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Oilfield Glossary
Oilfield Glossary
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Tools

toolface

1. n. [Drilling]
The angle measured in a plane perpendicular to the drillstring axis that is between a reference direction on the drillstring and a fixed reference. For near-vertical wells, north is the fixed reference and the angle is the magnetic toolface. For more-deviated wells, the top of the borehole is the fixed reference and the angle is the gravity toolface, or high side toolface.