Tex. Nat. Res. Code § 85.061

The commission may require any well, lease, refinery, plant, tank or storage, pipeline, or gathering line that belongs to or is under the control of a person who produces, stores, transports, refines, reclaims, treats, markets, or processes oil or gas or the products of either to be inspected or gauged by the agents of the commission whenever and as often as and for such periods as the commission considers necessary.