Usually there maybe more than the money involvrd. I am not sure about Louisiana law, but in Texas  the Mineral Estate is the dominate Estate over the surface  rights. As such, the mineral owner  actually has more to say about what can and will occur on the  surface of the land to acquire  the mineral estate. This has caused severe hardship for those  who did not own the mineral estate in Texas up to and including the mineral owner  allowing  drilling on the  surface land many times way too  close to the surface owners residence. This  cause severe devaluation of that property owners property value, and not the least of exposure to drilling activities as close as 200 ft from their homes. Allowing  right of  way to drilling activity and actually TAKING of surface property to drill without the surface  residence  agreement. Giving up say so and  surface rights  should be calcilated into any upfront money. Also remember those who offer ALWAYS know more than you. They would not make significant offers IF they thought they were going to lose. They nearly always have a plan  that might come back to dirupt your property. Always keep your mineral interest lease OK  but sell never JUst IMO.