Solutions such as underbalanced or pressurebalanced drilling could let more wells be sunk acceptably in reservoirs which are very pressure-depleted. Conventional methods will not work there.
These approaches provide better opportunities to manage or balance well pressure between the fracture pressure for the formation and pore pressure in the reservoir. That makes drilling and completion possible.
The PSA has looked at experience, plans and measures for preserving safety by adopting alternative drilling techniques in reservoirs which are becoming pressure-depleted.
In recent years, this work has included independent studies of well barrier philosophies when drilling and completing with such methods – particularly when using shared barrier elements.
The goal has been to establish whether such innovative techniques are as robust and good as conventional drilling.