The Petroleum Production System - Packer

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The packer 1 is a sealing device with a slip, cone, packing-element system, and body or mandrel.

Contributions

PetroWiki 1 defines the contributions of the packer in the petroleum production system as:

• Provides a seal between the tubing and casing
• Prevents downhole movement of the tubing string
• Supports some of the weight of the tubing
• Holds well-servicing fluid in the casing annulus
• Facilitate artificial lift through the A-annulus
• Protect the production casing from corrosion due to produced fluids and high pressures
• Can provide a means of separating multiple producing zones
• Allows the optimum size of well flow conduit (the tubing string) to meet the designed production or injection flowrates

Problem Areas and Solutions

• Packer seal failure due to 2
  • Improper storage, handling, and installation. Common approaches to mitigate this involve
    • Proper handling mechanism, training of staff and use of required equipments
  • Abnormal operation factors. Common approaches to mitigate this involve
    • Use of appropriate design safety factors
    • Proper lubrication
    • Carrying out tests on anticipated conditions prior to use
  • Reduction in packer seal service life due to varying factors. Common approaches to mitigate this involve
    • Increasing the hardness of the sealing material to improve resistance to wear
    • Corrosion prevention measures
    • Proper lubrication
  • Operating outside design minimum and maximum temperature. Common approaches to mitigate this involve
    • Seal design should accomodate for high temperature conditions
  • Pressure. Common approaches to mitigate this involve
    • Limit compression set
    • Seal design should accomodate limited swelling which can occur at high pressures
  • Large pressure differential over the seal. Common approaches to mitigate this involve
    • Increasing the hardness of the seal in order to increase its extrusion resistance
  • Pressure cycles. Common approaches to mitigate this involve
    • Selection of materials which are more resistant to explosive decompression
  • Dynamic application. Common approaches to mitigate this involve
    • Increase the hardness of the seal
    • Limit seal swell to 10 - 20%
  • Poor packer seal seat design. Common approaches to mitigate this involve
    • Seal design must allow for elastomeric swelling within 10 - 60% in oil and gas to prevent seal extrusion
    • Seal design should take into account the installation requirements of the seal
  • Penetration of hydrocarbons, Carbondioxide, and Hydrogen Sulphide into the elastomer. Common approaches to mitigate this involve
    • Proper compatibility tests must be undergone prior to use
  • Incompatibility with corrosion inhibitors and completion fluids. Common approaches to mitigate this involve
    • Elastomeric resistance should be determined by testing prior to use

Other types of packer failure include the following 3 :

• Body collapse
• Packing-element system failure
• Pin collapse at the body/guide connection
• Body to Guide failure
• Anchor attachment failure
• Body lock ring system failure
• Bearing failure

Up next, we will examine flow control accessories.

Standing on Giant’s shoulders (References):

• PetroWiki Packers
• DrillingforGas Causes of Packer Seal failure
• Luciano Oscar Fucello on Packer Failure