The units along the Texas border above Toledo Bend appear on the Sonris map to be larger than the standard 640. Is there an easy online method for looking up unit size?
You can look them up by determining the field in which they are located and then going through the Commissioner's Public Hearing schedule and reviewing the unit applications for that field. The plats will give the unit acreage.
Here's an example from the Greenwood-Waskom Field. Note the partial sections above and below the sections in this HK Unit application.
The standard seems to be 8 wells per section for Haynesville shale. I don't know if there's any legal restriction on number of wells. If the operator decided the best way was to drill 40 vertical wells, I guess there would be no specific legal restrictions. Some of the shallow oil formations had a lot more wells per section. I've seen some areas where there are probably hundreds of wells per section up near Benton.
I doubt anyone will ever start developing the Haynesville shale with much more than 8 wells per section. Since the standard calculation is that you drain gas from an area of 330' around the well bore, I guess you could drill 64 vertical wells per section on a 660' spacing, but that would be really dumb.
Are there any legal limits on the number of wells in a 640 acre HA unit?
Yes, HA spacing is 80 acre minimum per well by LOC regulation. What Les B. is referring to is 8 HA wells on 80 acre spacing and 8 BO wells on 80 acre spacing in the same section size unit. Both formations are usually contained in the unit depth definition for an HA unit but they must be drilled and produced from separate well bores. Thus 8 HA + 8 BO = spacing regulations allowing for a maximum of 16 wells in a section sized unit.
There could also be another 8 Smackover wells. Plus look at all the more shallow formations. They go to stirring up all the lower stuff and something is bound to migrate upward.
LOL! I agree with the additional SMK wells TDP although I must admit that I had given no thought to "stirring up the lower stuff" and the possibility of freeing some hydrocarbons for the shallower zones. Maybe you should write a scholarly paper on your theory.