AMER.L Regulatory News (AMER)

18 March 2013

Amerisur Resources Plc

Reserves Update

Amerisur Resources Plc ("Amerisur" or the "Company"), the oil and gas producer and explorer focused on South America (LSE: AMER), is pleased to report an update to the certified reserves for the Platanillo Field, Colombia.

Following receipt of an independent reserves report as at 31 December 2012 undertaken by Petrotech Engineering Ltd using the standards set by the Oil and Gas Reserves Committee of the Society of Petroleum Engineers, certified 2P (Proven and Probable) field reserves more than tripled, increasing from 7.7 MMBO to 29.9 MMBO (gross of royalties). These 2P reserves have been evaluated by Petrotech as representing a Net Present Value ("NPV"), to Amerisur after royalties of US$1,791m undiscounted and a 10% discounted NPV of $1,220m. Petrotech also calculated 3P (Proven, Probable and Possible) reserves at 45.6 MMBO.

John Wardle, CEO, said:

"Our active drilling strategy delivered a step change growth in our reserves, with a three-fold increase from only 4 new wells of the planned 8 well programme. This strong result was due to the especially good well results, including the significant oil columns and high reservoir qualities encountered. The drilling programme since the cut off date for the reserves report has continued to show exceptional results and I expect further significant reserves additions through this year. With two drilling rigs operating in continued development of our Platanillo field, a strong cash flow from our growing production, a fully funded forward programme and attractive prospects for new discoveries in our Put-12 block we expect to deliver continued strong growth."

Giles Clarke, Chairman, said:

"Amerisur is a company with substantial proven reserves and strong cashflow with a clear development path. I look forward to updating shareholders as we continue to deliver exceptional results in 2013."

- Ends -

Competent person: Technical information in this announcement has been reviewed by John Wardle Ph.D., the Company's Chief Executive. John Wardle has 28 years' experience in the industry, having worked for BP, Britoil, Emerald Energy and Pebercan, and is a trained drilling engineer.

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