Apply for exploration and production activity approval

Well suspension and abandonment

This page contains information on how to apply to suspend or abandon a well.

Suspend a well

There a two categories of suspension applications:

  • drilling suspension where the well is to be suspended without a downhole completion installed
  • production suspension where the well is to be suspended with a downhole completion installed.

All suspensions are to include the installation and validation of a minimum of two permanent barriers.

Temporary suspensions are not allowed. 

Barriers

If the production casing is sealed to the formation, pressure tested and not perforated (and the cement integrity has been or is programmed to be logged), then this would constitute one permanent barrier.

The installation and validation of a minimum of two permanent mechanical barriers applies to both tubing string and annulus.

The wellbore schematic must be accompanied by a wellhead profile clearly showing all wellhead barriers in both the production tubing and annulus.

How to apply

You must apply in writing and your letter of application must make reference to Clause 328 of the Schedule of Onshore Petroleum Exploration and Production Requirements 2016. It must be signed by the custodian.

Suspension applications must include all of the following:

  • suspension program reflecting the step by step procedures the rig will follow when installing and then validating the integrity of barriers (to be validated by either tagging or pressure testing)
  • proposed final well schematic with all well construction features labelled, including the proposed position of installed barriers. The well’s final brine weight is to be included 
  • for production suspensions, a wellhead and downhole profile schematic with clearly marked permanent barriers is also to be included (as below) identifying all permanent barriers in the tubing, annulus and wellhead. 

Sample diagram: a wellhead and downhole profile with clearly marked permanent barriers.

 A wellhead and downhole profile schematic with clearly marked permanent barriers

Well suspension activity close out report

For final close out you must supply all of the following:

  • daily drilling reports to be sent as usual and reflecting the entire well suspension until activity close-out
  • the final well schematic reflecting all well construction features (labelled) the position of all validated barriers and also the final brine weight
  • photographs of the fenced-off well site with wellhead (valve handles removed or with handles left in place, chained and padlocked) along with signage reflecting contacts in the event of an emergency. At least four photographs will be required.

Abandon a well

To plug and abandon (P&A) a well you are required to do all of the following:

  • address the requirements of Clause 329 appropriate to the construction and status of the well
  • include the installation and validation of a minimum of two permanent downhole barriers. 

How to apply

You must apply in writing and the letter of application, signed by the custodian of the project and making reference to Clause 328 of the Schedule of Onshore Petroleum Exploration and Production Requirements 2016.

You must include all of the following:

  • the specific reason for the P&A as per Clause 328 (5)(a)
  • the P&A program reflecting the step by step procedures the rig will follow when installing and then validating the integrity of barriers (to be validated by either tagging or pressure testing)
  • proposed final well schematic with all well construction features labelled, including the proposed position of installed barriers. The well’s final kill fluid weight is to be included (as in the sample diagram below).

No casing can be recovered if it will expose an abnormal pressure, lost circulation, hydrocarbon or water bearing zone.

All permanent barriers are to be clearly identified on the final well schematic.

Sample Diagram: Identifying all permanent barriers in the wellbore and signage at the surface.

Final well diagram identifying all permanent barriers 

Plug and abandonment activity close out

For close out you must submit all of the following

  • daily drilling reports to be sent as usual and reflecting the entire P & A until activity close-out
  • the final well schematic reflecting all well construction features (labelled) the position of ALL validated barriers and also the final brine weight.
  • details relating to all installed barriers are to include:
    • barrier type (cement plug, mechanical plug etc)
    • bottom depth of barrier (m)
    • top depth of barrier (m)
    • tagging weight (lbs), unless pressure tested
    • pressure test (psi), unless tagged.
  • photographs of the well site along with surface signage reflecting well and operator details. At least four photographs will be required.

How to submit applications

You must submit the letter and supporting documentation for the well suspension or abandonment to the Senior Director Petroleum Technology and Operations by emailing petroleum.operations@nt.gov.au.

Contact

For help you can contact the Petroleum Operations team by emailing petroleum.operations@nt.gov.au.

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Last updated: 13 October 2017