The calculated distance (air line) between Oberhausen-Rheinhausen and Duisburg is approximately 167 miles respectively 269 kilometers.
By car or train, the actual journey to Duisburg is certainly longer, as only the direct route (as the crow flies) between Oberhausen-Rheinhausen and Duisburg has been calculated here.
Air line (approximately)
269 kilometers
145 nautical miles