Tex. Nat. Res. Code § 53.022

None of the provisions of this subchapter shall apply to, alter, or affect any rights existing on June 22, 1955, under a valid permit issued by the commissioner under the provisions of Section 12, Chapter 271, General Laws, Acts of the 42nd Legislature, Regular Session, 1931, as amended (Article 5421c, Vernon's Texas Civil Statutes), but if the permittee desires that his lease continue as long as production is obtained in paying quantities, he shall pay lease payments and royalty provided in this subchapter.