Pro4D

Pro4D provides the needed tools for any timelapse study. The aim is to track production-related changes in the reservoir and determine areas of bypassed reserves or inefficient production. Pro4D’s complete suite of tools can model a whole range of anticipated reservoir scenarios, both at log and synthetic seismic scale in terms of temperature, pressure and fluid saturations.

Timelapse Modeling and Interpretation

Rock Physics & Synthetic Modeling

Rock Physics & Synthetic Modeling is the first stage in a timelapse study. Use rock physics relationships to bridge between the primary reservoir properties and the seismic response. Use Pro4D’s Systematic Changes Modeling to create a range of log and synthetic responses to predict how the seismic data will be affected by changes in fluid saturation, pressure and temperature. Compare these computed 2D or 3D synthetic volumes, with their modeled production effects, to “base” models and create modeled difference volumes to compare to the actual seismic data.

Timelapse Volume Calibration

Timelapse volume calibration removes non-production-related differences from the monitor seismic volumes. Pro4D has comprehensive survey calibration features that match the phase, frequency, amplitude and event times of base and monitor surveys in areas where production has not occurred. Sequence Processing applies these (and other) processes to the data in one pass, significantly improving project efficiency. Typically, you would assess the quality of the seismic match after each processing stage using Pro4D tools such as Volume Cross Correlation, Predictability, NRMS Difference Volumes and Volume Crossplot.

Timelapse Interpretation

Timelapse interpretation can be applied to both time delays and amplitude differences between base and monitor surveys as these tell us different things about reservoir changes. Use volumes of amplitude ratios, cross-correlation coefficients and time shifts to define the extent of production effects. Amplitude differences in the reservoir interval between vintages highlight reflectivity changes caused by the production process. Relate all these differences back to the synthetic models.

Key to time-lapse volume interpretation is the comparison of seismic attributes along horizons to characterize the reservoir interval. Pro4D includes advanced horizon management and manipulation functions which simplify the use of related horizons from multiple vintages of surveys or attribute volumes.