Look-ahead VSP. A Key Tool in Offshore Exploration and Development. Field Case - Shallow Waters Mexico

Abstract

Summary Zero offset Vertical Seismic Profiling (ZVSP) is a very well-known tool for time to depth calibration. This kind of geometry is specially demanded at the early stages of field development, when velocity models may still be under refinement. Borehole seismic surveys as such are usually scheduled with the wireline logs at the last section of the well, once the drilling program has already been completed. One of the questions from the ZVSP deployment is how this technology can provide decision support before the drilling is complete. Here we present a field case offshore Mexico, in the Tabasco coast shallow waters, where a ZVSP was successfully used as a geo-stopping technology in a “look-ahead” fashion, enabling the identification of an unexpected salt body ahead of the bit and a potential missing geologic formation in the sequence, which in turn allowed on-time well repositioning.