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ASHRAFI-KARABAKH SEISMIC FACIES ANALYSIS

F. Salamov
 Colorado School of Mines, Golden, Colorado

Karabakh, Ashrafi and Dan Ulduzu prospects are situated on the North Apsheron Anticlinorium located 20 km northeast of the prolific Apsheron Ridge. Azeri – Chirag – Gunashli are the direct field analogs for Karabakh, Ashrafi and Dan Ulduzu. Karabakh, Ashrafi and Dan Ulduzu are late Pliocene four0way anticline closures. The reservoir consists of a thick fluvio-deltaic sand sequence in the Middle Pliocene Productive Series.

Exploration activity in the northern part of the South Caspian Basin in the mid-to-late 90’s yielded no significant volumes yet a lot of information has been received on reservoir presence and distribution.

Mapping seismic facies and tying it to available well control should help to get the answers for the following questions:

  1. Sub regional reservoir distribution for Balakhany and Pereriva formations
  2. Paleo channels detection and observing them in regional scale; to observe their direction and changes in thicknesses 
  3. Net to gross variations in Balakhny fluvial sands, direction of paleoflow, influence of paleo-structure on deposition
  4. Confirming aquifer extent in Balakhany to ACG

The workflow included:

  • Preliminary quick review of seismic and well data
  • Defining the main goals of the project
  • Horizon interpretation. The main horizons (they are: Balakhany top, Bal_VIII_FS, Bal_IX (Karabakh area), Pereriva B, NKG, NKP and PK base) of Productive Series have been interpreted and attribute maps generated for each interpreted horizons. Also some horizons (BAL_V, NKG, NKP, PK_SB) in regional scale through both areas have been interpreted
  • Time-Depth converting 
  • Mapping in ZMAP (for structural and stratigraphic thickness maps generation)
  • CI volume (for Karabakh data) generation and loading it to Geoprobe software
  • Transfer all necessary data to Geoprobe (interpreted surfaces, wells)
  • Working in Geoprobe: Attribute maps generation (amplitude extraction maps from existing volumes); Spectral decomposition was applied (only for Karabakh) for channels detection.