I think you’re right in assuming those offers are motivated by increased drilling activity in your area. You said those offers are based on buying the producing wells but if you get into the details I expect you will find they are actually wanting to buy the full mineral interest the trust owns, not just the production from those wells.
As long as existing wells are producing they would hold any of your acreage that’s included in the units formed around those wells, or possibly all of the acreage covered by the lease if it didn’t include a Pugh or similar clauses requiring acreage outside units to be released at the end of the primary lease term. But you mentioned that your lease includes a depth clause excluding depths below 6,000 feet. If that is outside the current leases and not held in some other way those depths should be available for leasing and drilling now, and the current activity in Leon County is targeting depths well below 6000’.
If you’ll post a legal description, or simply a survey abstract number, where your acreage is located, or the name and operator of the wells you have an interest in, someone on here should be able to help you check out recent permitting and drilling activity the Railroad Commission’s map is show in your area.