CN111042777B - Perforating method of underground casing system and underground casing system - Google Patents
Perforating method of underground casing system and underground casing system Download PDFInfo
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- CN111042777B CN111042777B CN201911399171.5A CN201911399171A CN111042777B CN 111042777 B CN111042777 B CN 111042777B CN 201911399171 A CN201911399171 A CN 201911399171A CN 111042777 B CN111042777 B CN 111042777B
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- coiled tubing
- centralizer
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- central tube
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/11—Perforators; Permeators
- E21B43/116—Gun or shaped-charge perforators
- E21B43/117—Shaped-charge perforators
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
- E21B17/1078—Stabilisers or centralisers for casing, tubing or drill pipes
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B23/00—Apparatus for displacing, setting, locking, releasing, or removing tools, packers or the like in the boreholes or wells
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B23/00—Apparatus for displacing, setting, locking, releasing, or removing tools, packers or the like in the boreholes or wells
- E21B23/04—Apparatus for displacing, setting, locking, releasing, or removing tools, packers or the like in the boreholes or wells operated by fluid means, e.g. actuated by explosion
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/11—Perforators; Permeators
- E21B43/119—Details, e.g. for locating perforating place or direction
Abstract
The invention provides a perforation method of a downhole casing system and the downhole casing system. The perforation method comprises the following steps: sending a downhole casing system into a well, wherein the downhole casing system comprises a perforating pipe string, a coiled tubing tractor, a buffer, a coiled tubing joint and a coiled tubing which are connected with each other, and the perforating pipe string comprises a perforating gun; and opening the continuous oil pipe, and performing clustering perforation after the perforation pipe string is lowered to the bottom of the well to complete perforation operation. The downhole casing system comprises a perforating pipe string, a coiled tubing tractor, a buffer, a coiled tubing joint and a coiled tubing which are connected with each other. The perforating method of the invention utilizes the underground casing system to carry out perforation, can ensure that the perforating pipe string is put down to the bottom of the artificial well or the depth of a target well, and can well complete perforation. The underground casing system has a simple structure and is easy to process and manufacture.
Description
Technical Field
The invention relates to the technical field of petroleum and natural gas downhole construction, in particular to a perforating method of a downhole casing system and the downhole casing system.
Background
Shale gas development is currently dominated by drilling horizontal wells to increase single well production. When a horizontal well is drilled, a geosteering technology is generally adopted to improve the drilling encounter rate. I.e., multiple platform wells are drilled in a block, often as many as 8 wells per platform. In order to control the area of the platform well, some horizontal sections of the well have to be drilled in the direction of the upward inclination of the formation. The current method is to adopt a coiled tubing to carry out transmission perforation on a first construction section, then carry out sand fracturing, and from a second section, in order to improve the construction timeliness, a pumping bridge plug and a perforation tube string are often adopted to complete bridge plug setting and perforation. In addition, because the drilling machine is busy, in order to reduce the time occupied by the drilling machine, the previous scraping and washing work of a new well is sometimes finished by a coiled tubing machine. For a well with a horizontal section which is basically horizontal and the length of which is about 1500m or a well which is declined, the locking phenomenon of the coiled tubing can not occur basically in the running process, but in the well with a long horizontal section and a well with an upward horizontal section, the coiled tubing can be locked in the running process and can not be run to the target well depth.
Although the friction force between the coiled tubing and the well wall is reduced by adopting the metal drag reducer, the lowering capability of the coiled tubing in the upwarp well is greatly improved, but the coiled tubing still cannot be lowered to the target well depth for the well with large upwarp amplitude. The running depth of the coiled tubing in a long horizontal section well or a horizontal section upwarp well can be greatly increased by using the hydraulic oscillator, but the increasing depth is limited, and the coiled tubing still cannot run to the target well depth in some wells with large upwarp amplitude and long horizontal sections. And may not allow the coiled tubing to vibrate vigorously while running the string, thereby limiting the use of the hydro oscillator and limiting the horizontal length of such well completions.
Disclosure of Invention
In view of the deficiencies in the prior art, it is an object of the present invention to address one or more of the problems in the prior art as set forth above. For example, one of the objectives of the present invention is to provide a method for ensuring that a coiled tubing can be lowered to an artificial well bottom or a target well depth for perforation in an oil and gas well with a coiled tubing raised up in a horizontal section, which is especially suitable for perforation operation of oil and gas wells with long horizontal sections and raised up in a horizontal section.
To achieve the above object, an aspect of the present invention provides a perforating method of a downhole casing system, which may include the steps of: sending the underground casing system into the underground, wherein the underground casing system comprises a coiled tubing tractor, a perforating tube string, a buffer, a coiled tubing joint and a coiled tubing, wherein the tractor comprises a first centralizer, a central tube, a wrist, a circulation hole and a second centralizer, the inside of the central tube is of a hollow structure, the first centralizer and the second centralizer are respectively connected with two ends of the central tube, a fluid channel communicated with the central tube is arranged inside the first centralizer and the second centralizer, the wrist is positioned outside the central tube wall between the first centralizer and the second centralizer, the circulation hole is arranged on the wall of the central tube between the wrist and the second centralizer, the circulation hole is communicated with the hollow structure of the central tube, the perforating tube string is connected with the first centralizer of the coiled tubing tractor, one end of the buffer is connected with one end of the second centralizer, far away from the central tube, the other end of the buffer is connected with a coiled tubing joint, one end of the coiled tubing joint is connected with the other end of the buffer, the other end of the coiled tubing joint is connected with the coiled tubing, and the perforating string comprises a perforating gun;
and opening the continuous oil pipe, and performing clustering perforation to complete perforation operation after the perforation pipe string is put into the bottom of the well.
In an exemplary embodiment of the downhole casing system perforating method of the present invention, the clustered perforations comprise: lifting the perforating pipe string to be aligned with a first section of a first cluster of pressure-building detonation perforating gun; and lifting the perforating pipe string, and respectively aligning the first section of the second cluster and the third cluster to perform delayed initiation perforation to complete the first section of perforation operation.
In an exemplary embodiment of the downhole casing system perforating method of the present invention, the perforating method may further comprise: when the underground casing system is sent to the underground, if the underground casing system is difficult to send, the hanging weight obviously descends and the depth of the underground casing system is slowly increased or not increased, the underground casing system is slowly put down after working fluid is pumped from the small annular space displacement of the continuous oil pipe and the well to observe whether the hanging weight obviously descends or not, and along with the increase of the descending depth of the underground casing system, the annular space pumping displacement of the continuous oil pipe and the shaft is gradually increased until the perforating pipe string is put down to the bottom of the well.
In an exemplary embodiment of the downhole casing system perforating method of the present invention, both ends of the base pipe may be threadedly connected with a first centralizer and a second centralizer, respectively.
In an exemplary embodiment of the method for perforating a downhole casing system of the present invention, the outer sides of the first centralizer and the second centralizer may be equally circumferentially distributed with water troughs.
In an exemplary embodiment of the perforation method of the downhole casing system, the wrist can be a circular truncated cone structure, and the wrist can stretch and contract along the pipe diameter direction of the central pipe.
In an exemplary embodiment of the perforating method of the downhole casing system of the present invention, the number of the circulation holes may be 1 to 3.
In an exemplary embodiment of the perforating method of the downhole casing system of the invention, the downhole casing system may further comprise a coiled tubing hydraulic emergency release and a coiled tubing check valve, wherein one end of the coiled tubing hydraulic emergency release is connected with the buffer, and the other end of the coiled tubing hydraulic emergency release is connected with the coiled tubing check valve; one end of the coiled tubing check valve is connected with the other end of the coiled tubing hydraulic emergency release device, and the other end of the coiled tubing check valve is connected with the coiled tubing joint.
The invention provides a downhole casing system, which can comprise a coiled tubing tractor, a perforating tube string, a buffer, a coiled tubing joint and a coiled tubing, wherein the tractor comprises a first centralizer, a central tube, a wrist, a circulation hole and a second centralizer, the inside of the central tube is of a hollow structure, the first centralizer and the second centralizer are respectively connected with two ends of the central tube, fluid channels communicated with the central tube are arranged inside the first centralizer and the second centralizer, the wrist is positioned on the outer side of the wall of the central tube between the first centralizer and the second centralizer, the circulation hole is formed in the wall of the central tube between the wrist and the second centralizer, and the circulation hole is communicated with the hollow structure of the central tube; the perforating pipe string comprises a perforating gun, and is connected with a first centralizer of the coiled tubing tractor; one end of the buffer is connected with one end, far away from the central pipe, of the second centralizer, and the other end of the buffer is connected with the coiled tubing joint; one end of the coiled tubing joint is connected with the other end of the buffer, and the other end of the coiled tubing joint is connected with the coiled tubing.
In an exemplary embodiment of the downhole casing system of the present invention, the downhole casing system may further comprise a coiled tubing hydraulic emergency release and a coiled tubing check valve, wherein one end of the coiled tubing hydraulic emergency release is connected to the buffer and the other end of the coiled tubing hydraulic emergency release is connected to the coiled tubing check valve; one end of the coiled tubing check valve is connected with the other end of the coiled tubing hydraulic emergency release device, and the other end of the coiled tubing check valve is connected with the coiled tubing joint.
Compared with the prior art, the invention has the following effective effects:
(1) the perforating method of the invention utilizes the underground casing system to carry out perforating, can ensure that the perforating pipe string is put down to the artificial well bottom or the target well depth, can improve the putting-in capacity of the perforating pipe string in a long horizontal section well and a horizontal section upwarp well, and has simple perforating method and easy implementation;
(2) the underground casing system has a simple structure, is easy to process and manufacture, and can save cost without using a hydraulic oscillator and a metal drag reducer;
(3) the underground casing system can improve the running capability of the coiled tubing in a long horizontal section well and a horizontal section upturned well, and solves the problem that the coiled tubing cannot run to an artificial well bottom or a target well depth due to locking in the oil-gas well with the coiled tubing upturned in the horizontal section.
Drawings
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 illustrates a coiled tubing tractor schematic of an exemplary embodiment of the present invention;
description of reference numerals:
1-a first centralizer, 2-a central tube, 3-a wrist, 4-a circulation hole, 5-a second centralizer, 6-a centralizing boss and 7-a water tank.
Detailed Description
Hereinafter, a perforating method of a downhole casing system and the downhole casing system according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.
Fig. 1 is a schematic view of a coiled tubing tractor according to an exemplary embodiment of the present invention, wherein fig. (a) is a schematic view of a coiled tubing tractor structure, fig. (B) is a partial sectional view of a-a in fig. (a), and fig. (c) is a partial sectional view of B-B in fig (a).
One aspect of the present invention provides a downhole casing system perforating method, which, in one exemplary embodiment of the downhole casing system perforating method of the present invention, may comprise:
sending the underground casing system into the well, opening the continuous oil pipe, and performing clustering perforation to complete perforation operation after the perforation pipe string is put into the well bottom, wherein,
the downhole casing system may include a coiled tubing tractor, a perforating string, a buffer, a coiled tubing joint, and coiled tubing. As shown in fig. 1 (the upper part of fig. 1(a) is a cross-sectional view of a coiled tubing tractor), the coiled tubing tractor may include: a first centralizer 1, a central tube 2, a wrist 3, a circulation hole 4 and a second centralizer 5, wherein,
the interior of the central tube 2 may be provided as a hollow structure. The hollow structure enables the circulation of liquid inside the central tube 2.
The first centralizer 1 and the second centralizer 5 are respectively arranged at two ends of the central pipe 2. The first centralizer 1 can be sleeved with one end of the central pipe 2, and the second centralizer 5 can be sleeved with the other end of the central pipe 2. The central tube 2 may be threaded at both ends with a first centralizer 1 and a second centralizer 2, respectively, for example, a 2-3/PAC threaded connection may be used. And a flow passage which can enable liquid to flow is arranged in the middle of the first centralizer 1 and the second centralizer 5. The flow channels provided in the first centralizer 1 and the second centralizer 5 communicate with each other and the hollow structure in the central tube 2.
The leather wrist 3 can be embedded on the pipe wall of the central pipe 2. The wrist 3 may be located between the first centralizer 1 and the second centralizer 5. The wrist 3 can stretch along the pipe diameter direction of the central pipe 2. The wrist 3 can be used for sealing an annular space between the outer side of the wrist 3 and a shaft due to the fact that the wrist can stretch along the pipe diameter direction.
The circulation holes 4 are arranged on the wall of the central tube 2. The circulation holes 4 penetrate through the wall of the central pipe 2 and are communicated with the hollow structure of the central pipe 2. The number of the circulation holes 4 may be plural, for example, 1 to 3. The number and the aperture of the circulation holes can be set according to the working displacement of the coiled tubing during operation.
The perforating pipe string is connected with a first centralizer of the coiled tubing tractor, one end of the buffer is connected with one end, far away from the central pipe, of the second centralizer, the other end of the buffer is connected with the coiled tubing joint, one end of the coiled tubing joint is connected with the buffer, the other end of the coiled tubing joint is connected with the coiled tubing, and the perforating pipe string comprises a perforating gun. It is noted here that the perforating string includes perforating guns and perforation assistance devices commonly used in the art. For example, a perforating string may be a deep-hole string consisting of a primer tail, a body, a butt joint, and an initiator.
In the above, when pumping fluid into the annulus between the downhole casing system and the wellbore of the present invention, the fluid enters the base pipe through the circulation holes of the tractor and returns to the surface through the coiled tubing. When fluid passes through the circulation hole, throttling pressure difference is formed between an inlet and an outlet of the circulation hole, the pressure of the upper annular space of the pitman is larger than the pressure below the pitman, and due to the existence of the pressure difference, the tractor is pushed by the fluid to move downwards to assist in lowering the coiled tubing to the target well depth. Because the perforating pipe string is connected with the coiled tubing, when the coiled tubing is lowered to the target well depth, the perforating pipe string can be lowered to the target well depth to realize perforating operation.
In this embodiment, the clustered perforations may include staged multi-cluster perforations to the horizontal well. For example, the perforating method can perform cluster perforating on the first section of the horizontal well, and the cluster number of the first section of the perforating can be 2-5 clusters. Further, the number of clusters in the first stage of perforation may be 3 clusters. The clustered perforations may include: lifting the perforating gun in the perforating pipe string to a perforating position, and aligning to a first section of a horizontal well, and pressing and detonating the perforating gun; and lifting the perforating gun in the perforating pipe string to a perforating position, and respectively aligning the second cluster and the third cluster of the first section of the horizontal well to perform delayed initiation perforation to complete the first section of perforating operation. For the perforation method of other sections of the horizontal well, the perforating gun can be conveyed to a target depth by a method of using a cable to cooperate with pumping fluid, and the perforating gun is electrified and detonated for perforation. The number of the segmented sections of the horizontal well can be determined according to the actual field situation. In the above, the length of the first section of the horizontal well can be determined according to the actual field situation. For example, the length of the first section of the horizontal well can be 100-150 m.
In this embodiment, the perforation method may further include: when the underground casing system is sent to the underground, if the underground casing system is difficult to send, the hanging weight obviously descends and the depth of the underground casing system is slowly increased or not increased, the annular displacement pump injection of the continuous oil pipe and the shaft is reduced, whether the hanging weight obviously descends is observed, if the hanging weight obviously descends, the underground casing system is slowly put down, and the annular displacement pump injection of the continuous oil pipe and the shaft is gradually increased along with the increase of the descending depth of the underground casing system until the perforating pipe string is put down to the bottom of the well. Specifically, if the target depth is not reached after the use of the metal drag reducer and the hydraulic shaker, the string of perforations may be connected to a first centralizer (where the first centralizer may be the lower sub of the tractor) that in turn connects a buffer, a coiled tubing hydraulic emergency release tool, a coiled tubing check valve, a coiled tubing joint, coiled tubing above a second centralizer (where the first centralizer may be the upper sub of the tractor), according to software simulation results. When the coiled tubing is difficult to feed, the suspended weight obviously decreases and the depth of the tubing is slowly increased or not increased, the locking is basically judged to occur. At the moment, the annular small-displacement pump injection is carried out on the coiled tubing and the shaft, whether the hanging weight is obviously reduced or not is observed, if the hanging weight is obviously reduced, the coiled tubing can be slowly lowered, the traction force required by the coiled tubing is increased along with the increase of the lowering depth, the displacement can be gradually increased, the pressure difference between the inside and the outside of the coiled tubing is increased, the traction force is increased, but the pressure difference is controlled within a reasonable range, and the coiled tubing is prevented from being damaged by extrusion. After the perforating pipe string is lowered to the bottom of the artificial well, the perforating pipe string is lifted up to be aligned with the first section of the first cluster, the detonating perforating gun is suppressed, and the perforating pipe string is aligned with the first section of the second cluster and the third cluster respectively to carry out delayed detonating perforation.
In this embodiment, the outer surface of the first centralizer 1 may be equally distributed with centralizing bosses 6 and water tanks 7 along the circumferential direction, and the water tanks are disposed between the centralizing bosses 6, as shown in fig. 1 (b). Also, the outer surface of the second centralizer 5 may be distributed with centralizing bosses 6 and water grooves 7 equally along the circumferential direction, as shown in fig. 1 (c).
Another aspect of the present invention provides a downhole casing system that may be structurally combined in the same manner as the downhole casing system described above. For example, the downhole casing system may include a coiled tubing tractor, a perforating string, a buffer, a coiled tubing joint, and coiled tubing, where the tractor includes a first centralizer, a central tube, a wrist, a circulation hole, and a second centralizer, the inside of the central tube is a hollow structure, the first centralizer and the second centralizer are respectively connected to two ends of the central tube, a fluid channel communicated with the central tube is provided inside the first centralizer and the second centralizer, the wrist is located outside the central tube between the first centralizer and the second centralizer, the circulation hole is opened in a wall of the central tube between the wrist and the second centralizer, and the circulation hole is communicated with the hollow structure of the central tube; the perforating pipe string comprises a perforating gun, and is connected with a first centralizer of the coiled tubing tractor; one end of the buffer is connected with one end, far away from the central pipe, of the second centralizer, and the other end of the buffer is connected with the coiled tubing joint; one end of the coiled tubing joint is connected with the other end of the buffer, and the other end of the coiled tubing joint is connected with the coiled tubing.
In an exemplary embodiment of the downhole casing system of the present invention, the downhole casing system may further comprise a coiled tubing hydraulic emergency release and a coiled tubing check valve, wherein one end of the coiled tubing hydraulic emergency release is connected to the buffer and the other end of the coiled tubing hydraulic emergency release is connected to the coiled tubing check valve; one end of the coiled tubing check valve is connected with the other end of the coiled tubing hydraulic emergency release device, and the other end of the coiled tubing check valve is connected with the coiled tubing joint.
In conclusion, the perforating method of the invention utilizes the underground casing system to carry out perforation, can ensure that the perforating pipe string is put down to the artificial well bottom or the target well depth, and can improve the putting-in capacity of the perforating pipe string in the long horizontal section well and the horizontal section upwarp well; the underground casing system has a simple structure and is easy to process and manufacture; by using the downhole casing system, a hydraulic oscillator and a metal drag reducer can be omitted, and the cost can be saved.
Although the present invention has been described above in connection with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A method of perforating a downhole casing system, the method comprising the steps of:
feeding a downhole casing system downhole, wherein the downhole casing system comprises a coiled tubing tractor, a perforating string, a buffer, a coiled tubing joint, and coiled tubing,
wherein, the coiled tubing tractor comprises a first centralizer, a central tube, a wrist, a circulation hole and a second centralizer, the inside of the central tube is of a hollow structure, the first centralizer and the second centralizer are respectively connected with two ends of the central tube, fluid channels communicated with the central tube are arranged inside the first centralizer and the second centralizer, the wrist is positioned on the outer side of the wall of the central tube between the first centralizer and the second centralizer, the circulation hole is arranged on the wall of the central tube between the wrist and the second centralizer, the circulation hole is communicated with the hollow structure of the central tube,
the perforating pipe string is connected with a first centralizer of a coiled tubing tractor, one end of the buffer is connected with one end, far away from the central pipe, of the second centralizer, the other end of the buffer is connected with a coiled tubing joint, one end of the coiled tubing joint is connected with the other end of the buffer, the other end of the coiled tubing joint is connected with the coiled tubing, and the perforating pipe string comprises a perforating gun;
opening the continuous oil pipe, performing cluster perforation after the perforation pipe string is put into the bottom of the well to complete perforation operation,
in the process of putting the coiled tubing deep into the horizontal section, opening a valve in the flow from the coiled tubing to an outlet, when the feeding of the coiled tubing is difficult, the hanging weight obviously decreases and the depth of the tubing increases slowly or does not increase, starting pumping working fluid from the annular small displacement of the coiled tubing and the well, observing whether the hanging weight obviously decreases or not, if the hanging weight obviously decreases, slowly lowering the underground casing system, and gradually increasing the annular pumping displacement of the coiled tubing and the shaft until the perforating string is put into the bottom of the well or the target well depth along with the increase of the putting depth of the underground casing system.
2. The perforating method of the downhole casing system according to claim 1, wherein the clustering perforation comprises clustering perforation of a first section of the horizontal well, and the number of clusters of the first section is 2-5 clusters.
3. The downhole casing system perforating method of claim 2, wherein the first segment number of perforation clusters is 3 clusters, and the clustered perforations comprise:
lifting the perforating gun in the perforating pipe string to a perforating position, and aligning to a first section of a horizontal well, and pressing and detonating the perforating gun;
and lifting the perforating gun in the perforating pipe string to a perforating position, and respectively aligning the second cluster and the third cluster of the first section of the horizontal well to perform delayed initiation perforation to complete the first section of perforating operation.
4. The method of perforating a downhole casing system according to claim 1, wherein both ends of the base pipe are threadedly connected with a first centralizer and a second centralizer, respectively.
5. The method of perforating a downhole casing system of claim 1, wherein the outer sides of the first centralizer and the second centralizer are circumferentially equally distributed with water channels.
6. The perforating method of the downhole casing system according to claim 1, wherein the wrist is a cone structure, and the wrist can extend and retract along the diameter direction of the central pipe.
7. The downhole casing system perforating method of claim 1, wherein the downhole casing system further comprises a coiled tubing hydraulic emergency release and a coiled tubing check valve, wherein,
one end of the coiled tubing hydraulic emergency release device is connected with the buffer, and the other end of the coiled tubing hydraulic emergency release device is connected with the coiled tubing check valve;
one end of the coiled tubing check valve is connected with the other end of the coiled tubing hydraulic emergency release device, and the other end of the coiled tubing check valve is connected with the coiled tubing joint.
8. A downhole casing system, which is a system for implementing the perforating method of the downhole casing system according to any one of claims 1 to 7, and which comprises a coiled tubing tractor, a perforating string, a buffer, a coiled tubing joint, and coiled tubing, wherein the coiled tubing tractor comprises a first centralizer, a central tube, a wrist, a circulation hole, and a second centralizer, the central tube is hollow, the first centralizer and the second centralizer are respectively connected to two ends of the central tube, the first centralizer and the second centralizer are internally provided with a fluid channel communicated with the central tube, the wrist is located on the outer side of the wall of the central tube between the first centralizer and the second centralizer, the circulation hole is opened in the wall of the central tube between the wrist and the second centralizer, the circulating hole is communicated with the hollow structure of the central pipe;
the perforating pipe string comprises a perforating gun, and is connected with a first centralizer of the coiled tubing tractor;
one end of the buffer is connected with one end, far away from the central pipe, of the second centralizer, and the other end of the buffer is connected with the coiled tubing joint;
one end of the coiled tubing joint is connected with the other end of the buffer, the other end of the coiled tubing joint is connected with the coiled tubing, and when fluid is pumped into an annular space between the underground casing system and the shaft, the fluid enters the central tube through the circulation hole of the tractor and returns to the ground through the coiled tubing; when fluid passes through the circulation hole, throttling pressure difference is formed between an inlet and an outlet of the circulation hole, the pressure of the upper annular space of the pitman is larger than the pressure below the pitman, the tractor is pushed by the fluid to move downwards due to the existence of the pressure difference, and when the traction force required by the coiled tubing is increased, the traction force is increased by increasing the pressure difference between the inside and the outside of the coiled tubing, so that the coiled tubing is lowered to the artificial well bottom or the target well depth in an auxiliary mode.
9. The downhole casing system of claim 8, wherein the first centralizer and the second centralizer are circumferentially and equally distributed on the outer side thereof with centralizing bosses and water channels, and the water channels are arranged between the centralizing bosses.
10. The downhole casing system of claim 8, further comprising a coiled tubing hydraulic emergency release and a coiled tubing check valve, wherein,
one end of the coiled tubing hydraulic emergency release device is connected with the buffer, and the other end of the coiled tubing hydraulic emergency release device is connected with the coiled tubing check valve;
one end of the coiled tubing check valve is connected with the other end of the coiled tubing hydraulic emergency release device, and the other end of the coiled tubing check valve is connected with the coiled tubing joint.
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| CN201911399171.5A CN111042777B (en) | 2019-12-30 | 2019-12-30 | Perforating method of underground casing system and underground casing system |
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| CN201911399171.5A CN111042777B (en) | 2019-12-30 | 2019-12-30 | Perforating method of underground casing system and underground casing system |
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| CN111042777B true CN111042777B (en) | 2022-03-01 |
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| CN2714793Y (en) * | 2004-07-29 | 2005-08-03 | 冀东石油勘探开发公司 | Well top pressure tester |
| CN201963271U (en) * | 2011-03-03 | 2011-09-07 | 中国石油天然气股份有限公司 | Integral liquid discharge device for suctioning and discharging bubbles in gas well |
| CN105317409B (en) * | 2014-07-03 | 2018-03-09 | 中国石油化工股份有限公司 | A kind of staged fracturing of horizontal well pumps perforating methods |
| CN204920833U (en) * | 2015-09-25 | 2015-12-30 | 慕彩霞 | Foldable oil pipe buffer |
| CN106382100A (en) * | 2016-11-15 | 2017-02-08 | 刘代学 | Wax-scraping centralizer |
-
2019
- 2019-12-30 CN CN201911399171.5A patent/CN111042777B/en active Active
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