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Prevention device and method for seal integrality failure of casing annulus of gas well

A casing annulus and integrity technology, applied in sealing/isolation, earthwork drilling, wellbore/well components, etc., can solve the lack of solutions and control means, casing annulus sealing failure, cement sheath damage, etc. problems, to achieve the effect of preventing casing annulus seal integrity failure, avoiding failure damage, and low cost

Pending Publication Date: 2017-11-07
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this application document mentions that there are certain problems in annulus sealing through the cement sheath, oil and gas well cement is economical and convenient, its performance parameters can be adjusted, and its size can be controlled. Therefore, cement is used to seal the casing outer annulus still has a certain meaning
[0004] At present, there is a lack of effective solutions and control methods for the failure of the casing annulus seal caused by the material defect of the cement sheath itself, especially the damage to the cement sheath due to the change of downhole working conditions during the long-term production process after cementing

Method used

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  • Prevention device and method for seal integrality failure of casing annulus of gas well
  • Prevention device and method for seal integrality failure of casing annulus of gas well
  • Prevention device and method for seal integrality failure of casing annulus of gas well

Examples

Experimental program
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Effect test

Embodiment 1

[0044] A gas well casing annulus sealing integrity failure prevention device includes a sleeve 2 adhered to the outer periphery of the casing 1 and used to protect the cement sheath 3 under force. Wherein, the elastic modulus of the sleeve is 5MPa, the Poisson's ratio is 0.25, and the thickness is 4mm.

[0045] The material used to prepare the sleeve includes the following components in parts by weight: 100 parts of nitrile rubber; 5 parts of vulcanizing agent DCP; 0.45 parts of vulcanizing agent sulfur; 25 parts of high wear-resistant carbon black; 5 parts of semi-reinforcing carbon black ; 2 parts of anti-aging agent 445; 0.5 part of accelerator zinc oxide; 0.4 part of accelerator active magnesium oxide.

[0046] The present invention also provides a method for preventing the failure of gas well casing annulus sealing integrity, comprising the following steps:

[0047] S1: Perform dust removal, cleaning, sandblasting, and degreasing treatment on the outer periphery of the c...

Embodiment 2

[0052] A gas well casing annulus sealing integrity failure prevention device includes a sleeve 2 adhered to the outer periphery of the casing 1 and used to protect the cement sheath 3 under force. Wherein, the elastic modulus of the sleeve is 10MPa, the Poisson's ratio is 0.5, and the thickness is 8mm.

[0053] The material used to prepare the sleeve includes the following components in parts by weight: 100 parts of nitrile rubber; 7 parts of vulcanizing agent DCP; 0.9 parts of vulcanizing agent sulfur; 60 parts of high wear-resistant carbon black; 15 parts of semi-reinforcing carbon black ; 3 parts of anti-aging agent 445; 1 part of accelerator zinc oxide; 0.8 part of accelerator active magnesium oxide.

[0054] The method for preventing the failure of the gas well casing annulus sealing integrity is the same as that in Embodiment 1.

Embodiment 3

[0056] A gas well casing annulus sealing integrity failure prevention device includes a sleeve 2 adhered to the outer periphery of the casing 1 and used to protect the cement sheath 3 under force. Wherein, the elastic modulus of the sleeve is 7MPa, the Poisson's ratio is 0.35, and the thickness is 6mm.

[0057] The material used to prepare the sleeve includes the following components in parts by weight: 100 parts of nitrile rubber; 6 parts of vulcanizing agent DCP; 0.65 parts of vulcanizing agent sulfur; 45 parts of high wear-resistant carbon black; 10 parts of semi-reinforcing carbon black ; 3 parts of anti-aging agent 445; 0.7 part of accelerator zinc oxide; 0.6 part of accelerator active magnesium oxide.

[0058] The method for preventing the failure of the gas well casing annulus sealing integrity is the same as that in Embodiment 1.

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Abstract

The invention relates to a prevention device and method for a seal integrality failure of a casing annulus of a gas well. The prevention device comprises a sleeve adhered to the periphery of a casing for conducting force bearing protection on a cement ring. The elasticity modulus of the sleeve is 5-10 MPa, the Poisson ratio of the sleeve is 0.25-0.5, and the thickness of the sleeve is 4-8 mm. A layer of buffer medium is additionally arranged on the periphery of the casing, so that casing deformation caused by the pressure change of a downhole is absorbed totally or to a certain extent, the influence of the inner pressure of the casing on the cement ring is reduced, failure destruction of the cement ring when the inner pressure of the casing is too high is avoided, and the seal integrality failure of the casing annulus, and problems of under-pressure and channeling of the annulus due to the seal integrality failure of the casing annulus are prevented.

Description

technical field [0001] The invention relates to the field of natural gas exploration and development, in particular to a gas well casing annulus seal integrity failure prevention device and prevention method. Background technique [0002] Casing annulus pressure caused by gas channeling is one of the problems that high-pressure gas wells continue to face. The existing gas well annulus pressure control measures, such as cement squeeze repair and chemical plugging, have problems such as high cost, poor effect and difficult operation. In addition, frequent pressure monitoring and blowout operations will also increase the management difficulty and production cost of gas wells. Therefore, it can be said that once an annular pressure problem occurs in a gas well, no matter what remedial and treatment measures are taken, it will inevitably cost a lot of time, labor costs and high expenses, which will greatly reduce the economic benefits of gas well development. [0003] Chinese p...

Claims

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Application Information

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IPC IPC(8): E21B33/13E21B33/14C08L9/02C08K13/02C08K5/14C08K3/04C08K3/06C08K3/22B29C39/10B29C39/22B29C39/38
CPCE21B33/13E21B33/14C08K3/04C08K3/06C08K3/22C08K5/14C08K13/02B29C39/10B29C39/22B29C39/38C08K2003/2296C08K2003/222C08K2201/014C08L9/02
Inventor 赵效锋管志川
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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