Pumpable plug for isolation work in well

Abstract

FIELD: oil and gas production.SUBSTANCE: devices intended for the temporary blocking of a wellbore formed by tubing, which can be used in carrying out upper well completion work, as well as in carrying out routine and major well repairs. The invention includes a pumpable plug for insulation work in a well, comprising a core with a tip provided with a protrusion with an external conical surface, as well as a rubber cuff secured to the core. According to the invention, the core is made in the form of a solid cylindrical body with a cylindrical shank, on which a rubber cuff is fixed, with at least two sealing surfaces made in the form of cones, the bases of which are directed in the direction opposite to the movement of pushing the plug in the wellbore. The outer conical surface of the core tip projection is designed for tight contact with a similar surface in the wellbore, located at the wellbore isolation site. In this case, the core with the shank, the tip and the rubber cuff are made of materials that are soluble in the extracted hydrocarbon environment.EFFECT: ensuring control of local isolation (tightness) of the wellbore over time depending on the time of technological work.1 cl, 1 dwg

Description

[0001] The claimed technical solution relates to the field of oil and gas production, in particular to devices designed for the temporary blocking of a wellbore formed by tubing, and can be used in the upper completion of wells, as well as in the routine and capital repair of wells.

[0002] Specialized devices—packers and plugs—are used to seal off oil or gas wells. A packer, as a sealing tool, is lowered on pipes or a cable and secured at a specific wellbore depth during routine or major well workovers. After completion, the packer is raised, freeing the wellbore for the free flow of produced oil or gas. To install a plug at the desired location in the wellbore, a packer is used, followed by pressure being applied to the tubing string. This deforms and compacts the plug in the annular space, isolating the upper wellbore from the lower wellbore. After completion of the necessary wellbore repair and maintenance work, the plug is typically drilled out to free the sealed area from the plug, which can be made of either metallic or non-metallic materials.

[0003] A known prior art is a packer plug, extractable with a screw mechanism for oil and gas wells, comprising a housing, a lead screw, a lead nut screwed onto the lead screw and connected to a rod by means of shear elements, a sealing element, the packer plug additionally contains clamping crackers installed in the windows of the housing, which contact along inclined edges with a punch of the clamping crackers, the lead screw passes through the punch of the clamping crackers, the packer plug additionally contains keys that prevent the rod from turning relative to the housing, as well as a shank screwed onto the lead screw, and shear screws for controlling the torque, connecting the shank with a landing device, the lead screw and the lead nut form a "screw-nut" transmission and are designed with the possibility of clamping the sealing element for sealing the space between the inner surface of the pipe and the structural elements of the packer plug,and also with the possibility of activating the clamping biscuits by means of linear movement of the clamping biscuits punch and extension of the clamping biscuits into the space between the body and the inner surface of the pipe, and additionally with the possibility of fixing the clamping biscuits and the sealing element in the achieved position, the packer plug additionally comprises an expansion sleeve put on the rod using a set of seals for preliminary expansion of the sealing element with the possibility of reducing the degree of deformation of the sealing element during its compression during installation of the packer plug in the well, as well as control shear screws connecting the shank with the landing device, with the possibility of re-fixing the installation torque, the packer plug additionally comprises sealing washers, a limiting sleeve, a spring and a tip, wherein the expansion sleeve, the sealing element together with the sealing washers, the limiting sleeve,the spring and tip are mounted on the rod (patent RU 2851383 C1, published 11 / 24 / 2025).

[0004] The disadvantage of the well-known packer plug is the complexity of the design and significant material and time costs for carrying out isolation work in the wellbore, taking into account also the maintenance and repair work of the well.

[0005] A known plug comprises a core, a rubber cuff secured to the core, and a tip with a projection. The tip further comprises a retaining aluminum ring with a conical inner surface, and the projection of the tip is formed with an outer conical surface mating with the inner surface of the ring (patent RU 93454 U1, published 04 / 27 / 2010). The core of the plug is cylindrical with an internal cavity of variable cross-section, as follows from the description and illustration of patent RU 93454 U1.

[0006] A disadvantage of the known plug is its low efficiency, due to its suspended design and limited functionality—use in well cementing processes. This ultimately complicates and increases the overall time of wellbore operations due to the increased time required to remove (drill out) the plug from the wellbore. Furthermore, the design of the known suspended plug does not allow for effective well maintenance and workover operations, which involve raising and lowering tubing above the plug's installation location in the wellbore.

[0007] The technical objective of the present invention is to eliminate the said disadvantages, namely to increase the efficiency of using a plug when carrying out insulation work in a wellbore.

[0008] The technical result of the invention consists in ensuring control of local isolation (tightness) of the wellbore over time depending on the time of technological work.

[0009] The technical result is achieved in that in a pumpable plug for isolation work in a well, comprising a core with a tip provided with a projection with an external conical surface, and a rubber cuff secured to the core, according to the invention, the core is made in the form of a solid cylindrical body with a cylindrical shank, on which a rubber cuff is secured, with at least two sealing surfaces made in the form of cones, the bases of which are directed in the direction opposite to the movement of pushing the plug in the wellbore, and the external conical surface of the projection of the tip of the core is intended for tight contact with a similar surface in the wellbore, located at the location of the wellbore isolation, wherein the core with the shank, the tip and the rubber cuff are made of materials soluble in the produced hydrocarbon medium.

[0010] The invention is explained by a drawing, which shows in horizontal view a pumpable plug for isolation work on a well, placed in a seat inside the wellbore.

[0011] A pumpable plug for isolation work in a well comprises a core 1, made in the form of a solid cylindrical body with a cylindrical shank 2, on which a rubber cuff 3 is fixed, with at least two sealing surfaces 4, made in the form of cones, the bases of which are directed in the direction opposite to the pushing movement of the plug in the wellbore 5. This design of the rubber cuff 3 allows it to be used as an anchor element of the plug after its final installation in the seat of the wellbore 5. The tip 6 of the core 1 is provided with a projection 7 with an external conical surface 8, which is intended for tight contact with a similar surface (not shown conditionally) in the wellbore 5, located at the location of the wellbore 5 isolation. The core 1, the shank 2, the tip 6 and the rubber cuff 3 are made of materials soluble in the extracted hydrocarbon medium (oil).In particular, virtually all types of rubber are soluble in oil mixtures. Materials containing a chemically active metal selected from the group consisting of aluminum, calcium, and magnesium, and alloying elements such as lithium, gallium, indium, zinc, or bismuth, also dissolve well (and corrode intensely). Based on data on the dissolution rate of active metals and alloying elements, the size of the push plug for wellbore isolation operations can be selected, ensuring, with a minimum margin, the required time for dissolution of all plug components and timely depressurization of the wellbore for subsequent production of liquid hydrocarbons (oil).

[0012] The push plug for well isolation works as follows.

[0013] A push-through plug for performing isolation work on a well is installed at the top of the wellbore 5 in such a way that the tip 6 of the core 1 is directed towards the wellbore seat. Using a hydraulic mechanism, excess hydraulic pressure is created in the upper part of the wellbore 5, acting on the shank 2 of the plug, equipped with a rubber cuff 3 with conical surfaces 4. In this case, the cuff 3 with conical surfaces 4 functions as a feathering of the shank 2, which ensures the pushing of the plug due to the excess hydraulic pressure created in the upper part of the wellbore 5. The push-through plug, having reached the seat in the wellbore 5, with the conical surface 8 of the projection 7 of the tip 6 comes into tight contact with a similar surface in the wellbore 5, thereby ensuring the tightness of the upper part of the wellbore 5 from the lower one.The conical surfaces 4 of the rubber cuff 3 are further deformed by excess hydraulic pressure in the upper portion of the wellbore 5, pressing their edges against the outer surface of the wellbore 5, thereby preventing the plug from being ejected from its seat. Continuous contact of the tip 6 with the hydrocarbon environment in the lower portion of the wellbore will facilitate the gradual dissolution of the tip 6 material, and subsequently of the core 1 with the shank 2 and rubber cuff 3. By controlling the dissolution time of these plug components by selecting the plug size and soluble materials, it is possible to ensure the required time for routine or major well repairs, followed by independent depressurization of the wellbore after completion of the repairs.

Claims

A pumpable plug for isolation work in a well, comprising a core with a tip provided with a projection with an external conical surface, and a rubber cuff secured to the core, characterized in that the core is made in the form of a solid cylindrical body with a cylindrical shank, on which a rubber cuff is secured, with at least two sealing surfaces made in the form of cones, the bases of which are directed in the direction opposite to the movement of pushing the plug in the wellbore, and the external conical surface of the projection of the tip of the core is intended for tight contact with a similar surface in the wellbore, located at the location of the wellbore isolation, wherein the core with the shank, the tip and the rubber cuff are made of materials soluble in the produced hydrocarbon medium.

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