Okla. Stat. tit. 68 § 713
Any person operating any motor vehicle on the highways of this state as a special fuel user by importing special fuel into this state in the supply tanks of the motor vehicle who shall be liable for the tax levied by this act for the first time and who has not obtained a special fuel user's license and special fuel use vehicle permit, shall, for the purpose of determining the number of gallons of special fuel used on the highways of this state, be required to pay the Tax Commission the tax levied by this act on all special fuel contained in the fuel supply tank or tanks, and any other containers, for use in propelling said vehicle. Upon obtaining a special fuel user's license and proper vehicle permits and filing a report showing all of the operations of such person subject to the tax levied by this act, credit shall be allowed on said report for the tax paid under the provisions of this section, and any overpayment of the tax shall be refunded or credited to a future report. However, this credit shall not be allowed and no refund of such tax shall be made unless the report taking the credit or the claim for refund is filed within thirty (30) days from the date of payment of said tax.
Okla. Stat. tit. 68, § 713