When Salt Disappears: Why Should We Care About Welds?

Salt welds form due to salt thinning by mechanical (e.g., salt-flow) and/or chemical (e.g., salt-dissolution) processes. Despite being ubiquitous in salt-bearing sedimentary basins, where they may trap large volumes of hydrocarbons, little is published on weld thickness and composition. As a result, we have limited knowledge of the seal potential of welds, and the fundamental kinematics and mechanics of salt flow and related welding.

This webinar explores how we use 3-D seismic reflection, borehole, and biostratigraphic data from the Santos Basin, offshore Brazil, and the Atwater Valley protraction area of the northern Gulf of Mexico to constrain the thickness and composition of salt welds, and to test the predictions of analytical models for salt welding. We show that 3-D seismic reflection data may not resolve weld thickness, with the presence of relatively thin remnant salt lending support to models of welding based on viscous flow. The halite-dominated character of the weld also supports the hypothesis that tectonic purification may occur during salt flow.