The calculated distance (air line) between Al Ḩasakah and Deir ez-Zor is approximately 87 miles respectively 141 kilometers.
By car or train, the actual journey to Deir ez-Zor is certainly longer, as only the direct route (as the crow flies) between Al Ḩasakah and Deir ez-Zor has been calculated here.
Air line (approximately)
141 kilometers
76 nautical miles