A new and innovative approach for high-resolution seismic imaging and interpretation of diffraction energy.
Up to 50% of the subsurface information obtained from seismic data is believed to be either underutilized or lost using standard seismic imaging procedures. These imaging procedures remain biased towards high energy events defined by continuous reflectors or major discontinuities such as large faults. This energy is referred to as “specular” energy, and typically dominates the seismic data volumes used by seismic interpreters. While image processing techniques like coherency and volumetric curvature can help recover or enhance discontinuities in the seismic data, they cannot recover the high-resolution and lower energy details that have already been masked by standard processing and imaging procedures.
A significant amount of energy associated with high-resolution features such as small faults, stratigraphic edges and reservoir heterogeneities is recorded in the form of “diffraction” energy. The information encoded in diffraction energy can help explain reservoir compartmentalization, permeability and performance. It is this information that is masked by the dominant specular energy and irretrievably lost through the integration and stacking processes that are employed in standard seismic processing and imaging procedures. While these standard procedures improve signal-to-noise ratios, they do not recover the detail that can resolve subsurface complexities, influence prospectivity decisions, or control reservoir behavior.
The innovative EarthStudy 360™ system is able to both recover and separate specular and diffraction energy from recorded seismic data. The process decomposes the fully recorded seismic wavefield in-situ and in depth, without integration or stacking, so that the lower energy associated with subsurface diffractions can be isolated and subsequently enhanced.
EarthStudy 360 creates a new set of deliverables that can be easily worked into the seismic interpretation process. The key advantage of this system is the ability to decompose and separate the wavefield into specular reflection and diffraction energy. Specular reflection stacks can be used to emphasize and interpret major continuous events and major discontinuities, while diffraction stacks can be used to interpret and delineate high-resolution subsurface stratigraphic and structural features. Additionally, these diffraction images can detect reservoir heterogeneities that are completely obscured by standard imaging procedures.
The recovery of diffraction energy from seismic data is enabled by a rich multi-dimensional decomposition defined by full-azimuth directivity and reflectivity. Once diffraction energy is isolated, it can be followed by interpretation image enhancement techniques to create high-resolution images of subsurface stratigraphic and structural features.
This procedure is applicable to all exploration and field development projects, including deep water, shale plays, fractured carbonate reservoirs and mature fields. When used properly, it can lead to accurate, high-certainty seismic interpretation for risk-managed field development.