ABSTRACT: Advantages of simultaneous surface and borehole seismic acquisition and
data
synergy in processing and interpretation
Leaney, Scott1, Bill Borland2, Di Cao3,
Bill Harmony4, and Phil Johnston5
(1) Schlumberger, Gatwick, United
Kingdom
(2) Schlumberger, Jakarta, Indonesia
(3) Schlumberger, Fuchinobe, Sagamihara-shi,
Japan
(4) Maxus, Jakarta, Indonesia
(5) Unocal Indonesia Company, Balikpapan
Recording of seismic waves using surface or borehole receivers provides similar
information about the subsurface. Surface receivers have the advantage of effectively
unlimited lateral coverage with the disadvantage of uncertainties in the effects of
wavefield propagation through the earth as well as the spatial location of events. Unlike
surface sensor recording, borehole deployed receivers allow recording of both the upgoing
and downgoing wavefields. Analysis
of the downgoing wavefield provides information on
detrimental propagation effects such as spreading, attenuation and dispersion (pulse shape
changes) and anisotropy as well as multiples and conversion point locations. By making use
of dipole shear logs, detailed elastic
velocity
models can be derived to provide accurate
synthetics and depth processing. Through synergistic
data
analysis
a calibrated,
anisotropic, anelastic model has the potential of providing true relative amplitude
prestack images in depth.
While sequential recording of surface and borehole seismic can provide this
information, simultaneous acquisition provides the most cost-effective means of obtaining
this information. In this paper, two examples of simultaneous acquisition of surface and
borehole seismic will be described, one a converted wave acquisition and the other a towed
streamer rig undershoot. Anisotropy, Q and conversion point analysis
as well as
velocity
models and synthetic seismograms will be determined and used in surface processing.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia