Training

clastic-sedimentology;borehole-image-interpretation

Acknowledgements
The authors gratefully acknowledge the management of the Ourhoud Organisation and partners for permission to publish this manuscript.

OURHOUD FIELD LOCATION AND LITHOSTRATIGRAPHY

SEDIMENTOLOGICAL BACKGROUND
2 previous models
• chott basin - with m-scale meandering and braided channels large-scale meandering channels (15m point bars).
• these have different implications for sandbody connectivity and internal reservoir heterogeneity

AIMS OF BHI ASSESSMENT
The main aims were to assess:
• the scale of genetic associations, hence define or refine depositional models
• the geometry and preferred orientation of these associations

SEDIMENTARY BUILDING BLOCKS

STUDY DATABASE AND APPROACH
Over 30 UBI images have been calibrated with 22 fully cored wells.
• BAAL devise a descriptive, reproducible image facies and dip classification scheme
• qualitatively assess dip patterns and images
• integrate image data with:
• core-sedimentology logs
• autocar data
• interpretation of bedforms, macroforms, channel type and genetic element composition
• full-field reservoir correlation using an event stratigraphic approach
• reservoir layer mapping through integration of all available datasets

MACROFORMS AND GENETIC ELEMENTS
Bedforms stack to form two types of macroform:
• lateral Accretionary
• downstream Accretionary Seven genetic elements have been identified based on:
• component image facies
• dip pattern (eg. dominant bedform)
• inferred macroforms

SCHEMATIC EXAMPLES OF BEDFORMS

DOWNSTREAM ACCRETIONARY MACROFORMS: LOW SINUOSITY CHANNEL-FILLS 

LATERAL ACCRETIONARY MACROFORMS: HIGH-SINUOSITY CHANNEL-FILLS

OTHER EXAMPLES OF GENETIC ELEMENTS

LOW-AMPLITUDE ELEMENTS