A Dutch onshore gas well was drilled to a total depth of 5,136 m along hole
(3,700 m true vertical depth) with a maximum deviation of 89 degrees. The
well was completed with 193.7 mm (7 5/8 in.) 13% chrome (Cr13) tubing with
a 177.8 mm (7 in.) cemented liner across the reservoir providing full bore
access to the pay zone. Due to the very stratified nature of the reservoir,
the long-term sustained production depended on achieving vertical connecti
vity with all the layers. In order to achieve this and maximize productivit
y, a single run underbalanced perforating operation was required. Due to co
iled tubing limitations in this deep, high pressure well, a hydraulic worko
ver unit was selected to deploy and retrieve the guns. A total gross interv
al of 1,026 m was perforated in one run utilizing 85.725 mm (33/8 in.) deep
penetrating guns and thereafter snubbed from the well under live condition
s (46 MPa at surface). To date, it is understood that this is the longest s
ection of guns conveyed, fired underbalanced, and deployed out of a live we
ll. This paper addresses the perforating technique selection, the planning
and execution process, the major operational learning points, and discusses
final productivity results which demonstrate the validity of this techniqu
e.