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Interim Directive ID 91-06

26 July 1991

TO: ALL OIL, GAS, AND OIL SANDS OPERATORS

CASING, CEMENTING, SAMPLING AND LOGGING REQUIREMENTS SENEX, KIDNEY, TROUT, AND ASSOCIATED AREAS

The Energy Resources Conservation Board has been monitoring the drilling of wells within the severe lost circulation and oil sands areas outlined on the attached map. In addition to the lost circulation problem the Board is concerned about the bitumen bearing oil sands, more specifically, whether the oil sands exist in commercial amounts and whether the oil sands are being adequately protected or isolated for future development.

In accordance with good drilling practice, operators have been setting surface casing at or near the top of the Upper Devonian (Wabamun) before drilling into the lost circulation zone. Intermediate casing is then set over the lost circulation zone and the bottom portion of the casing is cemented up to the lost circulation zone. The problem is that there are no open-hole logs over either the surface or the intermediate hole and as a result virtually no information is available on the oil sands zone. In addition, it is felt that in at least some wells, the oil sands and the lost circulation interval in the Upper Devonian (Wabamun) are left in communication.

The ERCB believes that geological information on the Lower Cretaceous is required to determine the magnitude of the hydrocarbon resources and to ensure that those resources, when present, are adequately isolated. In view of this, the following requirements have been developed in conjunction with industry for the drilling of surface hole in these areas:

1. Conductor pipe is required to a depth of 20 m while drilling surface hole so that drilling returns may be sampled in order to identify the oil sands zones.
2. A Class I BOP or diverter system is required while drilling surface hole.
3. Drill cuttings (samples) will be required from 200 m to the top of the Upper Devonian (Wabamun) in all cases except where approval to waive this requirement has been obtained prior to issuance of the well licence.
4. Operators must have qualified personnel on site to evaluate the samples and to determine the appropriate surface casing setting depths.
5. If possible, the surface casing must be run to a depth below the bitumen bearing oil sand zone. It is recognized that in areas where the oil sands directly overlies the Upper Devonian (Wabamun) this may not be practical, as normally surface casing is set prior to penetration of the Wabamun lost circulation zone. As a minimum, the licensee must set surface casing to within l0 m of the Wabamun top on development wells and to within 20 m of the Wabamun top on exploration wells.
6. The surface casing must be cemented with thermal cement from the surface casing shoe to surface when oil sands are present.
7. From the effective date of this interim directive, an open-hole log or previously approved alternative logging program is required for the surface hole of the first well drilled in each quarter township. This requirement will be reviewed once enough data has been obtained to conduct a reasonable evaluation of bitumen potential within the area. At that time, a decision will be made whether to continue this requirement, require logging at a greater frequency, or, in the absence of significant crude bitumen reserves cancel this requirement.

In the event the licensee can show that it is possible to cement over the lost circulation zone then flexibility exists in connection with the surface casing setting depth.

Questions regarding this interim directive may be referred to members of the Drilling and Production Department at either 297-8186 or 297-3554. [Note: The contact information in this ID is now outdated. Please contact the EUB's Customer Contact Centre for assistance (Phone: 297-8311 - select 0; E-mail: eub.inquiries@gov.ab.ca)]

[Original signed by]

Dr. B. F. Bietz, P.Biol.
Board Member