Impact of Paleo-Current Analysis on Reservoir Description of Burgan Clastic Reservoirs, North Kuwait

Saikh Abdul Azim¹, Waleed Al-Awadi², Haifa Al-Ajeel², Yahya Hassan², Shehab A.M. Abdullah¹, and Ali A. Baradi³. (1) Fields Development Division (North), Kuwait Oil Company, PO BOX 9758, Ahmadi, 61008, Kuwait, phone: 965 130 71866, fax: 965 3987197, sazim@kockw.com, (2) Fields Development Division (North), Kuwait Oil Company, (3) Geoscience, Baker Atlas, PO BOX 8786, Abudhabi, United Arab Emirates

The Burgan Formation of Albian age hosting giant hydrocarbon reservoirs are under production for more than four decades. Most of the remaining reserves are in estuarine channel sequences and shoreface sand bodies. Of late, complex pattern of water movement in different parts of the field with areas of bypassed oil underscored the limitations of conventional reservoir description. An integrated study involving paleo-current analysis with core description, log signature analysis, reservoir pressure and production behavior was carried out to delineate features dominantly controlling reservoir heterogeneity. Imagelogs of wells spread over the Raudhatain field have been specially processed to capture the paleo-current directions in individual channels. The dip magnitudes interpreted from Image logs have been calibrated against cross beddings seen from cores and threshold dips were used for paleo-current analysis.

The Lower Burgan reservoir having coalesced braided sand bodies are either massive or exhibit very low dips. Lack of preferred channel orientation correlates with regular bottom water sweep. The Upper part show dominantly northeast trend of paleo-currents in thick estuarine-channels with deterioration of reservoir quality towards basin. The estuarine channels of Upper Burgan show more variable directions in addition to a dominantly northeast trend following sand isopachs. A highly variable individual channel orientation is a rule after this study than was ever thought of.

The channel orientations mapped from paleo-currents are immensely helpful in understanding fluid movements in the multilayered reservoir. Further delineation of major channels, identification of areas of bypassed oil and orientation of horizontal wells are being pursued on the basis of this study. The channel orientations are the key inputs in detailed reservoir descriptions for Static and dynamic model build. Stochastic facies models are now well constrained by the detailed description of channels. Paleo-current analysis has revitalized these mature reservoirs.

Revitalizing Mature Fields
2004 AAPG International Conference and Exhibition Technical Program