FUTURE WORK

Several additions are still necessary for a complete link between GOCAD and AVS:

• Completion of the Edit function.
• Updating to GOCAD++, which will soon be available at SEP.
• Ability to display well log data (e.g. velocity, dip meter, SP, etc).
• Improved gridding capabilities.

The final item poses the greatest problem. The current gridding algorithm is extremely limited in the range of models it can handle. In addition the velocity characterization is limited by the surface approach taken by GOCAD. The documentation of GOCAD++ states that it can grid constant velocity, compaction functions, and arbitrary x, y, and z functions within a layer. This is a significant improvement, but still not ideal. Ideally, we would like to be able at one stage to describe the velocity function within the domains at a very coarse level, and as our knowledge improves, to refine our definition. In addition we would like to have the connectivity between surfaces be recognized, eliminating the high frequency component of the velocity model that is common when characterizing domains. As a result SEP is considering two alternative approaches.

The first approach is to use tools already available in GOCAD. Specifically to characterize the velocity function within the domains by tetrahedra. As time goes along these tetrahedra become more numerous and get smaller. This approach would lean heavily on GOCAD's DSI algorithm to give reasonable values within the tetrahedra and for going from one level of model complexity to another. The boundary between domains would be smoothed by recognizing tetrahedra along the boundary and forcing a degree of continuity across the boundary.

The second alternative is to characterize the velocity function within the domains as a series of 3-D splines. This method is commonly used in 2-D problems and is effective in progressively refining the model (by adding additional coefficients). How to create continuity along the border of regions is unclear. One possible alternative is to define new domains along boundary regions that also have to be characterized by a limited number of spline coefficients.