ABSTRACT: Chasing Channel Sands in South East Asia

Lloyd, Peter M.¹, Bob Koch², David DesAutels³, Amirrudin M. Zain⁴, Roopa Gir⁵, Bob Davis⁵
(1) Schlumberger, Kuala Lumpur, Malaysia 
(2) Vico Indonesia, Jakarta, Indonesia  
(3) Santa Fe, Indonesia, Jakarta, Indonesia 
(4) Petronas Carigali, Kuala-lumpur, Malaysia 
(5) Schlumberger, Jakarta, Indonesia 

With technical advances in surface seismic and downhole imaging techniques, it is now possible to not only map the distribution of reservoir sandstones in the subsurface, but to accurately define the orientation of productive fairways, or "sweet-spots" within the sequence.

Channel sands frequently have favorable reservoir characteristics; having often been laid down in higher energy settings, they commonly have coarser and better sorted grains, less clay and improved poroperm characteristics. However, they often have limited lateral extent and shoe-string geometries which makes them more difficult to predict in the subsurface.

This paper will summarize the results of four case studies of how channel sands, laid down in different depositional environments, have been recognized with borehole imaging. Examples from deep sea, delta front, delta top fluvial and tidal settings will be presented. From sedimentary features and palaeocurrent directions within the channel sands it has been possible to determine their orientation.

A sound understanding of the depositional model and the integration of all the available data (outcrop studies, seismic attributes, cores, logs and downhole imagery) allows channel sands to be identified in a wide range of environments. The ability to orient the channels and so map them in the subsurface provides the basis for reducing risk and optimizing the success ratio of both appraisal and development wells. Because of their potential as stratigraphic traps and production fairways, they offer good prospects for increasing recoverable reserves.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia