of the downhole plug. It is inserted through the opening at the rear end into the hollow part of the mandrel and Things a method for temporarily blocking the wells with steps d) from the following a) using a wellbore occlusion device which is contained in the space in the setting tool:
a) Move the well closure device to an arbitrary position in the well and operate and install the downhole plug;
b) Disconnect the setting tool from the downhole plug and pull out the setting rod;
c) moving the obstacle in the setting tool to block the flow path in the hollow part of the mandrel;
d) A method for removing the obstacle and recovering the flow path after a predetermined time has elapsed is provided.

According to the present invention, in a well closing device including a setting tool and a downhole plug, an obstacle that closes the flow path of the downhole plug is included in the setting tool close to the downhole plug, thereby increasing the depth, etc. Under the increasingly severe and diverse mining conditions, it is possible to provide a well closing device that can supply obstacles to the downhole plug in a short time and safely. In addition, a method for temporarily closing a well using the well closing device can be provided.

It is a figure which shows one specific example of the well closure apparatus of this invention. It is a schematic front sectional view showing a specific example of the well closing device of the present invention. It is a figure which shows the external appearance of the flap plug which is a specific example of the downhole plug contained in the well closure apparatus of this invention. (A) is a schematic front sectional view showing a flack plug which is a specific example of a downhole plug included in the well closure device of the present invention, and (B) is a diagram of a downhole plug of (A). It is a rough front sectional view showing the state where it was installed and fixed in the well. (A) is a figure which shows the cross section of the circumferential direction of what cut off a part of setting rod of FIG. 2, and (B) cut off a part of setting rod of FIG. 2 in the shape of a curve. It is a figure which shows the cross section of the circumferential direction of a thing, (C) and (C ') are figures which show the cross section of the circumferential direction of what cut off a part of setting rod of FIG. (A) is a figure which shows the cross section of the circumferential direction of what put the curve-shaped groove | channel in the inner surface of the setting sleeve of FIG. 2, (B) and (C) are the inner surfaces of the setting sleeve of FIG. It is a figure which shows the cross section of the circumferential direction of what put the square-shaped groove | channel in.

The present invention relates to a downhole plug, a setting tool for installing the downhole plug, a well closing device including an obstacle for closing the flow path of the downhole plug, and a method for temporarily closing a well using the same. About. Hereinafter, an embodiment of a well closing device and a closing method according to the present invention will be described.

1. Well closure device The well closure device concerning this embodiment is explained with reference to drawings. The well closing device of the present embodiment includes a downhole plug 1, a setting tool 2, and an obstacle 3 for closing the flow path of the downhole plug. FIG. 1 is a specific example of means for solving the problems of the present invention, and the scope of the present invention is not limited to the well closing device of the embodiment shown in FIG.

(1) Downhole plug A downhole plug is a device installed in a well hole to close a part of a well and is called a flack plug, a bridge plug, or a packer. The downhole plug has at least one mandrel and one or more members mounted on an outer peripheral surface orthogonal to the axial direction of the mandrel. As an example of the downhole plug, the embodiment shown in FIG. Moreover, the external appearance of the flap plug 1 is shown in FIG. As shown in FIG. 3, the flap plug 1 includes a mandrel 11 and a member attached on an outer peripheral surface orthogonal to the axial direction of the mandrel 11.

1) Mandrel The mandrel 11 included in the flack plug 1 is a member that has a substantially circular cross section and is sufficiently long with respect to the diameter of the cross section, and basically ensures the strength of the flack plug 1. The diameter of the cross section of the mandrel 11 is appropriately selected according to the size of the well hole. When the diameter is slightly smaller than the inner diameter of the well hole, the flack plug 1 can move in the well hole. On the other hand, the diameter of the mandrel 11 and the inner diameter of the well hole have a difference in diameter that allows the well hole to be closed by expanding the diameter of the annular rubber member 15 that can be expanded as described later. The length of the mandrel 11 is, for example, about 5 to 20 times the diameter of the cross section, but is not limited thereto. Usually, the diameter of the cross section of the mandrel 11 is in the range of about 5 to 30 cm.

The mandrel 11 may be solid, but the mandrel 11 is a hollow mandrel having at least part of a hollow portion along the axial direction from the viewpoint of securing a flow path in the initial stage of fracturing and reducing the weight of the mandrel. It is preferable. That is, the hollow portion may penetrate the mandrel 11 along the axial direction, or may not penetrate the mandrel 11 along the axial direction. In addition, when the flack plug 1 is pushed and transferred into the well using a fluid, the mandrel 11 preferably has a hollow portion along the axial direction. When the mandrel 11 has a hollow portion along the axial direction, the cross-sectional shape of the mandrel 11 defines the diameter (outer diameter) of the mandrel 11 and the outer diameter of the hollow portion (corresponding to the inner diameter of the mandrel 11). It is an annular shape formed by two concentric circles. The ratio of the diameters of the two concentric circles, that is, the ratio of the outer diameter of the hollow portion to the diameter of the mandrel 11 is preferably 0.7 or less. Since the size of this ratio is in contradiction with the size of the thickness of the hollow mandrel 11 with respect to the diameter of the mandrel 11, determining the upper limit of the ratio determines the preferable lower limit of the thickness of the hollow mandrel. It can be said that it corresponds. If the thickness of the hollow mandrel is too thin, the strength (especially the tensile strength) of the hollow mandrel may be insufficient when the flack plug 1 is placed in the borehole or when closing or fracturing the borehole. In an extreme case, the flap plug 1 may be damaged. Therefore, the ratio of the outer diameter of the hollow portion to the diameter of the mandrel 11 is more preferably 0.6 or less, and even more preferably 0.5 or less.

The diameter of the mandrel 11 and the outer diameter of the hollow portion may be uniform along the axial direction of the mandrel 11, but may vary along the axial direction. That is, by changing the outer diameter of the mandrel 11 along the axial direction, a convex part, a step part, a flange part, a concave part (groove part) on the outer peripheral surface of the mandrel 11 and a thread part (usually a male screw structure). ) Or a bent portion such as a meshing portion of a ratchet mechanism to be described later. Further, when the outer diameter of the hollow portion (the inner diameter of the hollow mandrel 11) varies along the axial direction, the inner peripheral surface of the mandrel 11 has a convex portion, a step portion, a groove portion, and a screw portion (a male screw structure or a female screw). It is good also as what has bending parts, such as a structure. Further, the bent portion may have a tapered portion.

In addition, as will be described later, the well closing device according to the present embodiment is a space formed by the inner wall of the setting sleeve, the setting rod, and the rear end of the mandrel (hereinafter, this space may be referred to as “a space in the setting tool”). Since the obstacle is disposed on the rear end, the rear end of the mandrel may be cut out so that the obstacle can be disposed. The shape of the notch is preferably substantially the same as the surface shape of the obstacle.

The convex portion, stepped portion, flange portion and concave portion (groove portion) that can be provided on the outer peripheral surface or inner peripheral surface of the mandrel 11 can also be used as a support portion when the flack plug 1 is transferred in the well, It can also be used as a part for attaching or fixing another member to the outer peripheral surface or inner peripheral surface of the mandrel 11. Moreover, when the mandrel 11 has a hollow part, it can be set as the seat surface holding the obstruction | occlusion for flow path obstruction | occlusion. When the hollow portion of the mandrel 11 is present at least at the rear end, the mandrel 11 is in an open state. By using the opening as a seat that can hold the obstacle, the obstacle can be more securely seated. As a result, the flow path can be blocked more reliably. In addition, as a sheet | seat, not only the opening part of the mandrel 11 may be made into a sheet | seat shape, but the sheet | seat member which the center part opened may be attached to the mandrel 11. For example, when using a ball as an obstacle, the size of the opening in the seat (ball seat) of the downhole plug is appropriately selected to prevent the ball from cracking and coming out and to block the flow path more securely. can do. Further, the outer surface of the mandrel 11 is allowed to move in one direction along the axial direction of the mandrel together with the inner peripheral surface of the member attached on the outer peripheral surface orthogonal to the axial direction of the mandrel 11. However, a plurality of meshing portions that restrict movement in the opposite direction may be formed to constitute a ring-shaped ratchet mechanism that is orthogonal to the axial direction of the mandrel.

[Materials for forming mandrels]
The material forming the mandrel 11 provided in the downhole plug is not particularly limited, and a material conventionally used as a material forming the mandrel provided in the downhole plug can be used. For example, metal materials (such as aluminum, steel, and stainless steel), fibers, wood, composite materials, and resins can be used. Specifically, a composite material containing a reinforcing material such as carbon fiber, particularly a composite material containing a polymer such as an epoxy resin and a phenol resin can be given. Since the downhole plug of the present embodiment is a downhole plug that can reduce the cost of well drilling and shorten the process by facilitating the removal of the downhole plug and securing the flow path, the mandrel 11 is made of a degradable material. It is preferable that it is formed from.

(Degradable material)
In the downhole plug used in the present embodiment, when the mandrel 11 is formed of a degradable material, the degradable material may be a degradable material having biodegradability or hydrolyzability, or any other method. It is possible to use degradable materials that can be chemically decomposed.

In addition, materials that physically break down such as destruction and collapse by applying a large mechanical force, such as a metal material such as aluminum, which has been widely used as a mandrel for conventional downhole plugs, can be used for downhole plugs. It does not correspond to the degradable material forming the mandrel 11 provided. However, as seen in composites of degradable resins and metal materials or inorganic substances, the strength of the original resin is reduced due to a decrease in the degree of polymerization, etc., resulting in brittleness. The material that easily disintegrates and loses its shape corresponds to the degradable material. Specifically, a concave portion such as a recess having a predetermined shape is provided on a base material made of a degradable material such as polyglycolic acid (hereinafter sometimes referred to as “PGA”). Fit metal (metal piece, etc.) or inorganic material that matches the shape of the wire and fix it with an adhesive, or wrap a wire, fiber, etc. so that the metal piece or inorganic material and base material can be fixed. And fixing them.

In the downhole plug used in this embodiment, when the mandrel 11 is formed from a decomposable material, it is preferably a hydrolyzable material that decomposes with water at a predetermined temperature or higher. Further, the degradable material is preferably composed mainly of PGA, and among PGA, polyglycolic acid having a weight average molecular weight of 150,000 or more is preferred, and high molecular weight polyglycolic acid having a weight average molecular weight of 180,000 or more is preferred. Particularly preferred because of its high strength. That is, a downhole plug in which the mandrel 11 is formed of high molecular weight PGA is desirable. Further, the decomposable material may contain a reinforcing material, or may contain other compounding components. In addition, as a decomposable material for forming the mandrel 11, a decomposable metal can be used. The decomposable metal used for the mandrel 11 is preferably an Mg alloy because of its high strength.

2) Member attached on the outer peripheral surface orthogonal to the axial direction of the mandrel The downhole plug used in the present embodiment includes a mandrel and a member attached on the outer peripheral surface orthogonal to the axial direction of the mandrel. That is, in the downhole plug, the outer peripheral surface of the mandrel is usually used for the purpose of efficiently and reliably carrying out the plug transfer, installation, blocking the wellbore, and fracturing, and further improving the handleability. Various members are mounted on the top. The member attached on the outer peripheral surface orthogonal to the axial direction of the mandrel is not particularly limited as long as it is a member conventionally used in a downhole plug. In particular, the flack plug 1 preferably includes at least one selected from the group consisting of a slip 12, a wedge 13, a pair of ring-shaped fixing members 14, and an annular rubber member 15 capable of expanding the diameter, as shown in FIG. 3. It is done. These members are referred to as members in the sense that they include attachment members for attaching the respective members to the mandrel.

[Material for forming a member to be mounted on the outer peripheral surface orthogonal to the axial direction of the mandrel]
The material for forming the member attached to the outer peripheral surface of the mandrel used in the present embodiment is not particularly limited, and a material conventionally used as a material for forming the member included in the downhole plug is used. Can do. For example, metal materials (aluminum, steel, stainless steel, etc.), fibers, wood, composite materials and resins can be mentioned. Specifically, composite materials containing reinforcing materials such as carbon fibers, particularly epoxy Examples thereof include a composite material containing a resin and a polymer such as a phenol resin. From the viewpoint that the cost of well drilling can be reduced and the process can be shortened by facilitating the release of the blockage after use and the securing of the flow path, at least one of the above members is degradable in the same manner as described for the mandrel. It is preferably formed from a material.

(Degradable material)
In the downhole plug used in the present embodiment, as the degradable material forming at least one of the above members, the degradable material having biodegradability or hydrolyzability, as described in the mandrel, Degradable materials that can be chemically decomposed by some other method, degradable materials that can become brittle and easily disintegrate can be used. Further, when the member is an annular rubber member capable of expanding the diameter, examples of the decomposable material include aliphatic polyester rubber, polyurethane rubber, natural rubber, polyisoprene, acrylic rubber, aliphatic polyester rubber, polyester heat Decomposable rubbers such as plastic elastomers and polyamide-based thermoplastic elastomers can be used.

3) Operation and installation of downhole plug and closure of well hole The downhole plug used in the present embodiment is operated by a setting tool described later and installed in the well hole. For example, in the flack plug 1, the slip 12 rides on the upper surface of the slope of the wedge 13 by applying a force that reduces the axial distance of the mandrel between the pair of ring-shaped fixing members 14 and the axial direction of the mandrel. Move outwards perpendicular to each other. Then, the outermost peripheral surface orthogonal to the axial direction of the mandrel of the slip 12 abuts against the inner wall of the well hole, so that the plug can be installed at a predetermined position of the well hole. Further, as the diameter-expandable annular rubber member 15 is compressed in the axial direction of the mandrel and the axial distance is reduced (reduced diameter), the diameter-expandable annular rubber member 15 becomes the axis of the mandrel. The diameter is expanded in a direction orthogonal to the direction. The annular rubber member 15 is expanded in diameter, the outer part in the direction orthogonal to the axial direction abuts the inner wall of the well hole, and the inner part in the direction orthogonal to the axial direction is on the outer peripheral surface of the mandrel. By abutting, the space between the plug 1 and the well hole can be closed (seal) (blocking of the well hole). Next, fracturing can be performed in a state where the space between the plug and the well hole is closed (sealed).

(2) Setting tool The setting tool used in the well closing device of the present embodiment has a substantially cylindrical shape and includes a setting rod and a setting sleeve. The setting rod is generally rod-shaped, and is arranged at the center in the section of the setting tool (substantially parallel to the bottom of the cylinder). That is, the setting rod is inserted into the hollow portion of the setting tool. The setting sleeve has a cylindrical shape surrounding one end of the long axis of the setting rod.

The setting tool itself or a part thereof according to the present embodiment may be called an adapter kit, and the adapter kit includes a setting rod and a setting sleeve.

The setting tool used in this embodiment is arranged from the rear end of the downhole plug to the rear end side of the hollow portion, and the setting rod and the setting tool are in contact with the downhole plug. That is, the setting rod is directly or indirectly connected to the mandrel, and the setting sleeve is installed adjacent to a member attached on the outer peripheral surface orthogonal to the axial direction of the mandrel. When the setting tool is activated, the setting sleeve moves in the rear end direction while the setting sleeve moves in the rear end direction while the setting sleeve suppresses the movement in the rear end direction of the member mounted on the outer peripheral surface of the mandrel. , The mandrel is pulled out toward the rear end, and the downhole plug operates as described above. An example is a setting tool that includes a setting sleeve and a setting rod that operate on gas generated by an explosion.

1) Setting rod In the well closing device of this embodiment, the setting rod is connected to the mandrel, but the setting rod is usually directly or directly connected to the mandrel at the end opposite to the end surrounded by the setting sleeve. Connect indirectly. The setting rod is inserted into the hollow portion of the mandrel from the opening at the rear of the mandrel. The connection position of the mandrel with the setting rod may be on the rear end side, center, or front end side in the long axis direction of the mandrel, but if the mandrel is made of resin or the like and the compression strength is insufficient, connect to the front end side of the mandrel. It is preferable. In this case, the setting rod is connected from the rear end side of the mandrel to the front end side through the hollow portion. An example in which the setting rod and the front end of the mandrel are connected will be described below with reference to FIGS.

The setting rod 21 in FIG. 2 is connected to the downhole plug 1 at the connection portion 23. The connection part 23 is connected directly to and fixed to the front end of the mandrel 11 and indirectly connected via a connection member (not shown) installed at the front end of the mandrel 11. And a fixing method. As a method for fixing the connection portion 23 to the downhole plug 1, there are a method for fixing the connection portion 23 to the downhole plug 1 with a screw carved on the outer periphery of the connection portion 23 and a method for fixing with a pin. It is preferable that the screw and the pin are broken by the force applied in the axial direction of the mandrel, and the connection between the downhole plug and the setting tool is released.

As will be described later, the well closing device of the present embodiment places an obstacle in a space formed by a setting sleeve inner wall, a setting rod, and a mandrel rear end or a member attached to the rear end. Therefore, the setting rod may be deformed by denting, bending, or shaving it in a fan shape in the axial direction so that an obstacle (ball) can be included in the setting sleeve. That is, the setting rod may be provided with a groove or a notch structure in the axial direction.

As a specific example of deformation of the setting rod, a part of a circular shape which is a cross section of the setting rod is cut out in a straight line ((A) in FIG. 5), and a part cut out in a curved shape (( B)), or those cut into squares ((C) and (C ′) in FIG. 5).

As long as the function of the setting rod is not hindered, the position and length of deformation in the entire length of the setting rod are not particularly limited, but the deformed portion shown in FIG. 5 is the tip (front end) of the setting rod that is not connected to the down hole plug. It is preferable that it exists in the front end side among the length from the rear end of the down hole plug. The length of the deformed portion is preferably 10 mm or more in the axial direction of the setting rod.
2) Setting sleeve The setting sleeve 22 of the present embodiment is located adjacent to the rear end side of the member attached on the outer peripheral surface of the mandrel 11, and moves the member on the outer peripheral surface of the mandrel to the rear side. Has a function to suppress.

Also, like the setting rod, the setting sleeve may be provided with a groove or notch structure on the inner wall so that an obstacle (ball) can be enclosed. Specific examples of the groove on the inner wall of the setting sleeve include a curved groove ((A) in FIG. 6) or a square groove ((B) and (C) in FIG. 6) in the cross section of the setting sleeve, Is mentioned.

The groove on the inner wall of the setting sleeve may be any shape as long as an obstacle can be enclosed inside the setting sleeve, and the position, length and depth are not particularly limited, but the groove shown in FIG. The axial direction is preferably 10 mm or more, the width is 5 mm or more, and the depth is 1 mm or more.

[Material forming the setting tool]
The material forming the setting tool used in the present embodiment is not particularly limited, and a conventionally used material can be used.

(3) Obstacles for closing the flow path of the downhole plug The obstacles for closing the flow path of the downhole plug used in this embodiment are the setting sleeve inner wall of the setting tool, the setting rod and the rear end of the mandrel. Or it arrange | positions in the space formed of the member attached to the rear end. An obstacle for closing the flow path of the down hole plug has a function of installing the down hole plug in the well and closing the flow path of the down hole plug after the setting rod is removed. The shape of the obstacle is not particularly limited as long as it is a size and shape that can block the flow path of the downhole plug and fit in the space in the above setting tool, for example, a ball, a dirt, or The shape of a disk etc. is mentioned. Above all, the ball is preferable because the opening of the seat can be closed regardless of the seating direction, and the channel can be reliably closed.

[Material that forms an obstacle to block the channel of the downhole plug]
The material forming the obstacle for closing the flow path of the downhole plug used in the present embodiment is not particularly limited, and a material conventionally used as a material forming the obstacle may be used. it can. For example, metal materials (aluminum, steel, stainless steel, etc.), fibers, wood, composite materials and resins can be mentioned. Specifically, composite materials containing reinforcing materials such as carbon fibers, particularly epoxy Examples thereof include a composite material containing a resin and a polymer such as a phenol resin. From the viewpoint of reducing the cost of well drilling and shortening the process by facilitating the release of the blockage after use of the downhole plug and the securing of the flow path, at least one of the obstacles described above is the same as described for the mandrel. It is preferable that a part is formed from a degradable material. As the degradable material, it is more preferable that PGA is a main component. When PGA is the main component, the weight average molecular weight of PGA is preferably larger from the viewpoint of increasing strength, for example, preferably 50,000 or more, more preferably 100,000 or more, and even more preferably 150,000 or more.

(Degradable material)
As the degradable material for forming an obstacle for closing the flow path of the downhole plug used in the present embodiment, the degradable material having biodegradability and hydrolyzability is the same as described for the mandrel. Furthermore, a degradable material that can be chemically decomposed by some other method, or a degradable material that can be embrittled and easily disintegrated can be used. Among these, a degradable resin or a degradable metal is preferable as a degradable material used for the obstacle because the decomposition rate can be easily adjusted. In particular, because of its high strength, polyglycolic acid is preferable as the decomposable resin, and Mg alloy is preferable as the decomposable metal.

According to the well blocking device of the present embodiment described above, an obstacle that blocks the flow path of the downhole plug can be reliably supplied in a short time. Accordingly, it is possible to avoid the damage of the obstacle accompanying the conveyance of the obstacle, and to save the amount of fluid for conveying the obstacle. Thereby, while being able to reduce the cost of a well excavation, it becomes possible to shorten the process concerning a well excavation.

2. Well Closure Method The well closure device of this embodiment can be used regardless of the depth of the well and whether it is a vertical hole or a horizontal hole.

The well closing method using the well closing device of the present embodiment is as follows. First, the well closing device of this embodiment is moved to an arbitrary position in the well using a fluid or the like ((A) of FIG. 4). Thereafter, when the setting tool is operated, the downhole plug is installed and fixed to the inner wall of the wellbore by expanding the diameter of the annular rubber member and the slip ((B) of FIG. 4). Next, disconnect the setting tool from the downhole plug and remove the setting rod from the hollow part of the mandrel. The obstruction contained in the setting sleeve is supplied and arranged at a position where the flow path of the downhole plug is closed, for example, a seat (seat) installed on the mandrel, thereby completing the closing.

Here, when the obstacle is formed of, for example, a degradable material having hydrolyzability, the obstacle is decomposed by being exposed to water for a predetermined time, so that the obstacle is decomposed, dissolved or removed from the opening of the seat (receiver). It is possible to recover the flow path that has been blocked by.

3. Summary A device for closing a well, comprising a downhole plug, a setting tool disposed on a rear end side of the downhole plug, for operating and installing the downhole plug, and a flow path of the downhole plug One or more obstacles that occlude, the downhole plug includes a hollow mandrel that is open at least at the rear end, and the setting tool is directly or indirectly on the front end side of the mandrel. And a setting sleeve arranged to cover at least a part of the setting rod and at least a part of the downhole plug, the setting rod at a rear end of the mandrel The obstacle is inserted into the hollow part of the mandrel from the opening. Is a well closing device that is enclosed in a space in the setting tool.

Further, it is preferable that the mandrel contains a resin as a main component.

In addition, it is preferable that the mandrel contains a decomposable metal as a main component.

In addition, it is preferable that the mandrel contains a decomposable resin as a main component.

The downhole plug preferably includes a seat that receives the obstacle.

Further, the obstacle is preferably a ball, a dirt, or a disk.

Moreover, it is preferable that at least a part of the obstacle includes a degradable material.

Further, the decomposable material is preferably a decomposable resin or a degradable metal.

Also, it is preferable that the rear end of the mandrel has a notch structure so that an obstacle can be included in the space in the setting tool.

In addition, at least one of the setting rod and the setting sleeve preferably has a groove or a notch structure with respect to the axial direction so that an obstacle can be included in the space in the setting tool.

It is preferable that at least one of the setting rod or the setting sleeve has a fan-shaped notch structure with respect to the axial direction so that an obstacle can be included in the space in the setting tool.

The setting rod preferably has a groove or notch structure in the axial direction.

The setting sleeve preferably has a groove on the inner surface.

A downhole plug, a setting tool which is disposed on a rear end side of the downhole plug and operates and installs the downhole plug, and one or more obstacles which block the flow path of the downhole plug. A method of temporarily closing a well using a well closing device, wherein the downhole plug includes a hollow mandrel having at least a rear end opened, and the setting tool is on a front end side of the mandrel. A setting rod that is connected directly or indirectly to the setting rod, and a setting sleeve configured to cover at least a part of the setting rod and at least a part of the downhole plug, the setting rod including the mandrel It is inserted through the opening at the rear end into the hollow part of the mandrel and Things a method for temporarily blocking the wells with steps d) from the following a) using a wellbore occlusion device which is contained in the space in the setting tool:
a) Move the well closure device to an arbitrary position in the well and operate and install the downhole plug;
b) Disconnect the setting tool from the downhole plug and pull out the setting rod;
c) moving the obstacle in the setting tool to block the flow path in the hollow part of the mandrel;
d) After a predetermined time has elapsed, the obstacle is removed to restore the flow path.

The present invention relates to a well closing device including a setting tool and a downhole plug, and by incorporating an obstacle that closes the flow path of the downhole plug in the setting tool adjacent to the downhole plug, A well closure device that can supply obstacles quickly and safely, avoids damage to obstacles, reduces the cost of well drilling, including reducing the amount of fluid used to transport obstacles, and shortens the process. Because it is provided, it has high industrial applicability. Moreover, since the method of closing the well temporarily using the said well closing apparatus is provided, industrial applicability is high.

1: Flack plug 2: Setting tool 3: Ball 12a, 12b: Slip 13a, 13b: Wedge 14a, 14b: Ring-shaped fixing member 15: Expandable annular rubber member 21: Setting rod 22: Setting sleeve 23: Setting Connection part between tool and flack plug H: Inner wall of borehole

Claims

A device for closing a well,
Downhole plugs,
A setting tool which is arranged on the rear end side of the downhole plug and operates and installs the downhole plug;
One or more obstacles that block the flow path of the downhole plug,
The downhole plug includes a hollow mandrel having at least a rear end opened,
The setting tool includes a setting rod connected directly or indirectly to a front end side of the mandrel, and a setting sleeve arranged to cover at least a part of the setting rod and at least a part of the downhole plug. And including
The setting rod is inserted into the mandrel hollow from the rear end opening of the mandrel,
A well closing device in which the obstacle is included in a space in the setting tool.
The well closing device according to claim 1, wherein the mandrel includes a resin as a main component.
The well closing device according to claim 1, wherein the mandrel contains a degradable metal as a main component.
The well closing device according to claim 1, wherein the mandrel contains a degradable resin as a main component.
The well closing device according to claim 1, wherein the downhole plug includes a seat for receiving the obstacle.
The well blocking apparatus according to claim 1, wherein the obstacle is a ball, a dirt, or a disk.
The well blocking apparatus according to claim 1, wherein at least a part of the obstacle includes a degradable material.
The well closing device according to claim 7, wherein the degradable material is a degradable resin or a degradable metal.
The well closing device according to claim 1, wherein a rear end of the mandrel has a notch structure so that an obstacle can be included in a space in the setting tool.
The well closing device according to claim 1, wherein at least one of the setting rod and the setting sleeve has a groove or a notch structure in the axial direction so that an obstacle can be included in a space in the setting tool.
11. The well closing device according to claim 10, wherein at least one of the setting rod and the setting sleeve has a fan-shaped notch structure with respect to the axial direction so that an obstacle can be included in the space in the setting tool.
The well closing device according to claim 10, wherein the setting rod has a groove or a notch structure in the axial direction.
The well closing device according to claim 10, wherein the setting sleeve has a groove on an inner surface.
Downhole plugs,
A setting tool which is arranged on the rear end side of the downhole plug and operates and installs the downhole plug;
A method of temporarily closing a well using a well closing device including one or more obstacles for closing the flow path of the downhole plug,
The downhole plug includes a hollow mandrel having at least a rear end opened,
The setting tool includes a setting rod connected directly or indirectly to the front end side of the mandrel, and a setting sleeve having a shape covering at least a part of the setting rod and at least a part of the downhole plug. Including
The setting rod is inserted into the mandrel hollow from the rear end opening of the mandrel,
A method of temporarily closing a well by the following steps a) to d) using a well closing device in which the obstacle is included in a space in the setting tool:
a) Move the well closure device to an arbitrary position in the well and operate and install the downhole plug;
b) Disconnect the setting tool from the downhole plug and pull out the setting rod;
c) moving the obstacle in the setting tool to block the flow path in the hollow part of the mandrel;
d) After a predetermined time has elapsed, the obstacle is removed to restore the flow path.