Directive 008: Surface Casing Depth Requirements
Purpose of this Directive
This directive sets out requirements for designing appropriate depths of surface casing to assist with well control and groundwater protection.
Surface casing is an integral part of the well control system. It provides sufficient pressure integrity to facilitate the drilling of a well to total depth or to an intermediate casing point, as well as primary support for the wellhead and the landing loads of subsequent casing and tubing strings. It may also be used to cover zones of caving, sloughing, and lost circulation, as well as other weak zones.
Surface casing is a permanent structure of the wellbore that effectively protects in-use aquifers that supply domestic water wells.