workover rig, pulling unit & production rig are the same thing... They are designed for tripping-pipe:pulling tubing out of the wellbore 2 joints at a time & running tubing in 2 joints at a time... Most drilling rigs are 'triples' and can pull/run-in 3 joints at a time. TECO's "drilling rigs" are all workover rigs/pulling units/production rigs that have been modified with a mud pump & a rotary table. This does not include the rig in Belize which was designed for drilling water wells, if you question this information, then look at the pictures of the Belize rig: why is the derrek so small? where is the monkey board? I could go on for days...
By the way, the information about pulling units in the post that I am responding to is totally inaccurate...