darwin gas condensate discovery
Darwin comprises two adjacent tilted fault blocks, Darwin East and Darwin West. The discovery well is situated on Darwin East. A clear flat spot and amplitude conformance to structure help define the hydrocarbon charged reservoir.
The gross reservoir interval thickness is 84.5m, with net pay of 67.8m. Average porosity is 22% and average permeability 337 mD. The reservoir is a relatively immature, quartz-rich, shallow marine sandstone.
The reservoir occurs 2.8 km below the seabed. At reservoir temperature and pressure conditions the hydrocarbons are in a gas phase. At surface temperature and pressure conditions the fluid separates into a gas and liquid phase. The liquid has properties of a light crude oil, 46 to 49 API. The initial liquid yield is relatively rich, 123–140 stb/MMscf.
Based on current mapping of the combined Darwin East and Darwin West fault blocks, the estimated un-risked (PSO) recoverable resource is 360 million barrels.
A number of development scenarios have been considered, including the full development of Darwin East and Darwin West or a phased development. Engineering studies have demonstrated that the discovery, if successfully appraised, could be commercialised by a straightforward FPSO development, utilising proven, off-the-shelf technology. The liquids would be produced and the dry gas re-injected back into the reservoir. A leased FPSO would be located in either 2,000 metres of water, above the discovery, or in 1,100 metres of water using a 14 kilometre subsea flow line.