The calculated distance (air line) between Al Khafjī and Umm as Sāhik is approximately 151 miles respectively 243 kilometers.
By car or train, the actual journey to Umm as Sāhik is certainly longer, as only the direct route (as the crow flies) between Al Khafjī and Umm as Sāhik has been calculated here.
Air line (approximately)
243 kilometers
131 nautical miles