The calculated distance (air line) between Az̧ Z̧a‘āyin and Doha is approximately 20 miles respectively 33 kilometers.
By car or train, the actual journey to Doha is certainly longer, as only the direct route (as the crow flies) between Az̧ Z̧a‘āyin and Doha has been calculated here.
Air line (approximately)
33 kilometers
18 nautical miles