Seismic Stratigraphy

                                                                                                                     

OBJECTIVES

Prediction of stratigraphy Ahead of the Drill Bit

Petroleum system

Migration pathways

Reservoir characterization

Correlation of Sequences

Paleogeography and geologic history.

Seismic Stratigraphic studies

Large scale - Basin Studies : exploration plays

Small scale - Reservoir Studies: stratigraphic trap

Flow chart for Flow chart for seismic seismic stratigraphic stratigraphic interpretationinterpretation

Seismic facies

A seismic facies change is the change in the seismic character of a given sequence as it is traced laterally.

Analysizing the character of individual reflections • Waveform • Amplitude • Frequency

Analyzing reflections within sequences:      Geometry.       Continuity      Gross amplitude & frequency       Interval velocity

Geological Interpretation of Seismic Parameters

Reflection configuration

Reflection continuity

Reflection amplitude

External Form and Areal association

• Stratification patterns• Depositional processes• Erosion and Paleotopography

• Bedding Continuity • Depositional processes

• Velocity-Density contrast• Bed spacing• Fluid content• Gross Deposition

Environment• Sediment Source• Geologic settings

Seismic Facies parameters Geologic Interpretation

MAPPING SEISMIC FACIES

1. Sequence boundary

2. External configuration

3. Internal architecture

Sequence BoundariesSequence Boundaries

External ConfigurationExternal Configuration

Internal ArchitectureInternal Architecture

Characterization of seismic faciesCharacterization of seismic facies

Full range of environmental settings

Depends on competency and experience

No single characteristic provides a guide

Stratal Termination PatternsStratal Termination Patterns

ONLAPONLAP TOPLAPTOPLAP DOWNLAP DOWNLAP APPARENT TRUNCATION APPARENT TRUNCATION CONFORMABLECONFORMABLE