A ConocoPhillips-led joint venture reported a successful appraisal well in Barossa natural gas field in Bonaparte basin retention lease NT/RL5 in the eastern Timor Sea 300 km north of Darwin. The results enhance the field’s prospects as the best source to supply back-fill gas to the combine’s Darwin LNG plant that is currently supplied by Bayu-Undan field in the Timor Gap (OGJ Online, Apr. 20, 2017).
Well logs and pressure data from the Barossa-5 and Barossa-6 wells confirmed that the primary Elang reservoir is gas-saturated. The reservoir zone also is in communication with previous wells drilled in the field.
This information justified production testing to confirm reservoir productivity and to obtain dynamic data to incorporate into plans for field development.
The group chose Barossa-6 for the test because the reservoir interval there is similar to the high-quality reservoir with 104 m of net pay penetrated in the offset Barossa-3 well drilled in 2014 about 4.3 km east.
Barossa-6 flowed gas and condensate from the interval 4,103-4,144 m at a maximum rate of 65 MMcfd on a 68/64-inch choke. Condensate content was measured at the surface as 7 bbl/MMcf.
The combine said gas composition analysis showed that the percentage of inert gasses was “as expected.” Previous wells have recorded as much as 16% carbon dioxide in the field.
The Barossa-6 flow rate was constrained by test facilities and multiple samples were taken for further analysis.
All data will now be integrated into subsurface models to support a front-end engineering and design entry decision early next year.
Barossa field was discovered in November 2006 in 320 m of water. The first appraisal program—Barossa-2, 3, and 4—was completed during first-half 2015.
The Barossa discovery was predated by a smaller discovery about 20 km southwest at Caldita in 150 m of water during September 2005. Caldita-2 was drilled in 2007. That field is now held in retention lease NT/RL6.
A development plan, always referred to as Barossa-Caldita, will link the two discoveries.
Interest holders are operator ConocoPhillips with 37.5%, South Korean combine SK E&S also with 37.5%, and Adelaide company Santos Ltd. with 25%.
ConocoPhillips and Santos are also interest holders in the Darwin LNG plant.
