American Oil and Gas Reporter - May 2015 - 75

SpecialReport: Study In Geophysics

Seismic Improvements Add Knowledge
By Kari Johnson
Special Correspondent

Whether identifying the best drilling
locations in an onshore unconventional
resource play or accurately delineating
salt boundaries in deep water, advances
in geophysical capabilities continue to
help operators design and drill more productive wells and increase ultimate recoveries.
Examples of fast marching seismic
capabilities onshore range from more advanced attribute analysis and multicomponent recording that are enabling operators to high grade unconventional drilling
locations, to combining better microseismic detection with 3-D data to design
more effective fracture stimulations.
Offshore advances include such innovations as real-time positioning systems,
marine mammal detection, and accelerometers in receivers that allow processors
to calculate the precise directions of arriving wave fronts.
Additional developments in acquisition
technology for both on- and offshore include broadband sources and receivers
that are widening the amplitude spectrum
of acquired datasets, downhole tools for
fracture monitoring, and wireless data
"harvesting."
Meanwhile, new prestack time and
depth migration algorithms are enabling
geoscientists to extract valuable new information from vintage data. New interpretation software allows interpreters to
handle growing volumes of data, while
new techniques in boundary detection
and coherent noise management in 3-D
seismic data are improving image accuracy
and definition.

Back To The Future
Seismic technology is moving back to
the future as it reclaims its position as a
tool for determining where to drill, says
Stephen C. Jumper, chief executive officer
of Dawson Geophysical. "When I started
in the business, seismic crew activity was
a leading indicator," he observes. "Seismic
crew count in the lower-48 could be used
to project rig activity."
But unconventional resource development has flipped the process, he remarks. Initially, these plays were marked
by producers taking large lease positions
and starting their drilling programs before

acquiring seismic data. "Seismic data
were used primarily for geohazard detection," observes Jumper. "The objective
was to keep the horizontal wellbore in
zone as far as possible, avoiding faults
and karsting, and staying on dip within
the formation."
In other words, he says, seismic data
were utilized to determine where not to
drill.
Over time, techniques for acquiring
full-offset, full-azimuth data have led to
higher-end attribute analysis, Jumper observes. Interpreters are able to analyze the
seismic signature on successful wells and
create better analogs. As a result, he says,
seismic data are shifting back to a whereto-drill science. "Producers are using seismic to high grade drilling locations, reduce
risk, and lower finding and development
costs," he assesses, adding that seismic
data contribute directly to identifying areas
more conducive to completion techniques
by determining fracture orientation and
intensity, and key rock properties.
The seismic industry has made tremendous progress from a high-end analytical
perspective, Jumper says. "Whether it is
full-azimuth, full-offset, conventional 3D data, microseismic or a multicomponent
recording, producers are able to get an
improved understanding of both subsurface
structural components and stratigraphic
changes," he holds.
"From a design and attribute standpoint,
channel counts have stabilized somewhat,

along with acceptable densities of sources
and receivers in a 3-D survey," he continues. "The industry has found sets of
parameters in various basins that contribute
the attributes necessary to do high-end
analytics."
Variability in channel count is driven
more by the size and shape of a survey
than the actual number of live channels
recorded, for the most part, Jumper suggests. "Our saturation on the ground in
terms of channel count density is much
higher, and there will be areas where that
will continue to tighten," he predicts.
Most surveys today are rich in azimuth
and offset attributes, and any growth in
channel count only increases understanding, he asserts. Seismic attributes are
providing a potential road map for development and production, Jumper adds.

Multicomponent, Microseismic
Over the past several years, there has
been an increase in multicomponent
recordings in the lower-48 and Canada,
notes Jumper. In conventional plays, he
says, companies are looking for areas
that are conducive to accumulating hydrocarbons. Multicomponent recordings
as well as high resolution 3-D surveys
are aiding that search through improved
imaging of reservoir connectivity and
compartmentalization, he says.
In unconventional plays, Jumper says
conventional seismic data are important
for identifying geohazards such as faults,

An increase in multicomponent recordings in North America has contributed to improved
imaging of reservoir connectivity and compartmentalization, says Stephen C. Jumper,
chief executive officer of Dawson Geophysical, which has been conducting multicomponent surveys in areas such as the Bakken, Marcellus, Permian, and East Texas/Louisiana
for 15 years.

MAY 2015 75

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