BHP Billiton today announced that preliminary results from its current round of drilling in Block WA-12-R, located in the Exmouth Sub-basin off Western Australia, had successfully defined a number of oil accumulations.

Since May this year BHP Billiton has undertaken a six-well drilling campaign in the permit, which is located approximately 45 kilometres north of Exmouth.  Water depths in WA-12-R are in the range of 190 - 210 metres.

The results from the exploration and appraisal program have been positive and increase the overall volume of oil previously discovered in 2003 by BHP Billiton with its Ravensworth-1 well located in adjacent WA-155-P (1) and Crosby-1 in WA-12-R.

BHP Billiton Petroleum President Americas/Australia Operations and Technology, Mike Weill said the Stickle-1, Harrison-1, Crosby-2 and Ravensworth-2 results represent a series of oil discoveries over adjacent fault terraces.

“These accumulations occur in reservoirs of similar size and quality and are relatively close to one another.  We can develop these as a combined scheme and together they equate to a medium-sized oil reserve,” Mr Weill said.

BHP Billiton is currently undertaking engineering studies to select a development option for this project, which is known as ‘The Pyrenees Development’.

The success of this drilling program is a further example of how the Exmouth Sub-basin is evolving as an important oil province in Australian waters. The Exmouth Sub-basin has undergone a high level of drilling activity and BHP Billiton has executed a total of 18 wells in the basin over 2003 and 2004, comprising nine in WA-255-P (2), seven in the adjacent WA-12-R and two in WA-155-P (1) permits.

BHP Billiton owns a 71.43% interest and is operator of WA-12-R; 28.57% is held by Apache Energy Limited.  

BHP Billiton owns a 39.999% interest and is the operator of WA-155-P (1) with Apache Energy Limited holding 31.501% and INPEX with 28.500%.

BHP Billiton owns a 50% interest and is the operator of WA-255-P with 50% held by Woodside Energy Limited.

Background notes

In July 2004 BHP Billiton completed a successful drilling campaign in the adjacent Block WA-255-P (2), which has led to the commencement of development planning studies on the Stybarrow field. (See announcement of 19 July 2004).

  Recent drilling program summary in WA-12-R:

• Stickle-1 commenced drilling on 8 May and encountered a gross oil column of 26.8 metres. Water depth was 195 metres.
  
• Harrison-1 commenced drilling on 23 May and encountered a gross oil column of 7 metres. Water depth was 193 metres.
  
• Crosby-2 commenced drilling on 31 May and encountered a gross oil column of 25 metres. Water depth was 197 metres.
  
• Ravensworth-2 commenced drilling on 14 June and encountered a gross oil column of 29 metres. Water depth was 210 metres. The well location was approximately 2.1 kilometres north east of Ravensworth-1.
  
• Stickle-2 commenced drilling on 31 July and intersected a gross oil column of 23 metres. Water depth was 191 metres.
  
• The subsequent sidetrack well of Stickle-3, which is currently drilling, will obtain further well engineering and drilling data for developing planning.
  

Two exploration wells, Stickle-1 and Harrison-1, and two appraisal wells, Crosby-2 and Ravensworth-2, were drilled by the semi-submersible SEDCO 703.

Appraisal well Stickle-2 concluded this week with the subsequent sidetrack well Stickle-3 expected to finish early next week. The semi-submersible rig Atwood Eagle has drilled both wells.

Previous drilling WA-12-R in 2003:

• Crosby-1 was drilled in October and encountered a gross oil column of 34.7 metres with 29.4 metres of net pay in the Lower Barrow Group Sandstone Reservoir. Water depth was 200 metres.
  

Previous drilling in WA-155-P (1) in 2003:

• Ravensworth-1 was drilled in July and encountered a gross oil column of 37 metres and a gross gas column of 7 metres with 43.5 metres of net pay in the Lower Barrow Sandstone Reservoir. Water depth was 209 metres.
  
• Van Gogh-1 was drilled in September and encountered a gross oil column of 9 metres with 8 metres of net pay in the Lower Barrow Sandstone Reservoir. Water depth was 354 metres.