Karoon’s Block 144 is located on the eastern side of the Andes mountain range within the onshore Marañón Basin. The basin is the largest Peruvian sedimentary basin. It forms part of a much greater sub-Andean basin system that extends into the prolific Oriente Basin in Ecuador and the Putumayo Basin in Colombia. This large sub-Andean basin is a proven petroleum province with oil fields in all three countries. In Peru, the Marañón Basin is producing oil in the north and central areas of the basin from the fields in Block 1-AB, Block 67 and Block 8 with initial reserves of 720Mmbo, 250Mmbo and 320Mmbo respectively.

 

 

Leads within the block have been assessed to have prospective resource potential within the range 50 to 250mmbls . Additional leads potential have been recognized but are yet to be defined.

 

 

 

Total work program for the block comprises;

 

·        Phase-1 April 16 2009 - October 2011, Reprocess 1000km 2D seismic, geological and geophysical studies.

·        Phase-2  October 2011 - April 2013, Interpretation of 300km 2D seismic.

·        Phase-3  April 2013 - October 2015, Drill one well to a minimum depth of 4200m.

Currently the Phase -1 seismic reprocessing has been completed and mapping is underway in preparation for working up the acreage in preparation for drilling in 2013.

 

 

During the past four decades exploration activity was principally concentrated along a narrow belt on the shallower eastern flank of the basin that was based on a single play concept targeting pre-Eocene structures which contained Upper Cretaceous reservoirs sourced by an Upper Cretaceous source. A trans-Andean pipeline, the Oleoducto Nor Peruano, was completed in 1977 as a part of the development of the fields discovered using this play concept. This exploratory play was gradually exhausted and exploration activity has only recently recovered as alternative play types have proven successful spurred by new contract terms and structured bidding rounds. 

 

New plays are now being successfully explored in deeper parts of the basin on trend with Karoon's block. To the northeast on trend, Talisman has discovered oil in the Cretaceous Vivian Formation sands at the Situche Central field. Deeper Jurassic gas targets also being explored for.

 

The Oleoducto NorPeruano passes through the south of Karoon’s permit sending the 27˚ API oil produced from Block 8 in the East to the export terminal at Bayovar in the west and is estimated to have 60,000 bopd spare capacity (Talisman). The town of San Lorenzo, lies within the blocks southern edge and is the administrative centre for the sub-region of the same name.

 

The Marañón Basin contains approximately 4000 m of continental deposits derived predominantly from the Andes to the west. Production in the area comes from Upper and Lower Cretaceous reservoir sandstones of the Vivian, Chonta, Agua Caliente and Cushabatay formations. Karoon’s block and mapped structures lie on trend with Talisman’s light oil 36˚ API 100+ Mmbo Situche structural complex to the north. Oil in these Situche structures was tested from the Lower Vivian Formation (Talisman, 2008). Karoon’s Block 144 similarly lies on this western edge of the basin with potential for structural and stratigraphic plays.

 

Two major proven source rocks in the basin are the Pucara Fm of Jurassic age and the Chonta Fm of Cretaceous age (Core Labs, 1999). Potential also exists for a Permian Ene Fm source rock Mathalone, 1995).

 

Proven seal units in the Basin are the Raya Fm, Chonta Fm, and Yahuarango Fm as well as intraformational seals.

 

February 2010