All I can tell you is what our experience was several years ago. The oil company accepted (in Oklahoma) an Affidavit of Heirship to transfer payment of royalties to our parents four children but I did have to send them registered copies of the death certificates from California (County Coroners office) to the oil company. A few years later I found that our grandfather (who lived in and died in Oklahoma) has some mineral interests that we didn’t know about and the proceeds/royalties from those interests had been sitting in the Oklahoma Treasurer’s Office for years, unclaimed. The mineral interests themselves had been sold long before. In that case we had to get a lawyer in Oklahoma to probate our parents estate in Oklahoma with an Expedited (simple) Probate to get the State Treasurer to release the funds to us. This was because in California probate is not necessary if the person(s) have a family trust which automatically distributes property. However, Oklahoma does not accept a family trust so we had to do a probate in OK. Hope that helps. I think you need to just contact the oil company and ask them if an Affidavit is sufficient or if they require more documentation or a probate. If you do have to probate be sure you get a lawyer with experience in oil matters and has a good reputation. We had trouble because our lawyer did not have enough experience with mineral rights which ended up costing us time and more money. Of course, it’s not easy to handle these matters when you live in another state.