and Optimal Production from Thin-Bedded Turbidite
Cossey, Stephen P.J., Cossey
and Associates Inc, Durango,
An integrated study of eight Gulf of Mexico fields, one West Africa field, several outcrops and modern systems
has shown that thin-bedded turbidite (levee)
reservoirs have certain characteristics that can be exploited in the
development of these reservoirs to optimize production. A detailed reservoir
model was developed from outcrops and modern levee systems in which internal
levee shale barriers downlap onto the top of the
underlying HARP surface, resulting in poor reservoir continuity in the base of
the levee and better continuity towards the top. Poor or tortuous continuity,
shown by pressure data, was observed in the lower part of the levee in several
of the studied fields. The channel-fill (HAR) may be sand or shale, or both,
and may explain why the channel-fill may or may not communicate with the levee.
In one example, an individual channel-fill changes from shale to sand within a
distance of two miles. In addition, sandy splay-channels may enhance proximal
to distal continuity in the upper part of the levee.
monthly well production profiles were studied in order to characterize water
production, breakdown of internal barriers, drainage area and well design. It
was found that most wells have erratic or minimal water production and may even
stop water production after several years. The best cumulative and highest
daily rates of production are found in well bores that can be characterized as
“near” horizontal and penetrate the maximum number of thin-beds in a sequence.