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The next ‘grand challenge'

By RHONDA DUEY, Senior Editor, Hart Energy

SEAM's next phase will tackle land seismic issues. While some majors have maintained active R&D departments, others have opted for a more distributive model, funding research through service companies and universities. While this is often a good way to pursue targeted research, it makes it more difficult to address "grand challenges."

The Research Committee of the Society of Exploration Geophysicists (SEG) decided to buck this trend. Members envisioned, in 2004 and 2005, a collaborative research effort with a targeted industrial goal. The result was the SEG Advanced Modeling Corp. (SEAM), established in 2007. SEAM's goal is to identify a grand challenge within the area of geophysical modeling, conduct research phases, and offer earth models and simulated data representing significant geophysical challenges. Phase I, which began in March 2007, focused on deepwater subsalt tertiary basins. Expected to be complete in 2010, it was extended by an alliance with the Research Partnership to Secure Energy for America, which provided an additional US $2.6 million.

"We are particularly intrigued by the collaborative role a professional society, in this case SEG through its SEAM subsidiary, can assume in bringing together a broad industry consortium to conduct leading edge research," states C. Michael Ming, President, RPSEA.

Recently SEAM announced plans for Phase II, which will focus on land seismic challenges. Already several oil and service companies have signed on to discuss the definition of the challenge and the project scope.

Phase II will focus on three core challenge themes. The first is high-density and areal-extensive acquisition geometries. "Industry's experience has consistently been than subsurface images improve with every acquisition and processing advance that moves toward ‘true 3-D,'" the Phase II announcement document states. "Marine wide-azimuth acquisition is a good case in point. However, land channel counts have always been limited by what is technically, economically, and operationally feasible." The goal here is to provide simulated datasets to evaluate the technical benefits of high-density recording.

The second theme is near-surface complexities. Near-surface heterogeneities wreak havoc on noise suppression and data processing and include topography, sand dunes, dry river beds, steeply dipping layers, outcropping refractors, lateral velocity variations, velocity reversals, layered basalts, carbonate karst, and anisotropy.

The hope is to provide realistic near-surface earth models based on geological parameters transformed to rock physics parameters. "The efficiency of full elastic simulation codes continues to improve, driven in part by the activities of SEAM Phase I," the document states.

"Near-surface simulations can now be acquired for evaluation of acquisition, processing, and imaging schemes."

Finally there is a focus on fractured reservoirs, increasingly important due to the growing interest in unconventional plays. While seismic is recognized as a valuable tool for horizontal wellbore trajectory planning and sweet spot identification, its use is complicated by vertical transverse isotropy in both the overburden and the target interval. Horizontal transverse isotropy, on the other hand, provides a means to identify fracture density and horizontal stresses. Project leaders hope to ascertain the relative benefits of multicomponent data, bandwidth increases, and the need (or lack thereof) for seismic to be an essential component of a fractured reservoir exploration and development program.

Currently a three-year project plan is proposed, although participants in Phase II can modify this approach. The first year will focus on earth model design and fractured reservoir investigations; the second year on seismic modeling simulations and a fractured reservoir version of the base-case simulation model. A simulated dataset will be acquired in the third year.

"A new era in land seismic is at hand. Growing energy demand will spur greater efforts in exploration and development into regions of the world where hydrocarbons occur in land environments," T. Keho and P. Kelamis, Saudi Aramco, states in their expanded abstract A New Era in Land Seismic: The Near Surface Challenge. "Advances in seismic processing technology for processing the resulting huge data volumes will be made possible by continual growth in computational capability. These advances will for the first time allow acquisition of true 3D seismic data. This will not only result in better imaging of the subsurface, but will allow the near surface to be addressed as an imaging problem with better description of velocities and suppression of surface related noise."

For more information, visit SEAM Phase II Project.