When running a magnetic surveying instrument, the following guidelines shoud be adhered to:

• to eliminate external magnetic interference, surveys shall not be taken within 30 ft of a casing shoe
• all surveys should be corrected to grid co-ordinates
• all surveys must be read carefully and double-checked
  Note: A check survey shall be run if doubt exist as to the validity of the data.
• in order to avoid drillstring magnetic interference, the survey barrel must be configured such that the instrument is positioned centrally within a non-magnetic drill collar
• if the instrument is being run due to target constraints in a differently oriented well, interference calculations shall be performed to ascertain the length of additional non-magnetic drill collars required (and stabilisers if applicable).

Survey Reporting

All valid surveys should be reported in the Daily Drilling Report, stating Depth (MD), Drift Angle and Drift Direction.

For the last survey data, Depth (TVD), Vertical Section and Rectangular Co-ordinates should be calculated.

Verification of Multi-shot Surveys

The quality of all multi-shot surveys taken shall be checked by the Surveying Contractor and verified by the Drilling Supervisor using an approved acceptance criteria.