Using Seismic Information to Predict Pressure Variations and Fluid Migration Pathways to Optimize Reservoir Development Plans

By

Tom Guidish¹, Vladimir Pisetski²

(1) Geodata Consulting, Houston, TX (2) Trans Seismic International Inc, San Francisco,

 Reservoir Geophysics focuses on imaging geometry, inferring lithologic properties of the subsurface, and on the direct identification of hydrocarbons under certain conditions. Other important reservoir parameters in reservoir dynamics are stresses and the resulting pressure fields within the reservoir. These stresses affect the fluid migration pathways, optimized location of hydrocarbons and recovery schemes throughout the life of the reservoir. We present a technique where seismic information is used to estimate the changes in stresses and reservoir pressures within a reservoir and infer fluid movement and hydrocarbon accumulations zones within the reservoir.

The Dynamic Fluid Method, or DFM, couples basin stress evolution models, which correspond to subsurface fluid movements, with predictions of seismic response and specialized processing to emphasize that response. This technique has applicability optimize field development plans, identify redistribution of pressure within the reservoir due to production, identify missed pay and zones most conducive to recharging.

Our technique allows estimation of pressure variations within a defined reservoir zone. We can define zones or compartments of abnormal pressures, or areas that are most likely areas of fluid accumulation based on the derived parameters of fluid flow. In essence, the total pressure and its variation in the geological time scale determine the fluid dynamics and make the fluid migrate from the regions of compression into the regions of low pressures (the areas of decompression).

Besides discussion of the methodology of this technique, several case histories of this technique are provided, in both clastic and carbonate reservoirs.