Cichowski, Leonard¹, Roel Garcia¹, Robert James², David Paddock², Dan Shan²
(1) Seneca Resources Corporation, Houston, TX
(2) Schlumberger, Houston, TX

ABSTRACT: Redevelopment of a Mature Field in the Face of Seismic Uncertainty: Vermilion 252 Field, Gulf of Mexico

Vermilion 252 field was discovered in 1994 as a result of drilling well-defined amplitude anomalies on two reservoir horizons. However, after several years of production from both reservoirs it became clear that both reservoirs contained more oil than could be accommodated in rock volumes based on amplitude-derived net sand thickness. This presentation describes a method to resolve this discrepancy and to determine whether the additional oil volume represented an opportunity for further development of the field.
After phase-matching of the near-offset seismic cube an empirical relationship was developed between amplitude and net pay thickness, constrained by the maximum thickness of pay based on structural considerations. The resulting net pay predictions were then used to constrain a geocellular model, which was built using Sequential Indicator Simulation (SIS) to distribute reservoir facies. The model was then upscaled and subjected to flow simulation. However, no history match was possible for the initial model. The problem was solved by developing an SIS protocol to populate the reservoir by small shale bodies that were oriented parallel to some possible channel features seen on seismic horizon slices. Running the final history-matched simulation model in predictive mode then allowed development options to be evaluated. Both infill drilling and re-completion opportunities were identified.
Vermilion 252 is an example of a field in which subsurface uncertainty cannot be adequately constrained using the available seismic data alone. Only full integration of seismic modeling with stratigraphic analysis and reservoir simulation could provide a sound basis for defining redevelopment options.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.