Oil and gas interests are considered real property and as such are governed by the laws of the state in which the land is located. In order to transfer the interest according to a will, the will must be probated in the state in which the land is located. If there is no probate or if the will is not probated in the state in which the land is located, you should submit a completed Affidavit of Heirship (also known as Affidavit of Death and Heirship) and a copy of the death certificate.