Zonal isolation is the exclusion of fluids in one
zone from mixing with oil in another zone. For a
successful zonal isolation one needs to create a
hydraulic barrier between the casing and the
cement and between the cement and the
formation.
Our client is a LNG operator and drills  for Coals Seam Gas (CSG).
When drilling for CSG, groundwater is produced from within the coal
seams and the coals seam gas water gives a challenges to any
operator. The exploratory drilling impacts the environment in different
ways, including the areas groundwater aquifers, rivers and wetlands.
Injection water is treated to ensure that no contaminants are
introduced into the acquifer.

Zonal isolation should not fail. Not only may this have a negative
impact on production and injection efficiency, but it may also have a
long term impact on the environment. During the planning and
execution phase of the drilling campaign critically important decisions,
and their impact on costs and risks were analyzed and measured on
an ongoing base using a set of decision models.

The wells were drilled in a safe, efficient and cost-effective way.
Upfront Key Performance Indicators to measure zonal isolation were
agreed upon and continuously measured.
Zonal isolation: managing reputation risk
The failure to do so may lead to contamination of groundwater.
Zonal isolation is therefor a key requirement for environmental
sustainability.
The business solution was built around a set of proprietary decisions
models, called
WAFE. WAFE is the acronym for Well Assurance For
Engineers, which combines advanced analytics, procurements, well
planning, contract management , performance measurement and risk
management.