This biostratigrahic approach involves dating sediments (partly with the aid of strontium isotopes) and interpreting the deposition environments in which they were formed.

Of the various calcareous (shelly) microfossil groups present, rich populations of the larger foraminifera (unicellular marine organisms) have proved to be the most useful for both purposes.

Pilot studies were also carried out on fossil plant remains and nannofossils (very small calcareous marine fossils), but the relatively high energy of the shallow marine Asmari environment precluded significant preservation except towards the base of the formation.

Despite this minor limitation, detailed well studies have resulted in the construction of robust, high-resolution, time- (chrono-) and rock-stratigraphic frameworks.

Such frameworks are usually sufficient for predicting reservoir properties in sandstone reservoirs.

However, production from carbonates often depends on the superimposition of open fracture networks, whose distributions are extremely difficult to predict and characterise. This is the case here.

Much time has therefore been spent in jointly developing a sophisticated fracture modelling approach.