Amerisur Resources has provided the following update on operations at the Iguasa-1 well in the Fenix block in Colombia.

Highlights Nine discrete sand intervals below 4,031ft have hydrocarbon saturations with potential net pay true vertical thickness of approximately 150ft Light, sweet crude oil recovered from drill stem test of first sand interval tested Eight further sand intervals to be tested Additional substantial sands, with an apparent net thickness of approximately 205ft were encountered from a depth of 980 to 1,295ft, and appear to be hydrocarbon bearing - testing options being reviewed The Company set and successfully cemented a 7" liner over the section 3,931 to 5,605ft as planned. Interpretation of the electric logs over this section indicated that there are nine discrete sand intervals which have hydrocarbon saturations which could be sufficient to produce hydrocarbons. This potential net pay has a true vertical thickness of approximately 150ft. The log analysis did not indicate the presence of any water wet reservoirs within the interval. This section comprises the sub-units known as the K, L1 and L3 of the Esmeralda - La Paz formation.

A fluids and pressure test was performed on the deepest identified interval, 5,327 to 5,336ft using drill stem test equipment. This test included three short flow tests and pressure build up periods. 35˚API oil was recovered at surface, together with associated gas. The oil had 0% base sediment and water ("BS&W") and did not contain any identifiable concentrations of H2S. The oil tested is therefore Light, Sweet, Crude oil. The pressure and flow data are currently being analysed in order to plan the remainder of the testing programme in this zone and in the remaining eight intervals which the Company considers merit further investigation.

Given these excellent results, and the scale of the testing required, the Company decided to release the Petrex PTX-22 drilling rig in order to mobilise a smaller rig more suited to this type of operation. This change will reduce considerably the costs associated with the testing.

Additionally to the potential reservoir sections encountered in the lowest part of the well, the Company is also pleased to report that substantial sands, with an apparent net thickness of approximately 205ft were encountered beneath the first thrust fault from 980 to 1,295ft.

The electric logs over those sections have been analysed and indicate that the sands are hydrocarbon bearing. Significant shows of oil and gas were observed while drilling those zones. The Company is now reviewing options to test these potential accumulations.

John Wardle, CEO commented, "I am very pleased both with the analysis of the logs and the results of the initial test in the lowest zone, which has very similar characteristics to the remainder of our sands. I am hopeful that they may all be similarly productive.

"The oil quality is at the high end of the expected range. The quantity and quality of potential reservoir we have encountered is encouraging, and will need a detailed and thorough testing effort over the coming months. For that reason I welcome the change of rig, which follows our philosophy of conserving our cash while delivering best in class results. Although we have still to perform a definitive flow test of the zones, it is apparent that we have considerable production potential in the lower section of the well.

"The sands in the upper section, below the first fault are also very interesting and may represent a significant upside in the block, since they indicate that the prospect we call Rio Cachira may extend into the La Tigra area. In any event, the results of Iguasa-1 at all depths significantly de-risk the other prospects in the block, as well as considerably enhancing the potential of the Rio Cachira prospect.

"The drilling of this well completes our contractual commitment for this phase of the Exploration and Production Contract, demonstrating once more Amerisur´s commitment to delivery and compliance."

Giles Clarke, Chairman said, "This is a great result for Amerisur. We are focused on evaluating this well with a view to establishing production. It was a difficult and demanding well to drill and I congratulate our executive team in Colombia on achieving the well objectives safely, on time and within budget. We look forward to updating shareholders as the testing develops."

Tags: Amerisur Resources Plc