Amerisur Resources, the oil and gas explorer and developer focused on South America stated at the recent AGM that an announcement would be made once 3D acquisition was completed in the Fenix block. As a consequence of good progress, Amerisur provides the following trading update.

Platanillo

The civil works are complete for Platanillo-1 and the operator Ecopetrol has authorised the mobilisation of the Pride-17 drilling rig to the well location. The rig mobilisation is scheduled to take approximately three weeks and Amerisur expects the well to spud during the first half of September 2007, followed by testing and results in October 2007.

The Platanillo-2 well will be drilled 'back-to-back' with Platanillo-1, using the same rig. The location of the well will depend on the results obtained in Platanillo-1. Subject to the possibility of additional civil works, it is expected Platanillo-2 will be spudded during October 2007.

Amerisur expects the workover rig Pride-6 will be mobilised to the Alea-1 location during the first half of September 2007. Alea is an existing discovery, made in 1988, when the well flowed at rates of up to 533 barrels per day. It is anticipated that re-entry operations will commence during the second half of September, followed by testing and results in October 2007.

Negotiations continue with respect to the acquisition of an increased working interest in the Platanillo contract. Any such change in participation would be subject to approval by ANH.

Fenix

A 103 km^2 3-D seismic survey on the Fenix block in the Middle Magdalena basin has been completed, 20 days ahead of schedule. The program, which covered a number of leads identified by analysis of 2D seismic data, employed a workforce of over 500 people, and included the detonation of 2,880 shots and the laying of 270km of geophone lines.

The acquired data will be processed during September 2007 ahead of interpretation work. Amerisur expects interpretation to be completed and potential drilling locations identified during the course of Q1 2008.