Sequence stratigraphy

Sequence stratigraphy is study of genetically related strata. The sequence is defined as a relatively conformable genetically related strata bounded by unconformities or their correlative conformity (Mitchum, 1977). Log sequence stratigraphic analysis of the rock formations, combined with seismic sequence stratigraphic interpretation, can provide a powerful predictive tool for exploration and development reservoir work.

Sequence stratigraphy is a powerful tool in exploration for stratigraphic (non-structure) traps.

In recent decades there has been a growing shortage of newly discovered structural prospects, and smaller structural plays are left unexplored.

At the same time the exploration of non-structural prospects has not compensated for reduction in discovery of structural prospects.

This lack of uptake is due to both – healthy conservatism, due to high risks, and the lack of a well-developed exploration methodology for this type of trap.

Sequence stratigraphy helps predicting geologic aspects of sedimentary basins at different historical stages and therefore provides an opportunity for efficient development of non-structural plays.

Sequence stratigraphic approach to interpretation, leads to a better understanding of basin development and a more reliable mapping of reservoir and seal distribution. Having additional information sometimes enables identification of source rocks and their mapping. Reservoir properties, an important issue in field development, can in most cases be predicted based on the sequence stratigraphy interpreted framework. This is particularity important for exploration projects.

Sequence stratigraphy has many components:

• Sequence stratigraphic interpretation of well log data
• Sequence stratigraphic interpretation of seismic data in particular with possibility of total correlation of all reflections in a seismic cube
• Sequence stratigraphic interpretation of seismic attribute data and the integration of results of well logs and seismic data interpretations

Log Data

• Detailed core descriptions
• Sedimentological interpretation from core
• Sedimentation conditions derived from interpretation of logging data and borehole wall scanning data integrated with core description data
• Construction of a framework of sequence stratigraphy using the results of all studies
• Facies maps

Seismic Data

• Seismic sequence boundaries identification
• Seismic facies analysis and interpretation
• Interpretation of sedimentation conditions from seismic data
• Characterisation of depositional bodies from seismic attributes

We have broad experience in sequence stratigraphy interpretation from various basins and various depositional environments. Our specialists, and where needed, with involvement of our partners, can deliver a full spectra of sequence stratigraphic interpretations.