ABSTRACT

Technologies relating to seismic data collection and processing have improved greatly over the past 10 years. Advances in three dimensional imaging and the development of borehole techniques have extended seismic capabilities into the realm of reservoir description and monitoring. The inherent value in three dimensional seismic techniques lies in the spatial resolution that is several orders of magnitude higher than that possible with well data alone.

New methods have now been devised that allow the systematic integration of 3-D seismic data with well-bore petrophysical data to a level that has not been possible previously. Co-kriging techniques, for instance, statistically merge the spatial variations present in the seismic data with the petrophysical properties measured at well locations. This technology has the potential of greatly improving the initial reservoir descriptions that are used in production simulation.

Seismic techniques have also proven successful in monitoring the movement of flood fronts in some EOR (Enhanced Oil Recovery) processes. This monitoring is possible when the EOR process alters the acoustic properties of the reservoir rocks. Surveys recorded prior to EOR initiation capture the initial reservoir heterogeneity, while monitor surveys recorded after the EOR process has been implemented measure the change in the acoustic response of the reservoir. Differences between the base and monitor surveys can then be used to determine the areal and vertical dimensions of the flooded zones. This technology has been successfully applied in heavy oil thermal pilots, and research has now been completed that suggests miscible flooding and gas production by water drive can also be monitored. Further, it is possible that water-flooding of oil reservoirs may produce enough acoustic contrast for monitoring under some conditions, but present research indicates this is not expected to be widespread.

Currently, investigation is underway to determine the technical and economic feasibility of using 3-D and borehole seismic techniques in reservoir management. In order for the seismic data to be technically successful, there must be an integration of geophysical techniques with reservoir geology and engineering to a much greater level than the majority of work being done today. Economic feasibility will only be proven when the increased revenue from incremental oil recovery or increased production efficiency offsets the cost of including the seismic data in the development cycle.

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