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