Endeavour/Challenger swap stakes

May 7, 2007
Endeavour is ceding a 5% interest in its Emu prospect in the UK southern gas basin block 48/1a to Challenger Minerals North Sea. In exchange, Enedavour picks up a similar interest in the Acer prospect in block 16/18b in the South Viking Graben area of the central North Sea.

Offshore staff

ABERDEEN, UK --Endeavour is ceding a 5% interest in its Emu prospect in the UK southern gas basin block 48/1a to Challenger Minerals North Sea. In exchange, Enedavour picks up a similar interest in the Acer prospect in block 16/18b in the South Viking Graben area of the central North Sea.

This arrangement also gives Endeavour a 5% working interest on a well operated by ConocoPhillips that began drilling on Acer in late March. This is testing an Upper Jurassic sandstone target south of the Brae and Miller fields.

Endeavour will operate a well on Leman due to be spudded mid to late summer. This will test a Leman sandstone prospect close to two wells drilled in the 1990s, both of which had gas shows.

5/7/2007