AMER.L Regulatory News (AMER)

29th February 2012

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 the work over of the Platanillo-2 well in the Platanillo Field, Colombia as previously announced on 13 February 2012.

The poor zonal isolation across the N sand interval was successfully repaired by way of a cement squeeze and the zone was subsequently perforated using a Drill Stem Test (DST) assembly over the interval 7,746 to 7,759ft. The zone was then tested and produced 17.9° API oil with trace water cut. Flow rates of up to 250 BOPD were measured with a drawdown at the reservoir of approximately 80 psi in natural flow through a 36/64" choke. The API gravity of the oil produced demonstrated an upward trend, and further testing will be required to establish its final value.

The well is currently undergoing Pressure Build Up testing, after which the DST assembly will be removed from the well and an Electric Submersible Pump (ESP) will be installed. It is planned to further test the well at increasing levels of drawdown over the next three to four weeks.

The Company is in final negotiations for the drilling rig and plans to begin mobilisation shortly, spudding the first well of the drilling campaign during March.

John Wardle commented: "This excellent result from the N sand has validated our petrophysical model and demonstrates important additional reserves and production upside in the Platanillo field. The flow rates we have seen up to now are unlikely to be indicative of full production potential, given the very low drawdown pressure we have been able to apply to the reservoir in this configuration, whose purpose is to obtain accurate pressure data rather than offer flexibility on flow rates. I am very pleased by the result and excited by the potential when the ESP is installed, and look forward to updating shareholders as further data is acquired."

A presentation updated in February 2012 can be viewed on the Company website, www.amerisurresources.com  

Competent person: Technical information in this announcement has been reviewed by John Wardle Ph.D., the Company's Chief Executive. John Wardle has 26 years' experience in the industry, having worked for BP, Britoil, Emerald Energy and Pebercan, and is a trained drilling engineer.

-Ends-

ENQUIRIES: