Coiled tubing cutting device and cutting and fishing method

Abstract

The invention discloses a coiled tubing cutting device and a cutting and fishing method, and belongs to the technical field of oil extraction equipment. The coiled tubing cutting device is characterized by comprising a coiled tubing, a first anchoring mechanism, a second anchoring mechanism and a cutting mechanism, the first anchoring mechanism and the second anchoring mechanism are connected to the coiled tubing in the length direction of the coiled tubing. The cutting mechanism is connected to the coiled tubing, and the cutting mechanism is located between the first anchoring mechanism and the second anchoring mechanism. According to the continuous oil pipe cutting device and the cutting and fishing method, the impact damage risk of deformation stress of the cut completion pipe string can be effectively reduced, and the safety and efficiency of cutting and fishing operation are improved.

Description

Technical Field

[0001] The present application belongs to the technical field of oil production equipment, and in particular relates to a continuous oil pipe cutting device and a cutting and salvaging method. Background Art

[0002] In oil and gas fields, in order to control the annular pressure and protect the oil layer casing, packers are often installed on the downhole tubing to effectively resist the up and down movement of the oil well tubing and ensure the long-term stability of the completion tubing. However, due to changes in downhole working conditions, the packer may also move up and down, resulting in greater stress in the completion tubing, which is not conducive to the release of the packer and increases the difficulty of later salvage.

[0003] Considering that the packers are mostly made of hard alloy, the local stress of the connection parts is very large, and it is very difficult and costly to directly grind or cut them. For this reason, continuous tubing is often used to carry cutting tools to cut the pipe string. However, the pipe string will move axially at the moment of cutting, impacting and damaging the blowout preventer group at the wellhead, and other pipe strings or cable tools will fall into the well, causing secondary complex accidents; the pipe string is also easily affected by bending stress and spiral stress, causing the pipe to bend and deform at the cutting part of the pipe string, increasing the difficulty of later salvage. Summary of the invention

[0004] The present application provides a continuous tubing cutting device and cutting and salvaging method, which aims to at least to some extent solve the technical problem that downhole tubing cutting is susceptible to stress, impact damage to the blowout preventer group and surrounding tubing, components and equipment. To this end,

[0005] In one aspect, an embodiment of the present application provides a coiled tubing cutting device, including: a coiled tubing, a first anchoring mechanism, a second anchoring mechanism, and a cutting mechanism;

[0006] The first anchoring mechanism and the second anchoring mechanism are respectively connected to the coiled tubing along the length direction of the coiled tubing;

[0007] The cutting mechanism is connected to the coiled tubing, and the cutting mechanism is located between the first anchoring mechanism and the second anchoring mechanism.

[0008] In some embodiments, the coiled tubing cutting device further comprises a hydraulic expansion tube connected to an end of the coiled tubing.

[0009] In some embodiments, the cutting mechanism is a water cutting device;

[0010] Wherein, the water cutting equipment is equipped with a hydraulic drive device.

[0011] In some embodiments, the coiled tubing cutting device further comprises a shear joint, and the first anchoring mechanism and / or the second anchoring mechanism are respectively connected to the coiled tubing through the shear joint.

[0012] In some embodiments, the first anchoring mechanism and the second anchoring mechanism are hydraulic anchors.

[0013] Another aspect of the embodiment of the present application provides a cutting and salvaging method, which uses the continuous tubing cutting device to perform a cutting operation and then salvages the cut tubing.

[0014] In some embodiments, the cutting operation includes:

[0015] Lowering the cutting mechanism to a set cutting position;

[0016] The first anchoring mechanism and the second anchoring mechanism are anchored on the pipe string to be cut;

[0017] Cutting off the pipe string to be cut;

[0018] releasing the first anchoring mechanism and the second anchoring mechanism respectively and in order;

[0019] The coiled tubing and the cut tubing string are salvaged respectively.

[0020] In some embodiments, the cutting operation further comprises:

[0021] After the first anchoring mechanism and the second anchoring mechanism are anchored and before the cutting operation, prestressing the coiled tubing;

[0022] The prestress is comparable in size to the lower slip support force of the packer of the pipe string to be cut, and the direction of the prestress is set to buffer the deformation stress of the pipe string to be cut.

[0023] In some embodiments, applying prestress to the coiled tubing comprises:

[0024] The coiled tubing is pulled or pressed by a hydraulic expansion pipe connected to the wellhead end of the coiled tubing.

[0025] In some embodiments, the cutting position is a force balance point of the pipe string to be cut.

[0026] The embodiments of the present application have at least the following beneficial effects:

[0027] The continuous tubing cutting device and cutting and salvaging method provided in the embodiment of the present application uses the continuous tubing as a carrier to install the cutting mechanism and the first anchoring mechanism and the second anchoring mechanism, so as to facilitate lowering into the downhole tubing string to perform the cutting operation; and then the first anchoring mechanism and the second anchoring mechanism are arranged on both sides of the cutting mechanism and anchored to the inner wall of the downhole tubing string, so as to connect the downhole tubing string and the continuous tubing as one, so that after cutting the downhole tubing string, the stress in the downhole tubing string can be released, and the two sections of the tubing string can be fixed to the continuous tubing, so as to transfer part of the stress to the continuous tubing, so as to avoid the downhole tubing string from moving up and down and impacting and damaging the imported blowout prevention group and the surrounding tubing strings, components and equipment. On the other hand, after the cutting is completed, the first anchoring mechanism and the second anchoring mechanism are released, so as to lift the pipe and salvage other downhole equipment and components, thereby improving the convenience and safety of cutting and salvaging as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic structural diagram of a coiled tubing cutting device in an embodiment of the present application is shown.

[0030] Reference numerals:

[0031] 1-coiled tubing, 2-cutting mechanism, 3-first anchoring mechanism, 4-second anchoring mechanism, 5-hydraulic telescopic tube, 6-downhole tubing, 7-packer, 8-outer casing. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides various specific examples of processes and materials, but those of ordinary skill in the art may recognize the application of other processes and / or the use of other materials.

[0034] The present application is described below with reference to the accompanying drawings and specific embodiments:

[0035] The completion string is susceptible to axial and circumferential deformation stress caused by various factors. During cutting and salvaging, axial movement and impact are likely to damage the wellhead and downhole equipment, or bend the string, affecting the operation of the operator.

[0036] To this end, the embodiments of the present application provide a continuous tubing cutting device and a cutting and salvaging method, which aim to suppress the impact amplitude of the cutting pipe string to a certain extent, reduce the impact on surrounding equipment, structures and components, and improve the safety, convenience and efficiency of the cutting operation.

[0037] Figure 1 The schematic diagram of the structure of the coiled tubing cutting device in the embodiment of the present application is shown; see Figure 1 In some embodiments, the coiled tubing cutting device includes: a coiled tubing 1 , a first anchoring mechanism 3 , a second anchoring mechanism 4 and a cutting mechanism 2 .

[0038] The coiled tubing 1 is used as a carrier for carrying and installing the first anchoring mechanism 3, the second anchoring mechanism 4 and the cutting mechanism 2, so as to facilitate lowering the three into the well 6 for anchoring and cutting.

[0039] Among them, the first anchoring mechanism 3 and the second anchoring mechanism 4 are arranged on both sides of the cutting mechanism 2 along the length direction of the continuous oil pipe 1, and are used to anchor on the inner wall of the downhole pipe string 6, so that a stable support structure can be formed on both sides of the cutting mechanism 2, and the downhole pipe string 6 and the continuous oil pipe 1 are fixed together, providing a relatively static and stable cutting environment for the cutting mechanism 2, thereby improving the stability of the cutting operation.

[0040] On the other hand, after the cutting mechanism 2 cuts off the downhole tubular string 6, the deformation stress in the downhole tubular string 6 is released, and the deformation force is transmitted to the continuous oil pipe 1 through the first anchoring mechanism 3 and the second anchoring mechanism 4, and the cut downhole tubular string 6 is fixed on the continuous oil pipe 1, which greatly limits the axial movement amplitude of the downhole tubular string 6, thereby greatly reducing the risk of impact damage to the equipment, components and accessories connected to the downhole tubular string 6.

[0041] At the same time, the coiled tubing 1 itself is basically not connected to the surrounding permanent structures. Therefore, the stress transfer is completed at the moment of cutting, and the deformation stress is absorbed by the deformation of the coiled tubing 1 and the connected control equipment.

[0042] In some embodiments, in order to further reduce the axial stress impact of the continuous oil tubing 1, a hydraulic telescopic tube 5 can be set at the end of the continuous oil tubing to apply a pulling or pressing force to the continuous oil tubing 1 to match and buffer the axial movement force on the downhole oil tubing 6 at the moment of cutting.

[0043] The expansion and contraction range of the hydraulic expansion tube 5 and the applied prestress can be applied by the connected hydraulic equipment.

[0044] In some embodiments, the cutting mechanism 2 may be a water cutting device, and the water cutting device is provided with a hydraulic driving device, such as a circulating pump, which drives the water cutting device to operate by injecting a fluid medium.

[0045] By continuing to circulate and pump the coiled tubing, the water flow rate in the coiled tubing is increased, driving the screw cutting device in the water cutting equipment to complete the cutting of the tubing string.

[0046] Of course, in other embodiments, the cutting mechanism 2 may adopt cutting devices based on other principles.

[0047] In some embodiments, the first anchoring mechanism 3 and the second anchoring mechanism 4 may fail to unlock, resulting in the inability to pull out the tubing string or the cutting mechanism 2 respectively; for this purpose, the continuous tubing cutting device may also be provided with a shear joint, and the first anchoring mechanism 3 and / or the second anchoring mechanism 4 are respectively connected to the continuous tubing 1 through the shear joint, so that the continuous tubing 1 can be pulled forcefully to cut the shear joint, so that the first anchoring mechanism 3 and / or the second anchoring mechanism 4 are respectively detached from the continuous tubing 1 and smoothly pulled out from the well.

[0048] In some embodiments, the first anchoring mechanism 3 and the second anchoring mechanism 4 may be configured as hydraulic anchors, and of course, may also be anchors based on other principles.

[0049] The embodiment of the present application also provides a cutting and salvaging method, which uses the coiled tubing cutting device to perform a cutting operation and then salvages the cut tubing.

[0050] The cutting operation may include:

[0051] Lowering the cutting mechanism to a set cutting position;

[0052] The first anchoring mechanism 3 and the second anchoring mechanism 4 are anchored on the pipe string to be cut, that is, the downhole pipe string 6;

[0053] Cutting off the pipe string to be cut;

[0054] Respectively and orderly release the first anchoring mechanism 3 and the second anchoring mechanism 4;

[0055] The coiled tubing 1 and the cut tubing string are respectively salvaged, and the packer 7 in the outer casing 8 is also salvaged.

[0056] In some embodiments, the hydraulic expansion tube may be used to apply prestress to the coiled tubing to offset the impact force of the coiled tubing 1. The cutting operation may further include:

[0057] After the first anchoring mechanism 34 and the second anchoring mechanism 4 are anchored, before the cutting operation, prestress is applied to the coiled tubing.

[0058] The prestress is comparable in magnitude to the lower slip support force of the packer 7 of the pipe string to be cut, and the direction of the prestress is set to buffer the deformation stress of the pipe string to be cut.

[0059] The application of prestress to the coiled tubing can be achieved by pulling or pressing the coiled tubing 1 through a hydraulic expansion pipe connected to the wellhead end of the coiled tubing 1 .

[0060] In some embodiments, the cutting position may be a force balance point of the pipe string to be cut.

[0061] The force balance point can be determined based on the following formula, with the wellhead as the reference and the distance L to the wellhead as the force balance point.

[0062] L=(Fg-F1+F2) / ρs

[0063] Among them, F1-the pressure generated by the annulus natural gas column, F2-the pressure generated by the annulus liquid column, Fg-the support force of the slip under the packer, L-the cutting position (force balance point), ρs-the linear weight of the pipe string.

[0064] The prestress value of the tubing string P=Fg is determined by the completion tubing pre-lift test, and the coiled tubing is lowered into the wellbore and lifted to P by the hydraulic telescopic tube connected to the tubing.

[0065] The corresponding parameters can be determined according to the following derivation process:

[0066] S = 1 / 4 × 3.14 × (Dd)

[0067] V=S×H

[0068] F1=Pc×S

[0069] =(Hp-H)×ρ×S

[0070] Fg=ρs×L+F1+F2

[0071] That is, L = (Fg-F1+F2) / ρs

[0072] D-tubing outer diameter, D-casing inner diameter, S-casing annulus cross-sectional area, V-annulus volume, H-annulus liquid level depth, Pc-casing pressure, Pt-tubing pressure, Hp-packer setting depth, ρl-liquid column density.

[0073] The embodiments of the present application have at least the following beneficial effects:

[0074] The continuous tubing cutting device and cutting and salvaging method provided in the embodiment of the present application uses the continuous tubing as a carrier to install the cutting mechanism and the first anchoring mechanism and the second anchoring mechanism, so as to facilitate lowering into the downhole tubing string to perform the cutting operation; and then the first anchoring mechanism and the second anchoring mechanism are arranged on both sides of the cutting mechanism and anchored to the inner wall of the downhole tubing string, so as to connect the downhole tubing string and the continuous tubing as one, so that after cutting the downhole tubing string, the stress in the downhole tubing string can be released, and the two sections of the tubing string can be fixed to the continuous tubing, so as to transfer part of the stress to the continuous tubing, so as to avoid the downhole tubing string from moving up and down and impacting and damaging the imported blowout prevention group and the surrounding tubing strings, components and equipment. On the other hand, after the cutting is completed, the first anchoring mechanism and the second anchoring mechanism are released, so as to lift the pipe and salvage other downhole equipment and components, thereby improving the convenience and safety of cutting and salvaging as a whole.

[0075] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0076] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0077] It should be noted that all directional indications in the embodiments of the present application are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0078] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0079] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0081] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0082] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A coiled tubing cutting device, characterized in that: include: A coiled tubing, a first anchoring mechanism, a second anchoring mechanism, and a cutting mechanism; The first anchoring mechanism and the second anchoring mechanism are respectively connected to the coiled tubing along the length direction of the coiled tubing; The cutting mechanism is connected to the coiled tubing, and the cutting mechanism is located between the first anchoring mechanism and the second anchoring mechanism.

2. The coiled tubing cutting device according to claim 1, characterized in that: The coiled tubing cutting device further comprises a hydraulic expansion tube connected to the end of the coiled tubing.

3. The coiled tubing cutting device according to claim 1, characterized in that: The cutting mechanism is a water cutting device; Wherein, the water cutting equipment is equipped with a hydraulic drive device.

4. The coiled tubing cutting device according to claim 1, characterized in that: The coiled tubing cutting device further comprises a shear joint, and the first anchoring mechanism and / or the second anchoring mechanism are respectively connected to the coiled tubing through the shear joint.

5. The coiled tubing cutting device according to claim 1, characterized in that: The first anchoring mechanism and the second anchoring mechanism are hydraulic anchors.

6. A cutting and salvaging method, characterized in that: The continuous tubing cutting device according to any one of claims 1 to 5 is used to perform a cutting operation, and then the cut tubing is salvaged.

7. The cutting and salvaging method according to claim 6, characterized in that: The cutting operation includes: Lowering the cutting mechanism to a set cutting position; The first anchoring mechanism and the second anchoring mechanism are anchored on the pipe string to be cut; Cutting off the pipe string to be cut; releasing the first anchoring mechanism and the second anchoring mechanism respectively and in order; The coiled tubing and the cut tubing string are salvaged respectively.

8. The cutting and salvaging method according to claim 7, characterized in that: The cutting operation also includes: After the first anchoring mechanism and the second anchoring mechanism are anchored and before the cutting operation, prestressing the coiled tubing; The prestress is comparable in size to the lower slip support force of the packer of the pipe string to be cut, and the direction of the prestress is set to buffer the deformation stress of the pipe string to be cut.

9. The cutting and salvaging method according to claim 8, characterized in that: The applying prestress to the coiled tubing comprises: The coiled tubing is pulled or pressed by a hydraulic expansion pipe connected to the wellhead end of the coiled tubing.

10. The cutting and salvaging method according to claim 8, characterized in that: The cutting position is the force balance point of the pipe string to be cut.

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