AMER.L Regulatory News (AMER)

16 July 2013

Amerisur Resources Plc ("Amerisur" or the "Company")

Platanillo Update

Amerisur Resources Plc, the oil and gas producer and explorer focused on South America, is pleased to announce an update on its operations in the Platanillo field, Colombia.

·; Platanillo-12 produced 2,371BOPD of 31.8° API on test from U sands

·; Platanillo-2 ST1 sidetrack progressing well

·; Total field controlled production estimated at 8,500 bopd with the contribution of Platanillo-12

Platanillo-12

Platanillo-12, the eighth new well of the current Platanillo drilling programme and located on the Platform 5 South (5S) was drilled to a total depth of 8,634ft MD and completed for production. Platanillo-12 is a directional well with the reservoir target located 1,770ft to the south east of the 5S location.

The well encountered an interval of 65ft gross, 34ft net indicated pay in the U sand. An interval of 14ft in the U sand was perforated with tubing conveyed guns and the well flowed naturally 2,371 barrels of 31.8° API oil per day (BOPD) over a controlled choke with 166 psi at the wellhead and trace water.

The well has now been placed on controlled production at approximately 1,450 BOPD with 217 psi at the wellhead, in line with good reservoir management principles. It is estimated that Platanillo Field production going forward will be approximately 8,500 bopd with the contribution of this well.

Platanillo-2 ST1

Serinco rig D-10 is currently sidetracking well Platanillo-2 as Platanillo-2 ST1, and is drilling ahead at 3,675ft. Located on Platform A, 2.5km south of the well Platanillo-1ST1, Platanillo-2 has been in production since 2007, delivering 203,604BO during that period from the Upper U sand and 21,602BO from the N sand. Platanillo-2 is being sidetracked to a new position to the south of Pad A, a distance of approximately 3,400ft in orderto further delineate the oil columns in the Platanillo reservoirs; produce hydrocarbons from the U sand; and confirm the structural configuration shown by 3D/3C seismic. It is expected that log data will be acquired at the end of July.

Dr. John Wardle, Chief Executive commented:

"Platanillo-12 is an excellent result for the Company, with impressive production characteristics. With 8 new wells drilled and 2 successful sidetracks completed we continue our 100% success rate and are enhancing our understanding of this important field. Our surface facility work in the field continues to plan, adding 30,000 BO of additional oil storage by end August, together with additional production treatment trains which will facilitate the management of the wells. Oil delivery options continue to be tight and the Company continues to develop and pursue export capacity additions in both Colombia and Ecuador, in order to support continued growth in production over the coming months of 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 29 years' experience in the industry, having worked for BP, Britoil, Emerald Energy and Pebercan, and is a trained drilling engineer.

ENQUIRIES:

Ben Brewerton/Natalia Erikssen, Tel: +44 (0)207 831 3113

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Investec

Chris Sim / Ben Colegrave Tel: +44 (0)207 597 4000