Bulletin 2011-35 Legal Header

Rules and Directives

Surface Casing Vent Requirements for Wells

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Release Date: Dec 20, 2011

This bulletin clarifies Section 6.100(4) of the Oil and Gas Conservation Regulations (OGCR) and provide additional surface casing annular flow testing options to Interim Directive 2003-01: (1) Isolation Packer Testing, Reporting and Repair Requirements, (2) Surface Casing Vent Flow/Gas Migration Testing, Reporting and Repair Requirements, (3) Casing Failure Reporting and Repair Requirements (ID 2003-01). This clarification specifies the requirements for surface casing vent exemptions. As the ERCB already considers wells that meet the criteria in this bulletin of low risk to public safety and the environment, it has historically granted exemptions on a case-by-case basis for wells that meet these criteria. Although the ERCB has not previously required wells without vent assemblies to test for surface casing annular flow, the ERCB now requires them to be tested. If surface casing annular flow is detected, a vent assembly must be installed to allow for further testing. The new testing requirements will further reduce the risk to public safety and the environment by ensuring that companies and the ERCB can take appropriate action as required in ID 2003-01.

This bulletin supersedes all previous surface casing vent assembly exemptions issued under Section 6.100(4) of the OGCR. These exemptions are not applicable to thermal wells, which require a vent assembly. Acceptable testing methods for exempt wells with no surface casing vent assembly have been included in an attachment to this bulletin.

Background

  • Section 6.100(1) of the OGCR states: "the annulus between the second casing string and the surface casing [must be] open to the atmosphere in the manner described in subsection (2)." Currently, licensees must install a vent assembly to comply with this requirement.
  • Section 6.100(4) of the OGCR states: "The Board may exempt a well from the requirements of this section [installing a vent assembly] if the well pressures are such that annulus vents are not necessary, or if special circumstances require the vents to remain closed except when checking for pressure in the surface casing." This section does not include exemption criteria.
  • Section 2.3 of ID 2003-01 states: "Within 90 days of drilling rig release, licensees must test new wells for a vent flow." The interim directive does not include requirements for testing wells with no vent assembly.

Exemption Criteria for Section 6.100(4) of the OGCR

Exemption criteria intended to clarify Section 6.100(4) of the OGCR follows. In the event of a gas flow, see the attachment for further testing procedures.

Existing Wells

Wells drilled before the release of this bulletin that have surface casing but no vent assembly are not required to install a vent assembly if

  • the true vertical depth of the well is less than 1000 metres (m),
  • the gas deliverability is less than 28 103 m3 per day absolute open flow (AOF),
  • the hydrogen sulphide (H2S) content is 0.00 moles per kilomole,
  • the licensee has completed a satisfactory surface casing annular flow test using the testing procedures in the attachment, and
  • there is no evidence of surface casing annular flow of gas, water, or liquid hydrocarbon.

If gas, water, or liquid hydrocarbon is migrating to surface, the licensee must

  • install a permanent vent assembly on the well that meets the criteria outlined in Section 6.100(1) of the OGCR, and
  • test, report, and repair the vent flow in accordance with ID 2003-01.

Licensees are required to test all existing wells by October 2013.

New Wells

Effective immediately, wells drilled with surface casing, as defined in Directive 008: Surface Casing Depth Requirements, do not require a vent assembly if

  • the well meets all exemption criteria for existing wells,
  • the maximum pressure gradient of all zones penetrated is less than 10 kilopascals per metre,
  • the well is drilled in an established area as defined in Directive 008,
  • the production casing cement returns are visible at surface, and
  • the surface casing stub is at or above ground level.

If gas, water, or liquid hydrocarbon is migrating to surface, then the licensee must

  • install a permanent vent assembly on the well that meets the criteria in Section 6.100(1) of the OGCR, and
  • test, report, and repair the vent flow in accordance with ID 2003-01.

The licensee is required to test new wells within 90 days of the release of the drilling rig.

Documentation

Once a well has been tested, the licensee must document the test method, results, and conclusions. This information must be made available to the ERCB on request. As required in ID 2003-01, the licensee must retain documentation on the surface casing annular flow test for at least two years after the date of abandonment.

General

The ERCB’s compliance assurance process is in Directive 019: ERCB Compliance Assurance. A list of risk assessed noncompliances is available on the ERCB website at www.ercb.ca under Industry Zone: Compliance and Enforcement: Risk Assessed Noncompliance.

Any questions regarding this bulletin, the attachment, or any other matter relating to Section 6.100 of the OGCR or ID 2003-01 may be directed to the ERCB Well Operations Section by e-mail at welloperations@ercb.ca.

<original signed by>

Robin King
Executive Manager
Field Surveillance and Operations Branch