When you scan for resources, they disappear from the compass rather quickly. That's not much of a problem for resources that are only a few 100 meters away and in friendly terrain. However, when you're looking for oil that can be 2.5km away and on the far side of hostile and hard to navigate terrain, it gets very tedious very fast to have to rescan every few steps.
Either make the scan results stay up for (much) longer or, even better, allow us to pin one result to the compass indefinitely (clear it on the next scan for any resource)