Upstream Lifecycle · 02
Discovery and appraisal convert an exploration target into subsurface evidence. Wells, logs, cores, fluids, pressure data and well testing are integrated to determine what has been discovered and whether it warrants further appraisal and development.
Discovery & appraisal workflow
The exploration well provides the first direct subsurface evidence. Formation evaluation, core analysis, fluid sampling and well testing progressively replace pre-drill assumptions with measured reservoir information.
Drill the selected prospect to test the geological interpretation and determine whether hydrocarbons are present in the predicted reservoir intervals.
Key activities
Acquire and interpret well logs and related formation data to determine lithology, porosity, fluid saturation and reservoir quality.
Key activities
Use cores, cuttings and formation-fluid information to establish reservoir properties and improve understanding of the discovered accumulation.
Key activities
Evaluate the ability of the reservoir to deliver fluids and determine pressure behaviour, productivity and key reservoir characteristics.
Key activities
Integrate geological, petrophysical, pressure, fluid and well-test evidence to establish the size, quality and uncertainty of the discovery.
Key activities
Design additional wells and data acquisition programmes to reduce uncertainty and determine whether the discovery can support commercial development.
Key activities
Evidence integration
Appraisal is fundamentally an uncertainty-reduction process. Seismic interpretation provides structural context, logs describe the penetrated formations, cores provide direct rock measurements, fluid samples establish fluid properties and well tests reveal pressure and flow behaviour.
Evidence chain
Integrated disciplines
The objective is to establish reservoir quality, fluid behaviour, pressure conditions, connectivity and uncertainty well enough to support the next engineering decision.
Appraisal decision
Appraisal determines whether the available evidence is sufficient to define the reservoir and reduce the uncertainties that matter for development. Where uncertainty remains material, additional wells, testing or data acquisition may be required before progressing to field development.
Lifecycle navigation
With the discovery established, the next stage integrates geological, petrophysical, fluid and pressure information into a coherent reservoir description for development.