American Oil and Gas Reporter - November 2018 - 61

SpecialReport: Oil and Gas Computing

Advances 'Scale Up' Nodal Acquisition
By John Smythe
HOUSTON-Oil and gas companies
are continuously pressured to not only
do more with less, but do it faster, safer
and cheaper. This "new normal" in oil
and gas operations, spurred by market
volatility, makes it more important than
ever to mitigate risk and uncertainty as
much as possible in exploration, drilling,
completion and production workflows.
It also is driving significant new digital
oil field and geophysical innovations, including in seismic data acquisition.
Seismic technology is the key to unlocking predictive certainty and effective
reservoir management. In fact, whether
onshore or offshore, a reservoir's economic
performance over its full life cycle is
linked directly to the quality of the seismic
data used to image the subsurface, assess
recoverable reserves, mitigate risk and
guide drilling and development decisions.
When it comes to seismic, image really
is everything.
That largely explains why, even with
all the technological advancements taking
place throughout the industry, oil and
gas operators still tend to embark on exploratory drilling with a certain amount
of trepidation. They know any exploration
project has relatively high levels of uncertainty and risk, and a lack of confidence
in the seismic data will only increase the
risk profile and reduce the probability of
a successful drilling outcome.
As always, oil and gas companies are
utilizing a variety of available data to
manage that uncertainty-from seismic
and geologic data to well logs and production histories-but the industry is only
beginning to explore the frontiers of machine learning and artificial intelligence
to assimilate the vast amounts of raw
data pouring every day into corporate information technology systems. Data from
Industrial Internet of Things-enabled sensors can be synthesized to generate realtime actionable data that was not previously available.
Similarly, seismic solutions are evolving
and scaling up for application across the
full life cycle of an oil and gas asset. A
case in point is nodal seismic technology.
Initially envisioned as a production tool,
the nodal method historically has been
applied in smaller-scale surveys acquired
later in the reservoir development process

to enhance production and extend a field's
economic life. However, advances in data
recording and processing capabilities now
make it economically feasible to scale
up nodal acquisition systems to exploration-type surveys (Figure 1).
While nodes are being deployed in
onshore horizontal resource plays and in
shallow-water offshore blocks, the ability
to efficiently conduct large-scale nodal
surveys is a true game changer for deepwater operators. They now can benefit
from the superior imaging results the
technology makes possible beginning at
the exploration stage-and extending
throughout each subsequent phase of a
deepwater field's life-to significantly improve the quality of the 3-D data that
geoscientists and engineers use to find
and develop reservoirs in this higher-cost
environment. Even legacy towed-streamer
data can be improved with information
gained from node surveys.
Life-Of-Field Application
In the exploration phase, regional reconnaissance and drilling prospect identification are the greatest concerns. Off
shore, exploration often occurs in remote
and difficult-to-access areas, environmentally sensitive waters, areas of dense infrastructure, and/or geologic basins with

complex overburden, structure and stratigraphy.
Advanced ocean-bottom nodal systems
balance the competing exploration objectives of high-quality imaging, largescale affordability, acquisition efficiency
and minimal health, safety and environmental impact. Placing autonomous, cable-free nodes on the seafloor to acquire
data allows operators to circumvent the
surveying constraints and operational issues associated with towed streamers,
while capturing previously unavailable
data, even in areas in mature offshore
basins with dense infrastructures.
Once operations move into the appraisal
phase, the role of seismic shifts from regional reconnaissance to minimum economic field size identification. Seismic
is a valuable tool to solve the problem of
estimating reserves and economic reservoir
limits, along with well and platform locations and recovery strategies.
Development and enhanced recovery
phases force operators to again shift
gears to focus on reservoir management
and characterization. The data collected
from nodal technology are rich, with
full azimuths, long offsets, high vector
fidelities, good coupling, high signalto-noise ratios, and most importantly,
excellent repeatability. These attributes

FIGURE 1
Ocean-Bottom Seismic Data Acquisition with Nodes

NOVEMBER 2018 61

American Oil and Gas Reporter - November 2018

Table of Contents for the Digital Edition of American Oil and Gas Reporter - November 2018