Tex. Civ. Prac. & Rem. Code § 127.003
(a) Except as otherwise provided by this chapter, a covenant, promise, agreement, or understanding contained in, collateral to, or affecting an agreement pertaining to a well for oil, gas, or water or to a mine for a mineral is void if it purports to indemnify a person against loss or liability for damage that:
(2) arises from:
Acts 1985, 69th Leg., ch. 959, Sec. 1, eff. Sept. 1, 1985.