These cover blocks 35/23, 35/24, on the eastern margin of the Porcupine basin, the western half of block 35/25, and blocks 45/6, 45/11 and 45/16. The acreage extends more than 1,400 sq km (540 sq mi).
Historically, the company says, exploration of the Porcupine basin has focused on Jurassic targets, based on similar plays in the northern North Sea.
No wells have been drilled in the basin over the past decade, but there has been a re-think in light of successes in different types of reservoirs elsewhere, i.e. offshore West Africa and South America. There could be similar targets offshore Ireland, Petrel claims.
Since its award, the company has purchased additional seismic lines and re-interpreted the full integrated data set across both sets of blocks, calibrating the data against the relevant well logs.
It has now started a second phase of interpretation to detail and appraise potential prospects identified in the first phase of work. This will include acoustic inversion of selected seismic lines to assess the quality of the targeted reservoir sections. The program should be completed by end-September.
A separate seismic project is in progress, which is designed to detail the depositional facies and character of the identified sand bodies. All relevant well data has been acquired over the region and a full petrophysical appraisal performed of 17 wells. Following the inversion study, this should lead to improved control of the seismic data and potential prospects.
Another study will focus on the sedimentary provenance of the reservoir successions. It will involve initial petrographic analysis, followed by application of the Pb-in-feldspar technique to determine the provenance of first cycle material in the detrital components of the succession. This, Petrel stresses, is critical in the Porcupine basin where sediment input can be along the axis of the basin or from the basin margins.
A longer-term aim is to develop prospects to attract large farm-in partners, with a view to acquire more seismic followed by exploration drilling.