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CN-122014122-A - Back plug connector for anchoring and sealing fracturing and use method

CN122014122ACN 122014122 ACN122014122 ACN 122014122ACN-122014122-A

Abstract

The invention provides an anchor seal fracturing back-plugging connector and a use method thereof, belonging to a downhole tool field for sealing in drilling and completion of petroleum industry. The anchoring sealing part comprises a metal reticular cylinder and a limiting ring, the outer wall of the metal reticular cylinder is provided with reticular grooves, vulcanized rubber blocks are vulcanized in the reticular grooves, and dental blocks which are obliquely implanted downwards are arranged at the joints of all the net points of the reticular grooves. After the tieback tube is inserted into the tieback tube, the upper edge of the tieback tube can be limited, anchored and sealed with the anchoring sealing part by pressing down. The sealing part is inserted to seal the tieback cylinder, in the fracturing process, if upward pressure leakage occurs, the limiting ring at the lower part is influenced by the pressure to upwards extrude the rubber ring, and the extrusion of the limiting ring is obvious along with the increase of the pressure, so that the rubber ring is pressed more strongly, and the sealing performance is more obvious.

Inventors

  • GAO GUOCHENG
  • DENG KAI
  • WANG WENBIN
  • XU CHAOYANG
  • WANG JUNCHUANG
  • WAN XIANGCHEN
  • LIU XIAOLI
  • LIU ZHIXIONG
  • TANG KAI
  • CHEN NING

Assignees

  • 中国石油天然气集团有限公司
  • 中国石油集团川庆钻探工程有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (10)

  1. 1. The fracturing return plug connector for anchoring sealing is characterized by comprising an anchoring sealing part and an inserting sealing part, wherein the anchoring sealing part and the inserting sealing part are assembled on a pipe body (9), and the outer diameter of the upper end of the pipe body (9) is larger than that of the lower part.
  2. 2. The anchoring and sealing fracturing return plug connector according to claim 1, wherein the pipe body (9) is a metal pipe body and is integrally T-shaped, the outer diameter of the horizontal end of the T-shape is larger than that of the vertical end, and a coupling (8) with threads is arranged at the horizontal end.
  3. 3. The fracturing return plug for anchoring seal according to claim 1, wherein the anchoring seal part comprises a metal mesh cylinder (3) and a limiting ring (4), a mesh groove is formed in the outer wall of the metal mesh cylinder (3), vulcanized rubber blocks (1) are vulcanized in the mesh groove, dental blocks (2) which are obliquely implanted downwards are arranged at the joints of all the mesh points of the mesh groove, the metal mesh cylinder (3) is sleeved on a pipe body (9), the upper end of the metal mesh cylinder (3) is positioned at the lower surface of the maximum outer diameter of the pipe body (9), and the limiting ring (4) is sleeved on the pipe body (9) and is positioned below the metal mesh cylinder (3).
  4. 4. The anchoring and sealing fracturing back plug connector according to claim 3, wherein the dental block (2) is an alloy tooth or a ceramic tooth.
  5. 5. The anchoring and sealing fracturing back plug connector according to claim 4, wherein the assembled height of the dental block (2) is lower than the maximum outer diameter of the pipe body (9).
  6. 6. The fracturing return plug for anchoring and sealing according to claim 3, wherein the limiting ring (4) is a metal limiting ring with a notch, and the assembled height of the limiting ring (4) is the same as the maximum outer diameter of the pipe body (9).
  7. 7. The fracturing return plug for anchoring seal according to claim 1 is characterized in that the insertion seal part comprises a vulcanized rubber ring (5), rubber rings (6) and a limiting ring (7), the limiting ring (7) is arranged between the two rubber rings (6) to form a group of limiting seal components, the vulcanized rubber ring (5) and the limiting seal components are sequentially sleeved on a pipe body (9) from top to bottom, the vulcanized rubber ring (5) and the limiting seal components are multiple groups, and the vulcanized rubber ring (5) is in vulcanized sleeve connection on the pipe body (9) below the limiting ring (4) in the anchoring seal part.
  8. 8. The fracturing return plug for anchoring seal according to claim 7 is characterized in that the maximum outer diameter of the vulcanized rubber ring (5) is more than 2mm larger than the inner diameter of a return tube inserted by the inserted sealing part, the outer diameter of the rubber ring (6) is more than 2mm larger than the inner diameter of the return tube inserted by the inserted sealing part after assembly, and the outer diameter of the limiting ring (7) is more than 1mm smaller than the inner diameter of the return tube inserted by the inserted sealing part.
  9. 9. The anchoring and sealing fracturing return plug connector according to claim 7, wherein the limiting ring (7) is an open metal limiting ring.
  10. 10. The method for using the anchoring and sealing fracturing back-in connector according to any one of claims 1 to 9, which is characterized by comprising the following specific steps: After the anchoring sealing fracturing return plug is inserted into the return cylinder, the upper edge of the return cylinder is contacted with a limit ring (4) of the anchoring sealing part by pressing down, the limit ring (4) is pressed and moves upwards to extrude the metal mesh cylinder (5), when the metal mesh cylinder (5) is extruded, the inclined tooth blocks (2) on the mesh points can be expanded in the shape of umbrella ribs and supported between the pipe body (9) and the outer layer sleeve, and the whole pipe body (9) is riveted; After the anchoring sealing fracturing is inserted into the tieback cylinder, the vulcanized rubber ring (5) inserted into the sealing part forms a seal with the interior of the tieback cylinder, and in the fracturing process, if upward pressure leakage occurs, the lower limiting ring (7) is influenced by the pressure to upwards extrude the rubber ring (6), and along with the pressure increase, the limiting ring (7) is extruded, so that the rubber ring (6) is pressed to be strong, and the sealing performance is improved.

Description

Back plug connector for anchoring and sealing fracturing and use method Technical Field The invention belongs to the technical field of downhole tools for sealing in drilling and completion in petroleum industry, and particularly relates to a return plug for anchoring and sealing fracturing and a use method thereof. Background The back plug for fracturing is a key component for connecting and sealing a fracturing string and a tail pipe, and with the development of petroleum drilling technology, back plug fracturing can reduce pipe loss, reduce original shaft sealing loss and leakage between the fracturing string and the original shaft. Because the well cementation operation is not carried out above the hanger, the structural safety of the tieback sleeve at the upper part of the hanger is important, the construction can be smoothly carried out or not is directly influenced, and the complete well is scrapped due to serious sleeve failure. Therefore, the fracturing back plug in the prior art still has the defects. (1) The back-plugging tool for general fracturing needs to stably reinforce the fracturing plug through the anchoring device, but the anchoring device cannot be designed under the condition that the available wall thickness of the fracturing string is extremely narrow due to the fact that the requirement on the drift diameter is high in part, and the risk that the plug is stressed to be unhooked during fracturing exists. The utility model of a tieback fracturing string and a tailpipe hanger tieback connector thereof, such as the utility model with the authorized bulletin number (CN 211924112U), is characterized in that the tieback connector is fixed by hydraulic anchoring under the prior art. The utility model of patent publication number (CN 109267943B) is string-set by means of an open hole packer and an anchor. The fixation of the tool therefore needs to be stabilized by external structures. (2) The existing back plug for fracturing is sealed through a static O-shaped ring, when the insertion pipe is in the back connecting cylinder, the O-shaped ring is worn out when the O-shaped ring and the inner wall of the back connecting cylinder are rubbed relatively, and in the long-time fracturing process, the O-shaped ring can be worn out to cause the sealing failure of the O-shaped ring to appear from the high pressure side to the low pressure side to penetrate the leakage phenomenon. In similar patents, sealing performance is enhanced by adding O-ring sets or using wider O-rings, but in the face of dynamic friction, there is still friction loss with O-rings. The prior art therefore only considers the sealing effect in static sealing. There is no related technical solution for dynamic situations. The stability of the relative position of the return connection pipe and the return plug connector is improved through anchoring in the return plug fracturing pipe column adopted in the prior art, but the later fracturing has higher requirements on the drift diameter of the pipe string, for example, a sleeve with the phi of 114.3mm and the wall thickness of 8.65mm is put into a sleeve with the phi of 139.7mm and the wall thickness of 6.35mm, and the outer diameter of the return plug pipe column can only be 94-118mm because the inner diameter of the sleeve with the 139.7mm is 124.3mm, and an anchoring tool cannot be designed on the basis of the wall thickness of only 12mm, so that the anchoring cannot be realized through the anchoring tool under the working conditions. Under the condition that anchoring cannot be achieved, the suspended weight can be lowered to the tieback pipe through more pushing-down of the tieback pipe string, the relative position of the heavy-pressure stable pipe string is adopted, and sealing is still carried out through an O-shaped ring. With the increase of fracturing scale, fracturing intensity and fracturing time, the back-inserted fracturing head and the back-connected pipe are subjected to back-to-back under the influence of high-frequency liquid flow, the pipe column is subjected to creep deformation, so that the back-inserted fracturing head and the back-connected pipe are subjected to piston type reciprocating motion, and sealing leakage is caused after the O-shaped ring is worn. Disclosure of Invention In order to solve the problem that the sealing leakage is caused by the piston type reciprocating motion of the back-inserted fracturing head and the back-connected pipe due to the creep of the existing pipe column and the abrasion of the O-shaped ring, the invention provides the back-inserted joint for anchoring and sealing and the use method. The invention adopts the technical scheme that: the fracturing return plug head for anchoring seal comprises an anchoring seal part and an inserting seal part, wherein the anchoring seal part and the inserting seal part are assembled on a pipe body, and the outer diameter of the upper end of the pipe body is larger than that of the lower par