ATP Confirms Natural Gas Discovery on Helvellyn Prospect

ATP Oil & Gas has reached total depth at the Helvellyn well located in Block 47/10 in the Southern Gas Basin of the North Sea. An 1800' horizontal section was drilled and logged confirming the presence of the expected hydrocarbons in the Rotliegend and Carboniferous intervals. Completion operations are now underway in order to test the well prior to production.

In August 2002, ATP Oil & Gas (UK) Ltd. (ATP UK), as the operator, laid the 15.5 kilometer pipeline from the well site to the host Amethyst A2D Platform. The Field Development Plan for the Helvellyn Field comprising Block 47/10 was approved by the UK Department of Trade and Industry in July 2002.

Natural gas was initially discovered on this block in 1985 by BP with the successful drilling of the 47/10-1 well and, though that well was tested at a rate of 29.4 million cubic feet per day, the field was not developed. ATP UK acquired the block in 2001 and is the operator with a 50% working interest. The remaining 50% working interest is held by First Oil Expro Limited, a privately held UK company.