Is it still owned of record by your grandmother? How do you know it passed from your grandmother to your mother? To complete the transfer the ownership, if not done already, you will need to hire an attorney to probate both estates. He/she will get a personal representative appointed who can then execute/record a personal representative’s deed to the heirs. If you don’t want to front that expense now, a short-cut is to simply record an Affidavit of Heirship (their are a number of forms you can find online). Oftentimes, operators and lessee will rely on these, but will ultimately require the probate route before paying proceeds from production. Hope that helps!