Tex. Natural Resources Code § 131.205: SECURITY FOR BOND.

(a) The bond shall be executed by the operator and a corporate surety licensed to do business in this state, or the operator may elect to deposit cash or negotiable securities acceptable to the commission, or an assignment of a savings account in a Texas bank on an assignment deposit form prescribed by the commission's rules.

(b) A cash deposit or market value of the substitute collateral shall be equal to or greater than the amount of the bond required for the bonded area.

(c) Cash or other substitute collateral shall be deposited on the same terms as the terms on which surety bonds may be deposited.

Acts 1977, 65th Leg., p. 2627, ch. 871, art. I, Sec. 1, eff. Sept. 1, 1977.