Hydraulic delivery salvageable tubing plug and plugging method thereof

Abstract

The invention belongs to the technical field of oil production engineering in the oil industry, and discloses a hydraulic delivery salvageable tubing plug and a plugging method thereof.The hydraulic delivery salvageable tubing plug comprises a salvage assembly, an anchoring assembly, a sealing assembly and a delivery assembly, and the salvage assembly is composed of a salvage head, a connecting rod and a shear pin; the anchoring assembly is composed of a slip sleeve, a slip and a slip bowl. The sealing assembly is composed of a sealing leather cup, a sealing ring and a center rod. The delivery assembly is composed of a delivery leather cup and a guide head. The outer diameter of the delivery leather cup is larger than the inner diameter of the oil pipe to achieve interference sealing, the delivery leather cup is used for bearing upper pressure, and a through hole is formed in the middle of the delivery leather cup and can penetrate through the solid rod at the lower end of the center rod. The interior of the upper end of the guide head is a screw thread, the lower end of the guide head is a conical body, and the guide head has a guide function in the well entering process and is in screw thread connection with the lower end of the center rod for fixing a delivery leather cup. On-site operation is simple and reliable, secondary accidents are avoided, and the operation cost is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production engineering in the petroleum industry, and relates to a hydraulically delivered and salvageable oil pipe plugging device and a plugging method thereof. Background Art

[0002] During well workover under pressure in oil and water wells, pressure in the casing annulus and the pressure in the tubing are controlled by using pressure working equipment and matching plugging tools, so as to achieve tubing operation without well snubbing. Among them, tubing pressure control technology is a technology for effectively plugging the tubing, ensuring that there is no blowout in the tubing during pressure work, which is the prerequisite for successfully completing well workover under pressure.

[0003] The most commonly used plug is a hydraulically delivered plug. For example, CN200320131529.4 discloses a tubing plug, which includes an upper locking nut, a pressure plate, a support sleeve, a leather cup, a retaining ring, a rubber plug, a spindle, a supporting ring, a lower locking nut, an anchor body, a slider, a stopper, and a support sleeve. The tubing plug is hydraulically delivered, and after the tubing pressure is released, the plug is seated and sealed by the rubber parts under the reaction of the downhole pressure, but the plug cannot be salvaged.

[0004] Wireline operation delivery plugs are also used. For example, CN201820774382.7 discloses an oil pipe plug, including a core shaft, the upper end of which is provided with an upper joint connected to a wire rope mechanism; a hanging mechanism arranged in the middle of the core shaft, the hanging mechanism can be selectively fixed on the oil pipe; a friction block mechanism arranged on the upper part of the core shaft, the friction block mechanism is constructed to be close to the oil pipe when the core shaft is lifted, and the friction between the friction block mechanism and the oil pipe provides initial power for the hanging mechanism; a sealing rubber cylinder arranged at the lower part of the core shaft, the sealing rubber cylinder structure can be squeezed by the hanging mechanism and deformed, thereby sealing the lower pressure of the oil pipe. The oil pipe plug is delivered by wireline operation and sealed by lifting the wireline operation, but the plug has the problem of being unsalvageable.

[0005] However, the plugs mentioned above often have the problem of being unable to be pulled out of the tubing during pressurized operations, and normal water injection needs to be restored. However, since the plugs are blocked in the oil pipe and cannot be salvaged, the water injection channel is blocked, which brings greater difficulties to subsequent operations and production. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a hydraulically delivered and salvageable oil pipe plug and a plugging method thereof, which uses hydraulic delivery to deliver the plug to a predetermined position in the oil pipe, meets the plugging requirements of the oil pipe, and is safe and reliable to operate. When the blockage in the oil pipe needs to be relieved, the plug is salvaged by wire operation to achieve unblocked oil pipes and ensure rapid resumption of water injection.

[0007] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0008] A hydraulically delivered salvageable tubing plug comprises a salvage assembly, an anchor assembly, a sealing assembly and a delivery assembly, wherein the salvage assembly consists of a salvage head, a connecting rod and shear nails; the anchor assembly consists of a slip sleeve, a slip and a slip seat; the sealing assembly consists of a sealing leather cup, a sealing ring and a center rod; the delivery assembly consists of a delivery leather cup and a guide head; the outer diameter of the delivery leather cup is larger than the inner diameter of the tubing to achieve interference sealing and is used to bear upper pressure; the middle of the delivery leather cup is a through hole, which can be penetrated by a solid rod at the lower end of the center rod; the upper end of the guide head is threaded inside, and the lower end is a conical body, which has a guiding function during the well entry process; the upper end of the guide head is threadedly connected to the lower end of the center rod to fix the delivery leather cup.

[0009] Furthermore, the delivery cup is made of soluble rubber and has a tower shape with a group of cones on the outside.

[0010] Furthermore, the upper end of the salvage head is a cone, the lower end has an expanded diameter section, the lower end has a threaded interior, and the middle section is a reduced diameter section; the upper end of the connecting rod is a threaded section for connecting with the internal thread of the lower end of the salvage head; the lower end of the connecting rod is a sealing section, and the sealing section has two sets of sealing grooves for installing a sealing ring to seal the flow hole at the upper end of the center rod; the connecting rod and the center rod are connected by shear nails; there is a boss A in the middle of the upper end of the connecting rod; the connecting rod upward boss A can abut against the lower end of the slip sleeve to drive the slip sleeve upward.

[0011] Furthermore, the cava sleeve has a through hole in the middle and an expanded hole at the lower end, and four square holes are evenly distributed around the expanded hole section; the cava is a metal block with teeth on the outer side of its lower end and a conical surface on the inner side, with protrusions on both sides of the conical surface, the outer side of the upper end of the cava is a boss B, and the inner side is a circular arc surface; four inclined dovetail grooves are designed on the upper end of the cava seat, and the cava protrusions are inserted into the dovetail grooves of the cava seat and can slide freely in the dovetail grooves; the inner part of the lower end of the cava seat is a threaded buckle, which is connected to the outer thread of the upper part of the center rod; the lower end surface of the cava seat has a conical expanded hole, which abuts against the upper end of the sealing leather bowl and is used to fix and protect the sealing leather bowl.

[0012] Furthermore, the middle of the upper end of the sealing leather cup is a through hole for inserting the center rod, and the outer side is a conical surface; the lower end of the sealing leather cup is a conical surface, and the outer side is a cylindrical sealing surface, which is an interference seal with the inner diameter of the oil pipe; the upper section of the center rod has an inner hole, and the lower section of the inner hole is a reduced diameter sealing section, and there is a group of through flow holes in the middle of the sealing section for connecting the liquid flow; there is a group of through shear nail holes at 90 degrees on the same cross-section for installing shear nails; the lower section of the center rod is a solid rod, and the lower end is a threaded button; the sealing ring is installed in the sealing groove of the connecting rod, and the connecting rod with the sealing ring installed is inserted into the inner hole of the center rod to realize the center sealing of the entire plug, and the shear nails are used to connect the connecting rod and the center rod.

[0013] The sealing leather cup is made of nitrile rubber and is thin at the top and thick at the bottom, like an inverted bowl, for bearing downward pressure.

[0014] When the present invention is used on site, the delivery and sealing process includes the following steps:

[0015] Step 1, install the assembled plug in the lubricant preventer; connect the lower end of the lubricant preventer to the wellhead; close the oil pipe gate before connection;

[0016] Step 2: The upper end of the blowout preventer is connected to the high-pressure pipeline; the other end of the high-pressure pipeline is connected to the pump truck;

[0017] Step 3: Start the pump truck to pressurize; open the oil pipe gate before starting; the pump truck injects 0.5-0.6m 3 / min;

[0018] Step 4: Liquid is injected into the oil pipe, and the liquid pressure acts on the plug to push it downward;

[0019] Step 5: In step 4, since there is an interference seal between the delivery cup and the oil pipe and it has the function of bearing the upper pressure, the seal between the plug and the oil pipe is achieved;

[0020] Step 6, in step 4, the connecting rod with the sealing ring is inserted into the inner hole of the center rod to achieve the center seal of the plug as a whole; there is a side seal between the connecting rod and the center rod, and the connecting rod is not affected by the pressure in the well during the downward process;

[0021] Step 7: In step 4, since the sealing cup is inverted, it does not have the function of bearing the upper pressure; the liquid can be transferred to the upper end of the delivery cup by squeezing the sealing cup, pushing the plug downward as a whole;

[0022] Step 8, in step 4, during the downward movement of the plugging device, the slips are in a freely open state and move downward along the inner wall of the oil pipe under the action of gravity;

[0023] Step 9, when the plugging device moves down to the plugging position, the pump truck is turned off and the pressure is stopped; the plugging position can be controlled by the volume of the liquid pumped into the well; h (blocking position, unit m) = 331V (volume of injected liquid, unit m 3 );

[0024] Step 10, open the oil pipe gate and observe the wellhead pressure and overflow situation; if there is no pressure or liquid flow at the wellhead, it means that the plug is set;

[0025] Step 11, in step 10, the oil pipe pressure is released, and under the action of the bottom hole pressure, the sealing cup starts to work to achieve sealing inside the oil pipe;

[0026] Step 12, in step 10, the bottom hole pressure pushes the plug upward, and the slip seat squeezes the slip to be anchored on the inner wall of the oil pipe, so that the plug is anchored as a whole;

[0027] Step 13, after the plug is sealed, the delivery cup will be dissolved within 24 hours.

[0028] If the water injection pipe string cannot be lifted during pressure operation, water injection needs to be resumed and the plug needs to be fished out. When the present invention is used on site, the following steps are included:

[0029] Step 1, the salvage device is connected to the steel wire and installed in the blowout preventer;

[0030] Step 2: Connect the blowout preventer to the upper end of the wellhead; close the oil pipe gate before connection;

[0031] Step 3: lower the salvage device by wire operation; open the oil pipe gate before the operation;

[0032] Step 4: After the salvaging device is lowered to the plugging device position, the plugging device salvage head is salvaged by inertia as the salvaging device is lowered; the wire is lifted up for operation;

[0033] Step 5: In step 4, the wire is lifted up, and the lifting force is transmitted to the shear nails through the fishing head and the connecting rod; when the lifting force reaches 400 kg, the shear nails are cut off;

[0034] Step 6, in step 4, the shear pins are cut off, the connecting rod moves upward along with the fishing head, the sealing section of the center rod is raised, and the liquid under the sealing leather cup is transferred to the upper part of the sealing leather cup through the flow hole of the center rod, so as to achieve the upper and lower pressure balance of the plug;

[0035] Step 7, in step 4, the connecting rod moves upward, the boss A on the connecting rod abuts against the lower part of the slip sleeve, driving the slip sleeve upward, and the slip sleeve drives the slip to be forcibly recovered; the slip loses its anchoring function and moves upward accordingly;

[0036] Step 8, in step 4, the delivery cup has dissolved and does not pose any resistance to the salvage operation;

[0037] Step 9: Use the wire to lift the plug out of the wellbore as a whole; and resume water injection in the water injection well.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] After the plugging device is plugged by hydraulic means, when the pipe string cannot be pulled out during pressure operation, the plugging device in the oil pipe can be fished out by wire operation, the wellbore is restored to be unobstructed, and water injection is quickly resumed. The invention is simple and reliable to operate on site, avoids secondary accidents, and greatly reduces the operation cost.

[0040] The plug delivery cup is made of soluble rubber, which dissolves completely within 24 hours under the action of the downhole liquid medium, greatly reducing the upward resistance of the plug and providing one of the necessary conditions for the wireline salvage of the plug.

[0041] The plug center seal adopts the plug side hole sealing method. After the connecting rod is raised from the center rod sealing section, pressure balance is formed on the upper and lower sealing leather cups, which provides the second necessary condition for the plug wire operation salvage. The plug slip is sleeved on the slip sleeve, and the slip sleeve is driven upward by the connecting rod boss. The slip is forcibly recovered in the dovetail groove of the slip seat, which provides the third necessary condition for the plug wire operation salvage. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] When considered in conjunction with the accompanying drawings, the present invention can be more completely understood and many of the accompanying advantages can be easily known by referring to the following detailed description, but the drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The illustrative examples of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations of the present invention, wherein:

[0043] Figure 1 It is a schematic diagram of the pipe string structure of the hydraulically delivered salvageable oil pipe plugging process;

[0044] Figure 2 It is a schematic diagram of the structure of the tubing string of the hydraulically delivered salvageable tubing plugger salvage process;

[0045] Figure 3 It is a schematic diagram of the structure of a hydraulically delivered salvageable oil pipe plug;

[0046] Figure 4 yes Figure 3 Middle AA section;

[0047] Figure 5 yes Figure 3 Middle BB section;

[0048] Figure 6 It is a schematic diagram of the connecting rod structure;

[0049] Figure 7 is a schematic diagram of the center rod structure;

[0050] Figure 8 yes Figure 7 Middle AA section;

[0051] Fig. 9 This is a schematic diagram of one side of the slip structure;

[0052] Fig.10 This is a schematic diagram of the other side of the slip structure;

[0053] Fig.11 It is a schematic diagram of a convex structure.

[0054] In the figure, 1: fishing head, 2: connecting rod, 2.1: boss A, 2.2: sealing section, 2.3: sealing groove, 2.4: shear nail groove, 3: slip sleeve, 3.1: square hole, 4: slip, 4.1: boss B, 4.2: teeth, 4.3: convex body, 5: slip seat, 5.1: dovetail groove, 6: sealing leather cup, 7: sealing ring, 8: shear nail, 9: center rod, 9.1: sealing section, 9.2: flow hole, 9.3: shear nail hole, 9.4: solid rod, 10: delivery leather cup, 11: guide head. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present invention will be described in detail below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "inside", "outside", etc. 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 invention and simplifying the description, rather than indicating or implying that the referred parts must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] Example 1

[0058] like Figure 3-11 As shown, the hydraulically delivered salvageable oil pipe plug includes a salvaging assembly, an anchoring assembly, a sealing assembly and a delivery assembly.

[0059] The salvage assembly is composed of a salvage head 1, a connecting rod 2 and a shear nail 8; the upper end of the salvage head 1 is a cone, the lower end has an expanded diameter section, the lower end is threaded, and the middle section is a reduced diameter section; the upper end of the connecting rod 2 is threaded, which is used to connect with the internal thread at the lower end of the salvage head; the lower end of the connecting rod 2 is a sealing section 2.2, and the sealing section 2.2 has two groups of sealing grooves 2.3, which are used to install a sealing ring 7 and seal the flow hole 9.1 at the upper end of the center rod 9; the connecting rod 2 and the center rod 9 are connected by shear nails 8; there is a boss A2.1 in the middle of the upper end of the connecting rod 2; the upward boss A2.1 of the connecting rod 2 can abut against the lower end of the slip sleeve 3 to drive the slip sleeve 3 upward.

[0060] The anchoring assembly is composed of a cava sleeve 3, a cava 4 and a cava seat 5; the cava sleeve 3 is a through hole in the middle and has a reamed hole at the lower end, and four square holes 3.1 are evenly distributed circumferentially in the reamed hole section; the cava 4 is a metal block, with teeth 4.2 on the outer side of its lower end and a conical surface on the inner side, with protrusions 4.3 on both sides of the conical surface, the outer side of the upper end of the cava 4 is a boss B4.1, and the inner side is a circular arc surface; four inclined dovetail grooves 5.1 are designed on the upper end of the cava seat 5, and the protrusions 4.3 of the cava 4 are inserted into the dovetail grooves 5.1 of the cava seat 5 and can slide freely in the dovetail grooves 5.1; the inner part of the lower end of the cava seat 5 is a threaded thread connected to the outer thread of the upper part of the center rod; the lower end surface of the cava seat 5 has a conical reamed hole, which abuts against the upper end of the sealing leather cup 6 and is used to fix and protect the sealing leather cup 6.

[0061] The sealing assembly is composed of a sealing leather cup 6, a sealing ring 7 and a center rod 9; the sealing leather cup 6 is made of nitrile rubber, and its shape is thin at the top and thick at the bottom, like an inverted bowl, and is used to bear downward pressure; the middle of the upper end of the sealing leather cup 6 is a through hole for inserting the center rod 9, and the outer side is a conical body; the lower end of the sealing leather cup 6 is a conical surface, and the outer side is a cylindrical sealing surface, which is an interference seal with the inner diameter of the oil pipe; the upper section of the center rod 9 has an inner hole, and the lower section of the inner hole is a reduced diameter sealing section 9.1, which is sealed A group of through-flow holes 9.2 are provided in the middle of the sealing section 9.1 for connecting the liquid flow; a group of through-shear nail holes 9.3 are provided at 90 degrees on the same cross section for installing the shear nails 8; the lower section of the center rod 9 is a solid rod 9.4 with a threaded lower end; the sealing ring 7 is installed in the sealing groove 2.3 of the connecting rod 2, and the connecting rod 2 with the sealing ring 2.3 installed is inserted into the inner hole of the center rod 9 to realize the center sealing of the entire plug, and the shear nails 8 are used to connect the connecting rod 2 and the center rod 9.

[0062] The delivery component consists of a delivery leather cup 10 and a guide head 11; the delivery leather cup 10 is made of soluble rubber and has a tower-like shape. The outside is a group of conical bodies, and the outer diameter is larger than the inner diameter of the oil pipe to achieve interference sealing and is used to bear the upper pressure; the middle of the delivery leather cup 10 is a through hole, which can be penetrated by the solid rod 9.4 at the lower end of the center rod 9; the upper end of the guide head 11 is threaded inside, and the lower end is a conical body, which has a guiding function during the well entry process; the upper end of the guide head 11 is threadedly connected to the lower end of the center rod 9 for fixing the delivery leather cup 10.

[0063] Example 2

[0064] like Figure 1 , Figure 3-11 As shown, when the present invention is used on site, the delivery and sealing process includes the following steps:

[0065] Step 1, install the assembled plug in the lubricant preventer; connect the lower end of the lubricant preventer to the wellhead; close the oil pipe gate before connection;

[0066] Step 2: The upper end of the blowout preventer is connected to the high-pressure pipeline; the other end of the high-pressure pipeline is connected to the pump truck;

[0067] Step 3: Start the pump truck to pressurize; open the oil pipe gate before starting; the pump truck injects 0.5-0.6m 3 / min;

[0068] Step 4: Liquid is injected into the oil pipe, and the liquid pressure acts on the plug to push it downward;

[0069] Step 5: In step 4, since there is an interference seal between the delivery cup 10 and the oil pipe and it has the function of bearing the upper pressure, the seal between the plug and the oil pipe is achieved;

[0070] Step 6, in step 4, the connecting rod 2 with the sealing ring 7 is inserted into the inner hole of the center rod 9 to achieve the center seal of the plug as a whole; the connecting rod 2 and the center rod 9 are side sealed, and the connecting rod is not affected by the pressure in the well during the downward process;

[0071] Step 7, in step 4, since the sealing leather cup 6 is inverted, it does not have the function of bearing the upper pressure; the liquid can be transferred to the upper end of the delivery leather cup 10 by squeezing the sealing leather cup 6, pushing the plug downward as a whole;

[0072] Step 8, in step 4, during the downward movement of the plugging device, the slips 4 are in a freely open state and move downward along the inner wall of the oil pipe under the action of gravity;

[0073] Step 9, when the plugging device moves down to the plugging position, the pump truck is turned off and the pressure is stopped; the plugging position can be controlled by the volume of the liquid pumped into the well; h (blocking position, unit m) = 331V (volume of injected liquid, unit m 3 );

[0074] Step 10, open the oil pipe gate and observe the wellhead pressure and overflow situation; if there is no pressure or liquid flow at the wellhead, it means that the plug is set;

[0075] Step 11, in step 10, the oil pipe pressure is released, and under the action of the bottom hole pressure, the sealing leather cup 6 starts to work to achieve sealing inside the oil pipe;

[0076] Step 12, in step 10, the bottom hole pressure pushes the plug upward, and the slip seat 5 squeezes the slip 4 to be anchored on the inner wall of the oil pipe, so that the plug is anchored as a whole;

[0077] Step 13, after the plug is sealed, the delivery cup 10 is completely dissolved within 24 hours.

[0078] Example 3

[0079] like Figure 2 , Figure 3-11As shown, if the water injection pipe string cannot be lifted during pressure operation, water injection needs to be resumed and the plug needs to be fished out. When the present invention is used on site, the following steps are included:

[0080] Step 1, the salvage device is connected to the steel wire and installed in the blowout preventer;

[0081] Step 2: Connect the blowout preventer to the upper end of the wellhead; close the oil pipe gate before connection;

[0082] Step 3: lower the salvage device by wire operation; open the oil pipe gate before the operation;

[0083] Step 4, after the salvaging device is lowered to the plugging device position, as the salvaging device is lowered, the plugging device salvaging head 1 is salvaged by inertia; the wire is lifted up for operation;

[0084] Step 5, in step 4, the wire is lifted up, and the lifting force is transmitted to the shear nail 8 through the fishing head 1 and the connecting rod 2; when the lifting force reaches 400Kg, the shear nail 8 is cut off;

[0085] Step 6, in step 4, the shear nail 8 is cut off, the connecting rod 2 moves upward along with the fishing head 1, and the sealing section 9.1 of the center rod 9 is raised, and the liquid under the sealing leather cup 6 is transferred to the upper part of the sealing leather cup 6 through the flow hole 9.2 of the center rod 9, so as to achieve the upper and lower pressure balance of the plug;

[0086] Step 7, in step 4, the connecting rod 2 moves upward, and the boss A2.1 on the connecting rod 2 abuts against the lower part of the slip sleeve 3, driving the slip sleeve 3 upward, and the slip sleeve 3 drives the slip 4 to be forcibly recovered; the slip loses its anchoring function and moves upward accordingly;

[0087] Step 8, in step 4, the delivery cup 10 has dissolved and does not pose any resistance to the salvage operation;

[0088] Step 9: Use the wire to lift the plug out of the wellbore as a whole; and resume water injection in the water injection well.

[0089] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0090] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulically delivered salvageable oil pipe plug, comprising a salvaging assembly, an anchoring assembly, a sealing assembly and a delivery assembly, characterized in that: The salvaging assembly is composed of a salvaging head (1), a connecting rod (2) and a shear nail (8); the anchoring assembly is composed of a slip sleeve (3), a slip (4) and a slip seat (5); the sealing assembly is composed of a sealing leather cup (6), a sealing ring 7 and a center rod (9); the delivery assembly is composed of a delivery leather cup (10) and a guide head (11); the outer diameter of the delivery leather cup (10) is larger than the inner diameter of the oil pipe to achieve interference sealing and is used to bear the upper pressure; the middle of the delivery leather cup (10) is a through hole, through which a solid rod (9.4) at the lower end of the center rod (9) can be inserted; the upper end of the guide head (11) is threaded inside and the lower end is a conical body, which has a guiding function during the well entry process; the upper end of the guide head (11) is threadedly connected to the lower end of the center rod (9) and is used to fix the delivery leather cup (10).

2. The hydraulically delivered and salvageable oil pipe plug according to claim 1, characterized in that: The delivery leather cup (10) is made of soluble rubber and has a tower shape with a group of cones on the outside.

3. The hydraulically delivered and salvageable oil pipe plug according to claim 1 is characterized in that: The upper end of the fishing head (1) is a cone, the lower end is an expanded diameter section, the lower end is threaded, and the middle section is a reduced diameter section; the upper end of the connecting rod (2) is threaded and is used to connect with the internal thread at the lower end of the fishing head; the lower end of the connecting rod (2) is a sealing section (2.2), and the sealing section (2.2) has two groups of sealing grooves (2.3) for installing a sealing ring 7 to seal the flow hole (9.1) at the upper end of the center rod (9); the connecting rod (2) and the center rod (9) are connected by shear nails (8); there is a boss A (2.1) in the middle of the upper end of the connecting rod (2); the upward boss A (2.1) of the connecting rod (2) can abut against the lower end of the slip sleeve (3) to drive the slip sleeve (3) upward.

4. The hydraulically delivered and salvageable oil pipe plug according to claim 1, characterized in that: The middle of the cava sleeve (3) is a through hole, and the lower end is provided with a section of expanded hole, and four square holes (3.1) are evenly distributed in the circumferential direction of the expanded hole section; the cava (4) is a metal block, and the outer side of its lower end is provided with teeth (4.2), the inner side is a conical surface, and protrusions (4.3) are provided on both sides of the conical surface. The outer side of the upper end of the cava (4) is a boss B (4.1), and the inner side is a circular arc surface; four inclined dovetail grooves (5.1) are designed on the upper end of the cava seat (5), and the protrusions (4.3) of the cava (4) are inserted into the dovetail grooves (5.1) of the cava seat (5) and can slide freely in the dovetail grooves (5.1); the inner part of the lower end of the cava seat (5) is a threaded thread connected to the outer thread of the upper part of the center rod; the lower end surface of the cava seat (5) has a section of conical expanded hole, which abuts against the upper end of the sealing leather cup (6) and is used to fix and protect the sealing leather cup (6).

5. The hydraulically delivered and salvageable oil pipe plug according to claim 1, characterized in that: The middle of the upper end of the sealing leather cup (6) is a through hole for inserting the center rod (9), and the outer side is a conical body; the lower end of the sealing leather cup (6) is a conical surface, and the outer side is a cylindrical sealing surface, which is an interference seal with the inner diameter of the oil pipe; the upper section of the center rod (9) has an inner hole, and the lower section of the inner hole is a reduced diameter sealing section (9.1), and the middle of the sealing section (9.1) has a group of through-flow holes (9.2) for connecting the liquid flow; a group of through-flow shear holes 9.3 are provided at 90 degrees on the same cross section for installing shear nails (8); the lower section of the center rod (9) is a solid rod (9.4), and the lower end is a threaded thread; the sealing ring (7) is installed in the sealing groove (2.3) of the connecting rod (2), and the connecting rod (2) installed with the sealing ring (2.3) is inserted into the inner hole of the center rod (9) to achieve the center sealing of the entire plug, and the shear nail (8) is used to connect the connecting rod (2) and the center rod (9).

6. The hydraulically delivered and salvageable oil pipe plug according to claim 1, characterized in that: The sealing leather cup (6) is made of nitrile rubber and is thin at the top and thick at the bottom, like an inverted bowl, for bearing downward pressure.

7. The method for delivering and setting a hydraulically delivered and salvageable tubing plug according to claim 1, characterized in that: Contains the following steps: Step 1, install the assembled plug in the lubricant preventer; connect the lower end of the lubricant preventer to the wellhead; close the oil pipe gate before connection; Step 2: The upper end of the blowout preventer is connected to the high-pressure pipeline; the other end of the high-pressure pipeline is connected to the pump truck; Step 3: Start the pump truck to pressurize; open the oil pipe gate before starting; the pump truck injects 0.5-0.6m 3 / min; Step 4: Liquid is injected into the oil pipe, and the liquid pressure acts on the plug to push it downward; Step 5, in step 4, since there is an interference seal between the delivery leather cup (10) and the oil pipe and it has the function of bearing the upper pressure, the seal between the plug and the oil pipe is achieved; Step 6, in step 4, the connecting rod (2) with the sealing ring (7) is inserted into the inner hole of the center rod (9) to achieve the center sealing of the plug as a whole; the connecting rod (2) and the center rod (9) are side sealed, and the connecting rod is not affected by the pressure in the well during the downward movement; Step 7, in step 4, since the sealing leather cup (6) is inverted, it does not have the function of bearing the upper pressure; the liquid can be transferred to the upper end of the delivery leather cup (10) by squeezing the sealing leather cup (6), pushing the plug downward as a whole; Step 8, in step 4, during the downward movement of the plugging device, the slip (4) is in a freely open state and moves downward along the inner wall of the oil pipe under the action of gravity; Step 9, when the plug moves downward to the blocking position, the pump truck is turned off and the pressure is stopped; Step 10, the oil pipe gate is opened to observe the wellhead pressure and overflow; if there is no pressure or liquid flow at the wellhead, it means that the plug is set; Step 11, in step 10, the oil pipe pressure is released, and under the action of the bottom hole pressure, the sealing cup (6) starts to work to achieve sealing inside the oil pipe; Step 12, in step 10, the bottom hole pressure pushes the plug upward, and the slip seat 5 squeezes the slip (4) to anchor on the inner wall of the oil pipe, thereby achieving the overall anchoring of the plug; Step 13, after the plug is sealed, the delivery cup (10) is completely dissolved within 24 hours.

8. The method for salvaging a hydraulically delivered salvageable oil pipe plug according to claim 1, characterized in that: Contains the following steps: Step 1, the salvage device is connected to the steel wire and installed in the blowout preventer; Step 2: Connect the blowout preventer to the upper end of the wellhead; close the oil pipe gate before connection; Step 3: lower the salvage device by wire operation; open the oil pipe gate before the operation; Step 4, after the salvaging device is lowered to the plugging device position, the plugging device salvage head (1) is salvaged by inertia as the salvaging device is lowered; the wire is lifted up for operation; Step 5, in step 4, the wire is lifted up, and the lifting force is transmitted to the shear nail (8) through the fishing head (1) and the connecting rod (2); when the lifting force reaches 400 kg, the shear nail (8) is cut off; Step 6, in step 4, the shear pin (8) is cut off, the connecting rod (2) moves upward along with the fishing head (1), and the sealing section (9.1) of the center rod (9) is lifted out, and the liquid under the sealing leather cup (6) is transferred to the upper part of the sealing leather cup (6) through the flow hole (9.2) of the center rod (9), so as to achieve the balance of the upper and lower pressures of the plug; Step 7, in step 4, the connecting rod (2) moves upward, the boss A (2.1) on the connecting rod (2) abuts against the lower part of the slip sleeve (3), driving the slip sleeve (3) upward, and the slip sleeve (3) drives the slip (4) to be forcibly recovered; the slip loses its anchoring function and moves upward accordingly; Step 8, in step 4, the delivery cup (10) has dissolved and does not pose any resistance to the salvage operation; Step 9: Use the wire to lift the plug out of the wellbore as a whole; and resume water injection in the water injection well.

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