Fluid sampling, subsea processing help
maximize deepwater development
Design life cycle value curve
of a typical project.
Energy demands for oil and gas have driven offshore operators to explore for viable solutions to maximize the recoverable volume of deep offshore assets with innovative technologies.
Forecasts from a subsea processing game
changer report shows that expenditure on
subsea processing systems is expected to
exceed $3.4 billion, with deepwater expenditures expected to increase by 130% to $260
billion by 2018. A contributing factor driving this is the demand to deploy over 1,000
additional subsea multi-phase fowmeters,
(SMPFM) which provides well diagnostics
to measure individual phases (oil, gas, water) without the need for complex conventional testing operations.
Responding to the increase in subsea tree
orders for greenfeld developments, manufacturers are now developing more SMPFM
products to meet well diagnostic demands.
In addition, the industry is optimistic on
marginal feld development prospects
(on average 200 to 300 MMbbl each) and
growth in viable brownfelds. More than
70% of the world’s oil and gas production
comes from older brownfelds, marking a
trend for application of enhanced oil recovery (EOR) technologies to meet global
demands, such as subsea processing. Due
to current development trends, there is
pressure on operators to manage capex and
opex, increase effciencies, guarantee fow
assurance, and increase production.
The deepwater market requires higher
capex which is expected to rise from 38% in
2012 to 53% by 2017. This implies that deep-
water operators must increase production
by maximizing their operating wells in order
to future-proof return on investment (ROI).
Therefore, SMPFM plays an important role
in the fnancial ROI over the life of the feld,
and must be confgured to determine the
optimal recoverable reserves of each pro-
Growth trends in deep and ultra-deepwater development demonstrate a need to increase hydrocarbon output while improving
the asset’s net present value. The new application of subsea fuid sampling systems, subsea separators, compressors, multi-phase
pumps, and the qualifcation of critical components would enable remote long-distance
assets (even with low reservoir pressure)
to be developed economically. Offering improved fow assurance and energy effcient
processes to topside facilities, these subsea
processing technologies are being proven
and qualifed for deepwater operations, with
extensive qualifcations under way for ultra-deepwater developments.
Furthermore, the synergy of subsea fuid
sampling and subsea processing has evolved
into a solution for transforming potential oil
and gas reserves into economic ROI. Thus,
by adding accurate fuid samples, the potential value of subsea processing can be realized on increased production volume.
Field life cycle
The life cycle design for subsea engineer-
ing development requires six distinct proj-
ect phases: explore, appraise/select, FEED,
execute, operate, and abandon. The ability
to infuence the value of the design as it pro-
gresses from the appraisal/selection phase to
abandonment, follows a logarithmic curve.
The curve shows that the front-end-loading
(FEL) region of the engineering design (
ap-praisal/select through FEED) determines
the value of the design factor (time, availability and life circle cost). The FEL infuences
the value for subsea system development,
as 80% of the project life cycle is realized at
this phase of early engineering development,
which accounts for about 20% of the entire
project schedule. Therefore, time and effort
must be invested during early engineering to
get the right design at the conceptual phase.
Several large oil and gas felds are being
developed with multi-phase meters and wet-gas meters. These instruments provide
essential data for optimizing production,
measuring oil, gas, water fractions, and fowrates.
Recent research and development championed by major operators and original equipment
manufacturers is focusing on improving the performance of the metering systems; such as the
use of an SMPFM with the developed subsea
fuid sampling system implemented at mid-life of
the feld to check and calibrate the data.
This has created opportunities to improve
understanding of the well fow stream for reservoir monitoring, using available transient
multi-phase fow model and redundant metering sensors. Obtaining accurate fuid samples
for PVT and compositional analysis is vital to
understanding the reservoir characteristics,
enabling the design optimization and the advancement of subsea facilities.
ROV sampling systems
Oceaneering International, Inc., and others
have developed ROV capabilities for deploy-
ment on deepwater development, providing a
reasonable alternative for fuid sampling from
subsea facilities. The ability to acquire subsea
fuid samples from well production systems
without the need for a static platform is key.
The new generation of subsea fuid sampling technologies uses an ROV, a sample
collection device, known as a sampling skid,
and a storage facility for the collected fuid.
The collecting device recovers samples of
the fuid from the subsea tree, which is then