It sounds like the survey crew is working on a plat that shows the horizontal lateral path through the section(s). An operator must submit an application for alternate unit wells (all wells following the first, unit well). The application plat must show the surface location (well pad), the lateral paths with first and last "take points" that define the portion of the lateral that is perforated and therefore fracked, the distance of the well path from adjacent wells and the unit boundary. All those points must have distances shown from unit boundaries and from adjacent wells. If you are a land or mineral owner of public record in the section, you should receive a notice letter with a copy of the application when the operator is just about ready to submit it to the state. The application must go through a ten day pre-application review period which allows time for Interested Parties to object to the application before it is added to the Commissioner's public hearing schedule.
Since you are receiving offers to buy your minerals then either someone on the Interested Party list has shared the application notice or the ten day period has elapsed and the application is now on the public hearing agenda.
You're welcome. Good luck with your wells.