Key Highlights

  • Contingent resource estimates for the Borsum Sand and Homeseeker-B oil discoveries have been finalised.
  • Borsum Sand best estimate is 48,000 barrels gross, or 33,600 barrels net after a 30 percent Royalty burden.
  • Homeseeker-B best estimate is 40,000 barrels gross, or 28,000 barrels net.
  • Flow testing is the next step to assess well productivity and derive reserves.

Gulf Stream Energy Limited (ASX:GSE) has finalised contingent resource estimates for the Borsum Sand and Homeseeker-B oil discoveries at its Zydeco-1 well, according to a release dated 12 November 2026. The company says the volumes are material and could add value to the wider project. The estimates follow earlier reported gross volumes, and the company is now looking to establish whether the discoveries can be developed in full.

The estimates

For Borsum Sand, the low, best and high estimates are 36,000, 48,000 and 60,000 barrels gross, equal to 25,200, 33,600 and 42,000 barrels net. For Homeseeker-B, the figures are 30,000, 40,000 and 50,000 barrels gross, equal to 21,000, 28,000 and 35,000 barrels net. The net figures apply a 30 percent royalty burden, giving a 70 percent net Revenue interest. The company does not report a combined total.

The estimates are deterministic and have not been reviewed by an independent expert in the release. Contingent resources are not reserves and cannot yet be treated as commercially recoverable.

Flow testing and the path to reserves

Flow test results are the next critical step in assessing well productivity and commercial recoverability. They are required to derive proved, probable or possible reserves, which determine whether the oil discoveries are viable to develop. The board is fast-tracking the final steps toward reserves and will update the market in due course.

Final Word

Gulf Stream has moved its oil discoveries into a defined contingent resource category, but the volumes are modest in absolute terms and remain uncommercial until flow testing and reserves work are complete. The royalty burden also reduces the share of volumes attributable to the company. Investors will be watching the flow test outcome as the key determinant of whether the discoveries progress to development.