Crosswell Seismic in Three Dimensions

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Crosswell Seismic in Three Dimensions--TomoSeis, Inc., 1650 West Sam Houston Parkway North, , Houston, TX 77043-3115; (713) 461-7360
Dr. Spyros Lazaratos, Principal Investigator
Mr. Bruce P. Marion, Business Official
DOE Grant No. DE-FG03-97ER82502
Amount: $74,997

Improved recovery of oil and gas from mature domestic fields depends on the detailed characterization of reservoir structure and continuity. Crosswell seismic is a new technology that addresses this need by allowing the generation of reservoir images showing a level of detail at least ten times higher than what can be achieved with standard surface seismic methods. Although the promise of crosswell seismic has already been demonstrated, full realization of its potential depends on the ability of the data processing methods and algorithms to handle the real-world complexities. In particular, current crosswell data processing algorithms operate under the simplifying assumptions that the wells are vertical, or only slightly deviated, and that the geologic layers are nearly horizontal (not significantly dipping). The objective of the work in this project is to overcome these restricting assumptions by extending to three dimensions the basic crosswell imaging algorithms (traveltime tomography and reflection imaging). This will be achieved by generalizing the methods of tracing seismic rays from sources to receivers so that they work accurately and effectively, even for cases of significantly deviated wells and large
structural dips, and then by making modifications to the tomography and reflection imaging algorithms to take advantage of the improved ray tracing functionality. In Phase I, the above approach will be implemented and tested for relatively simple geologic models (continuous horizons, no faulting, folding or pinchouts). In Phase II, the algorithms will be further extended
so that they remain valid for more complex geologic models, and the focus of the work will shift to the three-dimensional visualization of crosswell results and the use of a combination of deterministic and geostatistical techniques for building reservoir models based on large multi-profile data sets.

Commercial Applications and Other Benefits as described by the awardee: The software that will be produced from this project will be of value to crosswell service contractors, as well as to geoscientists and engineers interpreting crosswell data. More generally, the technology developed under this project will enable the successful introduction of high-resolution borehole seismics and specifically crosswell seismics to the gas and oil exploitation and exploration marketplace.