The word “unit” can be used in various ways in various states. I have some wells that are called something like Smith Unit 1. In that case, it is a single well. Many old, old wells have a single well unit name. The larger ones like you listed above are secondary recovery units. This is when a reservoir was drilled originally by several operators and over time they realized that they were in the same sand or limestone reservoir. The pressure dropped due to production and infill drilling and waterflood or gas flood support was needed to get more oil out of the reservoir. In that case, the operators banded together, chose a single operator and filed for secondary recovery permission. This was then called a waterflood Unit and frequently the names of the original wells were changed and the unit was organized by tracts which were the drainage areas of the original wells. Sort of like city blocks all belonging to a neighborhood. Here is an example of one of yours…https://imaging.occ.ok.gov/OG/Unitization/005A7EF5.pdf The old Jones #1 well might be Tract 1, Ralph 1 is now Tract 2, etc.
The word “tract” can have several meanings. It can be a tract of land such as the SE4 SE4 SE4 that grandpa had his farm house on and might have had a single well or it can morph into a technical tract for a waterflood unit as above.