Operational Update - U and T sand discovery

25 September 2018

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

Operational Update - U and T sand discovery

Amerisur Resources Plc, the oil and gas producer and explorer focused on South America, provides an operational update at its various production and exploration assets in Colombia.  

Highlights:

● Pintadillo-1 well - N Sands dry, but potentially commercial hydrocarbon bearing reservoir confirmed in the T and U sands

o U sand found to be well developed with 12 feet of net pay logged

o T sand well developed. An indicated 15 feet of net pay within three sand bodies encountered

o Logs indicated no production potential in the N sand interval due to lithology change

● Flow testing of the T and U sands to commence shortly

● Successful testing of the T and U sands offers reserves upside for the Platanillo block

● To date the Company has successfully produced c.300,000 barrels of oil from the T sand at Platanillo-8 and Platanillo-20

● If testing is successful the crude produced from the T sand will be evacuated through the OBA pipeline in the initial testing, the long term testing and commercial production phases

● Commissioning of the Chiritza facility expected to complete in early October

● 43 kilometre of 2D seismic successfully acquired over the Coendu prospect

● Mobilisation to the Indico-1 drill site is on track and the well is expected to spud in the latter half of October.

Pintadillo-1, Platanillo, Colombia

The Pintadillo-1 well, targeting the N sands anomaly, the M2 sand, U sand and T sand in the north of the Platanillo field, was drilled to a total depth of 8,465 feet, passing through all of the targeted sands and completing in economic basement. The well was logged with both Logging While Drilling and wireline tools. The well encountered but has not, as yet, recovered hydrocarbons.

The N sand, the primary objective of the well, was found to display a strong development of limestone and calcareous sandstone at 63 feet total thickness, and logs indicated no hydrocarbon production potential. This result is unexpected, as the traditional environment of deposition for the N sand is considered to be lagunal with restricted marine influence, while the presence of large sections of Limestone and other calcareous deposits in this well suggest greater marine influence.

The Company is currently analysing the logs and samples obtained in order to determine whether the lithology encountered at the N sand level is likely to be the same or potentially different in the other identified anomalies, before any further drilling decision is undertaken in this three well programme.

The U sand was found to be well developed with 12 feet of net pay logged in the Lower U sand and the T sand was also found to be well developed and an indicated 15 feet of net pay within three sand bodies was encountered. In other wells within the Platanillo block, where the T sand has been tested and produced commercially, the oil quality was higher than within the U sand, at approximately 38 degrees API as opposed to approximately 31 degrees API for the U sand.

The oil encountered at Pintadillo-1 in the U and T sands is not currently included in any reserves evaluation for the Platanillo block. To date the Company has successfully produced c.300,000 barrels of oil from the T sand at Platanillo-8 and Platanillo-20.

The well has now been cased and cemented and the Company intends to perform flow testing of the T sand initially. It is anticipated that any oil produced from the T sand during the initial testing, and if successful the long term testing and commercial production phases, will be able to, due to its high quality, be evacuated through the OBA pipeline.

Chiritza Re-Pumping Station, Ecuador

Amerisur expects to complete commissioning of the Chiritza facility in early October, following installation of electrical power systems by PetroAmazonas EP, on budget and ahead of schedule. Once completed Amerisur will have access to a minimum daily carrying capacity of 9,000 bopd through the RODA system.

Put-12 2D Seismic - Coendu Prospect, Colombia

The six line 2D seismic programme of approximately 43 kilometres over the Coendu prospect has been fully acquired and is currently being processed in Bogota. This information will now be integrated into the existing data set in order to refine imaging and resource estimates for the Coendu prospect.

CPO-5 Indico-1, Colombia

The operator has informed the Company that rig mobilisation to the Indico-1 drill site is going to plan and the well is expected to be spudded in the latter half of October.

Put-8 Miraparriba-1, Colombia

The Company understands that the negotiations with Ecopetrol continue to proceed favourably and expects to be updated in the short term regarding the drilling of this well.

John Wardle, CEO of Amerisur said:

"While it is disappointing not to have encountered the N Sand as expected, we are encouraged by the development of the T and U sands in this area, in light of our success to date at Platanillo-8 and Platanillo-20. On success these accumulations offer reserves upside and useful bolt-on production volumes and I look forward to updating the market on test results.

"The anomalies mapped in the central part of the Platanillo block will now be re-assessed and following the testing of the T and U sands a decision will be made on what we will drill next to best exploit this resource.

"We are excited by the progress being made at Indico-1, the second of our exploration wells in our current drilling programme, which we believe has the potential to add significant production volumes and reserves to Amerisur. The programme in CPO-5 also includes a further two exploration wells, Aguila-1 and Sol-1, targeting separate structures before the end of the year.

"With respect to Miraparriba-1, I understand that the project has a high probability of proceeding as originally planned, drilling from the Cohembi 2 location. This agreement will allow the well to be drilled before the end of the year.

"I also look forward to the results of the new seismic in Put-12 and Put-9 over our important Coendu prospect. Initial processing workflows indicate excellent quality in terms of signal strength and frequency content and we look forward to integrating this new data into our current models. The environmental licensing process, including the collection of on-site data, continues on target, with drilling scheduled in 2019."

ENDS

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Glossary

Notes to editors

Amerisur Resources is an independent full-cycle oil and gas company focused on South America, with assets in Colombia and Paraguay and production from two fields in Colombia. In 2016 Amerisur successfully built and is 100% owner of the strategic OBA oil transfer line into Ecuador.

In Colombia, the Company is operator and has a 100% working interest in the Platanillo block which includes the Platanillo producing field in the Putumayo basin, and holds a 30% non-operated working interest in the CPO-5 block containing the Mariposa-1 producing field in the Llanos basin.

Amerisur has a strong position in the Putumayo basin and has a cluster of near term activity assets around the OBA export line.

These assessments are made in accordance with the standard defined in the SPE/WPC Petroleum Resources Management System (2007).

Competent person: Technical information in this announcement has been reviewed by John Wardle Ph.D., the Company's Chief Executive. John Wardle has 32 years' experience in the industry, having worked for BP, Britoil, Emerald Energy and Pebercan, and is a trained drilling engineer.

This announcement contains inside information as defined in EU Regulation No. 596/2014 and is in accordance with the Company's obligations under Article 17 of that Regulation.

www.amerisurresources.com