Industry News - Offshore Engineer Reports - Channel sands shift US Gulf E&P focusChannel sands shift US Gulf E&P focus
from: Offshore Engineer
by: Darius Snieckus
Friday, June 10, 2005
Channel sands have emerged as a key focal point for operators
in deepwater US Gulf of Mexico at a time when
production/reserve ratios have increased from historic lows of
10% to recent highs of 30%, according to a new report from
IHS Energy. Darius Snieckus reports.
These conclusions, along with those
showing recent finds have shifted
toward gas, are among the many
drawn from the analyst's Deepwater
Production Performance Study, an indepth
analysis of 72 existing of US Gulf
fields (67 active) in water depths greater
than 1000ft and reservoirs made up of
deepwater facies.
'We were surprised at the increased
emphasis on channel gas reservoirs when
all of the production performance
measures clearly point to sheet sands as
the target of choice,' said Tom Harris,
president of PetroSolutions, which
teamed with IHS Energy to publish the
study. Harris reckons the emphasis on
channel gas reservoirs may be a function
of seismic visibility along with robust
gas prices and technological advances in
the areas of completions and flow
assurance.
The study underscores that the
deepwater US Gulf continues to present
more active fields than any deepwater
arena worldwide with a growing resource
and production base, he said. Moreover,
the industry has witnessed an eight-fold
increase in maximum flow rates and
monthly production volumes during the
last 20 and 10 years, respectively.
In all, 550 completions for 467 wells
were evaluated to derive the study's
conclusions, including:
of the 72 fields studied, 67 are active.
The number of active producing wells in
these fields ranges from 41 to one. The
median field size has three active wells.
flow rates per completion for sheet
sands average 11,000b/d; channel sands
average 6000b/d and channel levee sands
average 4000b/d.
one oil well has produced almost 50
million barrels of oil; five gas wells have
each produced in excess of 100bcf each
with rates exceeding 200 million scf/d.
deepwater oil reservoirs are initially
undersaturated; three primary drive
mechanisms have been recognized: fluid
expansion, aquifer influx and formation
compressibility.
based on geocellular modeling and
petrophysical simulation for three fields,
there appears to be areas of unswept oil
in channel complexes and downdip oil
column potential in several channel
sands.
The objectives of the study were first to
categorize each completion by fluid type
and depositional environment, then
evaluate the production performance for
each zone to ascertain differences
between good versus poor performance.
The study evaluates only producing fields
where reservoir facies are limited to
deepwater environments and 3D seismic
data is also included with log-based
models to identify seismic AVO
signatures for a wide variety of fluid,
facies and production types.
Research methods relied on traditional
reservoir analytical techniques such as
decline-curve analysis, Nodal and
material balance as well as newer
methods that apply well-test theory on
monthly production data.
These methods were used to determine,
the original volumes of hydrocarbons-inplace,
an expected ultimate recoverable
volume, the schedule of recovery,
drainage areas, decline rates, plateau
periods, elapsed time for water
breakthrough, abandonment conditions
and reservoir-drive mechanisms to
evaluate efficiencies.
'The study provides the level of
regional, detailed benchmark information
necessary for effective
exploration strategies,' said Steve
Trammel, senior product manager, New
Product Development at IHS Energy. 'The
ability to access this baseline data at a
reasonable cost gives an operator more
time to focus on the high-level work
required for specific company prospects
and projects.'
With production data studied through
November 2003, the report, claimed to be
the only comprehensive deepwater US
Gulf study combining seismic analysis
with production performance methodologies,
is designed to assist exploration
and production companies in making
informed decisions about production
optimization and acquisition/exploration
targets in the deepwater operating
environment. OE
In depth shallow shelf study
IHS Energy plans to release an
update of a related production
performance study of the Gulf of
Mexico deep shelf in August,
providing in-depth analysis of
120 existing fields in water depths
less than 1000ft with perforations
deeper than 16,000ft.
Production from the shallow,
conventional shelf in the northern
US Gulf peaked in the 1980s and has
since declined, unlike the deep shelf
play that achieved a little below
30bcf/month of production through
last September. Some industry
observers have opined that the deep
shelf play is within the first 10% of
its lifespan, with estimated
recoverable reserves of
approximately 10tcf of gas. OE
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