Ithaca successfully acquired blocks 29/4b and 29/5e in the 25^th UK licensing round.  The blocks lie to the northwest of the Stella discovery and are within the HPHT (high pressure / high temperature) heartland of the Central North Sea. This acreage is of primary interest to Ithaca for its shallow Palaeocene potential, but significant potential could lie in deeper, HPHT gas condensate bearing reservoirs.  Ithaca has identified 6 leads in the Palaeocene section with gross in place resources in excess of 30 mmboe.

HPHT reservoirs in the Central Graben provide significant technical challenges in drilling and development, but also hold the greatest reward in terms of size and value of the gas condensate accumulations in this area often contain.  The HPHT play resides within deeper Triassic and Jurassic sandstones, which underlie the commonly developed Palaeocene and Cretaceous reservoirs in the area.  Earlier exploration in the Central Graben made a number of discoveries within the deeper sections after targeting Jurassic-aged structures.  These were not developed until recently due to the significant technical difficulties of drilling HPHT development wells and availability of suitable hydrocarbon export solutions.  HPHT fields are commonly defined as reservoirs deeper than 12,000 ft with pressures above 15,000 psi and temperatures in excess of 315 Degrees Fahrenheit.  Additional geological complexity arises from the pod-interpod plays, where varying thicknesses of the Jurassic and Triassic reservoirs have been preserved within small basins formed by the withdrawl of the underlying Zechstein salt.  This has traditionally made prospect definition difficult, but today advances in seismic acquisition and processing provide much better imaging of the deeper sections, mitigating some of the risk associated with targeting deep geological structures.

Advances in drilling, completion and production technologies have all contributed to HPHT reservoirs being successfully developed close to the Stella area, in particular the Shearwater and Elgin-Franklin Fields.  A number of HPHT discoveries such as Kessog and Puffin lie close to the Stella area and similar exploration potential exists in neighbouring blocks. 

The deep HPHT reservoirs of the Central North Sea Graben remain an exploration play of significant interest to major oil companies.  The exploration potential within blocks 29/4b and 29/5e has allowed Ithaca Energy to successfully farm out the HPHT plays to Maersk Oil as of February 2010. The existence of suitable offtake infrastructure within this area and Ithaca's presence in licence blocks around Stella places the company's activities in the heartland of this high value play.