136. The authorization holder must install a conductor casing if
(1) the surface casing is laid at a true vertical depth exceeding 650 m;
(2) it is foreseeable that a petroleum zone will be intersected before reaching the laying depth of the surface casing; and
(3) an adjacent wellbore encountered groundwater flow on the surface.
The conductor casing must be set in a competent formation.
If a shallow aquifer presents artesian pressure conditions, the conductor casing must be set directly above the aquifer.