Core damage caused by stress release is a source of potentially large errors in reservoir compaction predictions. Synthetic sandstone (with properties close to a certain reservoir rock) created under controlled stress conditions, can simulate the behaviour of both a virgin reservoir rock and a cored rock. The difference in behaviour is then an effect of coring. For low levels of depletion, uncorrected core measurements may lead to largely overestimated compaction in very weak sandstone. Core damage effects increase with stress and stress anisotropy. Field data supports the relation between core damage (seen through core recovery) and compaction behaviour.