Karst groundwaters provide fresh water resources to supply cities. In the case of deep groundwater resources around the Mediterranean basin there is a need to explore karst aquifers and gather data about their structure. Robots are well adapted for this task especially when exploring karst conduits at depths greater than 200m. However, as karst aquifers environment is very complex, robots need to exhibit a collection of abilities to ensure a safe exploration. Among them, being able to "center" safely within the karst conduits and avoid collisions is a key point to ensure the robot safety during its mission. We propose a new reactive way to do so, based on the Deformable Virtual Zone. This allows us to model the interaction of the robot with its environment as a physics inspired equation. We also prove the stability of this controller.