A Kick in the Salt, a Case Study of a Water Inflow using Sonic Log Advanced Processing

Sonic logging tools have been on the market for a long time. Since its inception, it has developed in design and grown past a simple formation velocity measuring tool with a single source and two receivers and grown to have many sources and receiver arrays to encompass plenty of other processing products, that range from porosity to anisotropy (Close, D. et al, 2009) and all the way to generating reflection images from events far from the borehole when an impedance contrast is present (Chang et al, 1998) . From time to time, some logged intervals generate datasets that allow for a very complete use of the various processing products that can come from a sonic tool logging run. This case study is one of such examples, where an igneous rock body inside a thick salt layer delivered a water inflow to the well. The advanced processing produced migrated images up to 20 meters deep inside the formation, and the images showed a faint reflection at the depth where the kick was recorded. These migrated images also show some layering inside the salt with varying dips, that agree with the dip direction seen in the seismic data. In the end, the sonic log advanced processing helped clear to some extent the mechanism that produced the water kick.