Mechanical Integrity Testing of Wells Equipped with Tension-Set Packers or Gas Lift Valves
To prevent unseating a tension-set packer during the required pressure test, the upward force on the packer must exceed the downward force on the packer. The upward force on the packer is a combination of the tension pulled on the tubing when the packer was set, the hydrostatic head of the fluid in the tubing, and the applied tubing pressure less any friction forces. The downward force on the packer is a combination of the hydrostatic head of the fluid in the tubing-casing annulus and the applied annulus pressure. Since most of the force variables can be changed, there are several options available that will allow the operator to meet Form H-5 test instruction 4(c) and concurrently avoid unseating a tension-set packer or opening the gas lift valves.
- Option 1:
- Do not completely load the annulus with water. Instead, pressure up the casing with compressed air or gas. A written request must be received in Technical Permitting for approval of this option. Approval will be contingent on a test period of at least 60 minutes.
- Option 2:
- Increase the tubing pressure during the test to offset the downward force on the tension-set packer due to the applied casing test pressure. The tubing pressure gradient shall not exceed 0.5 psig/ft unless a higher injection pressure gradient is permitted.
- Option 3:
- Pull more tension on the tubing string before the test.
- Option 4:
- Perform a two-part MIT by testing the casing with equalized casing and tubing pressure and then testing the tubing and packer by bleeding off the casing pressure at least 200 psig. To use this option the following procedure should be followed.
- Determine the minimum test pressure requirement from Form H-5, instruction 4(c).
- Apply this pressure to the tubing-casing annulus and concurrently apply enough tubing pressure to maintain the packer seal. The casing test pressure and tubing pressure may be equal during this part of the test.
- Monitor and record the pressures required for item 19 for a minimum of 30 minutes with the test pressure stabilized.
- Bleed off the casing pressure until a minimum differential of 200 psig exists between the tubing-casing annulus pressure and the tubing pressure.
- Monitor and record the pressures for an additional 30 minutes (stabilized) and record these on Form H-5, item 19.