Gas-Condensate
Discovery from the Sudair Formation of Kuwait—Exploration
Implications for Triassic Plays
Malek, Salah Abdul,
S. K. Bhattacharya, Riyasat Hussain,
Abdul Aziz Sajer, Terry O’Hearn, King Hoi Lau, Kuwait Oil Company, Ahmadi, Kuwait
Regionally, the Sudair Formation of
Early Triassic age is regarded as the top seal for the underlying Khuff reservoirs. However, in West
Kuwait, recent exploration wells in the Mutriba
area have established the flow of hydrocarbons from this formation. The Sudair consists of cyclical packages of dolomudstones,
laminated to bedded anhydrites and dolomitic shales deposited in an inner ramp lagoonal
setting. Conventional reservoir rock quality is poor as porosity is reduced by
pore-filling anhydrite. Matrix permeability values typically are <0.01 mD.
Fracture analysis shows that the fractures are confined within the dolomudstones and do not extend through the bedded
anhydrites. Fracture-related permeability values range up to 3.3 mD and flow is attributed to the fracture network preferentially
developed within the more brittle dolomudstones.
Contrary to this over the Burgan High and its northern extension in the eastern
Kuwait,
the Sudair is relatively thin, characterized by a
high percentage of anhydrites and poor reservoir facies.
Geochemical studies confirm the reservoir fluid as thermogenic gas condensate. Carbon isotope studies suggest
it is similar to the Qusaiba sourced oils found in Saudi Arabia.
This is the first report of Paleozoic sourced hydrocarbons in Kuwait.
The discovery
opens up a potential new play in Sudair Formation in
the Gulf region. For Kuwait,
the Sudair success establishes the presence of a
Triassic/Paleozoic Petroleum System and enhances prospectivity
of pre- Jurassic plays.
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