Horizon Oil (ASX:HZN) amended its senior debt facility agreement with Macquarie Bank, which funds the acquisition of an effective 7.5% working interest in the Sinphuhorm conventional gas and condensate field, and a 60% working interest in the Nam Phong conventional gas field, both in Thailand, according to a Tuesday Australian bourse filing.

The amended senior debt facility with the bank, a business of Macquarie Group (ASX:MQG) is structured as a reserves-based lending facility.

The tranche A under the facility will see an increase in the Mereenie available debt from around AU$40 million to up to AU$50 million, with the additional debt capacity supported by the recent infill well results and recently signed strategic gas sales agreements.

It will draw up to an additional $15 million of finance from the tranche B1 to initially fund the acquisition, supported by cashflows from the firm's working interest in the block 22/12 in China. Up to an additional $10 million of finance will be made available under tranche B2 of the facility following completion of the acquisition to fund any further development of the secured assets and for general corporate purposes.

Tranche A amortizes through to maturity at June 30, 2029, and continues to attract interest payable at the bank bill swap rates plus 5%. The tranches B1 and B2 both amortize to maturity at Dec. 31, 2027. Tranche B1 attracts interest payable at the secured overnight financing rate (SOFR) plus 5%, while tranche B2 attracts interest payable at SOFR plus 6%.